Suicidal behavior in twins: a replication

Objective: Our two previous reports showed that monozygotic (MZ) twins were significantly more concordant for both completed suicide and attempted sui cide than dizygotic (DZ) twins. We wished to replicate the finding that MZ co-twins showed greater concordance for suicidal behavior. Method: We colle cted a new series of 28 twin pairs in which one twin had committed suicide. Results: We found that 4 of the 13 MZ twin pairs were concordant for suici dal behavior compared with 0 of the 15 DZ twin pairs (P = 0.035). Conclusio ns: These data confirm our previous reports that MZ co-twins show greater c oncordance for suicidal behavior than DZ co-twins, consistent with genetic influence. (C) 2001 Elsevier Science BY. All rights reserved.