Biological approach: treating and explaining OCD

• The biological approach takes to two main explanations for OCD: genetic explanation and neural explanation.
• The genetic explanation:

  OCD seems to be polygenetic, OCD isn’t caused by one single gene but by a combination of genetic variations that together cause significant increase in vulnerability for having OCD
• Taylor (2013) found there could be up to 230 genes that are linked to OCD.
• Candidate genes - concordance rates from twin studies where specific genes create vulnerability. 5HT1-D beta gene affects the regulation of serotonin creating lower levels of the neurotransmitter across the synpase.
• The neural explanation: abnormal levels of neurotransmitters may cause the disorder.
• Dopamine and serotonin are important neurotransmitters involved in OCD
• Dopamine regulates mood, movement and motivation
• Serotonin regulates mood, emotion, appetite and motivation
• low levels of serotonin are associates with anxiety and linked to obsessive thoughts
• Several brain areas are implicated with expressions of symptoms of OCD. Frontal lobe is responsible for decision and logical thinking, thus may be functioning abnormally in people with OCD
• There is also evidence to suggest that an area called the left parahippocampus gyrus associated with unpleasant emotions functions abnormally in people with OCD.
• Evaluation of Explanation: + Evidence for a genetic contribution to OCD comes from family and twin studies. Nestadt et al (2000) found that first-degree relatives of people diagnosed with OCD had a five times greater risk of developing the disorder themselves than a control group. Additionally, a review of twin studies found that monozygotic (MZ) twins were more than twice as likely to be concordant for OCD as dizygotic twins were (68% vs 31%). This suggests that genes are an important contributor to the development of OCD.
• Evaluation of explanation: the genetic model of OCD is that there are also environmental risk factor's.
• Evaluation of explanation: there is supporting evidence from drug therapy that serotonin plays a role in the disorder. Pigott 1999 found that antidepressants like SSRI increase serotonin and are effective in reducing OCD symptoms
• Treatments for OCD: drug therapy
• Drug therapy aims to restore biological imbalances through drugs. The biological explanation suggests that OCD is a result of low levels of serotonin. Thus drug treatments focus on increasing serotonin levels through drugs that prevent the reuptake of neurotransmitters.
• SSRIs - selective serotonin reuptake inhibitors. These drugs block the reabsorption of serotonin into neurons so it remains active longer. It increases the amount of serotonin available in the synapse. They have been shown to reduce obsessional thoughts and compulsions by up to 50%. However they can cause side effects such as nausea, headaches and sexual dysfunction.
• Tricyclics - these drugs work similarly to SSRIs but affect other neurotransmitters too. They are less commonly used because they produce more side effects including drowsiness, dry mouth and constipation.
• Evaluation of drug therapy: drug treatments are effective at tackling symptoms of OCD - Soomro et al 2009 found better results for SSRI's than for placebos. Typically symptoms are reduced for around 70% of patients.
• Evaluation of drug therapy: drug treatments are cost-effective and non-disruptive
• Evaluation of Drug therapy: drug such as SSRI has a range of side effects although most side effects are temporary. Tricyclics can have more serious effects such as high blood pressure.
• Evaluation of drug therapy: drugs are criticised as they treat the symptom rather than the root cause.