Comorbidity means having two or more health conditions at the same time. In mental health, ADHD commonly coexists with anxiety, depression, sleep disorders and substance use, and each condition can mask or amplify the others.
Comorbidity is a key reason thorough assessment matters: treating anxiety alone while missing underlying ADHD, or the reverse, often produces poor results. Clinicians screen for co occurring conditions during assessment and sequence treatment so the most impairing condition is addressed first.