Serotonin Transporter Gene (5-HTT) Variation Impacts on Development of Anxiety and Depression: A Longitudinal Study

The data were extracted from two waves of a longitudinal study.  The two waves had 10 years apart. 

Due to the skewed nature of the outcomes (symptom scores of anxiety and depression), generalized linear models were applied in this study.  In addition, parameters were estimated based on GEE, and least-squared mean results were given to explain the 5-HTT gene effects on the developmental course of anxiety and depression, as well as the interactive effects between 5-HTT gene and early environmental factor (childhood abuse).

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Effects of 5-HTT gene variation on development of depressive symptom severity. 

Results showed that LaLa allele of 5-HTT gene had protective effects on developing anxiety symptoms in both adolescence and early adulthood.  With a childhood physical abuse history, the protective effects of LaLa allele became stronger than other situations of childhood abuse.  Similar to the effects on anxiety symptoms, LaLa allele was also found to have protective effects on developing depressive symptoms in adolescence and early adulthood.  The difference is that the protective effects may not be interactive with childhood abuse.