Psychological Medicine

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

E. C. NELSON a1c1, J. D. GRANT a1, K. K. BUCHOLZ a1, A. GLOWINSKI a1, P. A. F. MADDEN a1, W. REICH a1 and A. C. HEATH a1
a1 Missouri Alcoholism Research Center, Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA


Background. This report attempted to replicate and extend prior work examining social phobia (SP), co-morbid psychiatric illnesses, and the risk of suicidal ideation and suicide attempts incurred by their adolescent sufferers.

Methods. SP, alcohol dependence (ALD) and major depressive disorder (MDD) diagnoses, 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 sharing of genetic and environmental vulnerability between SP and co-morbid disorders.

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 similar sharing between SP and ALD (genetic r = 0·52, heritability for ALD 63%). SP with co-morbid MDD was associated with elevated risk for ALD and for suicide-related symptoms.

Conclusions. SP is a common illness often followed by co-morbid MDD and ALD. SP with co-morbid MDD predicts a substantially elevated risk of ALD and suicide-related symptoms, stressing the need for early SP detection.

c1 Department of Psychiatry, Washington University School of Medicine, 40 N. Kingshighway, St. Louis, MO 63108, USA.