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