Substance/Medication-Induced Sleep Disorder 413
a negative impact on mood, and 47.6% reporting a lack of energy. The most common conse-
quences of RLS are sleep disturbance, includ ing reduced sleep time , sleep fragmentation,
and overall disturbance; depression, generalize d anxiety disorder, panic disorder, and post-
traumatic stress disorder; and quality-of-life impairments. RLS can result in daytime sleep-
iness or fatigue and is frequently accompanied by significant distress or impairment in
affective, social, occupational, educational, academic, behavioral, or cognitive functioning. 
Differential Diagnosis 
The most important conditions in the differential diagnosis of RLS are leg cramps, posi-
tional discomfort, arthralgias/arthritis, myalgias, positional ischemia (numbness), leg
edema, peripheral neuropathy, radiculopathy,  and habitual foot tapping. “Knotting” of
the muscle (cramps), relief with a single postural shift, limitation to joints, soreness to pal-
pation (myalgias), and other abnormalities on physical exam ination are not characteristic
of RLS. Unlike RLS, nocturnal leg cramps do not typically present with the desire to move
the limbs nor are there frequent limb movements.  Less common conditions to be differen-
tiated from RLS include neuroleptic-induced akathisia, myelopathy, symptomatic venous
insufficiency, peripheral artery disease, ec zema, other orthopedic problems, and anxiety-
induced restlessness. Worsening at night an d periodic limb movements are more common
in RLS than in medication-induced akathisia or peripheral neuropathy. 
While is it important that RLS symptoms not be solely accounted for by another medical