Due to the fact that tricyclic antidepressants could not be used on some patients because of their side effect profile, from the 1970’s onwards efforts started to develop chemicals that act on the receptors of a neurotransmitter called serotonin, as now the importance of serotonin in the mechanism of depression was known. These studies yielded their first fruit in the 1980’s and the SSRI group of drugs were developed. Fluoxetine, paroxetine, fluvoxamin, sertraline, citalopram and finally escitalopram are drugs of this group.
The side effects of the drugs in the SSRI group are generally mild and insignificant, which allowed the drugs to be used widely. These side effects are conditions like dry mouth, nausea, dizziness, constipation/soft stools, which may occur at the initial stages of treatment but generally subside by themselves.
The effect of the SSRI group drugs is less than that of the tricyclic antidepressants. Due to the fact that for a large percentage of patient the effect proved insufficient, from the 1990’s onwards the next generation of antidepressants were developed which had an impact not only on the neurotransmitter serotonin but also on dopamine and noradrenalin. Venlafaxine, mirtazepine, buproprion, duloxetine are of this group of drugs. They have different impact mechanisms and side effect profiles.