I want to point out that there are currently more than 450 mental disorders - this is a massive amount! I have included an excerpt below from the Wikipedia page which sets out this controversy and provides a current list for you to peruse
There is quite diverse range of co-occurring conditions that sometimes live alongside ADHD.
No one has just ADHD, there is always at least two other conditions along for the life journey
occurs mainly with the Inattentive Type of ADHD, and thus is more common amongst females. It is characterised by widespread musculoskeletal pain at certain points in the body. The pain is accompanied by general fatigue, memory loss, mood and sleep problems. There is no cure for it. Fibromyalgia
Restless Leg Syndrome, RLS, is very often misdiagnosed and undiagnosed. People with RLS get strange and unpleasant sensations in their legs, creating an irresistible urge to move their legs in order to relieve the sensations.
Feelings that are usually described as “itchy,” or “creepy-crawly,” and even “pins and needles,” are experienced as well.
The symptoms usually occur when at rest, so are mainly felt at night. The symptoms usually come and go, one of the reasons for the poor diagnosis rate.
RLS can be treated quite easily and successfully.