Low back pain and depression have been recognized as key public health problems around the world. Back pain has been ranked as the highest cause of disability worldwide, and depression is also a leading cause of global health-related burden. Research has shown that these two conditions often occur together, but the question remains of which comes first? It could be that the long-lasting, painful nature of back pain contributes to depression, or that depression somehow promotes back pain.
Previous research has had limitations that this MIDUS study sought to overcome:
- Most research has been conducted with patients, which may limit generalizability of results. This study instead used MIDUS data from a national sample of adults from the general population. It also looked at both people who did and did not have back pain and depression.
- Most prior studies have looked at depression and back pain at one point in time. Instead, this study used longitudinal data from MIDUS to examine how both changed over time, in order to look at which came first.
- Most prior studies have examined whether depression promotes back pain or back pain promotes depression. This study, however, considered bidirectional associations, looking at whether back pain leads to depression and visa versa.
Researchers looked at over 2000 people, in whom they measured:
- Low back pain: Participants were considered to have low back pain if they reported having back pain almost every day or several times a week in the last 30 days.
- Major depression: was diagnosed based on reports of sadness or depression that lasted two weeks during the last year and included symptoms such as: losing interest in most things, feeling more tired than usual, having trouble falling asleep or concentrating, feeling worthless, and thinking about death.
- Both were measured at Time 1, then measured again 9 years later at Time 2.
- When analyzing the data, researchers took into account participants’ age and sex, socioeconomic status (education and personal earnings), and behavioral factors (exercise, smoking, alcohol consumption, and obesity).
Results showed that:
- Among those with back pain, 17.4% also reported major depression. This compared to only 10.5% of people without back pain who reported depression.
- Among those with major depression, 37.4% also reported back pain, compared to only 22.5% without depression who reported back pain.
- Having back pain at Time 1 was significantly associated with having depression at Time 2.
- However, having depression at Time 1 was also associated with having back pain at Time 2.
These results indicate that back pain and depression have a bidirectional association, such that each can contribute to the other. Further research is needed to look at the pathways through which this can happen. One possible explanation from recent brain imaging studies shows that depression and back pain may share a common neuroplasticity mechanism that helps the brain adapt. Another possibility is job strain, which has been linked to both back pain and depression. The researchers suggest that since both can be highly debilitating problems, it may be of value to assess patients presenting with depression for back pain, and visa versa.
Yang, H., Hurwitz, E. L., Li, J., de Luca, K., Tavares, P., Green, B., & Haldeman, S. (2023). Bidirectional comorbid associations between back pain and major depression in US adults. International Journal of Environmental Research and Public Health, 20(5), Article 4217. https://doi.org/10.3390/ijerph20054217Read the full article at: http://www.midus.wisc.edu/findings/pdfs/2656.pdf