Date Published: April 15, 2016
Publisher: Public Library of Science
Author(s): Claudia J. P. Simons, Agna A. Bartels-Velthuis, Gerdina H. M. Pijnenborg, Ruud van Winkel.
Studies have linked cognitive functioning to everyday social functioning in psychotic disorders, but the nature of the relationships between cognition, social cognition, symptoms, and social functioning remains unestablished. Modelling the contributions of non-social and social cognitive ability in the prediction of social functioning may help in more clearly defining therapeutic targets to improve functioning.
In a sample of 745 patients with a non-affective psychotic disorder, the associations between cognition and social cognition at baseline on the one hand, and self-reported social functioning three years later on the other, were analysed. First, case-control comparisons were conducted; associations were subsequently further explored in patients, investigating the potential mediating role of symptoms. Analyses were repeated in a subsample of 233 patients with recent-onset psychosis.
Information processing speed and immediate verbal memory were stronger associated with social functioning in patients than in healthy controls. Most cognition variables significantly predicted social functioning at follow-up, whereas social cognition was not associated with social functioning. Symptoms were robustly associated with follow-up social functioning, with negative symptoms fully mediating most associations between cognition and follow-up social functioning. Illness duration did not moderate the strength of the association between cognitive functioning and follow-up social functioning. No associations were found between (social) cognition and follow-up social functioning in patients with recent-onset psychosis.
Although cognitive functioning is associated with later social functioning in psychotic disorder, its role in explaining social functioning outcome above negative symptoms appears only modest. In recent-onset psychosis, cognition may have a negligible role in predicting later social functioning. Moreover, social cognition tasks may not predict self-reported social functioning.
Although there is some variability in the literature, most studies suggest psychotic disorder is characterized by a stable, diminished performance on the majority of cognitive domains [1,2], which presents itself before the onset of psychosis, and becomes more pronounced around the first psychotic episode, so that cognitive performance drops from approximately 0.5 SD below the healthy control mean in the prodromal stage to 1 to 2 SD below the healthy control mean in the first episode [3,4]. However, the exact course and pattern of alteration in cognitive functioning, and its relationship to functional outcome, remain unclear.
We examined longitudinal associations between cognition, social cognition and social functioning in a large sample of patients with a psychotic disorder. A longitudinal association with three-year follow-up social functioning was found for most cognitive variables, with information processing speed and verbal memory immediate recall showing stronger associations with social functioning outcome in patients compared with healthy controls. Thus, the findings tentatively suggest that cognitive functioning may be a predictor for social functioning. Of all cognitive variables, information processing speed showed the largest association with social functioning (r = 0.22). The latter finding is in line with previous literature . However, the proportion of the variance in social functioning that was explained by baseline cognitive functioning (<5%) or by the model of baseline cognitive functioning and negative symptoms (approximately 15%) is smaller than previous estimates of 25–50% as proportion of the variance that was explained by neurocognition alone, but larger than the percentage of 7.3% that was reported by Couture and colleagues for the model that included neurocognition as well as negative symptoms. At a cross-sectional level, cognitive functioning, associations between cognition and social functioning were larger than at the longitudinal level, but the proportion of the variance explained is still considerably smaller than the previous estimate of 25–50%. These findings are in line with Jabben and colleagues  who found weak cross-sectional associations between information processing speed in the absence of specific and unconfounded longitudinal associations. Also, most cognitive measures did not uniquely contribute to the explained variance, as results showed that symptoms and particularly negative symptoms −in line with previous literature [14,16,17,45]− meditated the association between cognitive functioning and social functioning. This may imply that factors such as a motivational deficits, social withdrawal, and impaired initiative may be underlying variables in the association between cognition and social functioning, which is in line with a previous study  suggesting that levels of intrinsic motivation are robustly and reliably associated with performance on cognitive tests, suggesting that shared motivation-cognition mechanisms should be investigated to enhance efforts to improve social functioning. In contrast to the other cognitive variables that were fully mediated by negative symptoms, information processing speed and attention/vigilance were only partly mediated and thus explained some of the variance in social functioning over and above negative symptoms. Source: http://doi.org/10.1371/journal.pone.0151299