7.2 Types of Psychological Disorders - Psychological Disorders

MCAT Behavioral Sciences Review - Kaplan Test Prep 2021–2022

7.2 Types of Psychological Disorders
Psychological Disorders


After Chapter 7.2, you will be able to:

· List the major positive symptoms and major negative symptoms of schizophrenia and psychotic disorders

· Recall the features of major depressive episodes, manic and hypomanic episodes

· Distinguish between the testable mood disorders

· Relate obsessions and compulsions to the symptoms of obsessive—compulsive disorder

· Describe and explain the symptoms of posttraumatic stress disorder (PTSD)

· Describe and distinguish dissociative and somatic symptom disorders

· Describe the features and individual disorders that fall under cluster A, B, and C personality disorders

As mentioned earlier, the DSM-5 categorizes common symptoms into 20 diagnostic classes. Many of these classes represent significant revisions from the DSM-5’s immediate predecessor, the DSM-IV-TR. The most heavily tested diagnostic classes on the MCAT are schizophrenia spectrum and other psychotic disorders, bipolar and related disorders, depressive disorders, anxiety disorders, obsessive—compulsive and related disorders, trauma- and stressor-related disorders, dissociative disorders, somatic symptom and related disorders, and personality disorders.


According to the DSM-5, individuals with a psychotic disorder present with one or more of the following symptoms: delusions, hallucinations, disorganized thought, disorganized behavior, catatonia, and negative symptoms. Like most psychological categories, psychotic disorders are on a spectrum. To delineate the psychotic disorders as described in the DSM-5, psychotic symptoms must be understood.

Real World

The term schizophrenia is a relatively recent term, coined in 1911 by Eugen Bleuler. Before Bleuler, schizophrenia was called dementia praecox. Schizophrenia literally means “split mind” because the disorder is characterized by distortions of reality and disturbances in the content and form of thought, perception, and affect. Unfortunately, this has led to confusion with dissociative identity disorder (formerly multiple personality disorder). By split mind, Bleuler did not mean that the mind is split into different personalities, but that the mind is split from reality.

Psychotic symptoms are divided into positive and negative types. Positive symptoms are behaviors, thoughts, or feelings added to normal behavior. In others words, positive symptoms are features that are experienced in individuals with psychotic disorders that are not present in the normal population. Examples include delusions and hallucinations, disorganized thought, and disorganized or catatonic behavior. Positive symptoms are considered by some to be two distinct dimensions—the psychotic dimension (delusions and hallucinations) and the disorganized dimension (disorganized thought and behavior)—perhaps with different underlying causes. Negative symptoms are those that involve the absence of normal or desired behavior, such as disturbance of affect and avolition.

Positive Symptoms

Delusions are false beliefs discordant with reality and not shared by others in the individual’s culture. These delusions are maintained often in spite of strong evidence to the contrary. Common delusions include delusions of reference, persecution, and grandeur. Delusions of reference involve the belief that common elements in the environment are directed toward the individual. For example, a person with a delusion of reference may believe that characters in a TV show are talking to him directly. Delusions of persecution involve the belief that the person is being deliberately interfered with, discriminated against, plotted against, or threatened. Delusions of grandeur, also common in bipolar I disorder, involve the belief that the person is remarkable in some significant way, such as being an inventor, historical figure, or religious icon. Other common delusions involve the concept of thought broadcasting, which is the belief that one’s thoughts are broadcast directly from one’s head to the external world, thought withdrawal, the belief that thoughts are being removed from one's head, and thought insertion, the belief that thoughts are being placed in one’s head.

MCAT Expertise

The fact that delusions must be considered deviant from the society in which an individual lives provides an excellent opportunity for the MCAT to integrate mental illness and sociology. For example, a belief in shamanism—which is common in the Caribbean, Central and South America, Africa, and in some Native American tribes—would not be considered a delusion within societies that endorse shamanic medicine.

Hallucinations are perceptions that are not due to external stimuli but which nevertheless seem real to the person perceiving them. The most common form of hallucination is auditory, involving voices that the individual perceives as coming from inside or outside his or her head. Visual and tactile hallucinations are less common, but may be seen in drug use or withdrawal.

Disorganized thought is characterized by loosening of associations. This may be exhibited as speech in which ideas shift from one subject to another in such a way that a listener would be unable to follow the train of thought. A patient’s speech may be so disorganized that it seems to have no structure—as though it were just words thrown together incomprehensibly. This is sometimes called word salad. In fact, a person with schizophrenia may even invent new words, called neologisms.


Word salad can be seen in severe schizophrenia as well as Wernicke’s (receptive) aphasia. Patients will string together unrelated words, although the prosody of the speech (its rhythm, stress, and intonation) remains intact. Aphasias are discussed in Chapter 3 of MCAT Behavioral Sciences Review.

Disorganized behavior refers to an inability to carry out activities of daily living, such as paying bills, maintaining hygiene, and keeping appointments. Catatonia refers to certain motor behaviors characteristic of some people with schizophrenia. The patient’s spontaneous movement and activity may be greatly reduced or the patient may maintain a rigid posture, refusing to be moved. At the other extreme, catatonic behavior may include useless and bizarre movements not caused by any external stimuli, echolalia (repeating another’s words), or echopraxia (imitating another’s actions).

