Antidepressants alter personality, study says

Published 12:01 am Tuesday, December 8, 2009

Antidepressant medications taken by about 7 percent of American adults effect profound personality changes in many patients with depression, far beyond simply lifting the veil of sadness, a study has found — raising the possibility that a basic shift in personality is what drives the cure.

The study found strong shifts in levels of neuroticism and extraversion in patients taking antidepressants, two of five traits thought to define personality and shape a person’s daily thoughts and behavior.

The medications would seem to relieve depression by chemically altering brain processes that spawn the negative thoughts to begin with rather than just alleviating symptoms associated with a depressed state, said Northwestern University psychologist Tony Tang, the lead author of the study.

The findings, published Monday in the journal Archives of General Psychiatry, were funded by the National Institute of Mental Health.

It is unclear how long-lasting the changes in personality are, the authors said. But the study found that patients whose personalities shifted the most were less likely to fall back into depression once treatment had ended. And they said that monitoring those altered traits could be a useful, early gauge of whether a medication is working and how likely a relapse would be.

In the study, 240 adults with moderate to severe depression participated in a trial designed to compare the benefits of medication and cognitive therapy.

Of these, 120 were give the selective serotonin reuptake inhibitor (SSRI) paroxetine, sold under the brand name Paxil, for 16 weeks. Another 60 received cognitive therapy but no medication for 16 weeks, and 60 others were given a placebo alone for eight weeks.

All subjects who reported improvements in their depression in response to psychotherapy or medication were followed for a year.

Patients who received paroxetine were more likely to have their symptoms ease, and they also showed more dramatic changes in personality.

But University of Illinois psychologist Brent Roberts cautioned that not all depressed patients — including the subjects in the new study — respond to SSRIs so favorably.

“And it would be foolish to base policy on the findings of one study,” he said.