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Compensatory cognitive training for people with severe mental illnesses in supported employment: A randomized controlled trial (Twamley et al., 2019)

Absence of conflict of interest. 

Citation

Twamley, E. W., Thomas, K. R., Burton, C. Z., Vella, L., Jeste, D. V., Heaton, R. K., & McGurk, S. R. (2019). Compensatory cognitive training for people with severe mental illnesses in supported employment: A randomized controlled trial. Schizophrenia Research 203, 41-48.

Highlights

  • The study’s objective was to examine the impact of Compensatory Cognitive Training (CCT) on attaining competitive employment, weeks worked, wages earned, mental illness symptom severity, and cognitive functioning. 

  • The study was a randomized controlled trial that used work outcome data collected by employment specialists or study staff and other outcome data collected from participants at baseline and follow-up visits.  

  • The study suggested that CCT program participants had less severe depressive symptoms and had higher working memory scores than comparison group participants did three months after the intervention. However, there was no statistically significant relationship between CCT and these outcomes longer-term or between CCT and any of the other outcomes either short-term or longer-term. 

  • The quality of causal evidence presented in this report is low because one employment specialist delivered CCT to the treatment group while another employment specialist provided services to the comparison group. As a result, the effect of CCT cannot be disentangled from the effect of receiving services from a specific employment specialist. This means we are not confident that the estimated effects are attributable to CCT; other factors are likely to have contributed. 

Intervention Examined

Compensatory Cognitive Training (CCT)

Features of the Intervention

Cognitive training interventions aim to help individuals with cognitive impairments compensate for difficulties with processing speed, attention, working memory, and executive functioning, thereby improving individuals’ everyday functioning and vocational outcomes. Cognitive training interventions have been tested primarily with patients who have schizophrenia disorders and have been tested both separately from and in conjunction with employment interventions. This study involved a 12-session compensatory strategy-based intervention to address prospective memory (remembering to do things), conversational and task vigilance, learning, and executive function in the context of supported employment. A master’s-level employment specialist delivered CCT individually to participants in 12 one-hour CCT sessions.

Features of the Study

This study was a randomized controlled trial in which individuals were randomized to the intervention group who received CCT in the context of supported employment (77 participants) or to the comparison group who received Enhanced Supported Employment only (76 participants). To be eligible for the study, individuals had to be adult outpatients with severe mental illness who had been unemployed for at least one month but had a goal of working, who were literate and fluent in English, and who did not have dementia or an intellectual disability.  

On average, participants were 44 years old. Forty-three percent of participants were female, and 38 percent identified as being from a racial/ethnic minority. Participants had experienced mental illness for an average of 24 years and were recruited via clinician referrals from the University of California, San Diego.  

CCT was delivered within the context of an employment intervention, Individual Placement and Support (IPS). IPS focuses on rapid, individualized help searching for competitive employment paired with follow-along mental health and employment services for an unlimited amount of time. In this case, supported employment services were available to both groups as needed for two years (the duration of the study). A different master’s-level employment specialist provided services to the comparison group. During the first 12 weeks of the study when the intervention group was receiving CCT, the comparison group was assigned to receive one extra supported employment session per week.  

Employment and earnings outcomes were collected weekly by the employment specialist or by a study rater. Other outcomes come from assessments conducted at baseline and quarterly for the first year; the symptom severity outcomes were also collected at 18- and 24-month follow-ups. Competitive work was defined as work that paid at least minimum wage and was not set aside for individuals with disabilities. Individuals who dropped out of the study were coded as not working for the duration of the study. Two standardized assessments were used to measure the severity of positive and negative psychosis symptoms (PANSS measures) and of depressive symptoms (HAM-D).  The MATRICS Consensus Cognitive Battery, along with supplemental standardized assessments, was used for the cognitive functioning measures; using these assessments, the authors created composite scores in the domains of processing speed, working memory, learning/memory, and executive functioning. The Continuous Performance Test - Identical Pairs (CPT-IP) was used to measure sustained attention and the Memory for Intentions Screening Test (MIST) was used to measure prospective memory.  

For the employment and earnings outcomes, the authors used t-tests to compare the two groups. For the remaining outcomes, the authors used analyses of covariance (ANCOVA) to compare changes from baseline to three months for the two groups and used hierarchical linear models to examine changes over time from baseline to 12- or 24-months depending on the outcomes. These analytic models controlled for diagnosis, age, education, gender, minority status, and the interaction of intervention group by diagnosis. 

Findings

Employment

  • The study found no statistically significant relationship between CCT and attaining competitive employment or the number of weeks worked during the two-year study period. 

Earnings and wages

  • The study found no statistically significant relationship between CCT and total wages earned during the two-year study period. 

Health and safety

  • The study found no statistically significant relationship between CCT and PANSS positive or negative syndrome scales, either short-term (three months post-intervention) or longer-term. The study suggested that CCT program participants had lower depressive symptom severity scores (as measured by the HAM-D) three months post-intervention than comparison group participants did. However, there was no relationship between CCT and HAM-D scores longer-term. 

Education and skills gains

  • The study found no statistically significant relationship between CCT and five of the six measures of cognitive functioning, either short-term (three months post-intervention) or longer-term. The study suggested that CCT program participants had higher working memory scores three months post-intervention than comparison group participants did. However, there was no relationship between CCT and working memory scores longer-term. 

Considerations for Interpreting the Findings

A single employment specialist delivered CCT to the treatment group, while a different employment specialist delivered services to the comparison group. As a result, the effect of CCT cannot be disentangled from the effect of receiving services from a specific person. 

Causal Evidence Rating

The quality of causal evidence presented in this report is low because the effect of CCT cannot be disentangled from the effect of receiving services from the specific person who provided services in this study. This means we are not confident that the estimated effects are attributable to CCT; other factors are likely to have contributed. 

Reviewed by CLEAR

November 2022