Negative Symptoms

The classic negative symptoms of schizophrenia and related psychotic disorders are disturbance of affect and avolition. Affect refers to the experience and display of emotion, so disturbance of affect is any disruption to these abilities. Affective symptoms may include blunting, in which there is a severe reduction in the intensity of affect expression; emotional flattening (flat affect), in which there are virtually no signs of emotional expression; or inappropriate affect, in which the affect is clearly discordant with the content of the individual’s speech. For example, a patient with inappropriate affect may begin to laugh hysterically while describing a parent’s death. Interestingly, it has become more difficult to assess the affective aspects of schizophrenia because the antipsychotic medications used in treatment frequently blunt and flatten affect as well. Finally, avolition is marked by decreased engagement in purposeful, goal-directed actions.


Schizophrenia is the prototypical psychotic disorder in this category of disorders. Schizophrenia is characterized by a break between an individual and reality. In fact, the term schizophrenia literally means "split mind." Eugen Bleuler coined the term in reference to the splitting of one's mind from reality. For an individual to be given the diagnosis of schizophrenia, he or she must show continuous signs of the disturbance for at least six months, and this six-month period must include at least one month of positive symptoms (delusions, hallucinations, or disorganized speech).

MCAT Expertise

When the MCAT tests schizophrenia, it is likely to include a connection to sociology through the downward drift hypothesis, which states that schizophrenia causes a decline in socioeconomic status, leading to worsening symptoms, which sets up a negative spiral for the patient toward poverty and psychosis. This is why rates of schizophrenia are much, much higher among the homeless and indigents.

Phases of Schizophrenia

The diagnosis and course of schizophrenia typically follows a specific path, termed the phases of schizophrenia. Before schizophrenia is diagnosed, a patient often goes through a phase characterized by poor adjustment. This phase is called the prodromal phase. The prodromal phase is exemplified by clear evidence of deterioration, social withdrawal, role functioning impairment, peculiar behavior, inappropriate affect, and unusual experiences. This is followed by the active phase in which pronounced psychotic symptoms are displayed. If schizophrenia development is slow, correct diagnosis is difficult and the prognosis is especially poor. If the onset of symptoms is intense and sudden, the diagnosis is readily made and the prognosis is better. Diagnosis usually occurs during the active phase. The residual phase, also called the recovery phase, occurs after an active episode and is characterized by mental clarity often resulting in concern or depression as the individual becomes aware of their previous behavior.

Other Psychotic Disorders

Other psychotic disorders differ from schizophrenia by the presence, severity, and duration of psychotic symptoms. As a general trend, the other psychotic disorders present symptoms to a lesser degree in comparison to schizophrenia.

· Schizotypal Personality Disorder: Include both personality disorder and psychotic symptoms, with the personality symptoms having been already established before psychotic symptoms present. This is covered in greater detail in Personality Disorders.

· Delusion Disorder: Psychotic symptoms are limited to delusions and are present for at least a month.

· Brief Psychotic Disorder: Positive psychotic symptoms are present for at least a day, but less than a month.

· Schizophreniform Disorder: Same diagnostic criteria as schizophrenia except in duration; the required duration for this diagnosis is only 1 month.

· Schizoaffective Disorder: Major mood episodes (major depressive episodes and manic episodes) while also presenting psychotic symptoms.


Sadness is a natural part of life, especially in response to stressful life events like the death of a loved one. During periods of sadness, a person might call him- or herself depressed. However, periodic sadness in response to life events is not a mental disorder. Depressive disorders, in contrast, are conditions characterized by feelings of sadness that are severe enough, in both magnitude and duration, to meet specific diagnostic criteria.

To understand the DSM-5's categorization of the spectrum of depressive disorders, we must first discuss the 9 depressive symptoms defined in the DSM-5. These symptoms can be recalled with the mnemonic sadness + SIG E. CAPS:

· Sadness: Depressed mood, feelings of sadness and emptiness

· Sleep: Insomnia or hypersomnia

· Interest: Loss of interest and pleasure in activities that previously sparked joy, termed anhedonia

· Guilt: A feeling of inappropriate guilt or worthlessness

· Energy: Lower levels of energy throughout the day

· Concentration: Decrease in ability to concentrate (self described, or observed by others)

· Appetite: Pronounced change in appetite (increase or decrease) resulting in a significant change (5%+) in weight.

· Psychomotor symptoms: Psychomotor retardation (slowed thoughts and physical movements) and psychomotor agitation (restlessness resulting in undesired movement)

· Suicidal thoughts: Recurrent suicidal thoughts

In addition to depressive symptoms, the DSM-5 also categorizes depressive disorders based on duration, timing, and cause of depressive symptoms.


Symptoms of a major depressive episode: SIG E. CAPS

Sadness +

· Sleep

· Interest

· Guilt

· Energy

· Concentration

· Appetite

· Psychomotor symptoms

· Suicidal thoughts

Major Depressive Disorder

The key diagnostic feature of major depressive disorder (MDD) is the presence of major depressive episodes. A major depressive episode is defined as a 2-week (or longer) period in which 5 of the 9 defined depressive symptoms are encountered, which must include either depressed mood or anhedonia (inability to feel and anticipate pleasure). In addition, the symptoms must be severe enough to impair one's daily social- or work-related activities.

