Atypical antidepressant

An atypical antidepressant is a type of antidepressant medication which acts in an atypical manner relative to most other antidepressants. Examples of atypical antidepressants include mirtazapine, bupropion, trazodone, nefazodone, and tianeptine. The newer agents vilazodone and vortioxetine are also partially atypical. Atypical antidepressants are as opposed to typical antidepressants like the SSRIs, SNRIs, TCAs, and MAOIs, which act mainly by increasing the levels of the monoamine neurotransmitters serotonin and/or norepinephrine. Among TCAs, trimipramine is an atypical agent in that it does not appear to do this.

Esketamine and buprenorphine/samidorphan (ALKS-5461) are antidepressants with novel mechanisms of action which are under development and, at present, would be considered to be atypical antidepressants. Unlike current agents, they are more rapid-acting antidepressants.