<p><strong>BACKGROUND: </strong>Primary care pediatricians increasingly care for children's mental health problems, but little is known about practice-level variation in diagnosis and psychotropic medication prescribing practices.</p>

<p><strong>METHODS: </strong>This retrospective review of electronic heath records from 43 US primary care practices included children aged 4 to 18 years with ≥1 office visit from January 1, 2009, to June 30, 2014. We examined variability in diagnosis and psychotropic prescribing across practices using logistic regression with practice fixed effects and evaluated associations of the availability of colocated or community-based mental health providers or the proportion of children in foster care with diagnosis and prescribing using generalized linear mixed models.</p>

<p><strong>RESULTS: </strong>Among 294 748 children, 40 932 (15%) received a mental health diagnosis and 39 695 (14%) were prescribed psychotropic medication. Attention deficit/hyperactivity disorder was most commonly diagnosed (1%-16% per practice). The proportion of children receiving any psychotropic medication (4%-26%) and the proportion receiving ≥2 medication classes (1%-12%) varied across practices. Prescribing of specific medication classes also varied (stimulants, 3%-18%; antidepressants, 1%-12%; α-agonists, 0%-8%; second-generation antipsychotics, 0%-5%). Variability was partially explained by community availability of psychiatrists (significantly higher odds of a diagnosis or prescription when not available) but not by colocation of mental health professionals or percentage of children in foster care.</p>

<p><strong>CONCLUSIONS: </strong>The prevalence of mental health diagnosis and psychotropic medication prescribing varies substantially across practices and is only partially explained by psychiatrist availability. Research is needed to better define the causes of variable practice-level diagnosis and prescribing and implications for child mental health outcomes.</p>