Cognitive Enhancement to Improve Substance Abuse Outcomes in Persons With Co-Occurring Disorders

Cognitive remediation has relevance to the treatment of alcohol and drug use disorders in people with co-occurring mental health conditions for several reasons. First, there is abundant evidence that alcohol use impairs cognitive functioning, both acutely and over the long term. It is also well established that drug use has prominent acute effects on worsening cognitive functioning in persons with a drug use disorder, although its longer-term impact is less clear. Second, impaired cognitive functioning is a common problem in people with severe mental illness, most notably schizophrenia but also severe mood and anxiety disorders, which have among the highest rates of comorbid substance use disorders of all clinical populations (Regier et al., 1990). Third, cognitive impairment attenuates benefits from psychosocial treatments in people with severe mental illness (Kurtz, 2011). Because psychosocial interventions are the primary treatment method for individuals with a substance use disorder, cognitive impairment may also impede response to treatment of these disorders. Fourth, cognitive enhancement (i.e., cognitive remediation) for persons with severe mental illness has been shown to improve psychosocial functioning when added to another psychosocial treatment program (such as social skills training or supported employment), but not when added to usual services (McGurk, Twamley, Sitzer, McHugo, & Mueser, 2007; Wykes, Huddy, Cellard, McGurk, & Czobar, 2011), suggesting that cognitive enhancement increases response to psychosocial treatment in this population. Thus, improving cognitive abilities in the context of alcohol or drug treatment could increase treatment efficacy and improve substance use outcomes. However, people with severe mental illness who have had comorbid substance use problems have been largely excluded from trials of cognitive enhancement, resulting in little evidence to bear on the potential benefits of cognitive approaches to addiction problems in this population.

The three studies included in this special section address the application of cognitive enhancement to the treatment of substance use disorders in people with co-occurring mental health issues. Two of the studies evaluate the effects of cognitive enhancement programs on cognition and substance use patterns in people with alcohol and/or cannabis use disorders. The third describes the potential applications of cognitive enhancement to people with a co-occurring stimulant use disorder.

Eack, Hogarty, Bangalore, Keshavan, and Cornelius (2016) examined alcohol and cannabis use trajectories among persons with schizophrenia and alcohol and cannabis use disorders randomized to usual care or cognitive enhancement therapy, an 18-month program that integrates computerized cognitive practice with group-based exercises addressing social cognition, and, for this study, alcohol and cannabis use. Individual growth curve analyses for participants in each of these conditions indicated that people receiving cognitive enhancement therapy reduced their use of alcohol to a greater extent and more rapidly than individuals receiving usual care, but similar effects were not found for cannabis. Eack et al. also explored the associations between cognitive improvements in cognitive enhancement therapy and changes in substance use patterns, with intriguing results. Improvements in visual memory and problem solving predicted reduced alcohol and cannabis usage, which could be related to improved ability to recognize substance-related cues that could trigger substance use and to develop effective solutions or plans to dealing with those situations.

Bell, Vissicchio, and Weinstein (2016) evaluated the effects of 13 weeks of daily computerized cognitive enhancement on verbal learning and memory in 31 veterans receiving treatment for an alcohol use disorder, who were randomized to work therapy or cognitive enhancement had and work therapy. About 15% of the participants had polysubstance use disorder and 30% had comorbid depressive or anxiety disorders. Of note, the participants were older (average age of 55) than those with psychiatric disorders generally included in studies of cognitive enhancement (average age of 36; McGurk et al., 2007; Wykes et al., 2011), and about 50% of participants had impaired verbal learning and memory at baseline, defined as performance at least one standard deviation below premorbid IQ. Participants randomized to cognitive enhancement had improved performance post-treatment on verbal learning and memory, with most gains retained at a three-month follow-up assessment and with only 20% still meeting criteria for verbal learning and memory impairment post-treatment. This encouraging study adds to the sparse research literature by demonstrating the potential of cognitive enhancement intervention to improve cognitive functioning in an older and more cognitively compromised sample of persons with a substance use disorder.

Sofuoglu, DeVito, Waters, and Carroll (2016) describe the possibility that cognitive enhancement interventions may help improve treatment outcomes among individuals with stimulant use disorder. They provide an overview of the literature on cognitive functioning in persons with a stimulant use disorder, which summarizes the growing research demonstrating the cognitive deficits associated with stimulant use problems, including effects on learning, executive functioning, memory, and information processing speed. However, the causes and stability of these deficits could reflect multiple processes aside from prolonged use, such as acute drug effects, short-term withdrawal effects, or preexisting vulnerability factors for addiction including comorbid psychiatric conditions. Poorer cognitive functioning in persons with a stimulant use disorder is associated with poorer treatment retention and worse outcomes, raising the question of whether cognitive enhancement could augment response to treatment. There are currently no published studies on the effects of cognitive enhancement for persons with a stimulant use disorder, with or without a mental health condition, suggesting the need for further research in this area.

The articles in this section address the feasibility and promise of providing cognitive enhancement intervention to bolster the effects of treatments for alcohol and drug use disorders and frequent co-occurring mental illness. The empirical studies by Eack et al. and Bell et al. demonstrate that people receiving treatment for a substance use disorder can be engaged in a cognitive enhancement program, although attrition can be a problem, and that participation is associated with improvements in cognitive functioning that are retained at follow-up. Sofuoglu et al. underscore the potential role of cognitive enhancement for improving response to treatment for stimulant use disorder. These articles are early and exploratory, but make important contributions that may begin to lay the foundation for more extensive, refined, and definitive research on cognitive enhancement for co-occurring substance use disorders.

Disclosures

Dr. McGurk reports no financial relationships with commercial interests with regard to this manuscript.