The biological approach to explaining and treating OCD - Psychopathology

AQA A-level Psychology: Revision Made Easy - Jean-Marc Lawton 2017

The biological approach to explaining and treating OCD


The biological approach sees obsessive—compulsive disorder (OCD) as occurring by physiological means through genetic transmission and faulty brain mechanisms.

The genetic explanation focuses on the degree to which OCD is inherited. Findings from twin and gene mapping studies indicate a genetic link, with particular genes seen as increasing vulnerability to the disorder. There is a possibility of varying rates of genetic influence upon different sub-types of OCD.

Some forms of OCD are linked to breakdowns in immune system functioning, like streptococcal throat infections, Lyme’s disease and influenza. This indicates that OCD may also develop from damage to brain mechanisms, with children more at risk from such factors than adults. PET scans have shown relatively low levels of serotonin activity in the brains of OCD sufferers. As drugs that increase serotonin activity reduce the symptoms of OCD, this suggests that the neurotransmitter may play a key role in determining the condition. Research also indicates faulty functioning of the orbital frontal cortex brain area, which results in sufferers having difficulties in ignoring impulses, so they turn into obsessions, resulting in compulsive behaviour.

The main biological treatment is drugs, with antidepressants that heighten serotonin activity most favoured.


Fig 4.7 Gene mapping studies allow researchers to test the genetic explanation

Focal study

Koran et al. (2000) investigated whether treating non-responsive forms of OCD with simultaneous drug treatments was more effective than single-drug treatments. Ten patients who had not responded to 10 weeks of treatment with the SRI antidepressant fluoxetine were the participants. All participants had been diagnosed with OCD for at least a year. Treatment with fluoxetine continued but increasing levels of another atypical antipsychotic drug, olanzapine, were also given for an additional period of 8 weeks. Nine participants completed the treatment and it was found that mean OCD symptom scores dropped by 16 per cent, with 1 patient showing a 68 per cent improvement and 2 others 30 and 29 per cent improvements. This suggests that giving simultaneous drug therapies can be more effective than single-drug treatment with resistant forms of OCD. However, 6 participants did experience significant weight increase, illustrating the possible side effects of such treatments.


• Hu (2006) compared serotonin activity levels between sufferers and non-sufferers of OCD and found that serotonin levels were significantly lower in OCD sufferers. This gives support to the idea that the neurotransmitter is involved in the development of the disorder.

• Fallon & Nields (1994) reported that 40 per cent of people contracting Lyme’s disease incur neural damage resulting in psychiatric conditions like OCD, supporting the idea that OCD may develop from damage to brain mechanisms.

• Stewart et al. (2007) used gene mapping on sufferers and non-sufferers of OCD, to find a link to chromosome 14 marker D14S588, indicating a possible genetic link to the condition.

• Julien (2007) reviewed studies of the effectiveness of SSRI antidepressants in treating OCD and reported that although symptoms do not fully disappear, between 50 and 80 per cent of patients show improvements that allow them to live a fairly normal lifestyle. This supports the effectiveness of the treatment.

Positive evaluation

Image Evidence suggests that genetic factors are more at work in the expression of certain types of OCD, especially those involving obsessions about contamination, aggression and religion, and compulsions involving washing, ordering and arranging. This implies that some types of OCD are more genetic in nature than others.

Image Drug treatments for OCD are effective, as they reduce symptom levels, are relatively cheap, do not require a therapist to administer them and are a familiar means of treatment.

Image Gene mapping studies have been useful in indicating that a single ’OCD’ gene does not exist, but that instead there are a number of genes that appear to contribute to increased vulnerability to the disorder.

Negative evaluation

Image Although research suggests a genetic component to OCD, there must also be an environmental influence because otherwise twin studies would show a concordance rate of 100 per cent in MZ twins, which they do not.

Image Not all OCD patients respond positively to drugs that increase serotonin activity, which lowers support for the idea that the neurotransmitter is involved in all cases of the disorder.

Image A limitation of treating OCD with drug therapies is that they can result in a wide range of unpleasant side effects, including loss of sex drive or sexual ability, irritability, sleep pattern disturbance, headaches and lack of appetite.

Practical application

Aside from drug therapies, another biological treatment of OCD is that of psychosurgery, but only for severe cases of the disorder which are non-responsive to other treatments. A more recent and less invasive treatment is deep-brain stimulation, which uses magnetic pulses to block out obsessional thoughts.