Cognitive remediation has emerged as an effective method for ameliorating the cognitive deficits associated with schizophrenia that undermine functional recovery (13
). Short-term trials conducted with childhood/early-onset patients focusing on neurocognitive dysfunction have suggested the potential benefits of cognitive remediation at the earliest stages of the illness (14
). To our knowledge, this is the first study to examine the long-term effects of a comprehensive neurocognitive and social-cognitive rehabilitation program on broad domains of cognition and functioning when applied in early schizophrenia. Results from this two-year trial broadly support our hypotheses that CET would improve cognitive and behavioral outcomes among this population. Individuals receiving CET demonstrated substantial cognitive gains during the two years of treatment, particularly in social cognition, where a broad array of social-cognitive improvements were found on multiple performance-based and clinician-rated measures. Most importantly, while specific mediator analyses are needed and will be the focus of subsequent reports, these cognitive gains appear to have translated into significant reductions in disability. Individuals in CET exhibited marked improvements in employment, social functioning, and global adjustment, as well as reductions in negative symptoms compared to their EST counterparts. These effects, which could not be accounted for by group differences in antipsychotic medication use or differential rates of attrition, highlight the potential functional benefits of sufficient exposure to early cognitive rehabilitation in schizophrenia.
It is important to note that the largest cognitive effects observed during CET were in social cognition, a domain that has been linked to functional outcome (37
) and remained largely unresponsive to pharmacological treatment (38
). While neurocognitive effects were moderate in size, it was surprising that early course patients receiving CET did not show any significant improvement in processing speed, which is in contrast to our previous study with long-term patients (19
). Comparison of average processing speed scores between this early course sample and those in our previous study indicated that early course patients performed significantly better on every measure of processing speed at baseline compared to chronic patients, all t
< −2.96, all df
= 56, all p
< .005. In fact, the pre-treatment means of individuals receiving CET in this study were comparable to the processing speed of chronic patients after two years of CET treatment (19
), pointing to the possibility of a ceiling effect for speed of processing. That processing speed and other aspects of attention are less impaired among early course patients is not novel (6
), and this research suggests that more complex social-cognitive processes may be the most critical targets for early intervention programs. CET may serve as a key adjunct to pharmacotherapy in this regard.
Despite the efficacy of CET for improving cognition and behavior among early course patients, the results of this research need to be interpreted in the context of a number of limitations. The patients studied were mostly male and Caucasian, and the results of this investigation may not generalize to more diverse samples. Treatment groups were also not matched for the number of hours of clinician contact, therefore results could reflect the non-specific effects of increased clinician contact on outcome. In addition, assessing clinicians were not blind to the treatments to which patients were assigned. As such, rater bias cannot be ruled out as a possible explanation for treatment effects. However, effects on performance-based measures of social cognition were equally strong as clinician-rated measures; and social adjustment effects were seen on an array of different measures, many of which leave little room for rater bias (e.g., employment - although employment data did rely largely on self-report). Further, robust neurocognitive effects were also found on performance-based measures of cognition, arguing against a substantial rater bias.
Increased familiarity with computerized testing associated with CET exposure may also explain some improvements in performance on computer-based neuropsychological tests. However, CET effects on neurocognition were seen primarily on paper and pencil examinations that bear little resemblance to computerized training software, suggesting that while it is possible CET influenced test-taking behavior in general, it is less likely that differential neurocognitive improvement favoring CET was the result of enhanced computer literacy or familiarity. In addition, within-composite analyses need to be interpreted with caution, as while a hierarchical approach was used to avoid excessively inflating Type I error, multiple univariate tests were conducted on within-composite measures. Finally, this research was characterized by a somewhat modest sample size (n
= 58), which may have precluded the detection of smaller treatment effects. However, to our knowledge this is the largest and longest early course study of cognitive rehabilitation to date, and our results indicate that our a priori
power analyses based on previous studies (19
) guided us toward a sample size that was sufficient to reliably detect the medium to large CET effects observed in this study. Consequently, it would appear that a sufficient number of individuals were studied to provide an adequate evaluation of the efficacy of CET in early schizophrenia. A one-year post-treatment follow-up study is currently being completed to ascertain the durability of these effects and determine whether they are comparable to the sustained benefits achieved by chronic patients (20