|Serotonin and the seasons|
|Polymorphism in 5-HT2A receptor gene is associated with seasonal depression|
Edward R. Winstead
March 12, 2001
Scientists report that a variant of the serotonin receptor gene was associated with an increased risk for a seasonal form of depression among a group of Spanish patients. The brain chemical serotonin is a factor in behavior that can vary with the seasons, such as sleeping, weight regulation, and mood. Researchers at the University of Barcelona investigated a link between major depression and a variant of the serotonin receptor gene, which comes in many forms. The study focused on a polymorphism in the 5-HT2A receptor gene.
"Our results in an independent sample of Spanish subjects showed that variability in the 5-HT2A receptor was associated with seasonal pattern depression," the researchers write in Molecular Psychiatry. They found that seasonal forms of depression were seven times more frequent among individuals with the 102C polymorphism compared to others in the study. The sample included 159 patients with major depression and 164 unrelated and healthy controls.
Among the 159 patients, there were patterns that distinguished the type of depression in each group. Those with seasonal depression tended to have an earlier age of onset, more suicide attempts and melancholia, and shorter length of episodes than did others in the study. These differencesand data from other studiessupport the notion that 'major depression' actually comprises a variety of conditions, some of which will involve different genes, the researchers say.
Seasonal changes in mood and behavior have been reported along a spectrum of severity. At one extreme is the clinically diagnosed syndrome known as seasonal affective disorder, or SAD, which tends to run in families and have a biological basis.
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