Anticipatory pleasure and approach motivation in schizophrenia-like negative symptoms

Abstract

Previous research of negative symptoms in schizophrenia has emphasized an anticipatory pleasure deficit, yet the relationship of this deficit to patients' motivation in everyday life is poorly understood. This study tested the link between anticipatory pleasure and two broad motivational systems that are said to regulate the intensity of approach and avoidance behavior, the Behavioral Inhibition system (BIS) and the Behavioral Activation System (BAS). It was hypothesized that high vulnerability for negative symptoms would be associated with low reward responsiveness and that this association will be mediated by the amount of anticipated pleasure. Students (n=171) with varying vulnerability for negative symptoms (assessed by the Community Assessment of Psychic Experiences) completed questionnaires regarding (a) anticipatory and consummatory pleasure, and (b) responsiveness to threat and reward. As hypothesized, anticipatory pleasure correlated significantly negatively with subclinical negative symptoms (r=−0.21) and significantly positively with BAS (r=0.55). Furthermore, evidence for a partial mediation effect was found. The findings support the notion of a close association between negative symptoms, the ability to anticipate pleasure and approach motivation that is evident even in healthy persons. It is suggested that the behavioral deficits immanent to negative symptoms reflect difficulties in the ability to translate emotions into motivation.

Introduction

Anhedonia, defined as diminished ability to experience positive emotions (Germans and Kring, 2000) is central in patients with negative symptoms of schizophrenia (Horan et al., 2006, Mäkinen et al., 2008). It impairs patients' engagement in everyday activities and strongly affects quality of life (Rector et al., 2005, Mäkinen et al., 2008). According to Meehl (1962) anhedonia is a possible indicator of a genetic vulnerability to schizophrenia. In support of this assumption, anhedonia has been found to be elevated in unaffected relatives of patients with schizophrenia (Kendler et al., 1996, Laurent et al., 2000) and in healthy participants exhibiting clinical characteristics similar to those seen in individuals with schizophrenia spectrum disorders (Blanchard et al., 2011). Those findings imply a continuity of negative symptoms in the population and healthy individuals seem to vary in their vulnerability for anhedonia. Thus, studying anhedonia at a subclinical level may help to identify mechanisms that are involved in transition from a healthy state to negative symptoms.

One important aspect of anhedonia is the differentiation between its consummatory and anticipatory components (Klein, 1984, Gard et al., 2006). Consummatory pleasure is the ability to actually experience pleasure in response to a pleasurable stimulus in the moment it occurs, whereas anticipatory pleasure refers to the experience of pleasure while anticipating future events (Kring and Caponigro, 2010). Several studies based on self-report measures and experience sampling methods have shown that anticipatory (but not consummatory) deficits are associated with anhedonia in schizophrenia (Horan et al., 2006, Gard et al., 2007, Favrod et al., 2009, Chan et al., 2010). In those studies, patients with schizophrenia reported less anticipated pleasure than controls but comparable levels of positive emotion when they were actually experiencing pleasurable activities. Strauss and Gold (2012) concluded that anhedonia should no longer be defined as diminished capacity for pleasure, but rather reflects beliefs of low pleasure or elevated negative emotions.

As in healthy persons, experience of emotion in schizophrenia is hypothesized to be closely linked to motivational systems (Kring and Caponigro, 2010). Based on Gray's (1970) neurobiological model there are two motivational systems that regulate the intensity of approach and avoidance behavior and are associated with specific emotions. The Behavioral Inhibition or Avoid System (BIS) is related to punishment avoidance and the Behavioral Activation or Approach System (BAS) is related to drive, fun seeking and reward responsiveness (Carver and White, 1994). Whereas BIS is said to inhibit behavior towards positive stimuli and to be sensitive to aversive stimuli associated with feelings such as frustration and anxiety, BAS is said to activate behavior towards positive stimuli associated with feelings such as hope and happiness (Gray, 1990). People have been found to differ in their motivation to avoid negative (potential punishing) or attend to positive (potential rewarding) stimuli (e.g., Carver and White, 1994, Derryberry and Reed, 1994, Heimpel et al., 2006). Moreover, it has been suggested that imbalances between BIS and BAS underlie affective vulnerability to psychopathological symptoms (Johnson et al., 2003, Becerra, 2010).

In schizophrenia, BIS but not BAS was found to be positively associated with overall negative symptoms (Scholten et al., 2006, Depp et al., 2011). With regard to anhedonia, Gard et al., 2006, Gard et al., 2007 found BAS but not BIS to be positively associated with anticipatory but not consummatory pleasure in schizophrenia. Similarly, Germans and Kring (2000) found anticipatory as well as consummatory pleasure to be positively associated with BAS but not BIS in a healthy sample with varying levels of anhedonia. Thus, it seems that BIS may be linked to overall negative symptoms whereas BAS may be uniquely related to anhedonia, possibly to its anticipatory component. Furthermore, because evidence suggests that patients with negative symptoms have difficulties to initiate goal-directed behavior (Gold et al., 2008) and motivational deficits in schizophrenia reflect problems in the ability to translate positive experiences into action (Heerey and Gold, 2007), the association between negative symptoms and BAS may be mediated by pleasure anticipation.

The goal of the present study was to examine the association between subclinical negative symptoms, anticipatory/consummatory pleasure and BIS/BAS motivation as well as to test if there is an interaction effect of subclinical negative symptoms and anticipatory pleasure on trait approach motivation (BAS). We studied a sample of healthy participants with varying vulnerability to negative symptoms. This approach appears justified by the fact that subclinical negative symptoms have been used as low-level criterion in high-risk studies (Yung et al., 2003, Lencz et al., 2004, Piskulic et al., 2012) and by the continuity not only of negative symptoms in general (Blanchard et al., 1998, Piskulic et al., 2012) but also of associated anhedonia (Blanchard et al., 2011, Piskulic et al., 2012). We hypothesized that (1) anticipatory, but not consummatory pleasure will be negatively related to subclinical negative symptoms, (2) BAS will be uniquely positively related to anticipatory pleasure, whereas (3) BIS will be positively related to overall subclinical negative symptoms and, (4) the association between subclinical negative symptoms and BAS will be mediated by the ability to experience anticipatory pleasure.