OCD

OCD

1. Emotional: anxiety, distress, awareness that it is excessive, leading to shame

2. Cognitive: recurrent, intrusive, uncontrollable thoughts (obsessions)

3. Behavioural: compulsive behaviours to reduce obsessive thought, not connected in a realistic way

4. Biological approach to explaining:

   • Genetic explanation
     • COMT gene - one allele more common in OCD, created high levels of dopamine (Tukel et al)
     • SERT gene - one allele more common in a family with OCD, creates low levels of serotonin (Ozaki et al)
     • Diathesis-stress - same genes linked to other disorders or no disorders at all, therefore genes create vulnerability
   • Neural explanation
     • Dopamine levels high in OCD - linked to compulsive behaviours in animals studies (Szechtman et al)
     • Serotonin levels low in OCD - antidepressants that increase serotonin most effective ( Janicke)
     • Worry circuit - damaged caudate nucleus doesn't suppress worry signals from OFC to thalamus
     • Serotonin and Dopamine linked to activity in these parts of the frontal lobe (Sukel)
   • + Twin studies, twice as likely to have OCD if MZ twins - Genes are not specific to OCD, also linked to Tourette's, autism and anorexia

5. Biological approach to treating

   • Drug therapy
     • Antidepressants increase serotonin
     • SSRIs prevent re-uptake of serotonin by pre-synaptic neuron
     • Tricyclics block re-uptake of noradrenaline and serotonin but have more severe side effects, so are 2nd choice treatment
     • Anxiety drugs, BZs enhance GABA, a neurotransmitter that slows down the nervous system
   • + SSRIs better than placebo over a short term (Soomro et al) + Drug therapies are preferred, less time and less effort the CBT - Side effects, SSRI's have insomnia, Tricyclics have hallucinations and BZs have addiction

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