There has been a substantial increase in the diagnosis and treatment of ADHD in the US in recent years. Most of this increase has been accounted for by adults and especially by women while prevalence of diagnosis and treatment in children has remained relatively stable. This uptick, coinciding with shortages in availability of prescribed stimulant medications for ADHD, has incited questions among healthcare professionals about the best methods for ensuring that ADHD is present and requires treatment. Co-occurring mental health conditions and learning disabilities, common in the presence of ADHD, further complicate diagnosis and treatment, especially in the presence of a first-time diagnosis in adulthood. Although procedures for thorough assessment of ADHD are well-established, there remain differences amongst practitioners in their utilization, and use of provisional diagnoses while collecting historical data requires patience and time on the part of the provider and patient. This presentation will discuss current prevalence statistics as well as options available for conducting thorough assessments of ADHD in the service of providing high quality diagnosis and treatment of ADHD for children and adults.