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Evidence / 2017

review

Adult ADHD and comorbid disorders: clinical implications of a dimensional approach

Katzman MA, Bilkey TS, Chokka PR, Fallu A, Klassen LJ (2017). BMC Psychiatry.

Population
Adults with ADHD and co-occurring psychiatric disorders
Sample
Clinical review (not a single sample)
Condition
Adult ADHD; anxiety, depression, substance use, bipolar and other comorbidity
Medication focus
Discussed in the context of comorbidity, not as a trial
Jurisdiction
International
Last reviewed
1 September 2026
PMID
28777251
DOI
10.1186/s12888-017-1463-3

Plain-language finding

Adult ADHD commonly co-occurs with mood, anxiety, substance-use and other psychiatric disorders. A dimensional view treats these as intersecting systems rather than mutually exclusive labels. Differential diagnosis still matters: bipolar disorder, for example, is not ‘ADHD with extra energy’.

Important limitation

A clinical review, not a new prevalence survey. Clinic populations over-represent comorbidity.

Why we cite this

A widely cited clinical map of adult ADHD comorbidity that argues for a dimensional, not winner-takes-all, model.

adhd · psych-comorbidity · differential · nd-overlap

Supported by clinical guidelines, regulatory information, systematic reviews, or well-established pharmacological knowledge. Still describes populations, not an individual.

Claims this source supports

  • Depression, anxiety, sleep disorders, OCD, trauma-related conditions, substance-use problems and eating disorders commonly co-occur with ADHD and/or autism. They may be separate, interacting, or both. A later developmental diagnosis does not mean the psychiatric diagnosis was imaginary.

    Last reviewed 1 September 2026

  • Bipolar disorder, borderline personality disorder and schizophrenia-spectrum disorders can share surface features with ADHD, autism, trauma or mood presentations. They can also coexist with neurodevelopmental conditions. They are not simply manifestations of neurodivergence. Correct differentiation can materially affect treatment.

    Last reviewed 1 September 2026