Emotional experience in patients with schizophrenia revisited: meta-analysis of laboratory studies

Abstract

Our understanding of the emotion deficits in schizophrenia is limited. Findings from studies employing trait emotion instruments suggest that patients have attenuated levels of positive emotion (ie, anhedonia) and increased levels of negative emotion. Conversely, patients and controls have not statistically differed in their subjective reactions to positive or negative valenced stimuli in most laboratory studies to date. Further obfuscating this issue is the fact that many of these laboratory studies are underpowered and a handful of emotion induction studies have found evidence of anhedonia. We conducted a meta-analysis of 26 published studies employing laboratory emotion induction procedures in patients with schizophrenia and healthy controls. Patients did not differ from controls when strictly rating their subjective hedonic reactions to the stimuli. However, they reported experiencing relatively strong aversion to both positive and neutral stimuli (Hedges D = .72 and .64, respectively). These findings were not the result of demonstrable sample or methodological differences across studies. Patients' ability to experience hedonic emotion is preserved, although they also show relatively strong, simultaneously occurring aversive emotion when processing laboratory stimuli considered by others to be pleasant or neutral.

Fig. 1.

Patients vs Controls: Effect Sizes Computed for Unipolar Hedonic, Unipolar Aversive, and Bipolar Emotion Ratings from the Positive, Negative, and Neutral Emotion Induction Conditions. Positive effect size values from hedonic and bipolar ratings reflect patients reporting more euphoria than controls following stimulus presentation. Positive effect size values from aversive ratings reflect patients reporting more dysphoria than controls following stimulus presentation. Dotted lines denote small (−.20 and .20) and medium (−.50 and .50) effect sizes. Dark solid line reflects weighted means.