Inclusion criteria:

Participants will meet the following

   - Outpatients between 8 and 17 years of age with only 12 to 17 years of age during year
   1

   - Diagnostic and Statistical Manual, 5th edition (DSM-5) criteria for Autism Spectrum
   Disorder (ASD) on the basis of clinical evaluation, confirmed with the Autism
   Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule,
   2nd Ed (ADOS-2)

   - Males and females

   - Availability of polysomnography (PSG) and actigraphy data

   - Sleep disturbances as assessed using Children's Sleep Habits Questionnaire (CSHQ) with
   a score of 41 or higher and sleep efficiency of 80% or less

   - care provider who can reliably bring participant to clinic visits, provide trustworthy
   ratings, and interacts with participant on a regular basis

   - stable medications for at least 4 weeks

   - no planned changes in psychosocial and biomedical interventions during the trial

   - willingness to provide additional saliva samples and participate in key study
   procedures (i.e., safety measurements every visit, PSG at weeks 4 and 8, and wear the
   actigraphy watch for 2 weeks before the beginning of trial as well as during the 8
   weeks of the trial)

   - requirement of dual protection contraception use in females who are sexually active
   and are of childbearing potential. Dual use contraceptive methods involve the use of
   both a hormonal method (oral contraceptives, long-acting reversible contraceptives,
   etc.) and a barrier method (condoms).

Exclusion criteria:

Participants will be excluded if one or more of the following is met

   - active suicidal ideation or DSM-5 diagnosis of schizophrenia, schizoaffective
   disorder, or psychotic disorder

   - active medical problems: migraine, asthma, seizure disorder, significant physical
   illness (e.g., anaphylaxis, serious liver, renal, or cardiac pathology), and hepatic
   insufficiency

   - evidence of a genetic mutation known to cause autism or intellectual disability (e.g.,
   Fragile X Syndrome), metabolic, or infectious etiology for the participant's autism on
   the basis of medical history, neurologic history, and available tests for inborn
   errors of metabolism and chromosomal analysis

   - pregnant or sexually active females not using a reliable method of contraception
   (urinary tests for pregnancy will be employed in this study)

   - individuals taking beta-blockers (local or systemic), benzodiazepines, antiepileptic
   medications, serotonin selective re-uptake inhibitors, melatonin, antihistamines and
   antidepressants

   - history of hypersensitivity to zolpidem

   - history of severe side effects from zolpidem

   - history of adequate trial of zolpidem

   - current use of any medications known to interact with zolpidem such as medications
   inhibiting CYP3A4 and CYP1A2

   - history of complex sleep-related behaviors

   - individuals using alcohol, marijuana and other substances.