A Northwestern-led research team recently discovered evidence indicating antidepressants may impact more elements of an individual’s psyche than they are prescribed for.
The study, published in the December issue of Archives of General Psychiatry, comes nearly 20 years after the psychiatrist Peter Kramer’s book, “Listening to Prozac.” The best-seller describes how antidepressants cause profound changes in brain chemistry, giving users boosted feelings of self-worth.
“In my patients, I was seeing that some who had responded well to (the treatments) weren’t just getting over whatever it was that the medicine was prescribed for,” said Kramer, a clinical professor at Brown University. “They would come in and say they were more confident.”
At the time of the book’s publication, there was little scientific evidence to support such phenomena. But NU’s study is one of the first pieces of research to shed light on how antidepressants may impact personality and why that may be important.
The experiment, led by clinical psychologist and NU Prof. Tony Tang, examined 240 adults with major depressive disorder. In a placebo-controlled study, those patients who were assigned to take the antidepressant paroxetine showed more than just an improvement in their symptoms-it appeared as if they took on substantially different personalities following their treatment.
Such alterations in personality may be crucial to overcoming depression in the long-term, said Tang, the study’s lead author.
“Treating depression in the short-term is not that difficult for the vast majority of patients,” he said. “But somewhere between 50 (and) 70 percent of people relapse within a year-that is where the real struggle is at.”
Patients were assessed by measuring the degree to which they exhibited two personality traits, extraversion and neuroticism, using a validated 60-item test known as the NEO Five Factor Inventory, said co-author Benjamin Schalet, a clinical psychology PhD student at NU. The research team was particularly interested in these two personality dimensions since previous research has drawn a link between neuroticism and extraversion levels and the likelihood of developing depression.
“People who are at risk for depression tend to have unusually high levels of neuroticism and unusually low levels of extraversion,” Tang said.
The data showed that those who took antidepressant medications like paroxetine experienced a much greater decrease in neuroticism and an increase in extraversion compared to patients who were only given placebos. These trait shifts may be driving forces behind long-term improvements in mood, Tang said.
The new findings raise the possibility that antidepressant medications like paroxetine directly produce changes in personality. This goes against the long-standing hypothesis that a patient’s increased extroversion and decreased neuroticism are by-products of alleviating depressive symptoms, not direct results of the drugs’ biochemical effects.
“It’s the contrary of what people had thought for many years,” Kramer said.
