Scientists have found that women and men respond differently to manipulation of serotonin levels, a biochemical whose reduced transmission has been implicated in major depressive disorder (MDD), a common mental disorder.
The study published in Biological Psychiatry involved a technique called acute tryptophan depletion to decrease serotonin levels in the brains of healthy participants.
Dr. Espen Walderhaug, one of the study's authors, said that the aim of the study was to determine important sex and genetic differences in the way that men and women react to reductions in serotonin function, specifically in terms of their mood and impulsivity.
The researcher said that men became more impulsive upon reduction in the serotonin levels in their brains, but did not show any mood changes in response to the induced chemical changes.
Women, on the other hand, reported a worsening of their mood and became more cautious, a response commonly associated with depression, they said.
The researchers said that the mood lowering effect in women was influenced by variation in the promotor region of the serotonin transporter gene (5-HTTLPR).
"We were surprised to find such a clear sex difference, as men and women normally experience the same effect when the brain chemistry is changed... Although we have the same serotonergic system in the brain, it is possible that men and women utilize serotonin differently," Dr. Walderhaug.
The researcher further said that the findings "might be relevant in understanding why women show a higher prevalence of mood and anxiety disorders compared to men, while men show a higher prevalence of alcoholism, ADHD and impulse control disorders."
Dr. John H. Krystal, Editor of Biological Psychiatry and affiliated with both Yale University School of Medicine and the VA Connecticut Healthcare System, said that the response patterns that emerged in the findings were "the beginnings of an understanding for these sex-related effects."