Cognitive Remediation in Schizophrenia: Current Status and Future Perspectives

Table 2

Meta-analyses of the efficacy of cognitive remediation in schizophrenia.

Authors	Types of study	Number of included studies (number of patients)	Main investigated areas	Cognitive remediation program	Clinical outcomes (average effect size*)	Neurocognitive outcomes (average effect size*)	Functional outcomes (average effect size*)	Main findings
Kurtz et al. [25]	RCT and laboratory studies	11 (181)	Executive functions (performance on WCTS) Attention Memory	Remediation strategies for improving performance on WCST	Not investigated	Improvement in executive functions: large mean ES (𝑑=0.98) Attention: mixed results Memory: nonconclusive results	Not investigated	Perseverative errors, categories achieved, and conceptual level responses can be improved utilizing extra instructions, repeated practice, or reinforcement
Twamley et al. [30]	RCT	17 (695)	Symptoms, cognitive performance and functioning	Computer assisted and noncomputer assisted, with and without strategy coaching and compensatory strategies	Reduction in symptom severity: small-to-medium ES (𝑑=0.26)	Improvement in neuropsychological performance: small-to-medium ES (𝑑=0.32)	Improvement in everyday functioning: small-to-medium ES (𝑑=0.51)	Both different types of approaches, computer assisted or not, have effective components that hold promise for improving cognitive performance, symptoms, and everyday functioning
Roder et al. [28]	RCT and open studies	30 independent; IPT studies (1393)	Symptoms, cognitive performance, and functioning	IPT (a group program that integrates neurocognitive, social cognitive, and psychosocial rehabilitation)	Reduction in symptom severity: moderate ES (𝑑=0.50)	Improvement in neuropsychological performance: moderate ES (𝑑=0.54)	Improvement in psychosocial functioning: moderate ES; (𝑑=0.41)	IPT obtained similarly favorable effects across the different outcome domains, assessment formats, settings, and phases of treatment
McGurk et al. [27]	RCT	26 (1151)	Symptoms, cognitive performance, and functioning	Individual versus group setting, computer versus noncomputer assisted, with and without strategy coaching, compensatory strategies, and social cognitive training	Reduction in symptom severity: small ES (𝑑=0.28)	Improvement in cognitive performance: medium ES (𝑑=0.41)	Improvement in psychosocial functioning: small-to-medium ES (𝑑=0.35)	The impact of cognitive remediation on functional outcomes is significantly greater in studies that also provided psychiatric rehabilitation, suggesting that these two treatment approaches may work in a synergistic way
Grynszpan et al. [24]	RCT	16 (805)	Cognitive performance and social cognition	Computer-assisted cognitive remediation (CACR)	Not investigated	Improvement in general cognition: small-to-moderate ES (𝑑=0.38); Improvement in social cognition: moderate ES (𝑑=0.64)	Not investigated	The results support the efficacy of CACR particularly in social cognition. The difficulty in targeting specific domains suggests a “nonspecific” effect of CACR
Wykes et al. [31]	RCT	40 (2104)	Symptoms, cognitive performance, and functioning	Individual versus group setting, computer versus noncomputer assisted, with and without strategy coaching, compensatory strategies, and social cognitive training	Reduction in symptom severity: small ES (𝑑=0.18), but no longer significant at followup	Improvement in global cognitive performance: moderate ES (𝑑=0.45); Improvement in social cognition moderate ES (𝑑=0.65)	Improvement in psychosocial functioning: moderate ES; (𝑑=0.42)	Significantly stronger effects on functioning are found when CR is provided together with another psychiatric rehabilitation. A much larger effect is present when a strategic approach is adopted
Roder et al. [29]	RCT and open studies	36 independent IPT studies (1601)	Symptoms, cognitive performance, social cognition, and functioning	IPT	Reduction in symptom severity: moderate ES (𝑑=0.52)	Improvement in neuropsychological performance: moderate; ES (𝑑=0.53); Improvement in social cognition: moderate-to-large ES (𝑑=0.70)	Improvement in psychosocial functioning: moderate ES; (𝑑=0.42)	The cognitive and social subprograms of IPT may work in a synergistic manner, thereby enhancing the transfer of therapy effects over time and improving functional recovery
Kurtz and Richardson [26]	RCT	19 (692)	Social cognition, symptoms, and community and institutional functioning	Social cognitive training	Reduction in symptoms: moderate-to-large ES (𝑑=0.68); No significant effect on positive and negative symptoms	Improvement in social cognition: (i) moderate-to-large ES on FAR: identification; (𝑑=0.71) and discrimination (𝑑=1.01),; (ii) small-to-moderate ES on ToM (𝑑=0.46); No significant effect on social cue perception and attributional style	Improvement in psychosocial functioning: moderate-to-large ES (𝑑=0.78)	This is the first meta-analysis on social cognitive training in schizophrenia. Social cognitive training is effective in improving community and institutional functioning

CR: cognitive remediation; ES: effect size (Cohen’s 𝑑); FAR: facial affect recognition; RCT: randomized controlled trials; WCST: Wisconsin Card Sorting Test.
*Effects were categorized as small (𝑑<0.5), moderate-large (𝑑=0.5–0.8), or large (𝑑>0.8 or greater) [75].