Depression

08 December 2009

Antidepressants alter personality

Taking antidepressants may not only help alleviate depression, but could make you more extroverted and less neurotic, new research suggests.

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Taking antidepressants may not only help alleviate depression, but could make you more extroverted and less neurotic, new research suggests.

Extraversion, which is associated with positive emotions, is believed to help protect from depression, while neuroticism, the tendency to experience negative emotions and emotional instability, is thought to contribute to depression.

Becoming more extroverted and less neurotic may help prevent a relapse of depression, said lead study author Tony Tang, an adjunct professor of psychology at Northwestern University in Evanston, Ill.

"People's personalities actually do change and quite substantially when they go through these antidepressant treatments," Tang said. "In the past, we tended to dismiss the personality changes as a side effect or something not very important. But our study suggests it's actually very important to treatment outcomes."

How the study was done

Extraversion and neuroticism are associated with the serotonin system, the brain's reward centre that helps regulate mood, sleep and appetite. In this study, participants took paroxetine, which is sold under the brand name Paxil, a selective serotonin reuptake inhibitor. Other SSRIs include Prozac, Zoloft and Celexa. Though those drugs were not tested, Tang said the impact on the personality would likely be similar.

The study findings are published in the Archives of General Psychiatry.

The researchers divided 240 adults with a major depressive disorder into three groups: 120 received paroxetine, 60 underwent cognitive therapy and 60 took a placebo. Personalities and depressive symptoms were assessed before, during and after treatment.

All groups experienced some improvement in their depression. But participants taking paroxetine became less neurotic and more extroverted than those receiving cognitive therapy or placebo.

It wasn't that the depressed patients suddenly became happy-go-lucky, carefree social butterflies, Tang said. On scales of extraversion and neuroticism, their levels were still barely in the normal range -- but they were better than they were before.

Relapse risk, personality change linked

Relapsing after stopping treatment, or even while still receiving treatment, is a problem for people with depression. About two-thirds of patients relapse within a year of halting medications, while about 45 to 50% relapse even if they're still on medication, Tang said.

"Our findings seem to suggest one of the very good predictors for how well you'll do over the long term is how much your personality changes in response to the medication," he said. "For example, how much your neuroticism improved predicted how likely you were to relapse in a year after the treatment."

Bernard Carroll, scientific director of the Pacific Behavioural Research Foundation in Carmel, Calif., said any excitement over the results should be tempered by the fact that the improvements in depression from taking paroxetine weren't much better than from a placebo or cognitive therapy.

"The study confirms that paroxetine is not an especially effective antidepressant drug," said Carroll, past chairman of the US Food and Drug Administration's (FDA) advisory committee for psychiatric drugs. "In this sample, it barely beat the placebo."

Instead, paroxetine is more commonly prescribed for anxiety disorders, which is why researchers may have noted the personality changes. "Paroxetine wouldn't be anybody's number one choice for depression," Carroll said. "But it just might make sense that improving certain personality dimensions helps the patient's resilience against future relapse."

Personality-affecting drugs 'not good'

Deciding whether to take an SSRI or not has to be weighed against possible side effects, Carroll said, citing a recent study in the British Journal of Psychiatry that found that many people taking SSRIs reported feeling that the medications had blunted their emotions, both negative and positive ones. Other side effects may include headache, changes in sleep patterns, gastrointestinal upset and changes in sexual functioning, according to background information in that study.

"This business about the drugs affecting personality is not all necessarily good," Carroll said.

In another study from the Archives of General Psychiatry, patients with bipolar disorder who were taking antiepileptic drugs did not have an increased risk of suicide.

Anti-seizure drugs -- including gabapentin, pregabalin, topiramate and carbamazepine -- are not only used to treat epilepsy, but nerve disorder and bipolar disorder, according to background information in study.

Last year, the FDA warned of increased risk of suicidal thoughts and behaviour related to the use of anti-seizure drugs, but voted not to require a black box warning label about suicide risk.

Researchers from the University of Illinois at Chicago analysed data on 47 918 patients with bipolar disorder, of which 13 385 patients received one of 11 anti-seizure drugs, while others received lithium or no treatment.

The rates of suicide among those taking anti-seizure drugs were no higher than for those taking lithium, or those who received no treatment. And for patients taking anti-seizure drugs, suicide rates were five times higher before starting treatment than afterward.

The researchers said those with more severe illness may be more likely to be prescribed anti-seizure drugs or lithium. - (HealthDay News, December 2009)

 

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Depression expert

Michael Simpson has been a senior psychiatric academic, researcher, and Professor in several countries, having worked at London University in the UK; McMaster University in Canada; Temple University in Philadelphia, USA.; and the University of Natal in South Africa.

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