Antidepressants can alter personality traits

Kathleen Blanchard's picture

A new study shows that taking antidepressants can alter personality traits. A benefit of taking the antidepressant paroxetene was found to produce less neuroticism and greater degrees of extroversion – lack of either characteristic are risk factors for depression.

The study comes from Tony Z. Tang, Ph.D., of Northwestern University, Evanston, Ill., and colleagues who specifically studied the antidepressant SSRI, paroxetine in 240 adults with major depressive disorder. One hundred twenty participants were randomly assigned to take paroxetine, 60 underwent cognitive therapy and 60 were given placebo for twelve months. The group taking paroxetine showed changes in personality traits that differed from the other study participants.


Personality traits and symptoms of depression were measured before, during and after treatment. Those taking the antidepressant paroxetine experienced 6.8 times as much change on neuroticism and 3.5 times as much change on extraversion, though each of the groups had improvement in depression symptoms.

Paroxetine, an antidepressant called an SSRI (selective serotonin reuptake inhibitor), seems to change personality traits in a way that is not just linked to relief of depression symptoms. The authors write, "One possibility is that the biochemical properties of SSRIs directly produce real personality change. Furthermore, because neuroticism is an important risk factor that captures much of the genetic vulnerability for major depressive disorder, change in neuroticism (and in neurobiological factors underlying neuroticism) might have contributed to depression improvement."

SSRI’s are first line choices for treating depression, but the way they work has not been entirely understood. The researchers say, "Investigating how SSRIs affect neuroticism and extraversion may thus lead toward a more parsimonious understanding of the mechanisms of SSRI’s.” The antidepressants are also shown to help treat eating disorders and anxiety, both of which are linked to high neuroticism and low extraversion.

Arch Gen Psychiatry. 2009;66[12]:1322-1330