In recent years the discussion around mental health has hit the mainstream. The conversation has been important in breaking down barriers and stigma but more than ever we need to know what we can do to improve mental health. I am sure I do not need to convince readers of this blog that depression is a global issue, however I cannot start without highlighting these statistics for young people:
- Depression is the leading contributor to the global burden of disease in young people under the age of 25 (Gore et al., 2011)
- Rates of depression rise steeply at the onset of puberty and throughout adolescence (Hankin et al., 1998)
- Both clinical and subclinical depression in young people predict depression and other mental health problems in adulthood (Naicker et al., 2013).
The statistics underline the need for early detection and treatment. However, worldwide most mental health service needs for young people are unmet, even in wealthier societies (Patel et al., 2007) and treatment dropout is common (DeHaan et al., 2013). There are significant barriers to young people accessing treatment, such as perceived stigma, waiting times and lack of mental health knowledge (Plaistow et al., 2014). Therefore, further research is essential to design a wide range of accessible and acceptable interventions.
Both depression and low activity levels are linked to negative health consequences (Lee et al., 2012; Goldstein et al., 2015), hence intuitively a promising avenue of research is into the benefits of exercise for depression. Physical activity as a treatment for mental health problems has been blogged about several times right here on The Mental Elf and recent meta-analytic reviews of adult trials have demonstrated that physical activity can reduce depressive symptoms with a moderate to large effect (Schuch et al., 2016).
Meta-analysis of child and adolescent trials have identified small to moderate effects for depression. However, previous research relied on trials delivered to healthy samples, samples with other primary presenting problems (e.g. obesity, anxiety) or with children under 12. It has not yet been established whether physical activity delivered as an intervention significantly improves depressive symptoms for young people (aged 12-25), particularly for those experiencing clinical levels of depressive symptoms.
This latest thorough systematic review and meta-analysis by Bailey et al., (2017) primarily aims to estimate the effect of physical activity on depressive symptoms. It also aims to answer these secondary research questions:
- Is physical activity an acceptable intervention for depression in young people?
- Does age group, diagnostic status, depression severity and type of control group modify the treatment effect?
- Does the type of physical activity in the intervention effect depressive symptoms?
A systematic search of electronic databases was conducted (PsycINFO, MEDLINE, EMBASE) from 1980 to June 2015. Adolescents and young adults aged 12 to 25 years with a diagnosis of depression, or depressive symptoms as defined by a cut-off score on a validated symptom measure were included. Studies that explicitly recruited samples with a co-morbid mental disorder diagnosis were excluded. Interventions were included if they aimed to treat or reduce depression or depressive symptoms with physical activity. Physical activity was defined as “any body movement resulting from the contraction of skeletal muscle that increases energy expenditure”.
Risk of bias (quality) assessment
The Cochrane Risk of Bias Tool was used. Two researchers conducted ratings independently and discrepancies were discussed in order to reach consensus. GRADE criteria included the limitations of study design, indirectness of evidence, inconsistency of results, imprecision of results and probability of significant publication bias.
Participant and trial characteristics
Overall, 17 trials met criteria for analysis. Sample sizes ranged from 20-106 participants (median =47) and mean age ranged from 15.4 to 25. Eight trials were conducted with female only participants, 5 recruited clinical samples and baseline depression severity ranged from mild n=4 to moderate n=10 to severe n=2.
Ten trials recruited an inactive sample, while seven did not report baseline activity level. Twelve trials used aerobic based physical activity, with considerable variation in type of activity. Intervention periods ranged from 5 to 12 weeks (median=8), with 1-5 activity sessions a week (median=3). Session duration ranged from 30-90 mins (median=60). Control groups ranged from no treatment (n=5), wait-list (n=5), and attention/activity placebo (n=7). Placebo conditions consisted of stretching/flexibility (n=3), relaxation (n=1), physical education (n=1), very light activity (n=1) and an unguided group meeting (n=1)
- Physical activity showed moderate to large effects for improving depression symptoms in young people who had experienced a diagnosis or a defined threshold of clinically significant symptoms of depression
- 11% of participants dropped out of the physical activity arms of the intervention, hence Bailey et al., (2017) concluded that physical activity was an acceptable and feasible intervention modality for young people experiencing depression
- Sub-group analyses suggest that the treatment effect may not be modified by characteristics such as age, depression severity, diagnostic status, physical activity type or intensity
- Overall the quality of evidence contributing to the meta-analysis was rated as low to very low, serious or very serious limitations in study design and suspected publication bias led to a downgrading of the evidence by two to three levels.
Bailey and colleagues conclude that physical activity is a promising primary intervention for adolescents and young people experiencing a diagnosis or threshold symptoms of depression.
However, they have concerns surrounding the methodological quality of the trials included, which limit their ability to draw robust conclusions. Therefore, large well-reported and robust trials conducted with help seeking clinical samples in real world treatment settings are required to increase the confidence in the current findings.
