OBJECTIVE-The objective of this study was to provide national estimates of psychotropic medication use among Medicaid-enrolled children with autism spectrum disorders and to examine child and health system characteristics associated with psychotropic medication use.METHODS-This cross-sectional study used Medicaid claims for calendar year 2001 from all 50 states and Washington, DC, to examine 60 641 children with an autism spectrum disorder diagnosis. Logistic regression with random effects was used to examine the child, county, and state factors associated with psychotropic medication use.RESULTS-Of the sample, 56% used at least 1 psychotropic medication, 20% of whom were prescribed ≥3 medications concurrently. Use was common even in children aged 0 to 2 years (18%) and 3 to 5 years (32%). Neuroleptic drugs were the most common psychotropic class (31%), followed by antidepressants (25%) and stimulants (22%). In adjusted analyses, male, older, and white children; those who were in foster care or in the Medicaid disability category; those who received additional psychiatric diagnoses; and those who used more autism spectrum disorder services were more likely to have used psychotropic drugs. Children who had a diagnosis of autistic disorder or who lived in counties with a lower percentage of white residents or greater urban density were less likely to use such medications.CONCLUSIONS-Psychotropic medication use is common among even very young children with autism spectrum disorders. Factors unrelated to clinical presentation seem highly associated with prescribing practices. Given the limited evidence base, there is an urgent need to assess the risks, There is ongoing debate regarding the role of psychotropic agents in ASD management. 2,3 Although no medications are known to address the core symptoms of ASDs, they often are prescribed as adjunctive therapy to address symptoms such as aggression, self-injurious behaviors, stereotypies, and hyperactivity. [4][5][6] Many medications have been tested with varying levels of scientific rigor, 7 but only risperidone, an atypical neuroleptic that reduces aggression and irritability, has received Food and Drug Administration approval for the treatment of these symptoms in individuals with ASDs. 8Medication use is common among children with ASDs and seems to be increasing. A 1995 survey found that 30% of children with ASDs were using some psychotropic medication 9 ; follow-up studies 6 years later found 46% using them. 10,11 Neuroleptic agents were most common in 2 of 3 studies, 9,11 with antidepressants the most common in the third. 10 In 2001, 21% were using >1 drug, compared with 8% in 1995. A 2005 international Internet survey found that 52% of parents reported that their children were using psychotropic drugs. 12 These studies provided important information regarding psychotropic medication use in children with ASDs, but all relied on parent report, the validity of which is unknown. With 1 exception, 12 they sampled relatively small geographic areas, and all exc...