Persistent Depressive Disorder

Considering the difference in naming between major depressive disorder and persistent depressive disorder, it may seem reasonable to assume that persistent depressive disorder is a lesser form of major depressive disorder. However, this is not the case. In fact major depressive episodes can coincide with persistent depressive disorder. A diagnosis of persistent depressive disorder (PDD), also known as dysthymia, is given when an individual experiences a period, lasting at least 2 years, in which they experience a depressed mood on the majority of days. With the primary diagnostic feature of PDD being time, a patient can receive both the PDD and MDD diagnosis if they meet both the duration and severity requirements of both disorders.

Other Depressive Disorders

Whereas major depressive disorder and persistent depressive disorder are characterized by severity and duration of depressive symptoms, other depressive disorders can be characterized by their age of incidence and apparent cause.

Children often exhibit more dramatic emotional responses than adults and in previous editions of the DSM, this has led to the potential over diagnosis of bipolar disorders in children. To address this concern the DSM-5 includes disruptive mood dysregulation disorder, which is typically diagnosed between the ages of 6 and 10, and has the key diagnostic feature of persistent and recurrent emotional irritability in multiple environments (school, home, etc.).

Depressive symptoms can also arise in response to specific times and situations; if these symptoms meet certain diagnostic criteria then they are considered disorders. Premenstrual dysphoric disorder is characterized by mood changes, often depressed mood, occurring a few days before menses and resolving after menses onset.

Although not freestanding diagnoses in the DSM-5, both seasonal affective disorder and postpartum depression are conditions that have an apparent cause. In seasonal affective disorder (SAD), the dark winter months are believed to be the source of depressive symptoms and thus the disorder is best categorized as major depressive disorder with seasonal onset, while in postpartum depression the rapid change in the mother's hormone levels just after birth is the cause of the depressive symptoms. In the case of seasonal affective disorder, depressive symptoms are present only in the winter months. This disorder may be related to abnormal melatonin metabolism; it is often treated with bright light therapy, where the patient is exposed to a bright light for a specified amount of time each day, as demonstrated with a plant in Figure 7.1.

ImageFigure 7.1. Bright Light Therapy for Seasonal Affective Disorder


The most common first-line treatment for depression is the class of medications called selective serotonin reuptake inhibitors (SSRIs). These block the reuptake of serotonin by the presynaptic neuron, resulting in higher levels of serotonin in the synapse and relief of symptoms. The nervous system is outlined in Chapter 1 of MCAT Behavioral Sciences Review and Chapter 4 of MCAT Biology Review.


This category of disorders is characterized by the presence of manic and depressive symptoms, which if severe and persistent enough can be labelled as episodes. Manic symptoms are associated with an exaggerated elevation in mood, accompanied by an increase in goal-directed activity and energy. Put simply, manic symptoms can be thought of as the prolonged and exaggerated emotion of happiness or joy. According to the DSM-5, there are 7 manic symptoms. These symptoms can be recalled with the mnemonic DIG FAST:

· Distractibility: Inability to remain focused on an activity

· Irresponsibility: Engaging in risky activities without considering future consequences

· Grandiosity: Exaggerated and unrealistic increase in self-esteem

· Flight of thoughts: Racing thoughts, self-reported or revealed through rapid speech

· Activity or agitation: Increase in goal-oriented work or social activities

· Sleep: Decreased need for sleep, e.g. sleeping for only a couple hours but feeling rested

· Talkative: Exaggerated desire to speak

The presence of manic symptoms are considered a hypomanic episode if the symptoms are present for at least 4 days and include at least 3 or more of the 7 defined manic symptoms, yet the symptoms are not severe enough to impair the person's social or work activities. However, the diagnosis progresses to a manic episode if the manic symptoms (3 or more of the defined 7) are severe enough to impair a person's social or work activities and persist for at least 7 days.

In addition to manic symptoms and their associated episodes, the presence or absence of depressive symptoms and their associated episodes are also used to differentiate bipolar and related disorders. Specifically, these disorders are classified by the presence or absence of manic, hypomanic, and major depressive episodes. Depressive symptoms were covered in Depressive Disorders.

Bipolar I Disorder

When manic episodes are present, a diagnosis of bipolar I disorder is likely to be made, as the key diagnostic feature of this disorder is the presence of manic episodes. While most diagnoses of bipolar I disorder also include depressive symptoms, often major depressive episodes, they are not a requirement. To illustrate this point consider two hypothetical patients: Patient A only experiences manic episodes, while Patient B regularly experiences both manic and major depressive episodes, cycling between the two regularly. Despite both patients presenting very differently, both fit the categorization of bipolar I disorder.

Bipolar II Disorder

The key feature of a bipolar II disorder diagnosis is the presence of both a major depressive episode and an accompanying hypomanic episode, but not a manic episode. To avoid confusion, it is worth noting that if a patient has experienced both major depressive episodes and manic episodes, a diagnosis of bipolar I disorder will likely be made. In addition, if a person experiences only major depressive symptoms (absence of hypomanic and manic episodes), then a diagnosis of major depressive disorder is likely to be made. Thus, the diagnosis of bipolar II only captures individuals who experience major depressive episodes and the lesser, hypomanic episodes.

