The effects of anhedonia and depression on hedonic responses

Abstract

Anhedonia is one of the key symptoms of major depression. The present study examined whether depressive symptoms and trait anhedonia are associated with deficits in anticipated, experienced, or recalled pleasure and satisfaction (hedonic responses, HR). Sixty-one college students tasted chocolate samples in the lab. Participants' anticipated, experienced, and recalled HR were obtained prior to the task, during the task, and 1 day later, respectively. Anticipatory anhedonia, but not consummatory anhedonia or depression, predicted anticipated HR. In contrast, participants' levels of anticipatory and consummatory anhedonia and depression were not predictive of their experienced and recalled HRs. Depressed individuals showed lower tendency to overpredict their HRs to the task relative to nondepressed individuals. We conclude that clinical reports of anhedonia and depression in a college student population primarily reflect low levels of anticipation of reward, and tendency to accurately estimate their enjoyment of future rewards. If replicated, these results may have important implications for assessing and managing anhedonia associated with depression in clinical settings.

Introduction

Anhedonia, or reduced ability to experience interest and pleasure in response to pleasurable activities, reflects a stable individual difference as well as a transitory state associated with a number of psychological disorders, and particularly with major depression (Loas, 1996). Anhedonia is one of the two essential features of major depression as defined by the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) (American Psychiatric Association, 1994), and one of the best indicators of the presence of this disorder (Brody et al., 1998). More than two-thirds of all individuals with major depression endorse this symptom (Buchwald and Rudick-Davis, 1993). Severity of anhedonia is positively correlated with severity of depressive symptoms among depressed and nondepressed individuals (Allen et al., 1999, Kaviani et al., 2004, Mathews and Barch, 2006). Despite this consistent pattern of association, few studies have compared the effects of anhedonia and depressive symptoms on hedonic responses (HR, defined as pleasure and interest in response to potentially rewarding stimuli).

Theories of depression and anhedonia suggest that anhedonic and/or depressed individuals display an experiential hedonic deficit (Meehl, 1975, Beck et al., 1979, Loas, 1996). Studies offer some support for this assumption, and show that depression and anhedonia are similarly associated with dampened HRs. Relative to nondepressed individuals, individuals with heightened levels of depression show diminished HR to pleasant imagery (Sloan et al., 1997, Allen et al., 1999), and films (Rottenberg et al., 2002, Renneberg et al., 2005). Similarly, individuals with heightened levels of anhedonia show diminished HR to pleasant words (Mathews and Barch, 2006), imagery (Fiorito and Simons, 1994), pictures (Fitzgibbons and Simons, 1992, Ferguson and Katkin, 1996), and films (Kaviani et al., 2004, but also see Berenbaum et al., 1987).

Many of these studies relied on complex and/or representational pleasant stimuli (e.g., films). These types of stimuli rely on individuals' ability to attend to them, appraise them or imagine enjoying them. In contrast, a few studies that examined responses to sensory stimuli, such as pleasant tastes, did not show a consistent pattern of association between depression, anhedonia, and HRs. Although some studies show that depression and anhedonia are associated with a reduction in ability to enjoy pleasant tastes (Amsterdam et al., 1987, Berlin et al., 1998), other studies do not replicate this pattern (Berenbaum and Oltmanns, 1992, Germans and Kring, 2000). It is possible that reports of depression and anhedonia are associated with deficits in appraisal, or ability to anticipate or imagine potentially rewarding stimuli, rather than deficits in sensory pleasure. In their daily lives, individuals with depression and anhedonia are likely to encounter both representational (e.g., reading), and sensory sources of pleasure (e.g., eating); thus, it is important to investigate the effects of depression and anhedonia on each.

In addition, it is important to make clear distinctions between deficits in anticipated (i.e., anticipating that an activity would be pleasurable), experienced (i.e., actually enjoying an activity), and recalled (i.e., remembering experienced pleasure after a delay) HRs. These types of responses are known to be distinct from each other at physiological, behavioral, and experiential levels (Klein, 1984, Berridge and Robinson, 1998, Barbano and Cador, 2007, Gard et al., 2007; also see Robinson and Clore, 2002). Clinical disorders may affect the association between these responses (Herbener et al., 2007). Both depression (Bradley et al., 1995, Sanz, 1996, MacLeod and Salaminiou, 2001) and anhedonia (Simons et al., 1982; but see Germans and Kring, 2000) are associated with deficits in anticipation and/or recall of pleasant experiences. Thus, it is important to examine whether depression, anhedonia, or their interaction affect anticipation, experience, and recall of HRs.

Finally, most previous studies focused on either depression or anhedonia, but not both. Thus, we do not know whether the effects of depression on HRs are accounted for by anhedonia, or vice versa. Only one study has demonstrated that depression did not account for anhedonia's association with dampened HRs (Mathews and Barch, 2006). This finding requires replication. None of the previous studies examined whether symptoms of depression and anhedonia interact in their effect on hedonic response. The present study builds on the extant literature by examining the contributions of anhedonia, depression, and their interaction to HR.

Based on previous research (Mathews and Barch, 2006), and on the fact that measures of anhedonia assess reported deficits in HR more systematically than measures of depression, we hypothesized that anhedonia will affect HR more than depression. Based on previous literature on anticipatory deficits associated with anhedonia (Gard et al., 2007), we hypothesized that anhedonia will affect anticipated HRs more than experienced HRs. In addition, based on previous literature on the effects of depression on anticipation and recall of positive emotional states (MacLeod and Salaminiou, 2001, Beck, 2002, Mennin and Miranda, 2007), we hypothesized that depressed individuals will show less intense positive biases in anticipating and remembering their HRs than nondepressed individuals. To test these hypotheses, we asked participants with different levels of reported depression and anhedonia to rate how much they may enjoy tasting chocolates, to actually taste chocolates, and to recall how enjoyable this task was 1 day after leaving the laboratory.