The biological approach to treating OCD

Most commonly used drug for OCD + depression. Low levels serotonin associated w/ both, drugs increase levels of these. Low levels serotonin implicated in 'worry circuit', so increasing levels may normalise circuit.

Antidepressants used to reduce anxiety associated w/ OCD. SSRIs preferred drug - brand names eg Prozac, Zoloft. Increases serotonin levels, regulates mood + anxiety.

Serotonin released into synapse from one nerve (neuron). Targets receptor cells on receiving neuron at receptor sites + afterwards re-absorbed by initial neuron sending message. To increase S levels at synapse + increase stimulation to receiving neuron, re-absorption inhibited.

1st antidepressant to be used for OCD + today primarily used in OCD treatment rather than depression. Block transporter mechanism that re-absorbs serotonin + noradrenaline into pre-synaptic cell after fired. As result, more of neurotransmitters left in synapse, prolonging activity, + easing transmission of next impulse.

Have adv of targeting more than one neurotransmitter. However, have greater side effects so used as second-line treatment for patients where SSRIs not effective.

Benzodiazepines (BZs) commonly used to reduce anxiety - brand names Xanax, Valium etc. Slow down acitivity of CNS by enhancing activity of neurotransmitter GABA - when released, quietening effect on many neurons in brain. Reacts w/ GABA receptors on outside of receiving neurons - when GABA locks w/ receptors, opens channel that increases flow of chloride ions into neuron. Chloride ions make it harder for neuron to be stimulated by other neurotransmitters, slows down its activity + makes person feel more relaxed.

Research found D-Cycloserine has effect on reducing anxiety, may be effective treatment for OCD, especially when used in conjunction w/ psychotherapy. Antibiotic used in treatment of tuberculosis. Also appears to enhance transmission of GABA, therefore reduces anxiety - Kushner et al (2007).

Effectiveness - Soomro et al (2008) - meta-analysis, 17 studies of use of SSRIs w/ OCD patients, found they were more effective than placebos in reducing symptoms up to 3 months after treatment (ST). 

Requires little effort, little input of time - less than CBT, therefore preferred treatment.

Soomro et al (2008) - SSRIs side effects nausea, headache + insomnia. Tricyclics - halluciniations + irregular heartbeats. BZs - increased aggressiveness, LT impairment of memory + addiction.

Koran et al (2007) - review of OCD treatments, suggested not lasting cure even tho commonly used, only ST. Maina et al (2001) - patients relapsed w/in few weeks if medicaiton stopped.

Turner et al (2008) - evidence of publication bias. Authors found positive results more likely to be published + published in way that conveyed positive outcome. Selective publication can -> doctors making inappropriate treatment decisions, may not be in best interest of patient.