Hormonal Status and Cognitivo-Emotional Profile in Real-Life Patients With Neuropathic Pain: A Case Control Study

The specific impact of neuropathic pain and recommended neuropathic pain treatments on the hormonal and immune status of patients has been so far poorly explored. This study aimed at studying, in real life, the hypothalamic-pituitary-adrenal axis and the cytokine profile of patients with neuropathic pain. It also explored their links with cognition, emotion, quality of life, and drug treatment.

This prospective study (clinicaltrials.gov NCT01543425) included 60 patients with neuropathic pain and 60 age- and gender-matched healthy volunteers after obtaining signatures of informed consent. A number of parameters were measured: adrenocorticotropic hormone, cortisol, cortisol awakening response, dehydroepiandrosterone sulphate, sex hormone binding globulin, testosterone, 17-β-estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, cytokines, brain-derived neurotrophic factor, and vitamin D. Psychological parameters were assessed by questionnaires.

Patients with neuropathic pain had lower levels of adrenocorticotropic hormone (P = 0.009) and dehydroepiandrosterone sulphate (P < 0.001) than controls, and the cortisol awakening response was impaired. Patients were more depressed and anxious (P < 0.001) and had a diminished quality of life (P < 0.001), which was influenced by cytokines (P = 0.0067) and testosterone (P = 0.028). Antidepressants and antiepileptics appeared to interfere with testosterone and cognitivo-emotional domains.

An impairment of the hormonal status and of the immune system was observed in patients. It identified testosterone as a potential pivotal mediator between antidepressants/antiepileptics and quality of life. Further studies must address the exact impact of different types of drugs on central effects, of gender differences, and of the immune system of neuropathic pain.