Chronic pain can greatly affect a patient's daily functioning and significantly impact health-related quality of life (Pain 2005;119:1-4). Undertreated or untreated chronic pain in children can be especially burdensome to families by disrupting routines, restricting the child's daily activities, and increasing risk of long-term disability (Paediatr Drugs 2002;4:737-46). Therefore, it is not unusual for chronic pain to be highly comorbid with psychiatric disorders. This association is mediated by significant overlap in biological pathways.
First, central and peripheral noradrenergic (NA) and serotoninergic (5-HT) pathways are affected in both pain and mood disorders (Prog Neuropsychopharmacol Biol Psychiatry 2018;87B:290-7; J Psychiatry Neurosci 2001;26:21-9). A pathway involving serotonergic neurons in the dorsal raphe nucleus has been implicated in chronic pain as well as depression (Nat Neurosci 2019;22:1612-4). Both NA and 5-HT brainstem-spinal descending systems suppress nociceptive signals from afferent neurons, and the activation of spinal...
