Anxiety and depression are two of the most commonly-measured components of psychological well-being in SCI. Symptoms of anxiety and/or depression are commonly-reported concerns amongst individuals with SCI, their care partners and/or healthcare providers, and are associated with negative outcomes among individuals with SCI including lower functional independence, more secondary complications, and less community and social integration (Fann et al., 2011). Unfortunately, the likeliness of individuals with SCI experiencing anxiety or depression is significantly higher than age-matched control without SCI (Williams & Murray, 2015). However, the outcome measures used to capture and evaluate symptoms of anxiety and depression in research vary, making the comparison of findings difficult. The goal for this section is to summarize the current state of the research investigating the role of LTPA on symptoms of anxiety and/or depression.
Description of studies. Overall, the studies included in this section found a positive or no relationship between LTPA and symptoms of anxiety and depression. Out of the 26 included studies, 9 were observational and 17 were interventional (8 RCTs, and 9 pre-post trials). The majority of the included studies (17/26) were conducted in North America (6 of which were RCTs, 8 pre-post, and 3 observational). Studies conducted outside of North America were observational studies (6/9) and included 1 in Poland, and 1 each from Australia, Italy, Japan, Korea, and Sweden. Out of the 3 intervention studies conducted outside of North America, 2 were from the UK (1 RCT and 1 pre-post), and 1 RCT from Turkey. Therefore, interpretations made in this section are heavily influenced by studies conducted within North America (5 RCTs, 3 pre-post, and 2 observational from Canada, and 1 RCT, 5 pre-post, and 1 observational from the USA). No studies examined just anxiety, but 16 examined depression (4 RCT, 7 pre-post, and 5 observational), and 10 examined both anxiety and depression (4 RCT, 2 pre-post, and 4 observational).
Overview of the LTPA and depression/anxiety relationship. The majority of RCT intervention studies (6/8) provided evidence in favour of the beneficial role of LTPA interventions on decreasing symptoms of depression. Interestingly, 6 of the 9 pre-post studies showed no significant effect of LTPA intervention on depressive symptoms. Anxiety was less studied; only 6/17 intervention studies (4 RCTs and 2 pre-post) included a measure of anxiety. The intervention studies that measured anxiety reported conflicting findings: 3 RCTs showed no significant effect of LTPA interventions on symptoms of anxiety while 1 RCT showed a decrease. Both pre-post studies showed a positive impact of LTPA interventions on decreasing symptoms of anxiety.
There was a large variety in the types of LTPA used in the intervention studies including arm ergometry, web-based physiotherapy exercises, yoga, tai chi, mobility/range of motion programs, activity coaching/counselling, support treadmill training (using body weight support, pulley assistance, or electrical stimulation), sport, and combined exercise programs (including progressive resistance, aerobic, and stretching training). Studies also varied in terms of the target/included SCI population, and in length and dosage of interventions. No obvious trends were seen with regards to type of LTPA intervention and effect on symptoms of anxiety and/or depression. Further, a remaining challenge is that most studies did not sample for individuals affected by anxiety or symptoms of depression and most of the included studies did not set out to primarily target anxiety or depression. With the exception of a few studies, the primary aims of included studies were related to fitness, function (e.g., walking ability) or LTPA behaviour. Another major limitation to fully understanding the role of LTPA on anxiety and depression is that no studies included individuals who were diagnosed with clinical depression and/or an anxiety disorder.
With regards to the observational studies, 5/9 looked at just depression, and 4/9 looked at both anxiety and depression. Among the 9 studies that measured depression, 7 studies showed a negative relationship between LTPA level and symptoms of depression (i.e., as physical activity increased, symptoms of depression decreased), 2 studies however showed no significant relationship between symptoms of depression and LTPA. These same 2 studies did show an inverse relationship between sports participation and symptoms of anxiety. The remaining 2 studies that looked at anxiety also supported the inverse relationship between LTPA levels and anxiety. Similar to intervention studies, the observational studies varied in the type of LTPA investigated: 4 studies looked at sports involvement while the other 5 looked at other types of LTPA. Noteworthy, the 4 studies that focused on sports ranged in sample size from n=121-1034, but 81-100% of these participants were male. Further research exploring the relationship between LTPA and symptoms of anxiety and depression across sex and/or gender is warranted.
Although the majority of observational studies reported significant findings describing the inverse relationship between LTPA levels and symptoms of anxiety and depression, we do not know if LTPA is improving these symptoms OR if having these symptoms preclude individuals with anxiety and depression to be active. It is likely that unique opportunities and behavioural strategies are needed to help support LTPA participation for individuals with anxiety or depression and SCI. For individuals who do not have a clinical diagnosis of depression or anxiety, the findings from this review suggest that LTPA is safe and may help improve mood/perceived symptoms of depression and anxiety or at least not make them worse. However, the findings from the observational studies reinforce that there is a lack of research among people with SCI with a clinical diagnosis of an anxiety or depression disorder.
Differences in the type and dosage of LTPA intervention as well as the variance in sample size and participant demographics most likely contribute to the conflicting findings across studies. Future studies and further analyses that attempt to control for type of LTPA intervention and dosage and/or SCI demographics such as age, gender, time post injury, and SCI location, and severity are needed to further explore the relationships between LTPA and anxiety and depression. Overall, there is still lots to learn about the role of LTPA on anxiety and depression in individuals with SCI. More research is needed with anxiety and/or depression as the primary outcome, that consider a global perspective and/or cultural/geographical considerations, that look at sex and/or gender differences, and that target individuals with clinical diagnoses of anxiety and depression at baseline. To inform clinical application, it would be helpful if future studies include detailed reports on intervention dosage and proposed mechanisms of effectiveness as well as measures at follow-up timepoints.
There is level 1a evidence from 6 RCTs – and support from level 4 evidence from 3 pre-post studies and level 5 evidence from 7 observational studies – that participation in LTPA can reduce symptoms of depression among persons with SCI. However, there is level 1b evidence from 1 RCT – along with level 4 and 5 evidence from 6 pre-post studies and 3 observational studies – showing no significant effect/relationship between LTPA and depressive symptoms among persons with SCI.
There is level 1a evidence from 2 RCTs supported by another lower level RCT that LTPA intervention had no significant effect on symptoms of anxiety among persons with SCI. There is level 4 evidence from 2 pre-post studies, supported by level 5 evidence of 4 observational studies, that LTPA participation is related to lower symptoms of anxiety for persons with SCI.