ADHD in adults is a currently under-diagnosed disorder. This report, based on the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project, aimed to determine whether one or two ADHD criteria could be identified that could serve as “gate” criteria for ADHD screening in adults.
A total of 1134 participants (male: n=476 [42.0%]; female: n=657 [58.0%])* completed a semi-structured, modified version of the Structured Clinical Interview DSM-IV† (SCID) for Axis I Disorders, based on DSM‑IV diagnostic criteria, with minor wording changes incorporated to reflect settings and situations likely experienced by an adult. For each ADHD criterion (18 in total),‡ sensitivity, specificity, and positive and negative predictive values were computed. The study sample was divided into two, and a validation and cross-validation analysis was performed in two sets of analyses: the first based on DSM-IV diagnostic criteria and the second based on the DSM-5TM.§
The frequency of ADHD diagnoses in the DSM-IV-based analysis was 18.0% (N=204 [validation sample: n=97, 17.3%; cross-validation sample: n=107, 18.7%]) and in the DSM-5TM-based analysis was 19.9% (N=226 [validation sample: n=112, 19.9%; cross-validation sample: n=114, 19.9%]). The most common psychiatric diagnoses in the DSM-IV-based analysis were major depressive disorder (37.7%), generalised anxiety disorder (30.0%), panic disorder (16.6%) and social phobia (30.4%).
The ADHD criterion with the highest sensitivity in both the validation and cross-validation samples was “difficulty sustaining attention”, in both the DSM-IV-based analysis (total sample: 81.9%; validation sample: 82.5%; cross-validation sample: 81.3%) and the DSM-5TM-based analysis (total sample: 79.6%). The negative predictive value of this criterion was 95.9% and 94.9% for DSM-IV and DSM-5TM diagnoses, respectively.
Examination of all 2-item combinations indicated that the greatest sensitivity was achieved when combining “difficulty sustaining attention” and “fidgets or squirms”, in both the DSM-IV-based analysis (total sample: 92.6%; validation sample: 94.8%; cross-validation sample: 90.7%) and the DSM-5TM-based analysis (total sample: 93.4%; validation sample: 96.4%; cross-validation sample: 90.4%). The negative predictive value of this combination was 98.0% for both ADHD diagnoses (DSM-IV-based analysis: validation sample: 98.6%; cross-validation sample: 97.4%; DSM-5TM-based analysis: validation sample: 98.9%; cross-validation sample: 97.1%).
Limitations of this study were: 1) analyses were based on a patient sample presenting for outpatient treatment at a single clinical practice, in which the majority were white, female, high-school graduates, thereby reducing the generalisability of the results; 2) patient reports were relied upon in the absence of collateral parental/spousal reports, and adults with ADHD have a tendency to under-report their symptoms; 3) the “gate” criteria identified were not evaluated in a separate patient cohort in order to determine how often these criteria were met despite a negative ADHD screen; 4) as a retrospective study, potential for recording false-positive results at screening existed; and 5) application of the DSM-5TM diagnostic algorithm was limited to the change in the number of ADHD symptom criteria required for an ADHD diagnosis from the DSM-IV to the DSM-5TM.
The authors recommended that clinicians may be able to screen for ADHD in adults by enquiring about two features of the disorder (difficulty sustaining attention and fidgetiness), and that the presence of these could capture most patients with ADHD and the absence could rule out the disorder.
Read more about a potential screening tool for adult ADHD here
*Not all n numbers total 1134; some data were missing
†DSM-IV: Diagnostic and Statistical Manual of Mental Disorders – 4th Edition
‡The operating characteristics of symptom criteria for DSM-IV ADHD were careless mistakes; difficulty sustaining attention; does not listen; fails to follow through; difficulty with organisation; avoids sustained attention; loses things; easily distracted; forgetful in daily activities; fidgets or squirms; difficulty remaining seated; restlessness; difficulty being quiet; constantly on the go; talks excessively; blurts out answers; difficulty waiting turn; and interrupts others
§DSM-5TM: Diagnostic and Statistical Manual of Mental Disorders – 5th Edition
Zimmerman M, Gorlin E, Dalrymple K, et al. A clinically useful screen for attention-deficit/hyperactivity disorder in adult psychiatric outpatients. Ann Clin Psychiatry 2017; 29: 160-166.