Associations of social phobia and general anxiety with alcohol and drug use in a community sample of adolescents.

AIMS: This study explores whether associations between anxiety and alcohol and other substance use are already evident in middle adolescence, and whether general anxiety or symptoms of social phobia affect continuity of frequent alcohol use, frequent drunkenness and cannabis use.
METHODS: Data from the Adolescent Mental Health Cohort Study, a school-based Finnish survey among adolescents aged 15-16 years at baseline, was utilized to assess prevalence, incidence and continuity of symptoms of social phobia, general anxiety, frequent alcohol use, frequent drunkenness and cannabis use (which in this context was smoked 'hashish' of unknown constituency), and the associations between the substance use variables and the anxiety variables in 2-year follow-up.
RESULTS: Anxiety preceded substance use while no reciprocal associations were observed. Depression mediated the associations between anxiety and substance use. Symptoms of social phobia did not elevate the incidence of substance use, but general anxiety did. Frequent drunkenness was less significantly associated with anxiety than the other two substance use variables. Co-morbid general anxiety increased the persistence of frequent alcohol use while co-morbid social phobia decreased its persistence. Continuity of frequent drunkenness and cannabis use were unaffected by co-morbid anxiety.
CONCLUSIONS: General anxiety in middle adolescence places adolescents at risk for concurrent and subsequent substance use. The risk may, however, be associated with co-morbid depression. Social phobia in middle adolescence may protect from substance use. Adolescents with internalizing symptoms may need guidance in coping with the symptoms even if the symptoms do not fulfil the criteria of mood or anxiety disorder.