Correlates of Fatigue in People With Schizophrenia

Schizophrenia is a severe mental illness affecting about 1% of worldwide population. Diagnostic relies on multiple symptoms, divided into three main categories: positive symptoms, negative symptoms and cognitive/dissociative symptoms. Antipsychotic medication is actually the main pharmacologic treatment in schizophrenia but adverse effects can exacerbate other symptoms such as fatigue. Fatigue has a high prevalence in schizophrenia. Unfortunately, fatigue has negative repercussions on daily living activities in this population, and no effective treatment has been identified for now. The lack of effective strategies to manage fatigue in schizophrenia can be due to the lack of knowledge about factors that can explain fatigue. As such, an explicative model of fatigue in schizophrenia has yet to be established. Because fatigue is a complex and multifactorial mechanism, investigating its correlates could allow to propose new avenues for its multidisciplinary management, in order to delay its onset or minimize its negative impact. In comparison to healthy subjects, people with schizophrenia show increased physical inactivity and sedentary levels, worsened physical fitness and higher risks of sarcopenia, disturbed sleep, altered cognitive function, increased consumption of psychoactive substances (coffee and tobacco), an increased fatigue catastrophizing. Moreover, negative symptoms could also be linked to fatigue as it has been shown that fatigue could contribute to anhedonia in schizophrenia. Finally, antipsychotic medication can induce sedation, overlapping with fatigue, contributing to an exacerbated experience of the symptom. Therefore, the goal of this study is to investigate whether physical inactivity, sedentary behaviour, physical fitness, sarcopenia risk, sleep, cognitive capacities, psychoactive substance consumption, fatigue catastrophizing, antipsychotic treatment and negative symptoms could contribute to fatigue in people in schizophrenia.