A    greater risk of suicide among adoptive rather than biologic relatives

A  suicide is related to the mental disorder rather than being familial and  associated with a family history of suicide

A        relatives of suicidal subjects have a four-fold increased risk compared to relatives of non-suicidal subjects

A        twin studies indicate a lower concordance of suicidal behavior between monozygotic rather than dizygotic twins

A   suicide has been found to have the same concordance rate in dizygotic as in monozygotic twins