4.1.4e - Biological Treatment of OCD

Monday 19th February ‘24

What are SSRIs?

  • Most common treatment option.

  • Antidepressants called SSRIs increase seratonin to minimise symptoms of OCD.

  • Typical daily dosage of fluoxetine is 20mg.

How do SSRIs work?

  • Pre-synaptic neuron releases vesicles containing seratonin into the synapse and binds to post-synaptic receptors.

  • SSRIs lodge themselves on presynaptic neuron (blocks reabsorption of neurotransmitters) so there is an accumulation of seratonin vesicles in the synapse, increases binding to the receptor sites.

  • OCD = seratonin remains low; neurotypical = seratonin stays high.

What are alternative treatments?

  • Tricyclics - acts on various systems inc seratonin system where it has same effect as SSRIs. EG clomipramine which has more severe side-effects.

  • SNRIs - different class of antidepressant drugs and increase levels of seratonin as well as another different neurotransmitter - norodrenaline.

  • Benzodiapepines - used to treat sleep and anxirty disorders. Act as GABA receptors and has an allosteric effect, hyperpolerises the channel through chloride ions.

    • 1. BZs bind to the GABA receptors; 2. Enhances action of GABA; 3. GABA opens ion channels; 4. Lets in lots of Cl⁻ ions, making the neuron less receptive.