Efficacy and Safety of Lisdexamfetamine Dimesylate in Adults With Chronic Fatigue Syndrome

Over the past decade, the Rochester Center for Behavioral Medicine (RCBM) has evaluated many patients with attention deficit hyperactivity disorder (ADHD). A recurrent finding in these patients is a history of unexplained fatigue and musculoskeletal pain. Treatment of these patients in our clinic has revealed that when their underlying ADHD is treated with psychostimulant medication, many patients report significant improvements with regard to their fatigue and musculoskeletal pain. Patients report less subjective fatigue and pain and note overall functional improvement, although the initial and primary objective was the treatment of their attention or hyperactivity problems. We speculate that stimulants are efficacious by offering two distinct clinical properties. 1) anti-fatigue properties and 2) properties that allow patients to filter out extraneous stimuli (i.e. chronic muscle pain).

As a result of these findings RCBM developed a chronic fatigue/fibromyalgia clinic in the early 2000's. This clinic was staffed by a board-certified rheumatologist and the psychiatric staff at RCBM. Through the major referral hospital in the area, patients with self-identified fibromyalgia and chronic fatigue were referred to our clinic. Over eighteen months, we evaluated 75 patients, and found that in patients who had comprehensive evaluations, nearly 70 percent also had a history of ADHD, inattentive or combined types. Diagnosis was made using clinical history and standardized symptom checklists. Oftentimes, the ADHD had been previously undiagnosed. This finding supports the link between ADHD and FMS/CFS. Results from these evaluations reinforced our initial findings: patients who are treated for their ADHD symptoms also show a reduction in their chronic pain and fatigue symptoms. This is true regardless of previous (unsuccessful) therapies to treat their fibromyalgia. As a result of these findings, we are conducting a controlled study to further demonstrate the efficacy of lisdexamfetamine dimesylate (LDX) in controlling fatigue symptoms in patients presenting with chronic fatigue syndrome. This is a double-blind, placebo-controlled study over a period of 8 weeks, where subjects are randomized to either LDX or placebo. We will evaluate subjects through standardized pain, fatigue and ADHD assessment scales.