What substances & therapies are most beneficial for adults with aspergers?

Depends on symptoms: There are no medications specific to Aspergers but like everyone if there are problems with anxiety, depression or attention some meds are worth trying. Learning how to interact with people and to understand their responses can make life a lot easier. Many psychologists have therapies focused on this goal.

Behavior modificatio: It depends upon what behaviors/symptoms one is trying to alter. Usually behavior therapies and cognitive behavior therapies work well. Depending on symptoms, some medications are helpful.