Cyclothymic Disorder

The diagnostic features of cyclothymic disorder are the presence of both manic and depressive symptoms that are not severe enough to be considered episodes. In other words, the patient has not experienced major depressive, manic, or hypomanic episodes. Or, more specifically, the patient has never experienced 3 or more of the 7 manic symptoms in a 4 day period (diagnostic criteria for hypomanic episode) and has never experienced 5 or more of the 9 depressive symptoms in a 2-week period (diagnostic criteria for a major depressive episode). Considering the relatively low threshold of symptom requirements, it may seem that everyone would be diagnosed with cyclothymic disorder. However despite the relatively low symptom requirements, the duration requirements for this disorder are high. For a diagnosis of cyclothymic disorder to be made, a person must have experienced numerous periods of manic and depressive symptoms for the majority of time over a 2-year (or longer) period.

Before moving on to anxiety disorders, a brief discussion of proposed neurological etiologies of mood disorders is warranted. The most common explanation revolves around the neurotransmitters norepinephrine and serotonin. These two are often linked together into what is called the monoamine or catecholamine theory of depression. This theory holds that too much norepinephrine and serotonin in the synapse leads to mania, while too little leads to depression. Although more recent research has shown that it is not that simple, you should be aware of this theory for the MCAT.

Real World

Depressive and manic episodes are essentially two sides of the same coin: Depression is associated with low norepinephrine and serotonin levels, and manic episodes are associated with high levels of these neurotransmitters. When patients are put on treatment for depression, they must be watched for signs of mania because antidepressant medications may trigger manic symptoms or episodes.


From an evolutionary perspective, emotions served to direct and modulate behavior based on environmental stimuli. As seen in bipolar and depressive disorders, when the regulation of emotions, such as happiness or sadness, are insufficient, then symptoms arise. In the case of anxiety, fear is the associated emotion. Fear is often defined as an emotional response to an immediate threat, while anxiety can be viewed as fear of an upcoming or future event. Like fear, anxiety is healthy and important in one's life. It is only considered an anxiety disorder when irrational and excessive fear or anxiety affects an individual’s daily functioning.

There are more than 10 disorders listed in the anxiety disorders portion of the DSM-5. These disorders are categorized by the situation or stimulus that induces anxiety.


For all anxiety disorders, clinicians must rule out hyperthyroidism—excessive levels of the thyroid hormones triiodothyronine (T3) and thyroxine (T4)—because increasing the whole body’s metabolic rate will create anxiety-like symptoms. Thyroid function is discussed in Chapter 5 of MCAT Biology Review.

Specific Phobias

The most common type of anxiety disorder is a phobia. A phobia is an irrational fear of something that results in a compelling desire to avoid it. Most of the phobias that you are likely familiar with are what the DSM-5 calls specific phobias. A specific phobia is one in which fear and anxiety are produced by a specific object or situation. Unlike other sources of anxiety, specific phobias lack a specific ideation or thought pattern and instead present as an immediate and irrational fear response to the specific object or situation. For example, claustrophobia is an irrational fear of closed places, acrophobia is an irrational fear of heights, and arachnophobia is an irrational fear of spiders.

ImageFigure 7.2. Specific PhobiaArachnophobia, the fear of spiders, is a common example of a specific phobia.

Separation Anxiety Disorder

Separation anxiety is the excessive fear of being separated from one's caregivers or home environment. Although some separation anxiety is common and to be expected in young children, when this anxiety is excessive and persists beyond the age where it is deemed developmentally appropriate, the person may be diagnosed with separation anxiety disorder. This diagnosis is accompanied by the ideation that when separated, the caregiver or the individual themselves will be harmed (e.g. kidnapping, getting sick). These persistent beliefs may result in avoidant behaviors such as refusal to leave the home, shadowing the caregiver, etc.

Social Anxiety Disorder

On the surface, social anxiety disorder can be viewed as a social phobia, that is, fear and anxiety towards social situations and encounters. However, unlike previously discussed specified phobias, social anxiety disorder has an accompanying ideation in which the individual thinks that they will be perceived negatively by others. Thus, the key diagnostic feature of social anxiety disorder is fear or anxiety towards social situations with the belief that the individual will be exposed, embarrassed, or simply negatively perceived by others.

Like other anxiety disorders, avoidant behaviors are often conditioned as a means to reduce the associated anxiety. In the case of social anxiety, this can be as broad as avoiding social situations entirely or as narrow as avoiding handshakes out of fear of sweaty palms. Avoidant behavior to the point of social or occupational impairment is necessary for a social anxiety disorder diagnosis.

Selective Mutism

Although categorized as a separate anxiety disorder, selective mutism is heavily associated with social anxiety disorder and characterized by the consistent inability to speak in situations where speaking is expected. However, in situations that are more relaxed or when communication is not expected, speaking is unaffected. From this perspective, selective mutism may be conceptualized as a patient’s fear of being negatively evaluated for what the patient might say.

Panic Disorder

The key diagnostic feature of panic disorder is the recurrence of unexpected panic attacks. To understand panic disorder, we must first cover panic attacks. From a physiological perspective, a panic attack is the misfiring of the sympathetic nervous system resulting in an unwanted fight or flight response. From an psychological perspective, a panic attack includes the associated emotions that accompany the sympathetic response, such as intense fear and a sense of impending doom/danger. Combining these two perspectives, a panic attack is the sudden surge of fear in which the individual feels that they are losing control of their body and/or that they are dying. The occurrence of an individual's attacks may be associated with specific triggers, in which case the attacks are termed expected panic attacks. If there is no clear trigger and the panic attacks are seemingly random, they are termed unexpected panic attacks.

