Affective Memory and Schizophrenic Anhedonia

Abstract

Two experiments attempted to isolate and measure schizophrenic anhedonia as it is reflected in the mnemonic processing of affectively laden stimuli. In the first experiment, subjects were required to sort a list of words repeatedly, each in terms of pleasantness, until a consistent sorting was achieved. Then, they were unexpectedly asked to recall the list. Schizophrenics' total recall was comparable to that of normals; but while normals recalled significantly more pleasant than unpleasant words (a Pollyanna tendency), such differential recall was absent in schizophrenics (anhedonia). These results were complicated, however, by the intrusion of semantic variables into the affective processing. In the second experiment, human faces were used to minimize semantic intrusions. Subjects were induced to encode photographs of faces in the context of favorable-unfavorable personality traits, and their recognition memory for these faces was subsequently tested. In spite of comparable overall performance, normals recognized significantly more favorably than unfavorably encoded faces, and such asymmetric recognition was absent in schizophrenics. Furthermore, a significant Group by Affect interaction emerged. The results were taken as evidence of schizophrenic anhedonia and normals' Pollyanna tendency. Nonschizophrenics also served as controls but their results were equivocal. Several problems which may be typical in the experimental investigation of affect were discussed.

The dual origin hypothesis: An evolutionary brain-behavior framework for analyzing psychiatric disorders

“…In contrast, other forms of memory, such as motor and cognitive procedural learning (which are not dependent upon hippocampal mechanisms), appear relatively preserved in schizophrenia (Clare et al, 1993;Goldberg et al, 1993;Schmand et al, 1992). Emotional memory is likewise reported to be intact in schizophrenia, although patients show a bias for recalling more negative-affect items, while controls subjects show a bias for recalling more positive-affect items (Koh et al, 1981), again consistent with preserved or overactive amygdaloid activity in this disorder. Attentional and executive dysfunction, related to frontal pathology, may also contribute to poor episodic memory performance in schizophrenia (Maher et al, 1995;McClain, 1983), and will be considered shortly.…”

Understanding anhedonia in schizophrenia through lexical analysis of natural speech

“…Anhedonic patients have shown selective biases in recalling negative words over positive and neutral words in several studies (Calev & 580 COHEN ET AL. Edelist, 1993;Koh, Grinker, Marusarz, & Forman, 1981) suggesting that subjects' pleasurable experiences may have been recalled with an overly negativistic tone. Similarly, recent work by Herbener and colleagues (Herbener, Rosen, Khine, & Sweeney, 2007) indicated that patients as a group show impairment in encoding positive, but not negative, stimuli.…”

Affect Memory in Depression: Evidence of Better Delayed Recall of Positive than Negative Affect Words

“…tend to retain the negative better than the positive. Koh et al [17] hy pothesized that schizophrenics' anhedonia will lead to belter recall of negative than pos itive affect materials. They indeed found better immediate recall for negative verbal ma terials in schizophrenics, and a 'Pollyanna tendency', that is.…”