When a combination is recognized as a unit already -- that is, it is a compound noun that is separate words -- there is no need for a hyphen when it is used as an adjective.
...substance abuse...
...substance abuse counseling...
...mental health...
...mental health evaluation...
...domestic violence...
...domestic violence situation...
The difficult thing, perhaps, is to decide whether something is a "recognized" unit. A dictionary is not always reliable because each specialty field has its own terminology.
Happy punctuating!
Margie