Treating Young Children With Attention Deficit Hyperactivity Disorder

History of taking Methylphenidate or Guanfacine. Prior use of other Attention-Deficit/Hyperactivity Disorder medications or other psychotropic medications is allowed.

Current use of other Attention-Deficit/Hyperactivity Disorder medications (e.g., amphetamines), other psychotropic medications (e.g., atypical antipsychotics or serotonin reuptake inhibitors), or centrally active depressants (such as phenothiazines, barbiturates, or benzodiazepines)

Electronic Health Record documentation of moderate to severe global developmental delay (F88) or intellectual disability (F70), or a score of <55 on the Vineland Adaptive Behavior Scales-3.

Medical contraindications to taking Methylphenidate or Guanfacine, including cardiac risk factors (e.g. known structural cardiac abnormalities, cardiomyopathy, serious cardiac arrhythmias, coronary artery disease, or other serious cardiac disease), increased intraocular pressure, glaucoma, verbal tics, Tourette's Syndrome, psychosis