Clinical implications of the study “Trait-based Dimensions Discriminating Adults with Attention Deficit Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD) and Co-occurring ADHD/ASD.

Artemios Pehlivanidis M.D., Professor of Psychiatry, National and Kapodistrian University of Athens Greece

We hypothesize that individual trait dimensions that derive from questionnaires with widely accepted psychometric properties may offer helpful information for the differential diagnosis and treatment of adults with normal intelligence that are referred with a suspected ADHD or ASD or ADHD/ASD diagnosis.

The study assesses the co-occurrence of ADHD and ASD in newly diagnosed adults of normal intelligence and the contribution of trait-based dimensions deriving from the Barkley Adult ADHD Rating Scale-IV (BAARS-IV), the Autism-Spectrum Quotient (AQ) and the Empathy Quotient (EQ) to the differentiation of patients with ADHD, ASD and ADHD/ASD.

Among the 238 normal intelligence adults that were assessed during a three-year period, 63.4% received an ADHD diagnosis only, 24.4% an ASD diagnosis only and 12.2% a dual ADHD/ASD diagnosis.

In stepwise logistic regression analyses past Hyperactivity, current Inattention and Impulsivity, Attention Switching, Communication, Imagination and EQ Total score discriminated ADHD from ASD patients. Attention to Details, Imagination and Total EQ score discriminated ADHD from ADHD/ASD cases, while past Hyperactivity and current Impulsivity discriminated ASD from ADHD/ASD subjects.

In clinical practice the finding that self-report of current impulsivity can discriminate ASD patients from ASD/ADHD patients has both diagnostic and treatment implications. Interviewing adults of normal intelligence with an ASD diagnosis for current impulsivity may lead to a co-occurring ADHD diagnosis which has to be treated accordingly (i.e. with stimulants).

The finding that EQ discriminates adults of normal intelligence with co-occurring ADHD/ASD from patients with ADHD has also important clinical implications. Interviewing for the capacity to detect other people’s  feelings when assessing adults for a possible ADHD diagnosis might reveal symptoms indicating the possible co-occurrence of ASD. Treating ADHD with co-occurring ASD is much more complex than treating ADHD as a sole diagnosis.
Being able to successfully categorize individuals with ADHD, ASD or ADHD/ASD by using clinical dimensions is an important first step towards identifying atypical brain function and structure underlying these clinical features.

Link to Pubmed