In reply
Unraveling the relationships between major mental disorders, substance abuse and dependence, and criminality is not easy because existing data suggest that they are rather complex. Assuming that they are linear and causal, as does Weiler, oversimplifies the problem and thereby limits the type of explanatory models that will be developed and the statistical analyses that can be performed.1There is now good evidence to suggest that among persons who develop schizophrenia, major depression, and bipolar disorder, rates of substance abuse and dependence are elevated compared with rates in persons without disorders.2-4(chap 9) As well, persons with major mental disorders are at increased risk for personality disorders4 (chap12),5 (S.H., J. Toupin, PhD, and L. Tremblay, PhD, unpublished data, 1991). Is the increased vulnerability for substance abuse related to the major disorder, to the personality disorder, or to both, or is it independent of the two? Is criminality related