Individuals taking a medication to treat depression may experience changes in their personality separate from the alleviation of depressive symptoms, according to a report in the December issue of Archives of General Psychiatry, one of the JAMA/Archives journals.
Two personality traits, neuroticism and extraversion, have been related to depression risk, according to background information in the article. Individuals who are neurotic tend to experience negative emotions and emotional instability, whereas extraversion refers not only to socially outgoing behavior but also to dominance and a tendency to experience positive emotions. Both traits have been linked to the brain's serotonin system, which is also targeted by the class of antidepressants known as selective serotonin reuptake inhibitors (SSRIs).
Tony Z. Tang, Ph.D., of Northwestern University, Evanston, Ill., and colleagues studied the effects of one particular SSRI, paroxetine, in a placebo-controlled trial involving 240 adults with major depressive disorder. A total of 120 participants were randomly assigned to take paroxetine, 60 to undergo cognitive therapy and 60 to take placebo for 12 months. Their personalities and depressive symptoms were assessed before, during and after treatment.
All participants experienced improvement in their symptoms of depression. However, even after controlling for these improvements, individuals taking paroxetine experienced a significantly greater decrease in neuroticism and increase in extraversion than those receiving cognitive therapy or placebo. "Patients taking paroxetine reported 6.8 times as much change on neuroticism and 3.5 times as much change on extraversion as placebo patients matched for depression improvement," the authors write.