Investigation of the role of the jumping-to-conclusions bias for short-term functional outcome in schizophrenia
Introduction
Schizophrenia is a severe disorder compromising multiple aspects of everyday functioning and well-being, such as independent living, interpersonal relations and vocational functioning (Green et al., 2004, Couture et al., 2006, Fett et al., 2011). These impairments often persist even after successful pharmacological treatment of psychotic symptoms (Hofer et al., 2006, Leifker et al., 2009). In light of low recovery rates in the disorder (Jaaskelainen et al., 2013), a growing body of research is devoted to understanding the factors associated with functional disability in schizophrenia, in the hope of developing interventions to improve functional recovery and quality of life (Andreasen et al., 2005, Green, 2007, Harvey and Penn, 2010, McDowd et al., 2011).
Several factors have been identified that affect various dimensions of functional outcome and quality of life in schizophrenia. These include premorbid functioning (Hofer et al., 2006), neuropsychological deficits (Green, 1996, Green, 2006), deficits in social cognition (Fett et al., 2011), and severity of psychopathology (Addington and Addington, 1993, Hofer et al., 2006, Ventura et al., 2009). However, the relative importance of these factors is not clear yet (McDowd et al., 2011), possibly depending on the specific patient sample characteristics and functional outcome measures implemented, which differ across various dimensions (e.g. self-report vs. observer-rated).
While the impact of neurocognitive deficits on outcome has been in the spotlight of a large body of research, to the best of our knowledge no study examined whether cognitive biases moderate outcome. Cognitive biases are distortions in the acquisition, processing and interpretation of information, and are implicated in the formation and/or maintenance of delusions (Garety and Freeman, 1999, Moritz et al., 2004, Bell et al., 2006, van der Gaag, 2006). The first one of these biases to be observed, and the best one studied so far, is the jumping-to-conclusions bias, i.e. the tendency of patients to arrive at a conclusion based on limited evidence. It is thought to constitute a trait characteristic of schizophrenia (Peters and Garety, 2006, So et al., 2012), but might also be amenable to specific metacognitive interventions (Moritz et al., 2011, Moritz et al., 2013, Ross et al., 2011, Waller et al., 2011). More importantly, there is some evidence that the latter interventions can lead to improvement of positive symptoms (Aghotor et al., 2008, Moritz et al., 2011, Favrod et al., 2014, Moritz et al., 2013) as well as quality of life (Moritz et al., 2011) in patients with schizophrenia, rendering the jumping-to-conclusions bias especially interesting for research into the outcome of the disorder. So far, the impact of the jumping-to-conclusions bias on the functional outcome and quality of life in patients with schizophrenia has not been investigated. It is possible that the positive effects of metacognitive interventions on quality of life are simply a by-product of symptom improvement, but this does not necessarily have to be the case: Hasty decision-making may foster problems in work and social contexts, since ignoring important evidence and cues might result in serious misjudgements. This effect might be more pronounced in individuals who lack awareness for their cognitive biases, such as patients with schizophrenia (Freeman et al., 2006). Thus, it is conceivable that jumping-to-conclusions has also an independent effect on functioning, over and beyond its association with symptoms.
The present study aimed to assess the relative contribution of the jumping-to-conclusions bias and other well-established factors, including psychopathology and neuropsychological deficits, to subjective and vocational outcomes after an acute psychotic exacerbation in patients with schizophrenia. One important methodological consideration was that most existing studies have either investigated correlates of functional outcome cross-sectionally (e.g. Addington and Addington, 1999, Dickerson et al., 1999b, Dickinson and Coursey, 2002, Hofer et al., 2006, Brekke et al., 2007, Lipkovich et al., 2009), or used baseline scores of the investigated variables to predict future outcomes (e.g. Dickerson et al., 1999a, Norman et al., 1999, Addington and Addington, 2000, Suslow et al., 2000, Velligan et al., 2000, Kurtz et al., 2005, Brekke et al., 2007, Lipkovich et al., 2009) – for extensive reviews on the subject, see (Green et al., 2004, Ventura et al., 2009). However, a question that might have significant implications in terms of shaping treatment priorities is how changes of predictor variables in the course of treatment dynamically affect changes in psychosocial functioning and quality of life. To our knowledge, only one study (Mohamed et al., 2008) has dealt with this question so far by assessing the effects of symptoms and neuropsychological deficits on quality of life over the course of treatment.
In the present study, we aimed to investigate the relative contribution of clinical and neuropsychological deficits, but also of jumping-to-conclusions and Theory-of-Mind, to subjective quality of life as well as vocational outcome and living status, both cross-sectionally at baseline, as well as longitudinally over the course of symptomatic improvement. As delineated above, we had reason to expect that jumping-to-conclusions might be associated with functional outcome and/or quality of life. However, we refrained from specific hypotheses regarding the exact nature of this contribution. Given that the jumping-to-conclusions bias is associated with symptoms, and has also recently been linked to working memory deficits (Garety et al., 2013), it was not possible to predict whether this cognitive bias would have a unique, independent effect on the outcome variables.
Section snippets
Participants
Participants were patients with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder undergoing an acute psychotic exacerbation. Patients were selected among participants of a randomized controlled trial of two non-pharmacological interventions as adjunctive treatments in patients with psychotic disorders – a metacognitive intervention addressing cognitive biases, and cognitive remediation training focusing on more elementary neuropsychological functions such as attention and memory (
Results
Results of the cross-sectional analyses are presented on Table 3. PANSS positive scores were a significant predictor of most WHOQOL-Bref domains with the exception of “environment”, for which disorganization scores were a significant predictor. Verbal memory scores were a significant predictor for overall health satisfaction and the WHOQOL domains “physical health” and “environment”. Gender also emerged as a significant predictor for overall quality of life and health satisfaction, with female
Discussion
The present study investigated predictors of subjective and vocational outcome in patients with schizophrenia and schizoaffective disorder, both cross-sectionally and longitudinally. In the cross-sectional analyses, positive and disorganization symptoms and verbal memory were the most significant correlates of subjective outcome, whereas none of the examined variables was significantly associated with vocational outcome or living status. On the other hand, the course of subjective quality of
Conflict of interest
None.
Acknowledgments
This work was supported by a grant from the Clinical Trial Program of the German Research Foundation (Deutsche Forschungsgemeinschaft; Mo 969/6-1).
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