Schizophrenia and physical health

The life expectancy of people with schizophrenia is approximately 20 years less than that of the general population and this mortality gap is widening. ^{Reference Saha, Chant and McGrath1} The predominant causes of this major public health problem are poor physical health and related cardiovascular disease (CVD). Primary prevention of and early secondary intervention for CVD risk factors are essential, yet people with serious mental illness are less likely to access health services, and if they do, are less likely to be investigated and treated. Furthermore, despite regular engagement with psychiatric services, the physical health of people with schizophrenia is still often neglected. The resulting poor health outcomes represent a major health inequality that would not be tolerated in any other minority or marginalised group.

The recent Schizophrenia Commission report described the inadequate management of physical health problems and the neglect of physical health improvement in the healthcare of people with schizophrenia as ‘a civil rights issue’. ² It recommends early intervention with health promotion programmes to prevent the rapid decline in physical health which often occurs after the onset of schizophrenia.

People with schizophrenia typically lead unhealthy, physically inactive lifestyles, ^{Reference McCreadie3} with high levels of dietary fat intake, smoking and alcohol use. Cardiovascular disease risk factors - including obesity, type 2 diabetes, hypertension and dyslipidaemia - are highly prevalent in this group and can all be improved by regular physical activity.

Benefits of physical activity

Regular physical activity improves physical and mental health in the general population and can similarly benefit people with schizophrenia. ^{Reference Gorczynski and Faulkner4} A recent review of 10 randomised controlled trials (n = 322) ^{Reference Vancampfort, Probst, Helvik Skjaerven, Catalán-Matamoros, Lundvik-Gyllensten and Gómez-Conesa5} demonstrated the beneficial effects of aerobic and muscle strength exercises, progressive muscle relaxation and yoga on positive and negative symptoms, anxiety and psychological distress in people with schizophrenia. Physical activity can also help manage antipsychotic-associated weight gain ^{Reference Álvarez-Jiménez, Hetrick, González-Blanch, Gleeson and McGorry6} and improve physical fitness. ^{Reference Vancampfort, Probst, Helvik Skjaerven, Catalán-Matamoros, Lundvik-Gyllensten and Gómez-Conesa5} Thus, lifestyle interventions involving exercise should reduce obesity-related cardiometabolic risk in people with schizophrenia. ^{Reference Vancampfort, Knapen, De Hert, van Winkel, Deckx and Maurissen7}

In the general population, increasing and maintaining physical fitness reduces all-cause mortality, including death from CVD, and increasing physical activity to recommended levels can reduce CVD by 20-35%. ⁸ Although not yet verified in schizophrenia, by extrapolation, increasing physical activity should equally reduce CVD in people with schizophrenia, and thereby help to close the widening mortality gap.

Schizophrenia and physical activity

Compared with the general population, people with schizophrenia are more sedentary, with only around 25% ^{Reference Faulkner, Cohn and Remington9} (v. approximately 34% in the general population ^{Reference Townsend, Bhatnagar, Wickramasinghe, Scarborough, Foster and Rayner10} ) engaging in the UK recommended amount of physical activity, defined as 150 min of moderate-intensity exercise such as brisk walking per week.

Increasing physical activity seems fundamental to prevent and manage many of the physical health problems prevalent in people with schizophrenia (including those relating to vascular risk), to reduce premature mortality and improve well-being. ^{Reference Richardson, Faulkner, McDevitt, Skrinar, Hutchinson and Piette11} Primary and secondary care treatment programmes should therefore target physical activity levels. But challenges exist; the evidence base is insufficient to confirm which behaviour-change methods are appropriate for people with schizophrenia and to identify the optimal means of providing such interventions. We urgently need better clinical trial evidence to determine how best to increase levels of physical activity in this population and reliably inform clinical practice.

The challenge of increasing physical activity in schizophrenia

Complex psychological, social, environmental and biological factors influence the uptake and maintenance of physical activity in the general population and there are many hurdles, such as cost of and access to exercise/leisure facilities. For people with schizophrenia, additional barriers to engaging with physical activity include lack of social support, positive and negative symptoms, and medication side-effects (including weight gain, excessive sweating and sedation). ^{Reference Johnstone, Nicol, Donaghy and Lawrie12} Although interventions designed to improve health in the general population might be similarly successful in people with schizophrenia, many trials of health promotion programmes specifically exclude people with serious mental illness. Consequently, the evidence base is insufficient to confirm how best to facilitate the uptake and maintenance of physical activity with consideration of the barriers that people with schizophrenia can face.

It has been suggested that flexible, tailored physical activity programmes aligned to psychiatric services and based on behaviour modification principles - action-planning, goal-setting, self-monitoring, social support and gradual change - are more likely to be effective in people with serious mental illness than simple advice and referral to exercise classes/gym sessions. ^{Reference Richardson, Faulkner, McDevitt, Skrinar, Hutchinson and Piette11} However, because the majority of the studies on increasing physical activity in schizophrenia have not been systematically developed from an explicit theoretical underpinning, we do not understand the underlying mechanisms of physical activity behaviour in this patient group. Which behavioural components should we therefore target, and how should we intervene to produce long-term engagement with regular physical activity? The lack of a rational basis from which to design studies and the existence of multiple behaviour-change theories make these questions challenging for researchers to answer.

The nature of the existing evidence

Interventions to increase physical activity can involve simple, free activities such as walking, can be easily incorporated into everyday life and can be cost-effective. Physical activity interventions for people with schizophrenia have been conducted in hospital and out-patient settings and involved aerobic and strength exercise programmes, walking, jogging, yoga and relaxation. Results have generally been positive, showing improvement in physical and/or mental health. ^{Reference Gorczynski and Faulkner4} Comparing studies and identifying their active components is however problematic because of their mixed quality, and heterogeneity of intervention, outcome measures and follow-up. ^{Reference Gorczynski and Faulkner4}

As few extant studies are developed within a theoretical framework and identify which components of behaviour they are targeting and why, they are limited in the extent to which they increase insight into the mechanisms that underlie physical activity behaviour change in this population. Interventions should be based on an understanding of the processes by which health outcomes are achieved, which can and do vary in different populations. Trials of interventions designed specifically for people with schizophrenia (and subsequent systematic reviews) will inform guidelines to help healthcare professionals identify and act on opportunities for behaviour change appropriately and effectively.

Replication of existing physical activity interventions is hampered by the lack of methodological manuals to guide practitioners. Furthermore, the relatively brief nature of most trials and the lack of long-term follow-up limit the conclusions that can be drawn regarding the maintenance of any positive changes in physical activity behaviour over time.

Additionally, there is too much focus on reducing antipsychotic-associated weight gain as an outcome measure for interventions. Regardless of the usefulness of physical activity as a strategy for managing weight gain, and the beneficial effects of reducing body mass index in those who are obese, increased cardiorespiratory fitness has been found to be a more important predictor of health outcomes than being overweight.

How might effective physical activity interventions for schizophrenia be designed, implemented and evaluated? One way might be for researchers to utilise the Medical Research Council framework for the development and evaluation of complex interventions to improve health. ^{Reference Campbell, Fitzpatrick, Haines, Kinmonth, Sandercock and Spiegelhalter13} Adhering to reporting guidelines might enable transparency such that intervention replication, testing and improvement can occur. Such consistency would produce a phased approach to intervention design by systematically building the evidence base on strong foundations. Use of other tools, such as the RE-AIM (Reach, Effectiveness, Adoption, Implementation and Maintenance) framework, ^{Reference Glasgow, Klesges, Dzewaltowski, Estabrooks and Vogt14} could also assist researchers through the process of translating health promotion research into practice.