Anhedonia and depression: Anticipatory, Consummatory, and Recall Deficits

Current conceptions of anhedonia as a key symptom of depression do not consider the importance of anticipatory, consummatory, and recall deficits involved in anhedonia. Sixty-one depressed and non-depressed, college-student participants provided reports of anticipated pleasure to tasting chocolates, tasted chocolates and rated their experience of pleasure, and provided recalled reports of pleasure to the experience one day later. Results demonstrated a deficit in the ability to anticipate experiencing pleasure for depressed participants when compared to non-depressed controls, however, their reports of consummatory pleasure and recalled pleasure did not differ significantly from nondepressed control participants. This study suggests that actual experiential deficits may not drive anhedonia, but instead cognitive deficits may be involved. Future studies need to focus more on the nature of this deficit, particularly in a clinical population. Anhedonia and Depression 4 Anhedonia and Depression: Anticipatory, Consummatory, and Recall Deficits Anhedonia, or the inability to experience pleasure when exposed to normally pleasurable stimuli, has long been accepted as a key symptom of disorders such as depression and schizophrenia. Studies have focused on a number of specific aspects of this deficit, such as differences between social and physical types of anhedonia (Chapman, Chapman, & Raulin, 1976) and state or trait characteristics of anhedonia (Klein, 1987; Chapman, Edell, & Chapman, 1980; Meehl, 1975). However, the role of anhedonia in depression and their effects on actual pleasure are not entirely understood. Some attempts have been made to isolate the anticipatory, consummatory, and recall deficits of anhedonia in relation to depression, but without decisive results (Klein, 1987; Dunbar & Lishman, 1984; Fawcett, Clark, Scheftner, & Gibbons, 1983). In order to understand anhedonia in relation to depression, it is necessary to consider these aspects of the cognitive and experiential deficits associated with anhedonia with more detail. Anhedonia: A History The French psychologist Ribot first introduced the term “anhedonia” in 1897, stating that this important concept had been largely understudied, as psychologists and philosophers at the time focused more on grief and other negative emotions than pleasure. His notion of anhedonia referred to a deficit across emotional responding and pleasure in particular, but differentiated between a lack of pain, or “analgesia”, and a lack of pleasure. William James (1906) recognized anhedonia as a part of what at the time was called “melancholy”, though currently understood as depression, but differentiated anhedonia from “neurotic melancholy”, which occurs after object loss, and “religious melancholy”, where the affect is blunted by guilt and intellectualization. Freud (1963) Anhedonia and Depression 5 also seized on the idea of anhedonia, associating it with the effects of repression in a neurotic conflict where anhedonia results from a lack of free libidinal energy in relation to repressed energy. These early proposals formed the theoretical basis for the more sophisticated, and empirically supported, theories that would follow. Meehl’s Conception of Anhedonia Later in the twentieth century, more detailed models surfaced for the general structure of anhedonia and its role in psychological disorders such as depression. Meehl’s (1975) influential article on hedonic capacity has since been widely cited and supported in various empirical studies (i.e. Dworkin & Saczynski, 1984; Peterson & Knudson, 1983). He was the first to conceive of the hedonic capacity model of anhedonia, which suggests that pleasure serves to attenuate negative emotions. Meehl proposed that the capacity to experience pleasure differs among individuals, and that some people simply have a lower capacity for pleasure than others, or “are born three drinks behind” (p. 298). According to the hedonic capacity model, the anhedonic patient experiences deficits in the subjective effectiveness of positive reinforcers, similar to the Ferster and Skinner theory of reinforcement schedules (1957). Thus, the anhedonic patient lives in a hypothetical Skinner box with quantitatively fewer or weaker positive reinforcers that can be used to soothe negative states, with implications such as a higher vulnerability for developing depression. Response to Positive Stimuli in Depression Limited research has been conducted in the area of actual response differences to pleasurable stimuli in depressed individuals compared to the healthy population. However, some other studies of response to more generally positive and/or rewarding Anhedonia and Depression 6 stimuli have demonstrated differences in responding between depressed participants and healthy controls. Pizzagalli and his colleagues (2005) based their method on the assumption that rewards provide positive reinforcement, and tested whether