This study examined the neuropsychological and personality functioning of four groups of "normal" subjects: (1) "clean"; (2) positive drug screen; (3) prior psychiatric diagnosis; and (4) first-degree relative with a psychiatric history. Researchers usually exclude these latter three groups based on the assumption that their neuropsychological functioning will be worse than "clean" normal subjects. Of the four groups, there was a trend for the drug group to perform worse on neuropsychological tasks and for subjects with a personal or family history of psychiatric disorder to perform better. Within the drug group, the five subjects who tested positive for cocaine or barbiturates showed worse performance than the marijuana group. Thus, it appears that it is important to screen normals for drugs, especially for cocaine and barbiturates, because of adverse neuropsychological performance.

The files of 283 hospitalized patients discharged with a diagnosis of schizophrenia, schizoaffective schizophrenia, or paranoid state were examined without knowledge of the patient's subsequent history. These patients, most of whom had originally been diagnosed by DSM-I criteria, were retrospectively diagnosed by New York Research Diagnostic Criteria (RDC), the New Haven Schizophrenia Index (NHSI), the St. Louis criteria, Taylor-Abrams 1978 criteria, Schneider's first-rank symptoms (FRS), the Washington IPSS 12-Point Flexible System, Astrup's process/nonprocess distinction, and DSM-III. Kappa values measuring pairwise diagnostic agreement among the nine systems were typically low except among RDC, DSM-III, and St. Louis criteria. Long-term followup status was not significantly predicted by the FRS, NHSI, or Taylor-Abrams criteria. Diagnosis by means of the other systems, especially the Astrup process/ nonprocess distinction, was significantly correlated with followup. However, Astrup's “process” schizophrenia is not operationally defined and could not be expected to be used with the degree of interrater reliability desired by researchers. On the other hand, of the operationally defined systems, DSM-III schizophrenia has the highest correlation with followup and is thus suggested for use by researchers desiring a highly homogenous, although narrowly defined, population. Investigators wishing to cast a wider net could use a less restrictive system such as the RDC, with or without schizoaffectives included.

Elevated levels of central D2 dopamine receptors were found on postmortem examination in cases of human narcolepsy. In vivo investigations using positron emission tomography (PET) and single photon emission tomography (SPET) found no changes of D2 binding in the striatal structures. To investigate whether the elevated D2 receptors in postmortem investigations are due to long-term treatment effects, we applied 123I-labeled (S)-2-hydroxy-3-iodo-6-methoxy-([1-ethyl-2-pyrrolidinyl]methyl) benzamide (IBZM) ([123I]IBZM, a highly selective CNS D2 dopamine receptor ligand) and SPET in narcoleptic patients in the course of treatment with stimulants and/or antidepressants. Before treatment we found no changes in D2 binding in 10 patients (in comparison to 10 normal controls). After treatment (performed in five patients for 3 months) we found changes in D2 binding in four of them, indicating that the results of the postmortem studies could have been influenced by long-term medications. Human narcolepsy seems not to be related to a striatal D2 dopaminergic disturbance.