Strengths and limitations
- Bailey and colleagues included Randomised Control Trials and used a comprehensive search and systematic methodology to identify trials and extract data
- Systematic tools were used to assess bias and overall evidence quality
- Participants were required to meet criteria for a diagnosis or threshold depression symptoms within a trial, potentially enhancing the clinical applicability of the findings.
- Each analysis was restricted to a very small number of trials and therefore bias cannot be ruled out from the overall effect size
- The subgroup analyses were observational and underpowered and should be interpreted with caution
- There was an over-representation of female-only samples
- A limited number of trials have been conducted using physical activity as an intervention, particularly in clinical samples
- Bailey et al., (2017) were unable to investigate the effect of physical activity over the longer term follow-up and the relative benefits of physical activity compared with established depression treatments such as medication and psychotherapy.
Implications for practice
The current findings highlight the potential for physical activity as a stand-alone intervention for young people with depression. However, this meta-analysis suggests the current evidence base is not of sufficient quality to make any clear recommendations. Instead it demonstrates the need for large scale replication trials particularly with clinical samples.
This review displays some common intervention characteristics, such as the use of supervised group sessions of aerobic activity, with moderate to vigorous intensity over 60-minute sessions multiple times per week through an eight-week period. These findings may help the design of future trials.
Bailey et al., (2017) also emphasised that more work is required to determine what ingredients of physical activity bring about improvement in depression and further investigation is necessary to understand how best to implement a physical activity intervention in clinical settings. Also missing from the current evidence base is an investigation of the effect that physical activity interventions have on physical health outcomes in depression. This is a key outcome variable that future research should look to include.
Trying my best not to sound like a broken record, but larger high-quality clinical trials are needed before real conclusions can be drawn about the benefits of physical activity as an intervention for depression in young people.
This meta-analysis does offer some useful pointers as to the potential designs of these interventions and helps to display the areas of necessary future research such as, the mechanisms physical activity works on, the implementation in clinical settings and the type of physical activity.
Considering all the other health benefits that are gained from exercise it is hard to see why it would not also be beneficial for depression in young people. However, at this stage we must remain sceptical in using it as a primary treatment for depression but continue to encourage healthy physical activity in day to day life.
Conflicts of interest
No conflict of interest.
Bailey AP, Hetrick SE, Rosenbaum S, Purcell R, Parker AG (2018). Treating depression with physical activity in adolescents and young adults: a systematic review and meta-analysis of randomised controlled trials. Psychological Medicine 48, 1068–1083. https://doi.org/10.1017/S0033291717002653
de Haan, A. M., Boon, A. E., de Jong, J. T., Hoeve, M., & Vermeiren, R. R. (2013). A meta-analytic review on treatment dropout in child and adolescent outpatient mental health care. Clinical psychology review, 33(5), 698-711.
Goldstein, B. I., Carnethon, M. R., Matthews, K. A., McIntyre, R. S., Miller, G. E., Raghuveer, G., Stoney, C., Wasiak, H., & McCrindle, B. W. (2015). Major depressive disorder and bipolar disorder predispose youth to accelerated atherosclerosis and early cardiovascular disease: a scientific statement from the American Heart Association. Circulation, CIR-0000000000000229.
Gore, F. M., Bloem, P. J., Patton, G. C., Ferguson, J., Joseph, V., Coffey, C., Sawyer, S., & Mathers, C. D. (2011). Global burden of disease in young people aged 10–24 years: a systematic analysis. The Lancet, 377 (9783), 2093-2102.
Gulliver, A., Griffiths, K. M., & Christensen, H. (2010). Perceived barriers and facilitators to mental health help-seeking in young people: a systematic review. BMC psychiatry, 10, 113.
Hankin, B., Abramson, L., Moffitt, T., Silva, P., McGee, R., & Angell, K. (1998). Development of depression from preadolescence to young adulthood: Emerging gender differences in a 10-year longitudinal study. Journal of Abnormal Psychology, 107, 128-140. doi: http://dx.doi.org/10.1037//0021-843x.107.1.128
Lee, I. M., Shiroma, E. J., Lobelo, F., Puska, P., Blair, S. N., Katzmarzyk, P. T., & Lancet Physical Activity Series Working Group. (2012). Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy. The lancet, 380(9838), 219-229.
Naicker, K., Galambos, N. L., Zeng, Y., Senthilselvan, A., & Colman, I. (2013). Social, demographic, and health outcomes in the 10 years following adolescent depression. Journal of Adolescent Health, 52, 533-538.
Patel, V., Flisher, A. J., Hetrick, S., & McGorry, P. (2007). Mental health of young people: a global public-health challenge. The Lancet, 369(9569), 1302-1313.
Plaistow, J., Masson, K., Koch, D., Wilson, J., Stark, R. M., Jones, P. B., & Lennox, B. R. (2014). Young people’s views of UK mental health services. Early intervention in psychiatry, 8, 12-23.
Schuch, F. B., Vancampfort, D., Richards, J., Rosenbaum, S., Ward, P. B., & Stubbs, B. (2016). Exercise as a treatment for depression: a meta-analysis adjusting for publication bias. Journal of psychiatric research, 77, 42-51.