Eighty-two healthy adolescent girls were genotyped for the BDNF val66met polymorphism, and their depressive symptoms and physical activity were assessed using questionnaires.
The low activity variants of the 5-HTT-linked polymorphic region in the serotonin transporter gene and the Met-allele of a single nucleotide polymorphism (Val66Met) in the gene encoding brain derived neurotrophic factor were independently associated with the presence of stressful life events prior to onset of depression, also when corrected for the effect of age, gender, marital status, personality disorder, neuroticism, and severity of depressive symptoms at the time of interview.
The BDNF Val66Met polymorphism was examined in DNA samples from the mothers and daughters, and measures of depressive symptoms and rumination were also obtained.