Neurocognitive and social cognitive predictors of interpersonal skill in schizophrenia

Abstract

Social dysfunction is among the major criteria for receiving a diagnosis of schizophrenia, and research indicates that the impairments in social functioning experienced by individuals with schizophrenia are strongly related to deficits in interpersonal skills. In turn, these deficits in interpersonal skills have been linked to impairments in general cognitive abilities and impairments in social cognition. This study explored the relationship between neurocognition, social cognition, and interpersonal skills in 49 outpatients with schizophrenia and 44 non-clinical control participants. Results indicate that individuals with schizophrenia demonstrated impaired performance across several domains of neurocognitive and social cognitive functioning as well as interpersonal skills. In addition, among the participants with schizophrenia, social cognition significantly contributed unique variance to interpersonal skill beyond that of neurocognition. This pattern was not observed in the non-clinical control sample. These findings have implications for the treatment of the disorder and represent an important step in understanding the role of social cognition in schizophrenia.

Introduction

Individuals with schizophrenia experience difficulties in multiple areas of social functioning including interpersonal relationships, work and personal achievement, finances, and self-care (Corrigan and Penn, 2001). These difficulties in social functioning have been linked to deficits in social/interpersonal skill. For instance, Bellack et al. (1990) reported that social dysfunction in schizophrenia may result from focal deficits in interpersonal skill rather than negative symptoms. In addition, several studies have demonstrated that individuals with schizophrenia show deficits in interpersonal skills compared with non-clinical controls (Fingeret et al., 1985, Donahoe et al., 1990, Mueser et al., 1991, Ikebuchi et al., 1999), and these deficits are not improved by medication alone (Bellack et al., 2004).

The identification of interpersonal skill deficits in individuals with schizophrenia has prompted an examination of factors that may underlie poor social functioning. One area that has received considerable attention is that of neurocognition. In particular, deficits in memory, attention, and cognitive flexibility are related to difficulties in problem solving (Green et al., 2000, Hatashita-Wong et al., 2002), and deficits in executive functioning, memory, and verbal fluency are related to poorer community living skills (Bartels et al., 1997, Green et al., 2000). Finally, neurocognitive deficits are related to impairments in interpersonal skills (Penn et al., 1995). Overall, the findings suggest that neurocognition explains between 20% and 60% of the variance in the functional outcomes of individuals with schizophrenia (Green et al., 2000).

Although neurocognitive models have contributed to the understanding of social dysfunction in schizophrenia, they are not without limitations. First, even though neurocognition accounts for a significant amount of variance in social functioning, a fair amount of variance in social outcome remains unexplained (i.e., between 40% and 80%; Penn et al., 1997, Corrigan and Penn, 2001). Second, there may be other domains of cognition, more proximal to actual social behavior, than those assessed by traditional neurocognitive paradigms. One such domain is social cognition.

Social cognition refers to the cognitive processes involved in how individuals perceive, interpret, or process social information and include “the human ability and capacity to perceive the intentions and dispositions of others” (Brothers, 1990, p. 28). In schizophrenia research, early work exploring social cognition investigated emotion perception (Dougherty et al., 1974), theory of mind (ToM; Frith, 1992), attributional style (Kaney and Bentall, 1989, Bentall et al., 1991), and knowledge of social situations (Corrigan et al., 1990, Corrigan and Addis, 1995), and these domains remain the cornerstones of studies of social cognition in schizophrenia (reviewed in Penn et al., in press). Although neurocognition and social cognition are related in schizophrenia (Bryson et al., 1997, Kee et al., 1998, Lancaster et al., 2003), there is also evidence from both clinical and non-clinical samples that neural activation and neural pathways for neurocogniton and social cognition are separable (for reviews, see Adolphs, 2001, Pinkham et al., 2003). This dissociation suggests that these domains are not overlapping, and that social cognition may enhance our understanding of social dysfunction in schizophrenia.

There is growing evidence that social cognition may contribute variance beyond cognition to social functioning in schizophrenia (Corrigan and Toomey, 1995, Penn et al., 1996, Ihnen et al., 1998, Roncone et al., 2002, Brüne, 2005). However, previous work in this area has generally not examined social cognition as a multidimensional construct. As mentioned previously, social cognition includes a vast array of abilities (i.e., emotion perception, social knowledge, and ToM), and with one exception in which both emotion perception and ToM were explored (Brüne, 2005), studies that have examined social cognition have usually focused on only one of these abilities at a time. Because of this, it is difficult to determine which social cognitive factors are most strongly related to social functioning. Likewise, few studies have investigated whether the association between neurocognition and social cognition with social functioning differs across clinical and non-clinical samples. Such differences are worth examining because they may provide additional information about the nature of the disorder.

The primary purpose of this study was to examine the relationships between neurocognition, social cognition, and interpersonal skill in schizophrenia. Consistent with previous research, it was hypothesized that individuals with schizophrenia would show impairments in all social cognitive domains and would also be less interpersonally skilled than non-clinical controls. Second, it was hypothesized that social cognitive factors would contribute significant incremental variance, beyond that of neurocognition, to a model predicting interpersonal skill. Third, based on previous research from our laboratory (Penn et al., 1993), it was predicted that the patterns of overall variance accounted for by neurocognition and social cognition would differ between groups. Finally, the last goal, which was exploratory in nature, was to isolate the domain of social cognition that contributed the most variance to interpersonal skill.