Neurocognitive Functioning of Individuals With Schizophrenia: Using and Not Using Drugs

Bahorik, Amber L.; Newhill, Christina E.; Eack, Shaun M.

doi:10.1093/schbul/sbt099

Cited by 28 publications

(16 citation statements)

References 89 publications

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“…Although substance use and educational variables were found to statistically significantly differ between groups, they were not utilized as covariates for either data analytic strategy. Research suggests that the effect of substance use on cognition in schizophrenia is mixed , with no clear indication of its specific influence. Furthermore, there is a dearth of literature addressing the effects of long‐term substance use on cognition in those with schizophrenia.…”

Section: Methodsmentioning

confidence: 99%

Differences in Neuropsychological Functioning Between Homicidal and Nonviolent Schizophrenia Samples

Stratton

Cobia

Reilly

et al. 2018

Journal of Forensic Sciences

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Few studies have compared performance on neurocognitive measures between violent and nonviolent schizophrenia samples. A better understanding of neurocognitive dysfunction in violent individuals with schizophrenia could increase the efficacy of violence reduction strategies and aid in risk assessment and adjudication processes. This study aimed to compare neuropsychological performance between 25 homicide offenders with schizophrenia and 25 nonviolent schizophrenia controls. The groups were matched for age, race, sex, and handedness. Independent t-tests and Mann-Whitney U-tests were used to compare the schizophrenia groups' performance on measures of cognition, including composite scores assessing domain level functioning and individual neuropsychological tests. Results indicated the violent schizophrenia group performed worse on measures of memory and executive functioning, and the Intellectual Functioning composite score, when compared to the nonviolent schizophrenia sample. These findings replicate previous research documenting neuropsychological deficits specific to violent individuals with schizophrenia and support research implicating fronto-limbic dysfunction among violent offenders with schizophrenia.

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Section: Methodsmentioning

confidence: 99%

Differences in Neuropsychological Functioning Between Homicidal and Nonviolent Schizophrenia Samples

Stratton

Cobia

Reilly

et al. 2018

Journal of Forensic Sciences

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“…Such individuals are frequently unstable (Schmidt, Hesse, & Lykke, 2011) and have challenges with medication adherence (Perkins et al, 2008), making them less ideal candidates for clinical trials of new interventions. There has also been controversy over the degree to which cognitive deficits are present in patients with substance use problems (Yücel et al, 2012), although larger studies using carefully assessed samples indicate impairments similar to those individuals not misusing substances (Bahorik, Newhill, & Eack, 2014; Wobrock et al, 2013). Given the general lack of efficacy of antipsychotic treatment on cognitive impairment in schizophrenia (Keefe et al, 2007), some patients may turn to substances to cope with residual cognitive deficits and associated social dysfunction (Blanchard, Brown, Horan, & Sherwood, 2000; Gregg, Barrowclough, & Haddock, 2007).…”

Section: Introductionmentioning

confidence: 99%

Cognitive Enhancement Therapy in substance misusing schizophrenia: Results of an 18-month feasibility trial

Eack

Hogarty

Greenwald

et al. 2015

Schizophrenia Research

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Substance use is a frequent problem in schizophrenia, and although many substance misusing patients with the disorder also experience considerable cognitive impairments, such individuals have been routinely excluded from clinical trials of cognitive remediation that could support their functional and addiction recovery. This study conducted a small-scale feasibility trial of Cognitive Enhancement Therapy (CET) in substance misusing schizophrenia patients to assess the feasibility and efficacy of implementing comprehensive neurocognitive and social-cognitive remediation in this population. A total of 31 schizophrenia outpatients meeting addiction severity criteria for alcohol and/or cannabis use were randomized to 18 months of CET or usual care. Feasibility findings indicated high degrees of satisfaction with CET, but also presented significant challenges in the recruitment and retention of substance misusing patients, with high levels of attrition (50%) over the study period, primarily due to positive symptom exacerbation. Intent-to-treat efficacy analyses showed large and significant improvements in neurocognition (d = .86), social cognition (d = 1.13), and social adjustment (d = .92) favoring CET. Further, individuals treated with CET were more likely to reduce alcohol use (67% vs. 25%) during treatment (p = .021). These results suggest that once engaged and stabilized, CET is a feasible and potentially effective treatment for cognitive impairments in patients with schizophrenia who misuse alcohol and/or cannabis. Substance misusing patients who are able to engage in treatment may be able to benefit from cognitive remediation, and the treatment of cognitive impairments may help improve substance use outcomes among this underserved population.

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“…Tobacco and alcohol are the most frequently used substances among people with schizophrenia and in CHR than in the general population (Addington et al, 2014; Buchy et al, in press; de Leon and Diaz, 2005) and have been associated with neurocognitive function in schizophrenia (Morisano et al, 2013; Wing et al, 2011; Yip et al, 2009)(Allen et al, 1999; Cantor-Graae et al, 2001; Fowler et al, 1998; Manning et al, 2009) Stimulant use also has a deleterious effect on cognitive functions in people diagnosed with a psychotic disorder (Bahorik et al, 2014; Serper et al, 2000a; Serper et al, 2000b; Smelson et al, 2003; van der Meer et al, 2014), and other studies have reported elevated neurocognition in people with schizophrenia currently using cocaine (Bahorik et al, 2014; Benaiges et al, 2013). Therefore, these variables must be taken into account when interpreting results of the relationship between cannabis use and IQ across the schizophrenia spectrum.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the relationship between cannabis use and IQ in youth and young adults at clinical high risk of psychosis

Buchy

Seidman

Cadenhead

et al. 2015

Psychiatry Research

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Among people with psychosis, those with a history of cannabis use show better cognitive performance than those who are cannabis naïve. It is unknown whether this pattern is present in youth at clinical high risk (CHR) of psychosis. We evaluated relationships between IQ and cannabis use while controlling for use of other substances known to impact cognition in 678 CHR and 263 healthy control (HC) participants. IQ was estimated using the Vocabulary and Block Design subtests of the Wechsler Abbreviated Scale of Intelligence. Drug and alcohol use severity and frequency were assessed with the Alcohol and Drug Use Scale, and we inquired participants’ age at first use. CHR were further separated into early and late age at onset of cannabis use sub-groups, and low-, moderate- and high-frequency sub-groups. No significant differences in IQ emerged between CHR or HC cannabis users vs. non-users, or between use frequency groups. CHR late-onset users showed significantly higher IQ than CHR early-onset users. Age at onset of cannabis use was significantly and positively correlated with IQ in CHR only. Results suggest that age at onset of cannabis may be a more important factor for IQ than use current use or use frequency in CHR.

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Neurocognitive Functioning of Individuals With Schizophrenia: Using and Not Using Drugs

Abstract: No positive effects of cannabis on cognitive function were observed, and drug use was not associated with improved neurocognition across most of the subgroup characteristics explored in this sample of schizophrenia patients.

Cited by 28 publications

References 89 publications

Differences in Neuropsychological Functioning Between Homicidal and Nonviolent Schizophrenia Samples

Differences in Neuropsychological Functioning Between Homicidal and Nonviolent Schizophrenia Samples

Cognitive Enhancement Therapy in substance misusing schizophrenia: Results of an 18-month feasibility trial

Evaluating the relationship between cannabis use and IQ in youth and young adults at clinical high risk of psychosis

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