In support of Bleuler: Objective evidence for increased affective ambivalence in schizophrenia based upon evocative testing

Background: Ambivalence and anhedonia have long been identified as schizophrenic symptoms. However, ambivalence has rarely been studied, and in most evocative studies, schizophrenia participants are not anhedonic. Affective neurosciences posit two evaluative systems (one for Positivity and one for Negativity), the coactivation of which produces ambivalence, and point to two asymmetries in affective processing: Positivity Offset (which measures our capacity to explore the environment) and Negativity Bias (a measure of reactivity to intense threat). These characteristics have not received much attention in schizophrenia research. Methods: Sixty-four individuals with schizophrenia and 32 non-patient control participants completed an evocative emotional task with pictures, sounds and words of various valences and intensities. Following each presentation, participants rated the level of pleasantness, unpleasantness, and arousal elicited by the stimulus. Finally, participants completed questionnaires on anhedonia, and practical life skills were assessed. Results: Schizophrenia participants showed higher levels of ambivalence, greater arousal, greater Positivity Offset, and non-significantly different hedonic capacities and Negativity Bias. Ambivalence to positive stimuli significantly correlated with duration of illness, current level of psychopathology, anhedonia questionnaires and practical life skills. Schizophrenia patients with negative symptoms did not differ from patients without negative symptoms on computer tasks. Conclusions: Ambivalence is greater in schizophrenia, and can be understood as a de-differentiation of the activation of the two evaluative systems. Ambivalence to positive stimuli, which may reflect early-stage affective processing is associated with impairments in higher-level emotional processes and in everyday functioning. Future studies should clarify the status of anhedonia in schizophrenia.