In the Journal of the American Academy of Child & Adolescent Psychiatry (December, 2021), an editorial by David Coghill, MB ChB MD raises the possibility of using cognitive measures to assist with diagnosis. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) relies on observational data, but this data can be ambiguous in mental health diagnoses that have similar characteristics.
One example would be the attention difficulties that are shared by young people who carry the diagnosis of Attention-Deficit/Hyperactivity Disorder (ADHD) and those who carry the diagnosis of Disruptive Mood Dysregulation Disorder (DMDD). The testing database that we have at The Neuropsychology Service tracks 149 measures, and as of July, 2022, we have 308 cases that fit the ADHD diagnostic criteria, and 26 cases that fit the DMDD criteria.
On an observational measure like the Behavior Assessment System for Children – Third Edition, the attention rating by parents was elevated identically in ADHD and DMDD both. In a continuous performance task like the Conners’ Continuous Performance Test, however, the ADHD group had trouble responding consistently (the Omissions measure was elevated), but the DMDD group did not.
The Adaptability measure was very low in the Behavior Assessment System for Children – Third Edition for the DMDD group; it was in the average range for the ADHD group. The WISC-V Matrix Reasoning subtest tends to need flexible thinking because the analogies keep changing. The DMDD group tended to have lower scores in Matrix Reasoning than the ADHD group. Measures of depression were elevated in the DMDD group but not in the ADHD group.
The summary IQ scores in our data base started with the WISC-IV, and we now track these scores using the WISC-V. The average Full Scale IQ score for the DMDD group was 95; the average for the ADHD group was 102.