Patients with ADHD (regardless of the subtype, inattentive, hyperactive-impulsive, or combined subtype) do not only exhibit difficulties with behavior and cognition, but can also present with irritability, poor frustration tolerance, anger, temper outbursts, excessive worry, racing thoughts, depressed mood, and other symptoms that are the hallmark symptoms of separate and distinct psychiatric disorders, such as anxiety and mood disorders.
Differential diagnosis of ADHD is complicated when anxiety and/or mood dysregulation are also present, making it difficult to tease apart from distinct psychiatric conditions with similar symptoms.
For example, a child with generalized anxiety disorder can present with similar symptoms as a child with ADHD - Inattentive type, and vice versa, which can lead to misdiagnosis and unsuitable treatment. Furthermore, psychiatric conditions, such as anxiety and mood disorders, often co-occur in ADHD, yet additionally complicating differential diagnosis. For example, about half of all patients diagnosed with ADHD are also diagnosed with a co-occurring anxiety disorder. Katzman, M.A., et al., BMC Psychiatry (2017), 17:302.
ADHD can be misdiagnosed as (or often co-occurs with) other psychiatric conditions, such as generalized anxiety disorder (GAD), oppositional defiant disorder (ODD), depression, disruptive mood dysregulation disorder (DMDD), post-traumatic stress disorder (PTSD), bipolar disorder I, bipolar disorder II, Tourette’s syndrome, and obsessive-compulsive disorder (OCD).
Comprehensive and careful evaluation for the differential diagnosis of all the presenting signs and symptoms, including anxiety and mood dysregulation, is key to optimal outcomes for patients with ADHD. Accurate diagnosis is vital, as it directs the most appropriate treatment plan, reducing errors, particularly in pharmacologic treatments that carry side effects. Optimal treatment reduces the risk for self-medicating and/or self-injurious behaviors, the onset of additional psychiatric conditions, and worsened psychosocial stressors downstream; all risks for patients with ADHD if symptoms are misdiagnosed and/or ineffectively treated. Ultimately, the correct diagnosis (and comprehensive treatment approach) improves overall health and enhances the quality of life for the patient with ADHD across settings, including at work and school, with improved self-esteem and self-efficacy, and at home, with reduced conflicts, improved relationships, and overall family functioning.