Genetic

• Genetic explanations suggest OCD is inherited and that individuals inherit specific genes which cause OCD.
• Two genes have been linked to OCD including the COMT gene and SERT gene.
• The COMT gene is associated with the production of catechol-O-methyltransferase, which regulates the neurotransmitter dopamine.
• High levels of dopamine produced by the COMT gene have been implicated in OCD.
• The SERT gene (5-HTT gene) has also been implicated in cases of OCD.
• The SERT gene is linked to the neurotransmitter serotonin and affects the transport of the serotonin.
• Lower levels of serotonin is associated with OCD (and depression).
• Genetic explanations suggest behaviour is inherited through biological mechanisms.
• The COMT gene and the SERT gene have been linked to a genetic vulnerability for OCD.
• Lewis (1936) observed that of his OCD patients, 37% also had OCD parents, and 21% had siblings with OCD.
• Many studies show that OCD runs in families, supporting the nature debate.
• The genes associated with OCD are called candidate genes.
• OCD is believed to be polygenic (caused by more than one gene).
• Taylor (2013) found up to 230 different genes implicated in OCD.
• The genetic explanation is closely linked to the neural explanation, in that candidate genes play a part in neurotransmitter production.
• The COMT gene provides instructions for making an enzyme called catechol-O-methyltransferase.