OUTLINE AND EVALUATE THE BIOLOGICAL THERAPIES OF DEPRESSION

One biological treatment for depression is drug therapy – the use of antidepressant drugs to alleviate the symptoms of depression. Monoamine oxidase inhibitors work by inhibiting the activity of monoamine oxidase which destroys serotonin and noradrenaline. This drug therefore reduces the chance that these neurotransmitters will be destroyed so there are higher levels of them across the synapse and post-synaptic neuron, resulting in palliation of the symptoms of depression. Tricyclics work by blocking the transporter mechanism that reabsorbs serotonin and noradrenaline molecules into the pre-synaptic synapse, which again means that there are higher levels of these neurotransmitters present in the synapse and the post-synaptic neuron. These drugs are typically taken for four to six months and despite their immediate effect on neurotransmitter levels they take around two weeks to mitigate the actual symptoms of depression.  

The efficacy of antidepressant drugs has been extensively supported by research, particularly through the use of placebos. Bennett found that there was a 50% success rate for MAOIs and 60-65% for tricyclics, and Kirsch found that whilst a placebo appeared to benefit moderately depressed individuals as it ‘gave them hope’, it had little effect on severely depressed patients presumably as they did not expect to benefit from any treatment.  A study conducted by The National Institute of Mental Health (Elkin) compared four different treatment groups over 16 weeks: Beck’s cognitive therapy; interpersonal therapy; the antidepressant drug Imipramine (a tricyclic); and the placebo group. The investigation found that all three active treatments eliminated symptoms in 50-60% of the participants compared to only 29% of the placebo group so all the of the treatments were successful in treating depression. There does not appear to be much difference in effectiveness of the treatments, but as Hollon suggests, psychotherapy combined with drug therapy is slightly more effective than either treatment alone. Hollon’s study on three groups of patients over a period of 12 months found that from those withdrawn from cognitive therapy, 31% suffered a relapse, 47% of those who received drug therapy throughout the 12 months relapsed and 76% of those withdrawn from drug therapy suffered a relapse. Keller et al also found that recovery rates were 55% using drugs alone, 52% using CBT alone but 85% when the two therapies were used in concordance with each other. This evidence suggests that drug therapy is mainly a palliative treatment and cognitive therapy is a curative treatment, however the recovery of depression is much more likely when both the biological and psychological aspects of the disorder are targeted.