There has been a surge of interest in the functional consequences of neurocognitive deficits in schizophrenia. The published literature in this area has doubled in the last few years. In this paper, we will attempt to confirm the conclusions from a previous review that certain neurocognitive domains (secondary verbal memory, immediate memory, executive functioning as measured by card sorting, and vigilance) are associated with functional outcome. In addition to surveying the number of replicated findings and tallying box scores of results, we will approach the review of the studies in a more thorough and empirical manner by applying a meta-analysis. Lastly, we will discuss what we see as a key limitation of this literature, specifically, the relatively narrow selection of predictor measures. This limitation has constrained identification of mediating variables that may explain the mechanisms for these relationships.
The Posttraumatic Stress Disorder Checklist (PCL-5; Weathers et al., 2013) was recently revised to reflect the changed diagnostic criteria for posttraumatic stress disorder (PTSD) in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; American Psychiatric Association, 2013). We investigated the psychometric properties of PCL-5 scores in a large cohort (N = 912) of military service members seeking PTSD treatment while stationed in garrison. We examined the internal consistency, convergent and discriminant validity, and DSM-5 factor structure of PCL-5 scores, their sensitivity to clinical change relative to PTSD Symptom Scale-Interview (PSS-I; Foa, Riggs, Dancu, & Rothbaum, 1993) scores, and their diagnostic utility for predicting a PTSD diagnosis based on various measures and scoring rules. PCL-5 scores exhibited high internal consistency. There was strong agreement between the order of hypothesized and observed correlations among PCL-5 and criterion measure scores. The best-fitting structural model was a 7-factor hybrid model (Armour et al., 2015), which demonstrated closer fit than all other models evaluated, including the DSM-5 model. The PCL-5's sensitivity to clinical change, pre- to posttreatment, was comparable with that of the PSS-I. Optimally efficient cut scores for predicting PTSD diagnosis were consistent with prior research with service members (Hoge, Riviere, Wilk, Herrell, & Weathers, 2014). The results indicate that the PCL-5 is a psychometrically sound measure of DSM-5 PTSD symptoms that is useful for identifying provisional PTSD diagnostic status, quantifying PTSD symptom severity, and detecting clinical change over time in PTSD symptoms among service members seeking treatment. (PsycINFO Database Record
Clinical researchers often propose (or review committees demand) pilot studies to determine whether a study is worth performing and to guide power calculations. The most likely outcomes are that (1) studies worth performing are aborted and (2) studies that are not aborted are underpowered. There are many excellent reasons for performing pilot studies. The argument herein is not meant to discourage clinical researchers from performing pilot studies (or review committees from requiring them) but simply to caution against their use for the objective of guiding power calculations.
The changes in white matter suggest that the adult brain is in a constant state of change roughly defined as periods of maturation continuing into the fifth decade of life followed by degeneration. Pathological states that interfere with such maturational processes could result in neurodevelopmental arrests in adulthood.
Co-norming a battery such as the MATRICS Consensus Cognitive Battery, comprising tests from independent test developers each with their own set of norms, facilitates valid interpretation of test scores and communication of findings across studies. These normative data will aid in estimating the magnitude of change during clinical trials of cognition-enhancing agents and make it possible to derive more directly interpretable composite scores.
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