biological approach to explaining OCD

• genetic explanation 


  OCD genetically inherited and runs in families - genetic vulnerability passed on not certainty - diathesis stress model, certain genes leave people more likely to suffer mental disorder not certain, some environmental stress needed to trigger condition - researchers identified genes create vulnerability called candidate genes (e.g. gene 9) - OCD polygenic - estimated as many as 230 different genes could be involved - different types of OCD caused by different combinations - family studies, higher percentage of 1st degree relatives have disorder (10%), prevalence rate (2%)
• neural explanation 1


  genes associated with OCD likely to affect levels of neurotransmitters and structures in brain - serotonin helps regulate mood - low serotonin transmission normal transmission of mood relevant information doesn't take place, persons mood affected - serotonin may be removed too quickly before transmitted signal - some OCD cases impaired decision making - may link to abnormal functioning of lateral frontal lobes (decision making)
• neural explanation 2


  cases found of abnormal functioning parahippocampal gyrus process unpleasant emotions - linked to anxiety and obsessions - research found hyperactivity in basal ganglia (linked to repetitive actions) - liked to compulsions - some sufferers have impaired orbits frontal cortex (worry circuit) - caudate nucleus-thalamus loop not able to filter small worries so worry circuit overactive (may be linked to anxiety in OCD)
• BIOLOGICAL EVALUATION - scientific


  focuses on observable and measurable biological features - e.g. MRI brain scans revealed some OCD patients appear to have brain abnormalities like loss of tissue in frontal lobe could indicate brain abnormality plays part in disorder - can be empirically tested
• BIOLOGICAL EVALUATION - twin studies


  Nestadt reviewed previous twin studies found 68% of MZ twins shared OCD compared to 31% of DZ twins - more genes we share with a sufferer more likely to develop OCD
• BIOLOGICAL EVALUATION - practical applications 


  drug therapies aim to correct neurotransmitter imbalances shown to be effective treating OCD - Soomro found SSRIs significantly more effective than placebos in treating OCD - approach useful in developing treatments - however not all patients respond to drug therapy
• BIOLOGICAL EVALUATION - biologically reductionist 


  reduces complex issue of mental health down to most basic parts like genes and ignores role of environment - e.g. although concordance rates often found to be higher in MZ than DZ twins for OCD, fact concordance rates aren't 100% in MZ twins shows environment must have a role - too simplistic - diathesis stress model of OCD more effective acknowledges both genes and environment play a role in OCD
• BIOLOGICAL EVALUATION - causation 


  difficult to establish whether neurochemical imbalances and structural abnormalities are causes of OCD or symptoms of disorder - research into cases of OCD tend to be retrospective, difficult to build up before and after picture in levels of neurotransmitters and brain structure - difficult to establish if neural impairments cause OCD or the other way round, casting doubt on validity