The diagnosis of panic disorder requires the recurrence of unexpected panic attacks. The unexpected panic attacks themselves can produce an associated anxiety. In other words, an individual may become anxious at the thought of having an unexpected panic attack. If this anxiety impairs one's daily functions and persists for at least a month, then the diagnosis of panic disorder is made.

It is worth noting that panic attacks themselves are not considered a psychological disorder. They may occur in the absence of physiological disorders or may be associated with anxiety disorders in which there is a clear trigger. For instance, an individual with arachnophobia may experience expected panic attacks when encountering a spider.


Notice that a large number of the symptoms of panic disorder are caused by excess activation of the sympathetic nervous system (autonomic overdrive). These include trembling, sweating, hyperventilation, shortness of breath, a racing heart rate, and palpitations. The autonomic nervous system is discussed in Chapter 1 of MCAT Behavioral Sciences Review and Chapter 4 of MCAT Biology Review.


Agoraphobia is an anxiety disorder characterized by a fear of being in places or situations where it might be difficult for an individual to escape. This fear may stem from the thought that the individual may experience a panic attack or similar event in which they would need to escape to avoid embarrassment. Agoraphobes tend to be uncomfortable leaving their homes, using public transport, being in open spaces, waiting in lines, or simply being in crowds. Due to agoraphobia's association with panic attacks and fear of being negatively evaluated by others, it is often comorbid with panic disorder, social anxiety disorder, and specific phobias.

Generalized Anxiety Disorder

As previously mentioned, the DSM-5 categorizes anxiety disorders based on the stimulus that induces fear or anxiety. For instance, anxiety towards social interactions is termed social anxiety; anxiety at the thought of separation from one's caregivers is termed separation anxiety. On the other hand, some individuals have more anxious temperaments, making them susceptible to anxiety triggered by a multitude of stimuli. It is for this reason that specific anxiety disorders are often comorbid with one another, resulting in patients having multiple diagnoses. However, a better diagnosis for some patients with many triggers for anxiety might be generalized anxiety disorder.

Generalized anxiety disorder (GAD) is defined as a disproportionate and persistent worry about many different things—making mortgage payments, doing a good job at work, returning emails, political issues, and so on—for at least six months. In addition, the worrying is difficult to control, even in cases where the individual knows that their worrying and fear is irrational. These individuals often have physical symptoms like fatigue, muscle tension, and sleep problems that accompany the worry. General anxiety disorder is relatively common in the US population, with approximately 3% of population experiencing GAD in a 12-month period. Furthermore, over the course of a lifetime, individuals have a 1 in 10 chance of meeting the diagnostic criteria for general anxiety disorder.


Formerly classified under anxiety and somatic symptom disorders, the disorders in this group were relabeled as obsessive—compulsive and related disorders in the DSM-5. The reason for this organizational change reveals the common feature among these conditions. Across all of the following disorders, individuals perceive a particular need and respond to the need by completing a particular action. Disorders in this category are differentiated by the compulsiveness of the need to be met as well as the nature of the action.

Obsessive—Compulsive Disorder

Obsessive—compulsive disorder (OCD) is characterized by obsessions (persistent, intrusive thoughts and impulses), which produce tension, and compulsions (repetitive tasks) that relieve tension but cause significant impairment in a person’s life. The relationship between the two is key: obsessions raise the individual’s stress level, and the compulsions relieve this stress. Obsessions and their compulsions are ego-dystonic, meaning that the individual knows that their behavior is irrational, but the anxiety that arises when compulsions are not performed cannot be ignored.

Obsessions are perceived needs with the accompanying ideation that if a particular need is not met, then disastrous events will follow. Actions paired with obsessions are termed compulsions. As individuals with OCD attempt to satisfy their obsessions, rituals or sets of rules are developed for how their compulsions must be performed. For example, an individual may need to wash their hands for a specific length of time or else the intrusive thought of getting sick occurs. Alternatively, an individual may need to check if their door is locked a specific number of times or else worry obsessively about getting robbed. To be diagnosed with OCD, the compulsions must impair one's daily activities, for instance by taking up a lot of time during the day.

Body Dysmorphic Disorder

In body dysmorphic disorder, a person has an unrealistic negative evaluation of their personal appearance and attractiveness, usually directed toward a certain body part. This is known as a preoccupation, a type of worry which lacks the disastrous ideation that accompanies obsessions. Patients with this disorder see their nose, skin, or stomach as ugly or even horrific when actually normal in appearance. This body—focused preoccupation also disrupts day-to-day life, and the sufferer may seek multiple plastic surgeries or other extreme interventions. A common association with this disorder is muscle dysmorphia, in which the individual believes that their body is too small or unmuscular (a preoccupation) and responds through working out. Like body dysmorphic disorder in general, this belief persists even with clear evidence to the contrary.

Hoarding Disorder

Hoarding disorder presents as a need to save or keep items and is often paired with excessive acquisition of objects. This behavior stems from several possible sources, ranging from the belief that kept items will eventually be useful to the feeling that the patient has a responsibility to care for the items. As a result, individuals with hoarding disorder often fill their homes with seemingly useless items even past the point where the accumulation of belongings impairs daily life.

