Physical activity participation in severe mental illness #ClosingTheGapSMI

It is now widely known that people with severe mental illness (SMI) are at greater risk of early mortality, resulting from greater physical health problems (Mishu et al, 2018). This topic has received much attention in past blogs due to its importance (Bell, 2018; Wallace, 2018; Tomlin, 2013). Cardiovascular disease, diabetes, respiratory diseases resulting from high cholesterol, blood pressure, blood glucose, obesity and lifestyle factors are all common in people with SMI (De Hert et al, 2011).

One solution to addressing this problem may be to target health behaviours linked to physical health problems in people with SMI. Some of the unhealthy behaviours observed in people with SMI are greater sedentary behaviours such-as sitting for long periods and limited physical activity (Stubbs et al., 2016a; Stubbs et al 2016b; Vancampfort et al., 2016; Vancampfort et al., 2017a). The benefits of physical activity are well reported in the general population, however, there is mixed evidence on the effectiveness of physical activity interventions and uptake in people with SMI (Rosenbaum et al, 2014; Firth et al, 2017; Vancampfort et al, 2017b; Ashdown-Franks et al, 2018; Pearsall et al, 2014). It is therefore clear that more ground work may be needed prior to developing interventions in order to make them more effective. Epidemiological studies identifying specific characteristics that are linked to physical activity in people with SMI (e.g. age, gender, BMI etc.) could help to inform and develop ‘tailor-made’ interventions to meet specific needs. For example, less vigorous physical activity interventions for people with a high BMI struggling with movement.

A review on people with schizophrenia, bipolar and major depressive disorder showed that lower moderate or vigorous physical activity was associated with higher antidepressant intake, a diagnosis of schizophrenia, being unemployed, being male, lower cigarette intake, higher BMI and lower cardiorespiratory fitness (Vancampfort et al, 2017b). Similar findings related to older age, being male and higher BMI have been reported in reviews considering bipolar disorder and schizophrenia independently (Stubbs et al, 2016a; Vancampfort et al, 2016). A limitation of this research area is that there is a lack of data on large samples of people with SMI; a larger sample size would afford greater statistical power and in theory, greater confidence in the generalisability of findings.

This blog considers a new paper published in ‘Social Psychiatry and Psychiatric Epidemiology’ that aims to address the limitations in this area, reporting data on factors influencing PA on a recruited cohort of 3,287 people with SMI in England.

Being more physically active could help reduce health problems and early death in people with severe mental illness.

Methods

Participants with the following characteristics were recruited in England via their mental health teams or general practitioners (GPs):

Either a diagnosis of schizophrenia, other psychotic disorders, bipolar disorders or depression with psychotic features,
Aged 18 and above,
Capacity to consent.

A survey covering demographic, biological, psychological and behavioural questions was completed by participants. The authors of this paper were interested in the amount of ‘regular physical activity’ as the main outcome. This was measured by grouping responses regarding frequency of physical activity participation into either ‘regularly undertaking physical activity’ or ‘not regularly undertaking physical activity’. An analysis accounting for multiple factors (multivariable logistic regression) was performed, to determine what predicted regular physical activity. The factors included were based on prior literature and analysis.

Results

Out of 3,257 participants, the majority were:

Male (59%)
White British (86%)
Classed as ‘not working, retired’ (68%).

In multivariable logistic regression analysis, doing less regular physical activity was predicted by:

Being female
Aged 65 years and over
Being underweight (body mass index of <18.5 kg/m²) or overweight (body mass index of >30 kg/m²)
Moderate and poor self-rated health
Perceptions that maintaining a healthy lifestyle was either ‘moderately important’ or ‘not important’
Consuming two or fewer portions of fruit and vegetables per day

Doing more regular physical activity was predicted by:

Reporting having health that did not limit activity

Factors that did not statistically predict doing regular physical activity:

Smoking status

Being female, older, under or overweight, having negative health perceptions and less frequent fruit and vegetable intake were associated with participating in less regular physical activity.

