Construction of an Effort Discounting Task (EDT)

The negative symptoms of schizophrenia (SCZ) are disabling, poorly understood, and weakly responsive to current treatments. Increasing evidence suggests that motivational deficits specifically represent a substantial problem within the negative symptom domain. Thus treating or minimizing the harmful effects of amotivation could have major therapeutic benefits. Unfortunately, a lack of clinical measurement approaches has limited research as to how amotivation in schizophrenia relates to disease pathology, functional outcome, or treatment options. One successful approach has been the use of computerized behavioral tasks designed to translate subjective human decision-making into an objective measure of motivation. This study utilized a computerized Effort Discounting Task (EDT) to assess motivational differences between SCZ patients and healthy controls. While prior studies have employed similar tasks to investigate reward valuation, this study uniquely included a newly programmed loss aversion EDT (L-EDT) task in addition to a gain seeking EDT (G-EDT) in order to dually examine participants' motivation to either earn or prevent the loss of a monetary reward. Deficits in the SCZ group and a greater sensitivity to losses in both groups were observed, as evidenced by task performance. EDT results were also associated with survey measures related to negative symptoms and motivated behavior in the SCZ group. These results suggest that separate gain and loss EDTs could be used in future work to identify clinically meaningful motivational differences between SCZ and healthy populations. The reliability of the L-EDT was lower than expectation and requires further investigation.