Nightshades have been associated with arthritis, fibromyalgia, autoimmune conditions and headaches.
For instance, antidepressants are now prescribed also for patients with fibromyalgia and anxiety disorders.
fibromyalgia fi·bro·my·al·gi·a (fī'brō-mī-āl'jē-ə, -jə)
A syndrome characterized by chronic pain in the muscles of soft tissues surrounding joints, fatigue, and tenderness at specific sites in the body. Also called fibromyositis, fibrositis.