Work, recovery and comorbidity in schizophrenia: A randomized controlled trial of cognitive remediation

Authors: McHugo, G., Drake, R., & Becker, Dl.
Year Published 2009
Publication Schizophrenia Bulletin
Volume 35
Number 2
Pages 319-335
Publisher Oxford University Press

A common theme that cuts across all definitions of recovery is work. Work is valued by most and it enables on to make a contribution to society and offers the promise of liberating consumers from financial dependence on others. In recent years, a recovery paradigm has emerged that offers a guiding vision for self-empowerment, treatment, and rehabilitation for individuals with schizophrenia and comorbid problems such as: cognitive impairment,9 substance abuse,10 and medical disorders. This study addressed the impact of comorbidity on recovery of work functioning and response to vocational rehabilitation, described strategies for minimizing its effects, and provided data from a new study targeting the problem of cognitive impairment in order to improve employment outcomes.


The purpose of the study is to evaluate the impact of adding cognitive remediation to vocational rehabilitation to determine the impact on comorbid substance abuse and medical disorders on work outcomes and response to the treatment program.


The study took place in a vocational rehabilitation program associated with an urban medical center.


The study included 34 participants who were 18 years or older, had severe mental illness, expressed an interest in work, had a history of being fired or quitting employment prior to locating new work. Participants received either vocational rehabilitation plus cognitive retraining or Vocational rehabilitation only.
In both groups, the majority of subjects were male (61% and 56%) black (61% and 63%) and had never been married (78% and 75%). The primary diagnosis was Schizophrenia (75% and 60%) and most had a comorbid disorder (67% and 81%). The mean age of the group members was (46 and 42 years).

Data Collection

Referrals were made by therapists and work services personnel. Those interested had a baseline assessment scheduled. Consumers were not paid for assessments. Following completion of the assessments, consumers were randomized to either vocational rehabilitation alone (VR) or vocational rehabilitation and cognitive remediation (VR and CR)using a computer program. The examiners compared the groups at baseline on the demographic, clinical, and cognitive measures using t-tests (continuous variables) and v2 analyses (categorical variables). Next they computed the percentage of consumers who were exposed to the cognitive remediation program, as completing 6 or more cognitive remediation sessions, the average number of sessions completed, and the number of weeks to complete them.

Then to evaluate changes over the treatment period in cognitive functioning and clinical variables, they performed a series of analyses of covariance (ANCOVAs), with the cognitive/symptom measures at posttreatment as the dependent variables, the cognitive/ symptom measures at baseline as the covariate, and treatment group as the independent variable. Finally they looked at work outcomes. Because continuous work outcomes were highly positively skewed, main treatment effects were evaluated by performing Mann-Whitney U tests comparing the 2 treatment groups on wages earned and hours and weeks worked. To evaluate whether substance abuse directly influenced vocational outcomes or interacted with treatment group, separate analyses were performed for current drug-use disorder and alcohol-use disorder. For these analyses, the work variables were log transformed to minimize skew. For each series of analyses, analysis of variance were performed with current drug-use disorder (or current alcohol-use disorder), treatment group, and their interactions as the independent variables and the work outcomes as the dependent variables. The main effect for drug-use disorder (or alcohol-use disorder) in these analyses was a test of whether the disorder had an overall impact on vocational outcomes, whereas the drug-use disorder (or alcohol-use disorder) by treatment group interaction effect was a test of whether the outcomes of the treatment groups differed significantly as a function of the disorders.


Participants were randomly assigned to either vocational rehabilitation alone or vocational rehabilitation and cognitive remediation using a computer-generated randomization program.


Statistical tests comparing consumers assigned to VR only or VR and CR indicated no significant differences in any demographic, diagnostic, or baseline clinical or cognitive performance measures.

The results of the ANCOVAs comparing changes over time in cognitive functioning and symptoms between consumers who received cognitive remediation and those who did not were summarized. Significant improvements favoring cognitive remediation were found for several cognitive measures. Results of the Mann-Whitney U tests comparing work outcomes for the 2 groups indicated that the VR and CR group worked significantly more internship weeks and hours and earned more wages than the VR-only group.

The VR and CR group also worked significantly more weeks than VR only, and there was a trend for them to earn more wages, although hours
worked did not differ between the groups. Number of weeks or hours of competitive work did not differ between the 2 groups nor did wages earned. Overall rates of competitive rates were 39% for the VR and CR group vs 31% for the VR-only group, which did not differ significantly. Analyses of relationship of substance-abuse disorder and medical comorbidity focused on total (log transformed) hours worked for each vocational outcome. Alcohol-use disorder was marginally significantly related to total hours worked with the absence of current alcohol-use disorder associated with more hours worked compared with the presence of an alcohol-use disorder. Drug-use disorder was also related to total hours worked, with absence of current drug-use disorder associated with more hours worked compared with the presence of a drug-use disorder.

There were no interactions between either alcohol or drug-use disorder and treatment group, suggesting that the addition of cognitive remediation to vocational services was just as helpful in the consumers with a substance-use disorder as those without. A similar analysis of total hours worked comparing consumers with high levels of medical comorbidity to those with low levels indicated that both the main effect for medical comorbidity and the interaction with treatment group were not significant. Thus, consumers with higher medical comorbidity burden appeared to have comparable vocational outcomes compared with those with less such burden. For the VR-only group, Spearman correlations between overall cognitive performance at baseline and total work over the study period were significant for total hours worked and wages earned and marginally significant for number of weeks worked, whereas for the VR and CR group, none of these correlations were significant Thus, cognitive performance at baseline was more predictive of work in the study for those in the control group than those in the cognitive remediation group.


Providing cognitive remediation in addition to vocational rehabilitation can improve cognitive functioning and employment outcomes for individuals with severe mental illness. Comorbid substance abuse impacts work outcomes while medical comorbidity does not. More research is needed to evaluate the impact of comorbidity and their interaction on treatment. More research is needed to evaluate the impact of comorbidity on work functioning in VR and its interaction with cognitive remediation.

Disabilities Emotional disturbance
Populations Hispanic or Latino | American Indian or Alaska Native | Asian | Black / African American | Male & Female
Outcomes Employment acquisition | Return to work
Research Design Randomized Controlled Trials (RCTs)
Peer Reviewed Yes