Introduction: Patients of specialized nicotine dependence clinics are hypothesized to form a distinct subpopulation of smokers due to the features associated with treatment seeking. The aim of the study was to describe this subpopulation of smokers and compare it to smokers in general population.

Material and methods: A chart review of 796 outpatients attending a specialized nicotine dependence clinic, located in Toronto, Ontario, Canada was performed. Client smoking patterns and sociodemographic characteristics were compared to smokers in the general population using two Ontario surveys – the Ontario Tobacco Survey (n = 898) and the Centre for Addiction and Mental Health Monitor (n = 457).

Results: Smokers who seek treatment tend to smoke more and be more heavily addicted. They were older, had longer history of smoking and greater number of unsuccessful quit attempts, both assisted and unassisted. They reported lower education and income, had less social support and were likely to live with other smokers.

Conclusions: Smokers who seek treatment in specialized centers differ from the smokers in general population on several important characteristics. These same characteristics are associated with lower chances for successful smoking cessation and sustained abstinence and should be taken into consideration during clinical assessment and treatment planning.

Reliability estimates for psychological tests are almost always reported for nonclinical populations (e.g., the normative samples). Such practice will no longer be sufficient as the new standards for testing call for an adequate assessment of psychometric properties within the specific population being tested. The purpose of this study was to provide internal consistency reliability estimates for clinical groups on the Wechsler Adult Intelligence Scale–Third Edition. The study included data from 403 clinical participants composed of 10 groups of adults recruited as part of the WAIS–III clinical validity studies. Split-half reliability coefficients were obtained for these groups replicating the procedure used in the WAIS–III. With 8 of the clinical groups, the split-half reliability coefficients were comparable to, or even higher than, those reported for the WAIS–III standardization sample. In general, the split-half coefficients for the Verbal subtests tended to be higher than the coefficients for the Performance subtests. The high magnitude and general pattern of these coefficients demonstrate that the WAIS–III scales do not include additional error variance above and beyond what is reported in the WAIS–III–WMS–III Technical Manual when it was used to assess certain clinical groups. For the ADHD/ADD and learning disabilities groups, however, the internal consistencies coefficients of some subtests were relatively lower, although not statistically significant, than the normative sample. These findings may reflect more heterogeneity within the groups. The implications for assessment and for using alternate methods of determining the psychometric properties in these populations are discussed. (JINS, 2001, 7, 862–866.)