Biochemical personality change?
SSRIs (selective serotonin re-uptake inhibitors) have been one of the most high-profile antidepressants in the past 15 or 20 years. The role of various neurotransmitters, including serotonin, in depression is still far from clear, which makes it hard to say exactly how SSRIs work (and why they sometimes don’t). A story from late last year adds another interesting complication: It appears that SSRIs might be capable of causing personality change, distinct from the effect they have on depression.
A study examined 240 depressed adults, some of whom received an SSRI (paroxetine); the others were given either a placebo or cognitive therapy. Their depressive symptoms and their personality traits were compared before, during, and after one year of treatment. All of the people in the study experienced relief from their depression. In addition to these changes, the people who took paroxetine also showed significant changes in two of the Big FIve personality traits: neuroticism and extraversion (a decrease in the former and an increase in the latter). Both of these traits have been linked with depression risk, extraversion more tentatively than neuroticism. (A high score for neuroticism appears to be a risk factor linked with genetic vulnerability to depression, and low levels of extraversion might also be a risk factor.)
This is a very interesting finding. The whole question of personality change seems complicated to me; my best take on it at the moment is that we probably do have some inborn tendencies and preferences that are hard to change, but that we can change how we express those traits. I’m not sure what to think about the idea of personality change through pharmaceuticals (assuming this finding is supported by future work). It’s also kind of interesting to think about the link between personality and emotion, in addition to that between personality and behavior. I also wonder what happens when the people in the study stop taking the SSRI.
The link in the first paragraph goes to a Science Daily article about the research. Here’s the reference for the paper itself:
Tony Z. Tang, Robert J. DeRubeis, Steven D. Hollon, Jay Amsterdam, Richard Shelton, Benjamin Schalet. Personality Change During Depression Treatment: A Placebo-Controlled Trial. Arch Gen Psychiatry, 2009; 66 (12): 1322-1330
SSRI’s have certainly been marketed well but have never conclusively been shown to either be:
• More effective than older style tricyclic antidepressants
• More effective than placebo sugar pills. When a placebo is active (i.e. produces just side effects) the negligible difference in efficacy between SSRI’s and antidepressants disappears completely.
A person’s expectations of future wellness play a major role in whether they actually do get better regardless of whether they are placed on placebo or an active mind altering drug.
It certainly wouldn’t matter so much if SSRI’s were just an effective (if expensive) placebo if it were not for the potentially lethal side effects. One of the best publicised side effects of SSRI’s is their potential to increase suicidal thoughts and acts. In a recent analysis of the data the FDA concluded that when compared to placebos SSRI’s double the risk of suicide in people under twenty four. (2)
No gene for depression has ever been found and the whole “low serotonin” bio-chemical model is now being questioned.
Artificially lowering serotonin in people doesn’t produce depression (3)
But, interestingly, there is an antidepressant developed and sold in France (tianeptine-sold as ‘Stablon’) which has the effect of lowering serotonin levels which is just as effective as SSRI’s and placebo. It seems the “active ingredient” of antidepressants, how they work, is positive expectation.
Mark
(1)See Irving Kirsch’s “The Emperor’s new drugs: Exploding the Antidepressant Myth’ 2009
(2)Tarek A.Hammond, Thomas Laughren and Judith Racoosin, 2006.
(3) H.G Ruhe, N.S. Mason and Aart H. Schene, 2007.
Very interesting, thanks! I’ve heard about the Irving Kirsch book but haven’t had the chance to read it yet.
the milder the depression, the less clear the benefits of antidepressants. AND the more severe the depression, the more clear the benefits.
i have seen several patients with clear and dramatic personality changes on ssri’s. typically it’s a type a, very driven, person who happens to become depressed. give them an ssri and suddenly they’re mellow. they’ve never been mellow before in their lives! usually they like it a lot, and their spouses like it even more. and once off meds, there seems to be some persistence of the new traits – as if they’ve seen things in a new way that they don’t forget.
a greater number will have similar but less dramatic personality effects.
most people will not have personality effects, however.