Effect of cigarette smoking on thyroid function in depressed patients

Dynamic associations of negative mood and smoking across the development of smoking in adolescence

Self-medication models of smoking posit that the emotional benefits of smoking reinforce and maintain cigarette use, yet research demonstrates both positive and adverse affective consequences of smoking. The current study examined longitudinal changes in adolescent mood variability and overall negative mood at various stages of smoking behavior to inform understanding of the etiology of adolescent smoking. Participants included 461 adolescents (M age = 15.67 years, SD = 0.61; 55% girls, 56.8% White) drawn from a longitudinal study of adolescent smoking. Youth provided data on smoking behavior at baseline and a 15-month follow-up wave. Ecological momentary assessments were used to measure overall levels of negative mood as well as within-person mood fluctuations (i.e., negative mood variability) at each wave. Findings revealed that smoking-mood relations vary across different stages of smoking behavior. Youth who rapidly escalated in their smoking during the study experienced improved mood regulation (for girls) and improved overall mood (for boys) as smoking increased. However, mood improvements were not observed among youth with sustained heavy use and symptoms of dependence. The current data argue for a model of smoking that accounts for changes in risk and maintenance factors at different points along the developmental trajectory of smoking, involving elements of both self-medication and dependence.

[Role of tobacco use on the incidence of depression in the SUN cohort study]

BACKGROUND AND OBJECTIVE

Several investigations, most of them cross-sectional, have analyzed the association between smoking and depression, but there are not enough evidences to establish the direction of the association. Our objective was to prospectively assess the association between smoking habit and depression incidence in the SUN (Seguimiento Universidad de Navarra) cohort.

SUBJECTS AND METHOD

Dynamic cohort study (recruitment permanently open) based on 8,556 graduate participants where depression incidence was ascertained during 6 years of follow-up. Depression was defined as the presence of a self-reported physician diagnosis and/or use of antidepressant medication in at least one of the 2-year, 4-year or 6-year follow-up questionnaires. The association between smoking and depression incidence was estimated through the calculation of hazard ratios (HR) and their 95% confidence intervals (CI) using Cox regression models (proportional hazards).

RESULTS

The mean follow-up period was 47.4 months. One hundred and ninety participants initially free of depression reported a physician diagnosis of depression during follow-up. A significantly higher risk was found for smokers (HR = 1.39; 95% CI, 1.00-1.93) when they were compared to non smokers, whereas an inverse association was found for ex-smokers who had quit smoking more than 10 years ago (HR = 0.42; 95% CI, 0.19-0.94).

CONCLUSIONS

This study supports, with a prospective design, an increased risk of depression associated to smoking.

Tobacco smoking and depressed mood in late childhood and early adolescence

OBJECTIVES

This study builds on previous observations about a suspected causal association linking tobacco smoking with depression. With prospective data, the study sheds new light on the temporal sequencing of tobacco smoking and depressed mood in late childhood and early adolescence.

METHODS

The epidemiologic sample that was studied consisted of 1731 youths (aged 8-9 to 13-14 years) attending public schools in a mid-Atlantic metropolitan area, who were assessed at least twice from 1989 to 1994. A survival analysis was used to examine the temporal relationship from antecedent tobacco smoking to subsequent onset of depressed mood, as well as from antecedent depressed mood to subsequent initiation of tobacco use.

RESULTS

Tobacco smoking signaled a modestly increased risk for the subsequent onset of depressed mood, but antecedent depressed mood was not associated with a later risk of starting to smoke tobacco cigarettes.

CONCLUSIONS

This evidence is consistent with a possible causal link from tobacco smoking to later depressed mood in late childhood and early adolescence, but not vice versa.