Affective Symptoms/diagnosis; Behavior/physiology; Cognition Disorders/diagnosis; Muscular Dystrophy, Duchenne/psychology; REM Sleep Behavior Disorder/diagnosis; Adolescent; Affective Symptoms/etiology; Affective Symptoms/physiopathology; Brain/metabolism; Brain/physiopathology; Caregivers/trends; Child, Preschool; Cognition Disorders/etiology; Cognition Disorders/physiopathology; Dystrophin/deficiency; Dystrophin/genetics; Glucocorticoids/adverse effects; Humans; Male; Muscular Dystrophy, Duchenne/complications; Muscular Dystrophy, Duchenne/drug therapy; Neurons/metabolism; Philadelphia; Psychopharmacology/standards; Psychopharmacology/trends; Psychotropic Drugs/therapeutic use; REM Sleep Behavior Disorder/etiology; REM Sleep Behavior Disorder/physiopathology; Risk Factors; Synaptic Transmission/genetics; United States