We report two patients with comorbid sleep problems treated by low-dose aripiprazole (APZ) who were evaluated by polysomnography.
 Case 1 was a late 10s female diagnosed with depression who had difficulty waking up. APZ (1 mg after dinner) improved her ability to wake up and reduced the nocturnal sleep time on actigraphy.
 Case 2 was a preteen male diagnosed with autism spectrum disorder who had enuresis since childhood. Before APZ administration, enuresis was observed nearly every day. After APZ (3 mg after dinner) was administered for irritability, the frequency of enuresis improved to once or twice a week.
 In both patients, there was almost no difference in the amount of time in stage N1, N2, N3, or REM sleep measured by polysomnography. However, low-dose APZ increased the number of K-complexes and Delta bursts, which represent subcortical arousal. These polysomnographic findings reflecting increased subcortical brain activity during sleep may be related to the activating effects of low-dose APZ on the dopaminergic system. This pharmacological action may also partly explain the ameliorating effects of APZ on difficulty waking up and nocturnal enuresis. Our study suggests evening administration of low-dose APZ as a new treatment option for difficulty waking up and nocturnal enuresis, but further studies are necessary to confirm these pharmacological effects.
 Authors' abstract