I use the DSM-5 cross-cutting symptom measure. I evaluate the domains the patient positively endorses using the SCID-5-CV. The ADHD module asks if several symptoms were present before age twelve.
To assess for severity, I use the ADHD-RS with my own embedded validity testing (Becke, 2021). I used the CAT-A, but it became too cumbersome to score.
In line with the literature (Ahmad, 2019; Sibley, 2018), complaints of ADHD in adults usually come along with significant co-morbidity. So, usually, after going through the SCID, I'm telling someone that I can't diagnose ADHD because something else better explains it. That something else is usually severe MDD, bipolar, PTSD--dissociative disorder, or substance use. I will usually make a co-morbid diagnosis if anxiety is mild or depression is remitted or part of persistent depressive disorder.
I've been getting many young women with really, really bad PTSD, avoiding their trauma and related emotions, coming to me FROM A THERAPIST for "suspected ADHD." Um, that's hypervigilance!
Yes, doing SCIDs on everyone does take time, but it is easier to tell someone it's likely not ADHD when you tell them their four other diagnoses in need of treatment.
My opinion is that the criteria for ADHD, which were formulated for children, become very non-specific when used in adults who have co-morbid "adult disorders." When I give my PTSD+BPD patients an ASRS, they score off the charts every time!
Ahmad, S. I., Owens, E. B. & Hinshaw, S. P. Little Evidence for Late-Onset ADHD in a Longitudinal Sample of Women. J. Consult. Clin. Psychol. 87, 112–117 (2019).
Becke, M. et al. Non-credible symptom report in the clinical evaluation of adult ADHD: development and initial validation of a new validity index embedded in the Conners’ adult ADHD rating scales. J. Neural Transmission 128, 1045–1063 (2021).
Sibley, M. H. et al. Late-Onset ADHD Reconsidered With Comprehensive Repeated Assessments Between Ages 10 and 25. Am. J. Psychiatry 175, 140–149 (2018).