Obsessive—Compulsive and Related Disorders with Body—focused Repetitive Behaviors

Trichotillomania and excoriation are two obsessive—compulsive and related disorders that both present with body-focused compulsions. In the case of trichotillomania, individuals are compelled to pull out their hair, while with excoriation disorder, individuals are compelled to pick at their skin. A required diagnostic feature in both of these disorders is that patients have previously attempted to stop their body-focused compulsions but have so far failed.


This category captures disorders where a traumatic event is the source of the symptoms and thus is a diagnostic requirement in these disorders. The typical response to traumatic events includes fear, helplessness, and perhaps anxiety. In trauma and stressor related disorders, however, individuals also present with maladaptive symptoms like anhedonia, dysphoria (generalized dissatisfaction with life), aggression, or dissociation.

By far, the most notable disorder in this category is posttraumatic stress disorder (PTSD). PTSD occurs after experiencing or witnessing a traumatic event, such as war, a home invasion, rape, or a natural disaster, and consists of intrusion symptoms, arousal symptoms, avoidance symptoms, and negative cognitive symptoms.

· Intrusion symptoms include recurrent reliving of the event, flashbacks, nightmares, and prolonged distress.

· Arousal symptoms include an increased startle response, irritability, anxiety, self-destructive or reckless behavior, and sleep disturbances.

· Avoidance symptoms include deliberate attempts to avoid the memories, people, places, activities, and objects associated with the trauma.

· Negative cognitive symptoms include an inability to recall key features of the event, negative mood or emotions, feeling distanced from others, and a persistent negative view of the world.

To meet the criteria of PTSD, a particular number of these symptoms must be present for at least one month. If the same symptoms last for less than one month (but more than three days), it may be called acute stress disorder.

From a behaviorist perspective, symptoms of PTSD can be explained by the traumatic event and one's reaction to it. Intrusion and arousal symptoms can be explained by associative learning, specifically classical conditioning, in which the event has become associated with traumatic triggers and has generalized to include everyday stimuli. Avoidance symptoms can be explained through operant conditioning, specifically avoidance learning, in which an individual learns behavior to avoid unpleasant stimuli, or involuntary responses in the case of PTSD. Finally, negative cognitive symptoms can be viewed as a form of dissociation, which is a defense mechanism to avoid unpleasant stimuli. Dissociation will be covered in greater detail in Dissociative Disorders.


Patients with dissociative disorders avoid stress by escaping from parts of their identity. Such patients otherwise still have an intact sense of reality. Examples of dissociative disorders include dissociative amnesia, dissociative identity disorder (formerly multiple personality disorder), and depersonalization/derealization disorder.

Dissociative Amnesia

Dissociative amnesia is characterized by an inability to recall past experiences. The qualifier dissociative simply means that the amnesia is not due to a neurological disorder. This disorder is often linked to trauma. Some individuals with this disorder may also experience dissociative fugue: a sudden, unexpected move or purposeless wandering away from one’s home or location of usual daily activities. Individuals in a fugue state are confused about their identity and can even assume a new identity. Significantly, they may actually believe that they are someone else, with a complete backstory.

Dissociative Identity Disorder

In dissociative identity disorder (DID, formerly multiple personality disorder), there are two or more personalities that recurrently take control of the patient’s behavior, as represented in Figure 7.3. This disorder results when the components of identity fail to integrate. In most cases, patients have suffered severe physical or sexual abuse as young children. After much therapy, the personalities can sometimes be integrated into one. The existence of dissociative identity disorder is justifiably debated within the medical community, but its characteristics are still important to recognize on Test Day.

ImageFigure 7.3. Dissociative Identity Disorder (DID)One artist’s interpretation of many personalities seen in DID.

Real World

One of the first and most famous cases of dissociative identity disorder in the media is Shirley Ardell Mason, also known as “Sybil,” who claimed to have at least 13 separate personalities. Mason underwent years of therapy in an attempt to combine her personalities into a single one. Two separate TV movies, both called Sybil, have been produced to tell the story of Sybil’s struggle with this disorder.

Depersonalization/Derealization Disorder

In depersonalization/derealization disorder, individuals feel detached from their own minds and bodies (depersonalization) or from their surroundings (derealization). This often presents as a feeling of automation, and can include symptoms like a failure to recognize one’s reflection. An out-of-body experience is an example of depersonalization. Derealization is often described as giving the world a dreamlike or insubstantial quality. Such patients may also experience depersonalization and derealization simultaneously. These feelings cause significant impairment of regular activities. However, even during these times, such patients do not display psychotic symptoms like delusions or hallucinations.


Diagnoses in this category are marked by somatic (bodily) symptoms that cause significant stress or impairment.

Somatic Symptom Disorder

Individuals with somatic symptom disorder have at least one somatic symptom, which may or may not be linked to an underlying medical condition, and that is accompanied by disproportionate concerns about its seriousness, devotion of an excessive amount of time and energy to it, or elevated levels of anxiety.

Illness Anxiety Disorder

Illness anxiety disorder is characterized by being consumed with thoughts about having or developing a serious medical condition. Individuals with this disorder are quick to become alarmed about their health, and either excessively check themselves for signs of illness or avoid medical appointments altogether. Most patients classified under hypochondriasis in the DSM-IV-TR now fit into either somatic symptom disorder if somatic symptoms are present, or illness anxiety disorder if they are not.

