Which neurotransmitter do many antidepressants change the activity of?

Answer 1

The most common antidepressants prescribed today come under a class of neuroactive drugs called 'selective serotonin reuptake inhibitors', or SSRIs for short. These include: Citalopram (Celexa), Fluoxetine (Prozac), Fluvoxamine (Luvox), Paroxetine (Paxil), Sertraline (Zoloft) and Venlafaxine (Effexor).

The primary mechanism of action for SSRIs to modify the way serotonin gets taken back up at the synapse. Not all SSRIs work on boosting serotonin levels though. Some like Venlafaxine also increase the amount of noradrenaline available at the synapse.

Older antidepressants like Clomipramine (Anafranil), referred to as 'trycyclic antidepressants', work primarily by inhibiting the reuptake of noradrenaline; although like some SSRIs, their selectively is never absolute, so they also have some effect on serotonin and dopamine reuptake too.

Atypical depressants like Bupropion (Wellbutrin) and monoamine oxidase inhibitors like Phenelzine (Nardil) also exert their effects via manipulating serotonin/noradreneline/dopamine levels.

Although each class differs subtly in their mechanism of action and specificity, they all essentially work to boost biogenic amine levels in the brain (i.e., serotonin and/or dopamaine and/or noradrenaline).

And then there is something like 5-HTP which is more effective then any of the SSRI's or Trycyclic antidepressants for the simple reason that 5-HTP actually helps to create more serotonine (5-HTP is the direct precursor for serotonine).