The use of the Diagnostic Interview Schedule in drug-dependent patients

In an attempt to diagnose other psychiatric disorders in substance abusers, some clinicians and investigators have utilized the NIMH Diagnostic Interview Schedule (DIS). This study assessed the validity of the DIS in a drug-dependent population by comparing DIS diagnoses with clinical diagnoses in 124 hospitalized drug abusers. Every attempt was made to establish the validity of the clinical diagnoses; these represented a consensus of two independent psychiatrists, based on repeated clinical interviews, observation of ward behavior, and information obtained from relatives regarding patient and family history. Concordance between clinical and DIS diagnoses (represented by the kappa statistic and percent agreement) was only moderate for DSM-III Axis I disorders other than substance abuse. In addition, the DIS diagnosed alcoholism less often and antisocial personality disorder more often than the clinicians. Factors contributing to the discrepancy between clinical and DIS diagnoses in this specific population include (a) drug abuse effects, whereby distinguishing between drug effects and primary psychiatric symptoms may be difficult; and (b) the effect of the treatment process itself, whereby patients are encouraged to rethink the role drugs have played in causing some of their difficulties. Patients' reports of the chronology of their symptoms may thus change according to what they have learned in treatment. The authors conclude that the DIS, like any single diagnostic interview, may have limited utility early in the treatment of drug-dependent patients, since their recollection of their previous symptoms may change dramatically as a result of treatment efforts.