Muscle weakness, clinical myotonia, and multiple systemic organ disturbances characterize myotonic dystrophy. Many of these systemic disturbances involve target organ insensitivity to aminergic or peptidergic (hormonal) stimulation. Reduced density or impaired function of aminergic and peptidergic (hormonal) receptors throughout the body may underlie this disorder. Tricyclic antidepressant augmentation of aminergic function ameliorates depressive symptoms, increases strength, and improves clinical myotonia in myotonic dystrophy patients.