ADHD and obsessive-compulsive disorder are comorbid illnesses. This means about one third of ADHD affected people also has OCD.
Characterized by unwanted repeated thoughts, people with OCD develop rituals of repeated behaviors to help temporarily quell the recurring thoughts in their minds. Rituals around cleanliness and hygiene are frequent, and can include obsessive handwashing, showering, teeth brushing or many other repetitious behaviors.
People with ADHD can experience a state of hyperfocus that allows them to near obsessively focus on a single topic. However, if such focus does not result in patterns of ritualistic behavior, it does not fit as an OCD symptom.