If you’re diagnosed with depression, chances are you’ll be prescribed one of a number of selective serotonin reuptake inhibitors (SSRIs)—the most prescribed drugs for the condition and among the best-selling drugs in medicine, full stop.
But there’s a non-drug treatment—simple exercise—that’s proving to be an effective alternative, and it’s not associated with the raft of serious, sometimes deadly, side-effects that the SSRIs are.
WDDTY examines the evidence to see how exercise compares with SSRIs in the treatment of depression.
American psychologist James Blumenthal, PhD, and his colleagues at Duke University in Durham, North Carolina, have conducted a number of studies comparing aerobic exercise with sertraline (sold as Lustral in the UK and Zoloft in the US), one of the more popular SSRIs.
In the first trial—known as the SMILE (Standard Medical Intervention versus Long-term Exercise) study—156 men and women with clinical depression were randomly assigned to one of three treatments: 45 minutes of group exercise three times a week; sertraline; or a combination of the two.
After four months, there were no significant differences in depressive symptoms across all three groups, suggesting that exercise and the antidepressant were equally effective.1
When the same researchers later added two more groups—a placebo group and a home-based exercise group—to the SMILE series of studies, again the efficacy of exercise seemed to be generally comparable to sertraline, and both tended to work better than the placebo.2
Blumenthal and his team also looked into the effects of exercise vs antidepressants in a group of heart-disease patients with depression and came up with the same findings: exercise and sertraline were equally effective at reducing depressive symptoms, and both topped a placebo.3
Things got really interesting when the Duke researchers looked into the long-term impact of the treatments. Among the 83 patients declared free of depression at the end of the first SMILE study, those who’d been in the exercise-only group were less likely to have seen their depression return during the six-month follow-up. Just 8 per cent of them relapsed, compared with 31 per cent of the exercise plus medication group, and 38 per cent of the medication-only group. What’s more, those who’d continued to exercise over the follow-up period were more than 50 per cent less likely to be depressed than non-exercisers.4
Similarly, when the participants of the second SMILE study were reassessed a year later, regardless of which initial treatment group they had been in, those who reported doing regular exercise even after the study ended were the least likely to be depressed a year later.5
Another team of researchers, this time from the Wake Forest School of Medicine in North Carolina, also pitted exercise against sertraline, albeit in a small pilot study of patients with mild depression.
An hour of exercise—a combination of aerobics and resistance training—three times a week for four months proved to be just as effective as sertraline for improving depressive symptoms, and both were better than ‘usual care’, which involved phone calls to check in on the patients and discuss their general health. But exercise, the researchers noted, had “the added benefit of improving physical functioning as well”.6
Exercise also seems able to improve depressed patients who’ve failed to respond to antidepressants. In a 10-week Scottish study of older adults who were at least mildly depressed despite taking drugs, a significantly larger proportion of the exercisers saw a more than 30 per cent reduction of depression compared with the non-exercisers, who attended health-education talks.7
When researchers at the Royal Edinburgh Hospital reviewed all the available evidence for exercise as a treatment for depression, including the prestigious Cochrane Collaboration’s trials register and Library, they came to the conclusion that exercise is “just as effective as antidepressant drugs”.8
There are several plausible reasons why exercise works against depression. For starters, physical activity can have positive physiological effects by boosting feel-good chemicals in the brain and lowering levels of the stress hormone cortisol. Social contact may also have something to do with it, especially as most of the exercise studies involved group exercise, and exercise could also serve as a diversion from negative thoughts.8
In contrast, the whole theory behind SSRIs—that depression is related to low levels of serotonin in the gaps between cells in the brain—has never been proven and could even be wrong, according to the latest research.9
Safety and side-effects
But the most important difference between exercise and SSRIs is its safety. Although some exercise-related injuries have been reported in trials, exercise is generally safe and beneficial for health, with perks for the heart, lungs, brain, bones, muscles and more. SSRIs, on the other hand, have been linked to a long list of side-effects—from insomnia, headaches and muscle pain to an increased risk of stroke and premature death.10 The drugs are even associated with aggressive and suicidal behaviours.11
The bottom line
The evidence suggests that exercise is a viable and valuable treatment option for depression—at least for the mild-to-moderate kind. Unlike drugs, it’s not associated with severe or life-threatening side-effects, and the benefits are long-lasting and have a positive impact on all aspects of health.
So it’s not surprising that a number of experts are now recommending it as a useful non-drug approach for depression. The key caveat is that exercise has to be treated like medicine.
According to Madhukar Trivedi, professor of psychiatry at the University of Texas Southwestern Medical Center in Dallas, “the dose of the treatment is very important; you can’t just go for a stroll in the park”. He recommends three to five sessions a week, each lasting 45 to 60 minutes, and the level of exertion should push patients to 50 to 85 per cent of their maximum heart rates.
Trivedi also says there has to be “constant vigilance about the monitoring of symptoms. If the treatment is not working, you need to do something.”
But that ‘something’ doesn’t necessarily need to be drugs. Besides exercise, a number of non-drug therapies have been proven to work for depression, including ‘talking therapies’, nutritional supplements and herbals like St John’s wort. Ultimately, a multipronged, holistic approach offers the best chance of success.
When Duke University researchers looked at how patients’ depression fared after treatment with exercise, the antidepressant sertraline or a combination of the two, 83 patients became free of depression, spread evenly across the three groups. But when the team checked in on these patients six months later, those in the exercise-only group were significantly less likely to see their depression return.
Just 8 per cent of them relapsed, compared with 31 per cent of the exercise plus medication group, and 38 per cent of the medication-only group.