Wednesday June 6 2012
New research does not mean exercise doesn't fight depression
“Exercise doesn't help depression,” according to The Guardian. The paper said that patients advised to exercise fare no better than those who receive only standard care.
Exercise is among the treatments for depression currently recommended by the NHS, with many patients 'prescribed' a course of physical activity as an alternative to antidepressant medication or therapy. Despite what several headlines have suggested, new research has not re-examined the effect of exercise on depression, but instead looked at whether giving depressed patients additional support to encourage exercise proved beneficial.
During the research, 361 adults with depression were randomly allocated to receive either standard treatment or standard treatment with additional encouragement and advice on exercise. Standard treatment can include medication, therapy and physical activity. This means that all participants could take up prescribed exercise, but some had greater encouragement to do so.
The research found that encouraging activity increased physical activity levels but did not reduce depressive symptoms more than standard care alone. This is a useful finding for NHS staff wishing to know the best way to help patients with depression. However, given that the study did not test the general effect of exercise, the results do not support the view that exercise is 'useless' for treating depression, as some news sources have suggested.
Exercise has a host of benefits for physical and mental health, which may help patients with depression in ways other than reducing their immediate depressive symptoms. These include reducing the risks of other diseases such as obesity, cardiovascular disease and diabetes.
Where did the story come from?
The study was carried out by researchers from the Universities of Bristol and Exeter, and the Peninsula Medical School. It was funded by the Department of Health as part of the National Institute for Health Research’s Health Technology Assessment programme.
The study was published in the peer-reviewed British Medical Journal.
Media reports of this story were slightly misleading, and may have given the impression that the researchers specifically tested the effect of exercise. This was not the case, as the research compared two groups of people who were offered the same range of treatments, but with one group receiving additional support and advice designed to encourage exercise. This meant that all participants had access to exercise-based treatments, but some received some additional encouragement.
The Metro newspaper went too far in saying that the study showed exercise “had no positive benefits on mental health”. The study in question looked at the effect of one particular exercise intervention programme on depression symptoms, so did not directly address other mental health problems or other exercise programmes.
What kind of research was this?
This UK-based multi-centre randomised controlled trial (RCT) looked at whether a specific exercise support programme helped reduce symptoms of depression in adults more than standard care alone. The study was 'pragmatic' in nature, which means it tested interventions in a real-world setting rather than in the highly artificial environment of many trials. For example, patients were prescribed the most appropriate form of treatment from a range currently used in clinical practice, rather than a set treatment that might not have been ideal for them. As such, the study was well designed to assess how the exercise programme would work in reality.
The authors say previous evidence suggests that exercise is beneficial for people with depression, but that this evidence has come from small, less well-designed studies using interventions that may not be practical for use by the NHS. Therefore, this latest research aimed to investigate whether depression symptoms could be reduced by an activity programme that could be practically implemented by the NHS if deemed effective.
This type of study is one of the most effective at demonstrating whether a particular health programme, or 'intervention', has a measurable benefit in patients.
What did the research involve?
The researchers recruited 361 patients, aged 18 to 69 years old, who had recently been diagnosed with depression by their GP. Participants were randomly divided into two groups, who received either usual care methods from their GP or usual care plus a physical activity intervention.
Participants were recruited if they were not taking antidepressant medication at the time of initial diagnosis or if they had been prescribed antidepressants but had not taken these for at least four weeks before their diagnosis. Patients with depression who had failed to respond previously to antidepressants were excluded from the study, as were people aged 70 or over.
Participants in both groups were asked to continue to follow the healthcare advice of their GP for their depression. This was classed as 'usual care' by the researchers. Both groups were, therefore, free to access any treatment usually available in primary care, including antidepressants, counselling, referral to 'exercise on prescription' schemes or secondary care mental health services. However, those in the physical activity group were also offered up to three face-to-face sessions and 10 telephone calls with a trained physical activity facilitator over eight months. The intervention aimed to provide individually tailored support and encouragement to help participants engage in physical activity.
Depression was measured before enrolment and then at four, eight and 12 months after the intervention to measure any changes. Depression was initially diagnosed using standard, recognised assessments, including the 'clinical interview schedule-revised' and the 'Beck depression inventory'. Subsequent changes in depression symptoms were based on self-reported symptoms of depression, as assessed by the Beck inventory score.
During a trial, researchers should aim to conceal, if possible, which treatments participants receive. This is known as 'blinding' and avoids the risk of bias from participants knowing which treatment they are getting. This study was a 'single blinded' RCT as treatment allocation was concealed from the study researchers. It was not feasible to blind the participants to which group they’d been allocated to.
The analysis of this study was appropriate and based on an 'intention to treat principle'. This means that everyone who was allocated to a group was included in the final analysis, irrespective of whether they followed the intervention or dropped out. This is good way of analysing the 'real world' effects of an intervention.
What were the basic results?
At month four, there were no statistically significant improvements in mood among participants encouraged to exercise compared to those in the usual care group. Similarly, there was no evidence that the intervention group had significantly improved mood at the 12-month follow-up compared to those receiving usual care only.
There was no evidence that the exercise intervention led to a statistically significant reduction in the use of antidepressants compared to usual care.
Using data from all three follow-up points combined (four months, eight months and 12 months), the participants in the intervention group reported significantly more physical activity during the follow-up period than those in the usual care group, which was maintained at 12 months. This suggested the activity-support intervention was successful at increasing activity levels. Importantly, the participants stuck with the intervention well and completed on average 7.2 sessions with their exercise advisor. By four months, 102 (56%) participants had at least five contacts with the advisors.
How did the researchers interpret the results?
The researchers concluded that adding an intervention to usual care that encouraged physical activity did not reduce symptoms of depression or the use of antidepressants compared to usual care alone, despite the exercise intervention significantly increasing physical activity levels.
This well-designed randomised control study provides strong evidence that adding an exercise-promoting support programme to standard care did not significantly reduce symptoms of depression compared to standard care alone.
While this study has many strengths, including its large size and randomised design, it is important to bear in mind its limitations.
This study assessed just one type of exercise intervention that involved facilitating greater activity levels. Therefore, this study does not tell us whether other types of support or exercise programme may have a positive effect on depression. Consequently, the study’s findings do not mean that no exercise interventions can reduce symptoms of depression, especially as there is some evidence from systematic reviews that certain types of exercise intervention may be therapeutic.
Also, there are other benefits of exercise beyond those related to mental health. The Daily Mail quoted an expert as saying: “It is important to note that increased physical activity is beneficial for people with other medical conditions such as obesity, diabetes and cardiovascular disease and, of course, these conditions can affect people with depression.” The trial did not assess whether exercise prevents depression.
Exercise has a host of benefits for physical and mental health that may help patients with depression in ways other than reducing their immediate symptoms. However, the finding that this exercise support intervention doesn’t seem to reduce depressive symptoms is very useful to NHS staff wishing to know what interventions may help patients with this condition.
Analysis by Bazian