Cognitive ability and motivation in a new effort-baed decision-making task testing healthy participants showing subclinical symptoms of schizophrenia
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- Institutt for psykologi 
Effort-based decision-making have been shown to be closely linked to the motivational deficits seen in negative symptoms in schizophrenia and other psychotic disorders, and several paradigms have been developed to be able to more objectively measure motivation and effort. These tasks measure how much effort one is willing to exert across different reward and probability conditions. However, there is substantial research suggesting that cognitive deficits affect these processes, and current paradigms do not consider how cognitive functioning may affect effort-based decision-making. In addition, previous research supports that individuals with schizophrenia show deficits in effort-cost computations, but less is known about individuals with subclinical symptoms of schizophrenia. By studying healthy individuals, one might get insight into behavioural, clinical and environmental risk and protective factors associated with the development of the disorder and to be able to limit the progression of illness. The aim of this study was to identify which of the several symptoms in psychotic disorders or schizophrenia contribute the most to the lack of motivation and goal-directed behaviour in a non-clinical sample. A recently developed effortbased decision-making paradigm was used, controlling for neurocognitive ability, metacognitive precision, probability and subjective cost. Fifty-three healthy individuals from the general population participated in the study. To measure subclinical symptoms, the participants completed the Community Assessment of Psychic Experiences. Our results showed that individuals scoring highly on one symptom dimension, scored highly on the other symptom dimensions as well, making it difficult to test our hypothesis properly. Nevertheless, elevated degrees of negative symptoms were associated with less effort. Interestingly, it was positive symptoms and not negative symptoms that was associated with neurocognitive deficits. Thus, in our study, deficits in neurocognition did not account for the reduced effort. Further, the cost of performing the task was the same for all participants, regardless of symptom severity. Lastly, all participants were rational in their decision making, i.e. they reduced their effort as the probability decreased. Due to the overlap of symptoms, more research is needed to see which of several symptoms in schizophrenia contribute the most to the lack of motivation and goal-directed behaviour.