PET Scans May Help Explain Seasonal Mood Change
Individuals had higher serotonin transporter binding potential values in fall and winter
THURSDAY, Sept. 4 (HealthDay News) -- Serotonin transporter binding was higher in individuals during the fall and winter than in the spring and summer in multiple brain regions, a finding that may help explain seasonal mood changes, according to research published in the September issue of the Archives of General Psychiatry.
Nicole Praschak-Rieder, M.D., of the University of Toronto in Ontario, Canada, and colleagues analyzed data from 88 healthy volunteers with no history of antidepressant or antipsychotic usage. Subjects underwent a positron emission tomography (PET) scan either between Sept. 23 to March 20 (fall and winter) or March 21 to Sept. 22 (spring and summer).
Serotonin transporter binding potential values were higher in those evaluated in fall and winter, which may encourage extracellular serotonin loss, leading to lower mood and lack of energy, the researchers write. The serotonin transporter binding potential values were higher in all investigated brain regions -- the anteromedial prefrontal cortex, anterior cingulate cortex, caudate, putamen, thalamus, and mesencephalon -- during fall and winter. The researchers also found that higher values occurred at times of less daily sunshine.
"Given that the serotonin transporter has a role in clearing extracellular serotonin, these findings have important implications for understanding seasonal mood change in healthy individuals, vulnerability to seasonal affective disorder, and the relationship of light exposure to mood," the authors write.