depressed and anhedonic participants responded less than normal participants to a positively reinforcing reward (money) in a response modulation task. As hypothesized, participants exhibiting higher depression scores and self-reported anhedonia failed to modulate their responses, suggesting lowered reward responsiveness. In addition, low reward responsiveness predicted higher levels of anhedonic symptoms when participants were retested one month later. Berenbaum and Connelly (1993) acknowledged that stress contributes to major depressive disorder (MDD) and that MDD is associated with lowered hedonic capacity, so they tested whether stress leads to a lowered hedonic capacity and if this is more pronounced in people with a high predisposition to developing MDD, such as people with a family history of the disorder. A sample of ROTC students completed a highly physically and emotionally stressful training day, while a control group did not, and then both groups watched disgusting and happy films, providing self-reports of happiness and disgust after the viewing. Participants with a family history of MDD (a diathesis for major depression) reported less enjoyment of the films after a stressful training day, suggesting that stress can lead to lowered hedonic capacity especially in people with a predisposition to developing MDD. Berlin, Givry-Steiner, Lecrubier, and Puech (1998) found that depressed participants showed a higher threshold for sweet taste perception than healthy participants, meaning that water and sucrose solutions needed to be saturated with more Anhedonia and Depression 7 sucrose for depressed participants than healthy controls in order to obtain the same rating of sweetness. However, both participant groups responded with similar levels of reported pleasure to solutions with the same amount of sucrose in them. Therefore, differences appear to exist in the way that depressed people or people predisposed to MDD respond to positive stimuli when compared to responding in healthy people. In addition, these differences are perhaps more subtle than what one would expect based on clinical descriptions, which describe a profound and lasting inability to experience pleasure. More carefully controlled studies of online responding in depressed populations are necessary in order to further understand these differences. Distinguishing Between Anticipatory, Consummatory, and Recall Deficits When anhedonia is assessed in clinical settings, it can be difficult to distinguish between anticipatory, consummatory, and recall deficits. For example, when a depressed individual is asked how much they would like to eat a delicious meal, the person may respond with little enthusiasm. This directly suggests an anticipatory deficit, since the person seems to anticipate deriving little pleasure from an otherwise enjoyable meal. This may additionally be related to a recall deficit, since he or she may recall the last instance involving a delicious meal and not remember experiencing significant pleasure. Therefore, the response may not be a reflection of their actual experience, if they were to eat the delicious meal, but may reflect a cognitive bias against normally pleasurable experiences. Anticipatory deficits are defined as deficits in the expectation of deriving pleasure from a normally pleasurable activity, and studies based on global self-report measures have shown that anhedonia is associated with anticipatory deficits in depressed Anhedonia and Depression 8 individuals. (Fawcett et al., 1983). Consummatory deficits are characterized as the inability to actually experience pleasure in response to a pleasurable stimulus (Klein, 1987). Finally, recall deficits involve deficits in the capacity to accurately remember the experience of pleasure, such as the finding that depressed individuals tend to remember negative information better than positive, known as the mood-congruency effect (Dunbar & Lishman, 1984). The theory that depression results in negative cognitive distortions is wellaccepted and well-supported. Depression is associated with a negative view of the future (Beck, 1961), as well as a negative bias for the recollection of past events (Beck, 1961; Dunbar & Lishman, 1984). Generally, due to mood congruency effects, a person’s current mood affects the ease with which a type of memory can be retrieved, so that negative mood facilitates retrieval of negative memories (Bower, Gilligan, & Monteiro, 1981). In the context of depression, the pervasive negative mood state has been shown to facilitate retrieval of negative material (Dunbar & Lishman, 1984). In addition, negative mood is associated with less accurate recall of pleasurable experiences, perhaps because people with lowered mood tend to interpret more events as negative (Seidlitz & Diener, 1993; also see Gotlib & Neubauer, 2000 for a review). Studies involving memory biases in depression have not differentiated between encoding and retrieval errors, so it is not clear which type of errors may