Genetic

• Lewis (1936) examined patients with OCD and found that 37% of the patients with OCD had parents with the disorder and 21% had siblings who suffered.
• Research from family studies, like Lewis (1936) provide support for a genetic explanation to OCD.
• The biological explanation does not account for environmental influences.
• The biological approach supports the nature debate in Psychology.
• The biological approach ignores the nurture debate.
• Support for the biological explanation of OCD comes from twin studies.
• Nestadt et al (2010) conducted a review of previous twin studies examining OCD.
• Nestadt et al (2010) found that 68% of identical twins and 31% of non-identical twins experience OCD, which suggests a very strong genetic component.
• The biological explanation for OCD is very reductionist.
• The biological approach does not take into account cognitions and learning.
• Some psychologists suggest that OCD may be learnt through classical conditioning and maintained through operant conditioning.
• Identical twins (MZ) provide strong support for the genetic explanation of behaviour.
• Cromer et al (2007) found that over half the OCD patients in their study experienced a traumatic event, supporting the nurture side of the debate.
• Genetic vulnerability is believed to only be half of the cause. The diathesis-stress model, includes external influences in the cause of disorders.
• The diathesis-stress model suggests that people have a biological predisposition which is triggered by an external environmental stressor, causing disorders.
• Ahmari (2016) used animal studies to show particular genes are involved in repetitive behaviour in rats.
• Animal studies like Ahmari (2016) cannot be generalised to humans.
• Van Grootheest et al (2005) conducted a meta-analysis of 28 twin studies and found support for the genetic explanation of OCD.
• Van Grootheest et al (2005) found genetic influences ranged from 45% to 65% in children and 27% to 47% in adults.
• Samuels et al (2007) found a genetic link in hoarding behaviour in OCD patients.
• Twin studies can be criticised as nature and nurture are difficult to separate.
• There is much science to support the idea for the genetic explanation of OCD and it has practical application in identifying the potential for genetic vulnerability in families.
• Research from family studies suggests that there is a genetic component to OCD, as individuals with a family history of the disorder are more likely to develop OCD themselves.
• According to Pauls (2010) approximately 25-40% of patients with OCD have parents with the disorder.