Del D. Miller and Susan K. Schultz
The University of Iowa
Iowa City, Iowa
Schizophrenia is one of the first diagnoses that should come to mind when a clinician encounters a patient experiencing delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behavior, or negative symptoms (i.e., affective flattening, alogia, or avolition). However, the clinician must keep in mind that there is no one pathognomonic feature of schizophrenia. The above symptoms can, and often do, occur in other psychiatric, neurological, and medical conditions, as well as with certain medications and substance abuse ( 1). It cannot be emphasized enough that no single feature (e.g., cross-sectional symptomatology, course, family history, response to treatment, or laboratory findings) will alone determine a diagnosis of schizophrenia. In general, the reliability of differentiating schizophrenia from the other disorders is strengthened by the presence of several of these characteristic features occurring in a manner consistent with the persistent courses and social/occupational impairment as outlined in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) ( 2).