Do Antidepressants Change Your Personality?

Researchers have been trying to answer this crucial question for years.

Before deciding to start taking an antidepressant, a prescription medication that treats depression and anxiety, you may wonder if it will change your mood or personality. Personality, according to the American Psychological Association's (APA) definition, refers to individual differences in characteristic patterns of thinking, feeling, and behaving.

It's an important question for many people. According to the Centers for Disease Control and Prevention (CDC), 13.2% of American adults said they used antidepressants in the 30 days before being asked.

Many people with depression are thought to have low levels of serotonin, according to research published in 2020 in Molecular Psychiatry. A popular class of medications called SSRIs, or selective serotonin-reuptake inhibitors, has been used for more than 30 years (according to a history of the development of SSRIs in a 2015 study in Experimental and Clinical Psychopharmacology) as a way to boost serotonin, a neurotransmitter that helps nerve cells communicate.

The notion that drugs—and specifically SSRIs—can cause personality changes has been investigated by researchers for years.

While some researchers have indeed attributed improved symptoms associated with depression to personality changes, other experts have been skeptical that drugs such as SSRIs have independent effects on personality. They attribute changes to a patient's improved mood.

The Evidence for Personality Changes

In 2009, a key study published in the Archives of General Psychology grabbed attention when it found that people who took the SSRI Paxil (paroxetine) had a drop in neuroticism, which is a tendency toward emotional instability and negative mood. These patients also had an increase in extroversion, which is a tendency toward outgoingness and positive mood, compared to similarly depressed people taking a placebo, a medication with no effects. Study authors suggested that the SSRI may have altered two key personality traits linked to depression—neuroticism and extroversion—independently of their effect on depression symptoms.

"Medication can definitely change people's personalities, and change them quite substantially," said the lead author of the study, Tony Z. Tang, PhD, a Visiting Scholar at the University of Pennsylvania.

The more drastic the personality shift, the less likely depressed patients were to relapse, according to the study, which is still cited among researchers.

Although the study looked only at Paxil, other SSRIs (such as Prozac and Zoloft) are likely to have the same effect on personality, said Dr. Tang.

In the study, the researchers randomly assigned 240 people with moderate to severe depression to Paxil, placebo, or cognitive therapy (a form of talk therapy). In order to separate out the effect of Paxil and depressive symptoms on personality, the researchers matched participants in the Paxil and placebo groups according to how much their symptoms improved.

After eight weeks, the group of patients who took Paxil reported a reduction in neuroticism nearly seven times greater than that reported by the patients taking placebo whose depression symptoms had improved a comparable amount. The increase in extraversion reported by the Paxil group was 3.5 times greater than that among the matched placebo patients. (The changes in personality were measured using a standard questionnaire.)

Social Benefits of Antidepressants

Psychiatrist Peter D. Kramer, MD, the author of the landmark 1993 book, Listening to Prozac (which described how patients treated with antidepressants often became more at ease socially and less sensitive to rejection), described the 2009 study as a confirmation of what he observed years before.

"It looks like a lot of what gives people relief is that they're feeling whatever the opposite of neuroticism is," said Dr. Kramer, a clinical professor of psychology and human behavior at Brown University in Providence, RI. "Getting better very solidly seems to predict a longer period before the next episode. That argues against the notion that these medications are just band-aids [that] get people through."

Psychiatrists have come to expect personality changes in patients being treated for depression, said Dr. Kramer. Thirty years ago, he says, a person who was "no longer in acute pain, remained pessimistic and socially shy and socially anxious and feeling inferior" was considered cured of depression.

Today, he said, "clinical people now want to see these personality changes."

In Listening to Prozac, Dr. Kramer expressed concern that SSRIs might usher in an era of "cosmetic psychopharmacology," with non-depressed people popping pills to make themselves more attractive, energetic, and confident. But this hasn't come to pass, he said. "I've never had anyone come into my office or ever had an extended phone conversation with someone who was on these medications for trivial reasons."

Questions About Personality Changes Remain

However, in 2012, a five-year observational study of depressed patients published in the Journal of Affective Disorders concluded that it was the improvement in anxiety and depression that altered the personality traits of neuroticism and extroversion. "Although the personality scores of many patients changed significantly over the five-year study, none of these changes were associated with changes in antidepressant pharmacotherapy," the authors wrote.

And in 2017, a review of the literature regarding personality change and therapeutic intervention was published in Psychological Bulletin. The review looked at 207 studies that tracked changes in personality traits during interventions. The study found decreases in neuroticism and increases in extroversion as a result of the interventions which were designed to target mental health problems. The authors also found that the type of therapy employed (cognitive, behavioral, psychoanalytic, or pharmacological) was not strongly associated with the amount of change in personality traits.

Although such studies shed some light on the relationship between SSRIs and personality, there is much that remains unknown about how these drugs work and what effects they have on patients.

"The theory of how these medications work is actually still a mystery," said Dr. Tang.

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