Prior studies point at a modest correlation between the PANSS

Prior studies point at a modest correlation between the PANSS cognitive factor and comprehensive neuropsychological assessments, for instance as reported by Good et al. (2004) among antipsychotic naïve, first episode psychosis patients. However, Bowie et al. (2002) reported a modest but significant relationship between the negative total symptom score of PANSS and the MMSE, as well as between the MMSE and the Alzheimer’s Disease Assessment Scale—Late Version Cognitive factor, ADAS-L-Cog, among geriatric schizophrenia patients with severe impairment. Although no correlation was found in this thyrotropin receptor study between duration of illness and MMSE scores or performance on the PANSS cognitive factor, the possible mediating effect of this and other variables on cognitive performance bears further investigation.


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Substance misuse and cognitive deficits both impede the treatment and recovery of persons with schizophrenia (). Studies show that cognitive performance is one to two standard deviations below average in schizophrenia () and that such deficits span neurocognitive and social–cognitive domains (), lead to poor long-term outcomes (), and may become worsened when those with the disorder misuse substances (). However, while alcohol and cannabis misuse has been associated with poorer cognitive outcomes among healthy adults (), these relations are much more complex in schizophrenia.
Studies of the cognitive impact of alcohol or cannabis misuse in schizophrenia have yielded mixed results (). Cannabis-misusing schizophrenia patients tend to demonstrate better cognitive performance than their non-cannabis-misusing thyrotropin receptor counterparts (), yet a few studies have reported no between-group differences (). In contrast, alcohol-misusing schizophrenia patients exhibit worse cognitive performance than their non-alcohol-misusing counterparts (), with a few studies reporting no between-group differences ().
Regarding the mixed findings reported between substance misusing and non-misusing schizophrenia patients on cognitive outcomes, several questions about the way in which the severity associated with alcohol, cannabis, or the concurrent use of these substances impacts cognition among those seeking treatment to improve these deficits remain. Variability in the degree of severity, which has been defined within the context of the problems that necessitate substance use treatment (), may reveal important cognitive differences within Recombinant joint subgroup. To date, however, the way in which such misuse impacts cognition in substance-misusing schizophrenia (SMS) has remained largely unexamined. The objectives of this study were to investigate cognitive performance differences between SMS, schizophrenia, and control participants, and examine whether alcohol or cannabis severity impacts cognition within the SMS sample.
Participants included 32 SMS, 28 schizophrenia, and 37 control participants partaking in studies of Cognitive Enhancement Therapy (CET []) at the University of Pittsburgh. Inclusion criteria for schizophrenia outpatients consisted of an IQ ≥ 80; age 18 to 60; antipsychotic medication adherent; and schizophrenia/schizoaffective disorder confirmed by the Structured Clinical Interview for DSM-IV (SCID []). Inclusion criteria for SMS outpatients consisted of these criteria, as well as Addiction Severity Index (ASI []) severity ratings ≥ 4 for alcohol or cannabis, and significant cognitive and social disability confirmed by the Cognitive Styles and Social Cognition Eligibility Interview (). Cognitive and social disability criteria were part of the inclusion criteria for SMS patients to ensure that such participants had sufficient disability to need treatment. Inclusion criteria for controls consisted of an age 18 to 50; free from psychiatric diagnosis per the SCID; no substance abuse within 3 months. Participants’ characteristics are presented in .