Healint's First study on Depression

Depression and pain are both common and disabling conditions that often co-occur. While many studies have reported a strong association between depression and pain, the nature of this relationship remains unclear. Some researchers have suggested that depression may contribute to the development or exacerbation of pain, while others have proposed that pain may trigger or worsen depressive symptoms. Additionally, a few studies have challenged the notion of a direct causal relationship between the two conditions, proposing that shared underlying genetic or environmental factors may largely explain the observed association.

Several studies have provided evidence supporting the link between depression and pain. For instance, Dersh et al. (2002) found that individuals with depression were more likely to report pain and functional impairments than those without depression. Similarly, Bair et al. (2004) found that depression was associated with higher levels of pain and disability in a sample of patients with chronic pain. Furthermore, treating depression has been found to lead to improvements in pain outcomes, suggesting that addressing both conditions may be important for optimal patient care.

On the other hand, Sullivan et al. (2018) found that the association between depression and pain was largely explained by shared genetic and environmental factors, rather than a direct causal relationship. This challenges the notion that depression causes pain, or vice versa, and suggests that a more nuanced understanding of the relationship between these conditions is needed.

In light of these different findings, the study conducted by Healint aimed to interrogate individuals who suffer from depression and assess their level of pain or disability according to their level of depressive symptoms and according to whether they are diagnosed or treated for depression. We used clinically validated scales to establish the assessments, including the Patient Health Questionnaire (PHQ9) for depressive symptoms, the Pain Frequency, Intensity and Burden Scale (P-FIBS) for pain, and the Sheehan Disability Scale (SDS) for disability. The ultimate goal of this study was to shed light on the relationship between depression and pain, and to provide insights that may inform the development of effective interventions for these common and debilitating conditions.

The study included 185 participants with a mean age of 40.6 years. Among them, 71.9% were diagnosed and 28.1% were not diagnosed for depression. The proportion of diagnosed individuals was higher among those with lower income (<$20,000 per annum) compared to those with higher income (>$100,000 per annum), with 76.9% and 56.5% respectively.

Distribution of the participants by various income levels.

61.1% of participants were being treated for depression. Of those who were diagnosed, 51.5% were diagnosed by a psychiatrist, 27.9% by a general practitioner, and 14.7% by another mental health specialist.

The PHQ9 score was found to be higher in individuals with lower income (24.1) compared to those with higher income (18.6). The score decreased as the income increased, with scores of 22.4 for individuals making between $20,000 and $50,000 per annum, and 21.0 for individuals making between $50,000 and $100,000 per annum. Additionally, the PHQ9 score was higher in individuals diagnosed with depression (23.1) and those being treated for depression (23.1) compared to those without a diagnosis (18.5) or treatment (19.8) for depression.

The P-FIBS score was also higher in individuals with lower income (19.6) compared to those with higher income (17.1). The score decreased as the income increased, with scores of 18.1 for individuals making between $20,000 and $50,000 per annum, and 17.6 for individuals making between $50,000 and $100,000 per annum. Similarly, the P-FIBS score was higher in individuals diagnosed with depression (18.7) and those being treated for depression (19.2) compared to those without a diagnosis (16.6) or treatment (16.3) for depression.

The SDS score was found to be similar in all income ranges except for individuals with an income higher than $100,000 per annum, who had a lower score of 9.5. The SDS score was also higher in individuals diagnosed with depression (14.7) and those being treated for depression (14.9) compared to those without a diagnosis (8.6) or treatment (9.9) for depression. Additionally, individuals diagnosed with depression and those being treated for depression reported a higher number of days lost over the last week (2.8 and 2.9 days lost respectively) compared to those without a diagnosis or treatment (1.5 and 1.6 days lost respectively).

Interestingly, no direct correlation was found between P-FIBS score and PHQ9 score (R2=0.18), PHQ9 and SDS score (R2=0.38), or SDS and P-FIBS score (R2=0.18).

Overall, the data suggest that there is a link between depression, pain, and disability. Participants with lower income, those diagnosed with depression, and those being treated for depression had higher scores on the PHQ9 and P-FIBS scales, as well as higher SDS scores and a higher number of days lost due to disability. However, there was no direct correlation found between the three scales, indicating that depression, pain, and disability may be independent factors in some cases.

Bair, M. J., Wu, J., Damush, T. M., Sutherland, J. M., & Kroenke, K. (2004). Association of depression and anxiety alone and in combination with chronic musculoskeletal pain in primary care patients. Psychosomatic Medicine, 66(6), 898-902.

Dersh, J., Gatchel, R. J., Polatin, P. B., & Mayer, T. G. (2002). Prevalence of psychiatric disorders in patients with chronic disabling occupational spinal disorders. Spine, 27(1), 75-81.

Sullivan, P. F., Agrawal, A., Bulik, C. M., Andreassen, O. A., Børglum, A. D., Breen, G., ... & Duncan, L. (2018). Psychiatric genomics: an update and an agenda. American Journal of Psychiatry, 175(1), 15-27.