Paxil and Personality: A Complex Relationship

When assessing a patient for major depressive disorder (MDD) and choosing the most appropriate course of treatment, personality type is a major consideration. Research has demonstrated that people with high levels of neuroticism and/or low levels of extraversion often respond less well to treatment and have higher relapse rates. Briefly, neuroticism is a personality trait that includes a tendency toward negative emotions and emotional instability. Extraversion, on the other hand, describes a tendency toward positive feelings, including but not limited to higher levels of socialization and self-confidence. A recent study published in the Archives of General Psychiatry examined the links between personality type, cognitive therapy, and the antidepressant medication Paxil (paroxetine).

In multiple studies of the drug Paxil, participants who showed significant improvement in their depression also reported greater feelings of confidence and liveliness. The authors of these studies generally describe these personality changes as effects of the overall improving mood of the patients. A more recent study ponders whether selective serotonin reuptake inhibitors (SSRI) medications, Paxil in this case, do in fact work to change personality states resulting in a lessening of depressive symptoms. The study was broken into three groups: a placebo group, a therapy group, and a group receiving Paxil. Depression and personality ratings were gathered from each participant at regular intervals throughout the 16-week study.

As many previous studies have shown, even people receiving placebo showed noteworthy improvement in their depression. However, the personality trait scores underlined a potentially significant fact. Neuroticism and extraversion were both relatively unchanged in the placebo group, while those receiving Paxil or cognitive therapy showed improvement in both of these key areas. This suggests that Paxil may work to alter personality traits on the molecular level. Cognitive therapy also led to decreased neuroticism and increased extraversion, but the reasons for these changes are not as clear. What is clear is that these personality changes predict a better long-term outcome for patients and a lower chance of relapse.

The lesson from this research is that clinicians should be mindful of specific personality traits when treating an individual with MDD. Paxil, and possibly all of the SSRI medications, may work to improve depression on a more fundamental level than anyone realized. The data has always been there, in a sense, but perhaps the interpretation was lacking. As researchers unlock the mysterious relationship between moods and chemical neurotransmitters, more specifically targeted drugs will be developed. Furthermore, as the early warning signs of depression—neuroticism, low extraversion—are better identified, interventions will be possible to prevent this debilitating mental health condition before it occurs.


  1. Depression (major depression) – (n.d.). Mayo Clinic. Retrieved March 8, 2012, from
  2. Tang, T.Z., DeRubeis, R.J., Hollon, S.D., Amsterdam, J., Shelton, R., & Schalet, B. (2009). A placebo-controlled test of the effects of paroxetine and cognitive therapy on personality risk factors in depression. Archives of General Psychiatry, 66, (12), 1322-1330.

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