Two cases of misdiagnosis: some essentials of intake.

This article traces the history of two clinical cases. The first case describes a substance abusing patient who enacted the part of a narcotics addict. This enactment was affirmed by both alcohol and narcotic treatment programs, leading to a misdiagnosis. The second case describes a substance using client misdiagnosed as a result of assumptions made by the referral source. Biases inherent in the assessment of drug involved patients are illustrated and the utility of the hypotheses testing approach as a method of diagnostic error reduction and correction is discussed.