Internet and Psychiatry

Sher L, Rosenthal NE, Wehr TA.
Section on Biological Rhythms, National Institute of Mental Health, Bethesda, MD 20892-1390, USA.
J Affect Disord. 1999 Dec;56(2-3):195-9.

Seasonal affective disorder (SAD) is characterized by recurrent episodes of depression in the fall and winter that alternate with nondepressed periods in the spring and summer. Because some symptoms of SAD, such as decreased energy and weight gain, also occur in hypothyroidism, it is possible that individuals with SAD have a subtle decrease in thyroid function. To test this hypothesis, we studied blood levels of free thyroxine (T4) and thyroid-stimulating hormone (TSH) in SAD patients and matched controls in the winter.

Levitan RD.
Department of Psychiatry, University of Toronto, Canada.
Dialogues Clin Neurosci. 2007;9(3):315-24.

This review summarizes research on the chronobiology and neurobiology of winter seasonal affective disorder (SAD), a recurrent subtype of depression characterized by a predictable onset in the fall/winter months and spontaneous remission in the spring/summer period. Chronobiological mechanisms related to circadian rhythms, melatonin, and photoperiodism play a significant role in many cases of SAD, and treatment of SAD can be optimized by considering individual differences in key chronobiological markers.

Levitan RD, Masellis M, Lam RW, Kaplan AS, Davis C, Tharmalingam S, Mackenzie B, Basile VS, Kennedy JL.
Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
Neuropsychopharmacology. 2006 Nov;31(11):2498-503.

We have recently described an association between the hypofunctional 7-repeat allele (7R) of the dopamine-4 receptor gene (DRD4), weight gain, and obesity in women with seasonal affective disorder (SAD). In the current study, we examined whether season-of-birth might interact with the 7R allele to influence body weight regulation in SAD. In 182 female probands with SAD, we performed an analysis of covariance predicting maximum lifetime body mass index (BMI) with both the exon-3 variable number of tandem repeat polymorphism of DRD4 and season-of-birth as independent variables, and age as the covariate.

Sher L, Greenberg BD, Murphy DL, Rosenthal NE, Sirota LA, Hamer DH.
Section on Biological Rhythms, National Institute of Mental Health, Bethesda, Maryland, USA.
Psychiatr Genet. 2000 Sep;10(3):125-30.

Pleiotropy refers to the ability of a single gene to influence multiple traits. A polymorphism in the regulatory region of the serotonin transporter gene (5-HTTLPR) has previously been found to be associated both with the personality trait of neuroticism and with seasonal changes in mood and behavior, or seasonality. Hypothesizing that the contribution of the serotonin transporter gene to seasonality is specific, i.e. independent of neuroticism, we measured 5-HTTLPR genotypes and both psychological traits in 236 healthy volunteers.