Results highlight the need for continued training on the importance of validity testing practices across different countries and all assessment settings, and identify groups of neuropsychologists to whom training could be targeted to maximize effectiveness.

Compared to ineligible cannabis users, eligible cannabis-using respondents were significantly younger, used cannabis more frequently, used alcohol less frequently, and were less likely to have a history of other drug use, a psychiatric diagnosis, or to have used psychiatric medication. Conclusions/Importance: Our findings indicate that eligible/pure cannabis users are not representative of typical cannabis users in the general community (i.e., ineligible users with polysubstance use and/or psychiatric diagnoses) who ultimately comprised the majority of our cannabis-using sample (65.2%). Thus, typical cannabis users may be more accurately characterized as polysubstance users, posing a number of challenges related to the generalizability of findings from studies utilizing pure samples of cannabis users. Recruiting samples of typical cannabis users will improve external validity in research. Furthermore, reporting comprehensive characteristics of such samples will enable consumers to gauge the applicability of study findings to populations of interest.

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Results suggest that neuropsychologists believe that cannabis use results in broad but mild cognitive deficits, consistent with meta-analytic findings of active chronic cannabis users, particularly for males and for individuals using cannabis for medicinal purposes. Interestingly, neuropsychologists expected fewer cognitive effects in recreational cannabis users. Further, duration of use (rather than frequency) was believed to be the primary factor contributing to cognitive deficits.

Objective To examine whether Test of Premorbid Functioning (TOPF) and Wide Range Achievement Test—Word Reading subtest (WRAT WR) are interchangeable measures, and the relationship between these measures and intelligence, among patients with schizophrenia. Method In this archival study, the authors examined neuropsychology referrals of an inpatient forensic state hospital. Patients with a schizophrenia spectrum disorder (SSD) who received the Wechsler Adult Intelligence Scale—Fourth Edition or the Wechsler Abbreviated Scale of Intelligence—Second Edition and either TOPF or WRAT WR were considered for inclusion. The final sample consisted of 119 individuals (73.1% male). Results Although there was a linear relationship between most TOPF variables and WRAT WR, their concordance was weak (concordance correlation coefficients [CCC] < 0.90). Poor concordance was also observed between current FSIQ and all standard scores (SS) derived from word reading measures. FSIQ-word reading measure discrepancy scores differed significantly from a hypothesized mean of 0 (mean discrepancy range = −7.42 to −16.60). Discrepancies greater than one standard deviation (>1 SD) were highest among demographics-based SS (i.e. TOPF Predicted and Simple without TOPF). Performance-based SS, particularly TOPF Actual and WRAT4 WR, had the fewest discrepancy scores >1 SD fromFSIQ. Conclusions TOPF and WRAT WR should not be used interchangeably among institutionalized patients with SSDs. TOPF and WRAT WR were discrepant from FSIQ, with demographic variables producing higher SS relative to performance-based variables. Future research is needed to determine which of these measures more accurately estimates intelligence among inpatients withSSDs.