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.

What's in a face? Effects of stimulus duration and inversion on face processing in schizophrenia.

A number of studies show deficits in early-stage visual processing in schizophrenia. Deficits are also seen at more complex levels, such as ability to discriminate faces. This study investigated the "face inversion" effect, which reflects intrinsic cortical processing within the ventral visual stream, as well as contrast sensitivity, which reflects low-level visual processing, in order to evaluate integrity of specific stages of face processing in schizophrenia. Patients with schizophrenia and controls discriminated between pairs of upright or inverted faces or houses that had been manipulated to differ in the shape of the parts or the spatial distance among parts. The duration threshold for above chance performance on upright stimuli was obtained for patients using a house discrimination task. Contrast sensitivity was assessed for gratings of three spatial frequencies ranging from 0.5 to 21 cycles/degree. Patients needed significantly longer time to obtain 70% correct for upright stimuli and showed decreased contrast sensitivity. Increased duration threshold correlated with reduced contrast sensitivity to low (magnocellular-biased) but not medium or high spatial frequency stimuli. Using increased durations, patients showed significant inversion effects that were equivalent to those of controls on the face part and spacing tasks. Like controls, patients did not show inversion effects on the house tasks. These findings show that patients have difficulty integrating visual information as shown by increased duration thresholds. However, when faces were presented at these longer duration thresholds, patients showed the same relative processing ability for upright vs. inverted faces as controls, suggesting preserved intrinsic processing within cortical face processing regions. Similar inversion effects for face part and spacing for both groups suggest that they are using the same holistic face processing mechanism.

Anticipated, on-line and remembered positive experience in schizophrenia.

BACKGROUND: Three temporal stages in the evaluation of positive affect can be identified: anticipation, experience (hedonia) and memory. In schizophrenia, despite research indicating non-impaired hedonic capacities, little is known about anticipation and memory of positive affect. Moreover, the role of positive affect evaluations on motivation has rarely been studied in schizophrenia. METHOD: Seventy individuals with schizophrenia and 35 non-patient control participants completed an evocative emotional task consisting of pictures and sounds. Following each presentation, participants rated their hedonic experience. Ratings of pre-test anticipated and post-test remembered pleasures were also obtained. Finally, explicit motivation to repeat the task was assessed. RESULTS: Compared to control participants, schizophrenia participants demonstrated similar levels of anticipation, hedonia and motivation, as well as significantly increased remembered pleasure. In schizophrenia, affective processes had lower correlations with motivation than in controls, and only remembered pleasure predicted motivation. Moreover, the predictive value of hedonia was significantly lower in schizophrenia. CONCLUSIONS: The affective and cognitive processes involved in the anticipation, experience and memory of positive affective events showed no deficit, and to the contrary, immediately remembered pleasure was higher in schizophrenia. However, important deficits resided in the inter-connectivity between affective evaluations and motivational processes. The major deficit in schizophrenia participants' reward system was not in hedonic experiences but in the translation of pleasurable experiences into motivational states.

Theory of Mind (ToM) and counterfactuality deficits in schizophrenia: misperception or misinterpretation?

BACKGROUND: Theory of Mind (ToM) refers to the ability to infer another person's mental state based upon interactional information. ToM deficits have been suggested to underlie crucial aspects of social interaction failure in disorders such as autism and schizophrenia, although the development of paradigms for demonstrating such deficits remains an ongoing area of research. Recent studies have explored the use of sarcasm perception, in which subjects must infer an individual's sincerity or lack thereof, as a 'real-life' index of ToM ability, and as an index of functioning of specific right hemispheric structures. Sarcastic detection ability has not previously been studied in schizophrenia, although patients have been shown to have deficits in ability to decode emotional information from speech ('affective prosody'). METHOD: Twenty-two schizophrenia patients and 17 control subjects were tested on their ability to detect sarcasm from spoken speech as well as measures of affective prosody and basic pitch perception. RESULTS: Despite normal overall intelligence, patients performed substantially worse than controls in ability to detect sarcasm (d=2.2), showing both decreased sensitivity (A') in detection of sincerity versus sarcasm and an increased bias (B'') toward sincerity. Correlations across groups revealed significant relationships between impairments in sarcasm recognition, affective prosody and basic pitch perception. CONCLUSIONS: These findings demonstrate substantial deficits in ability to infer an internal subjective state based upon vocal modulation among subjects with schizophrenia. Deficits were related to, but were significantly more severe than, more general forms of prosodic and sensorial misperception, and are consistent with both right hemispheric and 'bottom-up' theories of the disorder.