Selective mutism and social anxiety disorder: all in the family?

OBJECTIVE To examine the history of lifetime psychiatric disorders in the parents of children with selective mutism (SM) compared to parents of children in a control group. METHOD Seventy parent dyads (n = 140) of children with lifetime SM and 31 parent dyads (n = 62) of children without SM were interviewed with the Structured Clinical Interview for DSM-IV (IV and II) anxiety disorders, mood disorders, avoidant personality disorder, and schizoid personality disorder modules via telephone. Interviewers were blind to proband status. The NEO Personality Inventory was also administered. RESULTS Lifetime generalized social phobia was present in 37.0% of SM parents compared to 14.1% of control parents (chi2 = 10.98; p < .001; odds ratio 3.6, 95% confidence interval 1.6-7.9). Avoidant personality disorder was present in 17.5% of the SM parents compared to 4.7% of control parents (chi2 = 6.18; p < .05; odds ratio 4.3, 95% confidence interval 1.3-14.9). The proportion of parents with other psychiatric disorders was not different between groups. SM parents had higher neuroticism and lower openness scores on the NEO Personality Inventory than control parents. CONCLUSIONS These results support earlier uncontrolled findings of a familial relationship between generalized social phobia and SM.