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
When it comes to behaviour and ADHD, some people refer to the “three degrees” or 3 stages of ADHD.
The least troublesome is ADD, the Inattentive Type, then the Combined Type, and then finally the Hyperactive Type being the most disruptive.
The Inattentive Type is predominantly female. The lack of disruption is the primary reason why so many girls and women have slipped through the cracks when it comes to diagnosing the Inattentive Type
The next stage of behaviour severity is Oppositional Defiance Disorder. This where the person with ODD simply refuses to obey or follow instructions. I like to think of this as jabbing titanium high-heel spikes deep into concrete and refusing to budge.
The percentage of ADDers who have ODD is surprisingly high at 67%, by far the most common co-occurring behaviour.