Conversion Disorder

Conversion disorder, also known as functional neurological symptom disorder, is characterized by symptoms affecting voluntary motor or sensory functions that are incompatible with the patient's neurophysiological condition. The symptoms generally begin soon after the individual experiences high levels of stress or a traumatic event, but may not develop until some time has passed after the initiating experience. Examples include paralysis or blindness without evidence of neurological damage. The patient may be surprisingly unconcerned by the symptom—what is called la belle indifférence. Conversion disorder was historically called hysteria. The symptoms seen in conversion disorder may sometimes be connected with the inciting event in a literal or poetic way; for example, a woman going blind shortly after watching her son die tragically.


A personality disorder is a pattern of behavior that is inflexible and maladaptive, causing distress or impaired functioning in at least two of the following: cognition, emotions, interpersonal functioning, or impulse control. Personality disorders are considered ego-syntonic, meaning that the individual perceives her behavior as correct, normal, or in harmony with her goals. This is in contrast to the other disorders covered in this chapter that are ego-dystonic, meaning that the individual sees the illness as something thrust upon her that is intrusive and bothersome. In addition to general personality disorder (which fits the diagnostic criteria described above), there are ten personality disorders grouped into three clusters: cluster A (paranoid, schizotypal, and schizoid), cluster B (antisocial, borderline, histrionic, and narcissistic), and cluster C (avoidant, dependent, and obsessive—compulsive). Personality disorder criteria will continue changing over time; the DSM-5 includes a section specifically devoted to research models for redefining personality disorders.


The distinction between ego-syntonic and ego-dystonic symptoms is a key feature in differential diagnosis of disorders in the DSM-5. For instance, social anxiety disorder shares many of the same symptoms as avoidant personality disorder, such as anxiety directed towards social interactions and maladaptive avoidance behavior. The distinction between these disorders is that individuals with social anxiety disorder often know that their fear of being ridiculed is irrational (ego-dystonic), while individuals with avoidant personality disorder actually believe they are inferior and that their fear of ridicule is valid (ego-syntonic).

Cluster A (Paranoid, Schizotypal, and Schizoid Personality Disorders)

The cluster A personality disorders are all marked by behavior that is labeled as odd or eccentric by others. Its three examples include paranoid, schizotypal, and schizoid personality disorders.

Paranoid personality disorder is marked by a pervasive distrust of others and suspicion regarding their motives. In some cases, these patients may actually be in the prodromal phase of schizophrenia and are termed premorbid.

Schizotypal personality disorder refers to a pattern of odd or eccentric thinking. These individuals may have ideas of reference (similar to delusions of reference, but not as extreme in intensity) as well as magical thinking, such as superstitiousness or a belief in clairvoyance.

Finally, schizoid personality disorder is a pervasive pattern of detachment from social relationships and a restricted range of emotional expression. People with this disorder show little desire for social interactions, have few or no close friends, and have poor social skills. It should be noted that neither schizotypal nor schizoid personality disorder are the same as schizophrenia.

Cluster B (Antisocial, Borderline, Histrionic, and Narcissistic Personality Disorders)

The cluster B personality disorders are all marked by behavior that is labeled as dramatic, emotional, or erratic by others. Its four examples include antisocial, borderline, histrionic, and narcissistic personality disorders.

Antisocial personality disorder is three times more common in males than in females. The essential feature of the disorder is a pattern of disregard for and violations of the rights of others. This is evidenced by repeated illegal acts, deceitfulness, aggressiveness, or a lack of remorse for said actions. Many serial killers and career criminals who show no guilt for their actions have this disorder. Additionally, people with this disorder comprise about 20 to 40 percent of prison populations.

Borderline personality disorder is two times more common in females than in males. In this disorder, there is pervasive instability in interpersonal behavior, mood, and self-image. Interpersonal relationships are often intense and unstable. There may be profound identity disturbance with uncertainty about self-image, sexual identity, long-term goals, or values. There is often intense fear of abandonment. Individuals with borderline personality disorder may use splitting as a defense mechanism, in which they view others as either all good or all bad (an angel vs. devil mentality). Suicide attempts and self-mutilation (cutting or burning) are common.

Histrionic personality disorder is characterized by constant attention-seeking behavior. These individuals often wear colorful clothing, are dramatic, and are exceptionally extroverted. They may also use seductive behavior to gain attention.

In narcissistic personality disorder, the patient has a grandiose sense of self-importance or uniqueness, preoccupation with fantasies of success, a need for constant admiration and attention, and characteristic disturbances in interpersonal relationships such as feelings of entitlement. As used in everyday language, narcissism refers to those who like themselves too much. However, people with narcissistic personality disorder have very fragile self-esteem and are constantly concerned with how others view them. There may be marked feelings of rage, inferiority, shame, humiliation, or emptiness when these individuals are not viewed favorably by others.

Cluster C (Avoidant, Dependent, and Obsessive—Compulsive Personality Disorders)

The cluster C personality disorders are all marked by behavior that is labeled as anxious or fearful by others. Its three examples include avoidant, dependent, and obsessive—compulsive personality disorders.

