Objective: The Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5), classifies
attention-deficit/hyperactivity disorder (
ADHD) as a
neurodevelopmental disorder, with symptoms becoming apparent as early as the preschool years. Early recognition can lead to interventions such as parent/teacher-administered behavior therapy, the recommended first-line treatment for preschool patients. There are few data, however, to inform the use of second-line,
pharmacotherapy options in this population. In this review, we identified recent literature on the diagnosis and treatment of
ADHD in preschool children. Methods: A PubMed and clinicaltrials.gov search was conducted for trials assessing efficacy or safety of
ADHD medications in children aged <6 years. Diagnostic methods and criteria focusing on recognition of
ADHD in preschool children were also surveyed. Results: The DSM-5 describes different manifestations of
ADHD in preschool versus school-aged children, but does not list separate criteria by age group. Importantly, behaviors indicative of
ADHD in older children may be developmentally appropriate in preschool children. Several behavioral rating scales have been validated in children younger than 6 years of age for assessing
ADHD. The Preschool
ADHD Treatment Study (PATS) has provided the most extensive efficacy and safety data on
methylphenidate (MPH) for
ADHD in preschoolers to date, with significant improvement in
ADHD symptoms observed with MPH compared with placebo, although adverse event-related discontinuation was higher in PATS compared with studies of MPH for
ADHD in school-aged children. Since PATS was conducted, few studies designed to assess
ADHD medication effectiveness in preschool children have been published. One article reported significant improvement in
ADHD symptoms with MPH (immediate release) versus placebo, two studies showed no difference between MPH and
risperidone or MPH plus
risperidone in relief of
ADHD symptoms, and one study demonstrated the efficacy of
atomoxetine versus placebo for
ADHD symptoms in preschoolers. Conclusions: Further research is needed on
pharmacotherapy for preschool children with
ADHD.