Social phobia in a population-based female adolescent twin sample: co-morbidity and associated suicide-related symptoms

Background. This report attempted to replicate and extend prior work examin ing social phobia (SP), co-morbid psychiatric illnesses, and the risk of su icidal ideation and suicide attempts incurred by their adolescent sufferers . Methods. SP, alcohol dependence (ALD) and major depressive disorder (MDD) d iagnoses, and suicide-related symptoms, were assessed in a population-based adolescent female twin sample. The differentiation of risks as a function of co-morbidity was explored. A trivariate model was fitted to estimate sha ring of genetic and environmental vulnerability between SP and co-morbid di sorders. Results. The lifetime prevalence of SP was 16.3 %. Significant risk for co- morbid MDD (OR = 3.2) and ALD (OR = 2.1) was observed. Strong evidence for shared genetic vulnerability between SP and MDD (respective heritabilities 28 %, 45 %; genetic r = 1.0) was observed with moderate support noted for s imilar sharing between SP and ALD (genetic r = 0.52, heritability for ALD 6 3 %). SP with co-morbid MDD was associated with elevated risk for ALD and f or suicide-related symptoms. Conclusions. SP is a common illness often followed by co-morbid MDD and ALD . SP with comorbid MDD predicts a substantially elevated risk of ALD and su icide-related symptoms, stressing the need for early SP detection.