In avoidant personality disorder, the affected individual has extreme shyness and fear of rejection. The individual will see herself as socially inept and is often socially isolated, despite an intense desire for social affection and acceptance. These individuals tend to stay in the same jobs, life situations, and relationships despite wanting to change.

Dependent personality disorder is characterized by a continuous need for reassurance. Individuals with dependent personality disorder tend to remain dependent on one specific person, such as a parent or significant other, to take actions and make decisions.

In obsessive—compulsive personality disorder (OCPD), the individual is perfectionistic and inflexible, tending to like rules and order. Other characteristics may include an inability to discard worn-out objects, lack of desire to change, excessive stubbornness, lack of a sense of humor, and maintenance of careful routines. Note that obsessive—compulsive personality disorder is not the same as obsessive—compulsive disorder. Whereas OCD has obsessions and compulsions that are focal and acquired, OCPD is lifelong. OCD is also ego-dystonic (I can’t stop washing my hands because of the germs!), whereas OCPD is ego-syntonic (I just like rules and order!).

Behavioral Sciences Guided Example With Expert Thinking


Expert Thinking

The following individuals are patients at an inpatient mental health facility.

Patient A’s hospitalization is the result of an intense argument with a family member that involved threats of violence, which prompted the police to be called. For the first two weeks of her stay, Patient A spoke often about plans to start several online business ventures, saying that she felt she was a “business genius” and that she would be a billionaire by the end of the year. She slept very little and was irritable, often becoming angry with clinic staff when they tried to reason with her about the soundness of her plans. In the following weeks of Patient A’s stay, her mood leveled and she expressed regret over her treatment of her family.

A: Elevated mood, irritable, rapid speech. Lasts 2 weeks.

Patient B arrived at the clinic as a result of complaints from his neighbors. When police entered his apartment, they found it in complete disrepair, and it was clear that he had stopped attending to his personal hygiene long ago. During the first few weeks of his stay, Patient B made no effort to speak to staff or other patients. When he did respond to questions, his answers were short phrases, sometimes unrelated to the question, and sometimes simply a repetition of a few words from the question. He spent his days isolated, often sitting, immobile and unresponsive to occurrences around him.

B: Not taking care of himself, not talking or reacting to others.

Based only on the information provided, what diagnosis from the DSM-5 is most likely for each of these patients?

If you’re asked to make a diagnosis for a hypothetical patient, make a checklist of the symptoms described in the passage or question, and then match them to what you know about the disorders that are within the scope of the MCAT. It is worth taking a moment to consider the severity of the symptoms as well, since it can help to differentiate between similar disorders (depression and dysthymic disorder, for example).

Patient A exhibits grandiose self-esteem, rapid speech, a lack of need for sleep, and irritability, which are all symptoms of mania and together are sufficient to apply the label of manic episode. The described transition out of mania into a different mood state suggests bipolar disorder. Specifically, the presence of a full manic episode rules out bipolar II and would lead to a diagnosis of bipolar I, which does not require a depressive episode to follow.

Patient B is trickier, but consider that the writers of the MCAT know that you are not a trained psychiatrist and so will not require a nuanced diagnosis from you. The symptoms that they present will be straightforward and should add up to a description of a disorder that you are familiar with. For patient B, those symptoms are avolition (an inability to perform basic goal-directed activities), flat or blunted affect (lack of emotional expression), and alogia (reduction in speaking). These are all negative symptoms of schizophrenia. The description of patient B also includes echolalia (repetition of words or short phrases), which is a positive symptom and is a signal to you as a test taker that this is indeed schizophrenia, rather than a case of severe depression. While there is still the possibility that Patient B has another, related disorder, the MCAT would not present you with a choice that would require you to distinguish between, say, schizophrenia and schizoid personality disorder without substantial additional information allowing that decision to be made.

In summary, patient A is most likely experiencing bipolar I disorder, and patient B is most likely experiencing schizophrenia or a related disorder.

Key Concept

Obsessive—compulsive disorder (OCD) and obsessive—compulsive personality disorder (OCPD) are not synonymous. OCD is marked by obsessions (intrusive thoughts causing tension) and compulsions (repetitive tasks that relieve this tension but cause significant impairment). OCPD is a personality disorder in which individuals are perfectionistic and inflexible.

MCAT Concept Check 7.2:

Before you move on, assess your understanding of the material with these questions.

1. A schizophrenic patient is started on the atypical antipsychotic risperidone, which is effective for treatment of the positive symptoms of schizophrenia, but not the negative symptoms. Which of the patient's symptoms are likely to improve, and which are not?

2. What are the features of a major depressive episode? Of a manic episode?

o Major depressive episode:

o Manic episode:

3. For each of the following disorders, briefly describe their makeup with respect to depressive episodes, manic episodes, and other mood disturbances:

o Major depressive disorder:

o Bipolar I disorder:

o Bipolar II disorder:

o Cyclothymic disorder:

4. A patient with obsessive—compulsive disorder believes that she must check the latch on her apartment door five times before she goes to bed. If she does not check the latch five times, she cannot sleep for fear that someone will break into her apartment. Identify her obsession, her compulsion, and how they are related in obsessive—compulsive disorder.

o Obsession:

o Compulsion:

o Relationship:

5. What features describe each cluster of personality disorders? Which personality disorders fall into each cluster?



Personality Disorders