Depression in Fibromyalgia Patients May Require Low-Dose Naltrexone to Respond: A Case Report

Fibromyalgia and depression are frequently comorbid. We propose a hormonal system model in understanding the underlying endogenous opioid system dysregulation in fibromyalgia with the utilization of the cold pressor test (CPT) in clinical practice to monitor treatment response to low-dose naltrexone (LDN) and the subsequent remission of major depressive disorder by restoring opioid tone. A 60-year-old professional on permanent disability presented with refractory depression and chronic widespread pain after years of multiple failed medication trials. Rating scales confirmed severe depression, Hamilton Rating Scale for Depression (HAM-D) of 20, a short cold pressor test (CPT) time of 21 seconds, and a face pain scale (FPS) of 8/10. Physical examination assessing for fibromyalgia was diagnostic, with 18/18 positive tender points. LDN, a minor increase in trazodone, and transference-focused psychotherapy were employed. The patient's CPT time increased modestly. The patient achieved remission of both conditions in 10 weeks when both disorders were treated at once (FPS and HAM-D of zero), restoring the quality of life, relatedness, and motivation. Some fibromyalgia patients may achieve remission of comorbid depression with concomitant low-dose naltrexone (LDN) treatment that is widely used "off label" to treat pain. LDN is a promising alternative for the treatment of chronic pain in fibromyalgia with its safety profile, high tolerability, and absence of abuse potential. Our unique finding is that without successful LDN treatment of fibromyalgia, remission of depression may be unlikely.