Introduction: Adult Attention Deficit/Hyperactivity Disorder (ADHD) is prone to misdiagnosis because its symptoms are subjective, share features with a broad range of mental, behavioral and physical disorders, and express themselves heterogeneously. Furthermore, Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria for adult ADHD diagnosis remain underdeveloped, prompting a need for systematic and empirically-informed guidelines. Method: This article presents a brief history of research on adult ADHD and reviews common sources of false positive and false negative diagnoses. A systematic, stepped diagnostic procedure is described that adheres to DSM guidelines and integrates the latest science on adult ADHD assessment and diagnosis. Results: Seven steps are recommended: a structured diagnostic interview with the patient, collection of informant ratings, casting a wide net on symptoms using “or rule” to integrate informant reports, providing checks and balances on the “or rule” by enforcing the impairment criterion, chronicling a symptom timeline, ruling out alternative explanations for symptoms, and finalizing the diagnosis. Conclusions: Based on the extant research, it is expected that the stepped diagnostic procedure will increase detection of malingering, improve diagnostic accuracy, and detect non-ADHD cases with subclinical difficulties or non-ADHD pathologies.
