Central pain processing abnormalities are present in all chronic pain conditions, and some of these conditions are believed to be primarily centralized.
Fibromyalgia is a chronic condition associated with widespread pain and tenderness, as well as general fatigue. Fibromyalgia is considered by many to be a condition that is largely mediated by the central nervous system, given that fibromyalgia sufferers often present without a direct peripheral insult or injury. People suffering from fibromyalgia also often experience sleep disruption, depressed mood, and cognitive impairment. Currently, there are only three FDA-approved pharmacologic treatments for fibromyalgia, but they have limited efficacy and burdensome side effects in many patients.
Neuropathic pain, associated with various conditions, affects an estimated 7% to 9% of the U.S. population. Individuals suffering from this condition, regardless of the underlying disorder, are currently treated with a variety of therapies including antidepressants, anticonvulsants, and opioids. These medications offer inadequate efficacy for a large proportion of patients, are often poorly tolerated due to side effects, and in some cases are associated with abuse.
Diabetic nerve pain is one of the largest neuropathic pain conditions. This condition develops in 60% to 70% of people with diabetes when chronically high glucose levels damages nerves and causes pain, as well as numbness, issues with balance and coordination, and muscle weakness.
Approximately eight and a half million people in the United States suffer from PTSD. PTSD results from a traumatic experience and is characterized by intrusive memories, hyperarousal, withdrawal, and negative changes in cognition, mood and sleep. PTSD can result from various forms of trauma, including combat exposure, car accidents, sexual or other physical assault, abuse, natural disasters, and others. The lifetime prevalence of PTSD is approximately seven percent in the general population but is much higher in populations at risk for exposure to trauma, such as military service members and first responders. In addition to the challenges associated with the direct symptoms, PTSD sufferers have a higher rate of suicide and often struggle with simultaneous addiction, leading to an even greater social and economic burden. Available therapeutic options are limited, including only two approved conventional SSRI antidepressants, which have limited efficacy, undesirable side effects, and target only the symptoms of PTSD, not the underlying disorder.
Cognitive impairment affects approximately half of patients with Parkinson’s disease. It is believed that the loss of dopamine, which is known to be associated with the motor symptoms of the disease, leads to dysregulation in NMDA receptor-associated processes that are important for cognitive function. Cognitive impairment associated with Parkinson’s disease is distinct from other forms of dementia. Attention, memory, executive functioning, and visuospatial function are the most prominently disrupted domains in people with Parkinson’s disease.