Philadelphia, PA -- Many people with schizophrenia have marked problems with motivation, failing to initiate and persist in goal-directed behavior. These negative symptoms of schizophrenia can be disabling and prevent individuals from realizing their potential.
For many years it was thought this was due to an inability to experience pleasure associated with successful goal attainment. However, recent laboratory studies have shown that hedonic experience is actually intact in people with schizophrenia, calling for new approaches to better understand these motivational deficits.
In a new study published in Biological Psychiatry, Dr. James Gold, at the University of Maryland School of Medicine, and his colleagues now provide a new clue to the relationship between motivational deficits and functional impairment.
They theorized that the lack of motivation may stem from a decreased willingness to expend effort to gain rewards. In other words, individuals with schizophrenia may be less able to properly evaluate future reward in terms of the 'cost' of the effort required.
To test this, the researchers recruited individuals with schizophrenia and a comparison group of healthy individuals. The individuals with schizophrenia were also evaluated for their symptom levels. All participants completed a computerized effort-cost decision-making task in the laboratory. This task required them to make decisions between two alternatives: an easy option with a minimal reward, and a harder option with a higher-value reward.
They found that schizophrenia patients, especially those with prominent negative symptoms, were more likely to choose the less demanding tasks that provided smaller rewards and were less likely than healthy subjects to choose more demanding tasks that offered greater rewards.
"In essence, patients with severe negative symptoms calculate the 'cost' of potential effort versus the value of potenti
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