https://cris.maastrichtuniversity.nl/ws/files/64205713/viechtbauer_2011_the_relationship_between_neurocognition_and.pdf

The relationship between neurocognition and social cognition with functional outcomes in schizophrenia: a meta-analysis.

Identification of separable cognitive factors in schizophrenia.

Context In focusing on potentially localizable cognitive impairments, the schizophrenia meta-analytic literature has overlooked the largest single impairment: on digit symbol coding tasks. Objective To compare the magnitude of the schizophrenia impairment on coding tasks with impairments on other traditional neuropsychological instruments. Data Sources MEDLINE and PsycINFO electronic databases and reference lists from identified articles. Study Selection English-language studies from 1990 to present, comparing performance of patients with schizophrenia and healthy controls on coding tasks and cognitive measures representing at least 2 other cognitive domains. Of 182 studies identified, 40 met all criteria for inclusion in the meta-analysis. Data Extraction Means, standard deviations, and sample sizes were extracted for digit symbol coding and 36 other cognitive variables. In addition, we recorded potential clinical moderator variables, including chronicity/severity, medication status, age, and education, and potential study design moderators, including coding task variant, matching, and study publication date. Data Synthesis Main analyses synthesized data from 37 studies comprising 1961 patients with schizophrenia and 1444 comparison subjects. Combination of mean effect sizes across studies by means of a random effects model yielded a weighted mean effect for digit symbol coding of g  = −1.57 (95% confidence interval, −1.66 to −1.48). This effect compared with a grand mean effect of g  = −0.98 and was significantly larger than effects for widely used measures of episodic memory, executive functioning, and working memory. Moderator variable analyses indicated that clinical and study design differences between studies had little effect on the coding task effect. Comparison with previous meta-analyses suggested that current results were representative of the broader literature. Subsidiary analysis of data from relatives of patients with schizophrenia also suggested prominent coding task impairments in this group. Conclusion The 5-minute digit symbol coding task, reliable and easy to administer, taps an information processing inefficiency that is a central feature of the cognitive deficit in schizophrenia and deserves systematic investigation.

https://jamanetwork.com/journals/jamapsychiatry/articlepdf/482291/yoa60086_532_542.pdf

Overlooking the obvious: a meta-analytic comparison of digit symbol coding tasks and other cognitive measures in schizophrenia.

Objective:Research and clinical translation in schizophrenia is limited by inconsistent definitions of treatment resistance and response. To address this issue, the authors evaluated current approaches and then developed consensus criteria and guidelines.Method:A systematic review of randomized antipsychotic clinical trials in treatment-resistant schizophrenia was performed, and definitions of treatment resistance were extracted. Subsequently, consensus operationalized criteria were developed through 1) a multiphase, mixed methods approach, 2) identification of key criteria via an online survey, and 3) meetings to achieve consensus.Results:Of 2,808 studies identified, 42 met inclusion criteria. Of these, 21 studies (50%) did not provide operationalized criteria. In the remaining studies, criteria varied considerably, particularly regarding symptom severity, prior treatment duration, and antipsychotic dosage thresholds; only two studies (5%) utilized the same criteria. The consensus group identified minimu...

Treatment-Resistant Schizophrenia: Treatment Response and Resistance in Psychosis (TRRIP) Working Group Consensus Guidelines on Diagnosis and Terminology.

Until recently, the dominant view was that schizophrenia patients have limited, if any, neuropsychological impairments, and those that are observed are only secondary to the florid symptoms of the disorder. This view has dramatically changed. This review integrates recent evidence demonstrating the severity and profile of neuropsychological impairments in schizophrenia. We present quantitative evaluation of the literature demonstrating that the most severe impairments are apparent in episodic memory and executive control processes, evident on a background of a generalized cognitive deficit. The neuropsychological impairments potentially represent genetic liability to the disorder, as similar, yet milder, impairments are evident in schizophrenia patients even before the onset of psychotic symptoms, as well as in the nonpsychotic relatives of schizophrenia patients. Corresponding cognitive neuroimaging literature on executive functions, episodic memory, and working memory in schizophrenia documenting abnormalities in frontal and medial temporal lobes is summarized, and current models integrating neuropsychological and neuroimaging data are discussed.

Leigh Coughenour

Papers

The Brief Assessment of Cognition in Schizophrenia: reliability, sensitivity, and comparison with a standard neurocognitive battery.

Brief Assessment of Cognition in Schizophrenia