Physical activity, lifestyle-related factors and psychological determinants among patients with schizophrenia.

Abstract

Approximately 75% of all deaths in patients with schizophrenia are caused by physical illness. Cardiovascular disease is the commonest cause of death. Unhealthy lifestyle choices, such as lack of physical activity (PA), poor sleep quality, unhealthy diets and tobacco smoking as well as psychological determinants (i.e., low autonomous motivation and self-esteem) contribute to this excessive morbidity and mortality. In addition, the overlapping of lifestyle-related factors and psychological determinants and with additional factors (e.g., psychiatric medication), affects the quality of life (QoL) of this population. In the last decade, the relevance of healthy lifestyle behaviours in patients with schizophrenia has been reported. However there are still several research gaps that need to be clarified. Specifically, in the Portuguese reality, research focusing in this population is almost non-existent. Therefore, the main purpose of this doctoral thesis was to explore lifestyle-related factors and psychological determinants, and to analyse the impact of these in QoL in patients with schizophrenia. This doctoral thesis included six studies that aimed to: i) examine the construct validity of the Portuguese version of the Behavioural Regulation in Exercise Questionnaire - 2 (BREQ-2) as well as the Portuguese version of the BREQ-3; ii) investigate among a number of barriers what predicts the most on PA; iii) assess the associations between PA levels and sleep quality; iv) compare the sleep quality and QoL between regular physical active and the non-physical active patients with schizophrenia; v) assess the dietary intake and adherence to Mediterranean Diet, specifically analysing the difference between treatment setting (i.e., inpatients and outpatients); and vi) explore the association between lifestyle-related factors, psychological determinants and QoL. In order to accomplish these aims, 118 patients with schizophrenia (25% women and 50% inpatients) were included. Standardized assessment tools (i.e., questionnaires and field test) were applied to evaluate lifestyle-related factors, psychological determinants and QoL. Results of the studies showed that: i) the Portuguese version of the BREQ-3 revealed to be an appropriate measure to assess controlled and autonomous motivation towards PA; ii) autonomous motivation and global domain of QoL was found to be the most significant predictors of PA; iii) sleep quality was positively associated with time of moderate and total PA per week; iv) patients of regular physical active group have better sleep quality and QoL; v) patients reported a high consumption of caffeine, while deficits were evident for fibre and folate intakes. Outpatients showed a significant higher consumption of meat and meat products, and fruits and nuts, compared with inpatients; and vi) PA behaviours and self-esteem predicted better QoL across all domains of QoL. This doctoral thesis provided new and relevant evidence regarding lifestyle-related factors and psychologicalXIIdeterminants in patients with schizophrenia. Several practical considerations could be highlighted in order to influence interventions integrated in patient's treatment.