Objectives To examine the association between duration and place of second-hand smoke (SHS) exposure and psychological distress in adolescents.

Methods A cross-sectional study conducted in 2008 and 2009 in a representative sample of 4th-year students of secondary education (mean age 15.7 years) in the region of Madrid, Spain. The 2215 students who were not smokers were selected for the analysis. Duration of SHS exposure within and outside the home was obtained by self-report. Psychological distress was defined as a score ≥3 points in the General Health Questionnaire (GHQ-12). The analyses were made using logistic regression adjusted for demographic variables, lifestyles and family characteristics.

Results Among non-smoking adolescents, 27.8% (95% CI 25.5 to 30.0) were exposed to SHS in the home, and 33.6% (95% CI 31.3 to 36.0) outside the home. Compared with those with no SHS exposure in the home, the multivariate OR for psychological distress was 1.23 (95% CI 0.92 to 1.64) in individuals with SHS exposure <1 h/day, 2.07 (95% CI 1.30 to 3.28) for exposure 1–3 h/day, and 2.24 (95% CI 1.45 to 3.47) for exposure >3 h/day (p for linear trend <0.001). No association was observed between SHS exposure outside the home and psychological distress.

Conclusions In non-smoking adolescents, duration of exposure to SHS in the home had a positive dose-response relationship with the frequency of psychological distress. However SHS exposure outside the home did not show an association with mental health.