Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
-
Neuropsychopharmacology · Dec 2009
Contribution of hypothalamic-pituitary-adrenal activity and environmental stress to vulnerability for smoking in adolescents.
Although tobacco smoking, which has been linked to depression, is a major public health problem, little is known about the neurobiological factors that confer vulnerability to smoking in youngsters and the effects of adolescent smoking on the course of depression. This study examined whether hypothalamic-pituitary-adrenal (HPA) activity and stressful life experiences are related to smoking behavior in depressed and non-depressed adolescents, and whether smoking predicts a worsening course of depression. Smoking history and stressful experiences were assessed in 151 adolescents (48 with no personal or family history of psychiatric disorder, 48 with no psychiatric history, but at high risk for depression by virtue of parental depression, and 55 with current major depressive disorder). ⋯ A model that included stressful experiences and cortisol levels reduced the contribution of smoking per se to depression. High evening/night-time cortisol level appears to be a vulnerability marker for smoking in adolescents, with stressful experiences further increasing the risk for smoking in vulnerable youth. High evening/night-time cortisol levels and stressful experiences accounted, at least partially, for the association between depressive illness and smoking behavior.
-
Neuropsychopharmacology · Dec 2009
Controlled Clinical TrialDifferential effects of tri-allelic 5-HTTLPR polymorphisms in healthy subjects on mood and stress performance after tryptophan challenge.
Earlier data suggest that a polymorphism at the serotonin (5-HT) transporter gene (5-HTTLPR) may affect depression particularly in the face of stress due to interactions between 5-HT vulnerability and stress exposure. However, this interaction between 5-HT transporter-linked transcriptional promoter region (5-HTTLPR), 5-HT vulnerability and the affective effects of stress exposure has not yet been investigated. As participants with short-allele 5-HTTLPR genotypes may exhibit enhanced 5-HT vulnerability, this study examines the effects of tryptophan challenge on stress reactivity and performance in healthy participants with S'/S' vs L'/L' genotypes. ⋯ Although there were no 5-HTTLPR-related differences in stress responses, significant beneficial effects of tryptophan challenge on mood and stress performance were exclusively found in participants with S'/S' genotypes. These findings suggest greater brain 5-HT vulnerability to tryptophan manipulations in participants with S'/S' as compared with L'/L' 5-HTTLPR genotypes. This apparent genetic 5-HT vulnerability may become a meaningful risk factor for depression when brain 5-HT falls below functional need in the face of real severe stressful life events.