Conclusions

The authors concluded that: “The findings supported existing literature that being physically active is a complex behaviour in patients with SMI…” given the association between physical activity, self-perceptions of health and maintaining healthy lifestyles.

They also suggested that future work should focus on the development of interventions to increase physical activity in people with SMI. However, they argue that in order to inform and develop interventions based on meeting specific needs, further work identifying factors that support, hinder and preferences for physical activity are needed for people with SMI.

We need to understand the barriers and facilitators of physical activity better, to inform future interventions for people with severe mental illness.

Strengths and limitations

This is one of the largest cohorts of people with SMI recruited to a research study and one of the first studies to explore predictors of physical activity in such a large sample, thereby addressing gaps and limitations of previous work.

Self-reported physical activity in people with SMI is liable to error. The measure of physical activity used in the survey was also not validated in either people with SMI or those in the general population. Therefore, the accuracy of physical activity is unclear. Other variables such as height and weight to calculate BMI and fruit intake also relied on participant responses and may contain inaccuracies.

It is unclear whether some exposures (BMI, self-perceived health) were predictive of physical activity or vice versa, as the outcome and predictors were collected at the same time point. However, the study is part of a larger project which aims to follow participants over time, so further analysis could be conducted.

The representativeness of the sample is unclear:
- There is no indication of the response rate, or whether any differences existed between those that took part and declined. Ethnic minorities are also underrepresented despite the greater occurrence of psychosis in black ethnic groups (Qassem et al, 2015).
- GPs and mental health teams contacted participants for recruitment and it is possible that those who engaged with health services were more likely to participate. However, many people with SMI do not engage with health services and it is unclear whether ‘hard-to-reach’ participants were recruited.
- Understandably, the inclusion criterion was specific to those with mental capacity. However, there may have been a greater need for health improvement amongst those who were more acutely unwell.

The variables entered into statistical models were based on prior literature. However, other systematic reviews explored the effect of different healthcare settings and employment on physical activity and despite being available, were not included in the multivariable analysis. In fact, employment was statistically associated to physical activity participation in bivariate analysis, but there is no indication why it was not included in multivariable analysis.

Implications for practice

Future research should:

Explore the use of physical activity measures that do not rely on participant responses such as accelerometers and stronger methods of measuring exposure data (e.g. clinical measures of height and weight) where possible. Validated measures should be used if relying on self-report.

Recruit large representative samples of people with SMI including: ‘hard-to-reach groups’, those that are acutely unwell and ethnic minority groups.

Explore longitudinal methods (where the exposure is collected before the physical activity outcome occurs) to clarify issues of causality based on recommendations made in prior work (Hassan et al., 2019).

Explore the impact of psychological and cognitive factors on different types of physical activity with large representative samples to determine whether trials should be based on health perceptions and needs.

Explore the effect of other variables on physical activity/ types of physical activity participation including: mental health symptoms, medications, illness duration, differences between different healthcare settings, employment and area-level factors.

Some findings overlapped with prior cross-sectional systematic reviews including the association between older age, higher BMI and less physical activity (Stubbs et al, 2016a; Vancampfort et al, 2016). These findings may imply that low intensity physical activity interventions should be developed for such groups. Alternatively, targeting patients at the early stages of their illness could be important for the uptake of physical activity. However, more work replicating such findings with representative samples should inform the basis of such recommendations.

It was encouraging that most people reported wanting to change their lifestyle by doing more physical activity in this study. This further strengthens the argument that research should be continued in this area to develop interventions that work for people with SMI.

In this study, most people with severe mental illness reported wanting to change their lifestyle by doing more physical activity.

Conflicts of interest

Suzan Hassan is currently completing a PhD funded by the National Institute for Health Research (NIHR) School for Primary Care Research (SPCR) based on similar research, exploring factors that may influence health behaviours in people with severe mental illness.