explanations OCD

• one explanation of OCD is the genetic explanation, stating that OCD is polygenetic (caused by multiple genes) is a psychological feature, passed through genes from your parents
• one explanation of OCD is the neural explanation, which suggests that OCD is caused by a faulty brain structure and neurones
• diathesis-stress model= genetic vulnerability + environmental factors causes ocd
• candidate genes suggest ocd is genetically inherited from parents- COMT (dopamine) and SERT (serotonin)
• brain structure to ocd- basal ganglia involved in compulsions- if someone has an overactive basal ganglia they're more susceptible to ocd
• worry circuit- orbital frontal cortex (inputs sensory info), thalamus (receives info from orbital frontal cortex and triggers worry signals), caudate nucleus (calms worry signals) so people with OCD have a dysfunctional candate nucleus
• neurochemicals in explaining ocd= low serotonin explains the co-morbidity with depression, high dopamine is involved in the compulsive elements
• supportive evidence of the bio (genetic) approach to OCD- lewis et al- 37% of ocd patients had a parent with ocd, and 21% had a sibling with ocd - suggests their is a genetic predisposition
• limitation of genetic explanation of OCD - environmental risk factors - environmental factors may trigger genes linked to OCD - Cromer et al - over half of OCD patients had experienced a traumatic event - suggests the genetic explanation is only a partial explanation
• candidate genes - give a person a genetic vulnerability to OCD - COMT and SERT gene are inherited from parents (mutated versions)
• strength of the neural explanation of OCD - multiple studies using PET scans have shown hyperactivity in the orbital frontal cortex and candate nucleus in those with OCD, both when the brain is at rest and when it is stimulated - But there is a problem with this research as it os correlational, researchers can't be sure if the hyperactivity is caused by OCD or if it is an implication of having OCD, lowering internal validity
• genetic explanation - OCD is aetiologically heterogenous meaning that the genes that cause a type of OCD in one individual may be different in another individual
• strength of neural explanation - Max et al - found cutting the neural pathways between OFC and basal ganglia (where the thalamus and caudate nucleus are) reduced the symptoms of OCD
• supportive evidence for neural explanations - Max et al - cutting neural pathways between orbital frontal cortex and basal ganglia (contains thalamus and caudate nucleus) reduced the symptoms of OCD - shows the connections between dysfunctional brain structures are linked to OCD symptoms - adds external validity