Although pain is not listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM) as a symptom of major depressive disorder (MDD), previous studies have shown that a large proportion of patients with depressive report symptoms of pain. In addition, research has shown that pain and depression may share common pathways in the body. They may be connected through stress and the hypothalamic-pituitary-adrenal axis.
This study aimed to see how baseline levels of pain affect outcomes in patients treated for MDD with fluoxetine. Specifically, the study hypothesized that severity of baseline would be associated with poorer outcomes and a distinct clinical profile. For 6 weeks in an in-patient hospital, 119 MDD patients were given 20 mg fluoxetine daily doses and monitored for various outcomes. Outcomes included adherence, pain severity and pain interference (measured by the body pain index of the Medical Outcomes Study Short-Form), symptom severity (measured by the Hamilton Rating Scale for Depression), social functioning (measured by the Work and Social Adjustment Scale), and adverse event severity (Utvalg for Kliniske Undersogelser Side Effect Rating Scale).
Results from this study showed that pain and multiple aspects of MDD were associated and that patients with higher baseline levels of pain experienced more severe depressive symptoms. Specifically, subjects with higher levels of pain had greater risk of suicide and stressful life events. They also had less improvement in depressive symptoms despite receiving the same fluoxetine treatment as well as more functional impairment.
This study reminds me of the pain lecture from Dr. Pruskowski as she also explained the connection between depression and pain. Being cognizant of this connection can help us better understand our patients as pharmacists. Perhaps we can inquire about MDD patients’ pain levels during medication therapy management. I would be curious to see if there is evidence supporting the use of pain treatments to help improve depressive symptoms in those with both severe pain and depression. If so, many patients may have a drug therapy problem of needing additional therapy.