Hooked on Benadryl: It’s Much More Than a Harmless Dependency The concept may sound a little silly, especially when there are millions of people battling much more serious addictions. However Benadryl, or diphenhydramine, has been linked to serious mental complications when used in excess and for long periods of time. Benadryl is an anticholinergic drug. Some people use it as an over-the-counter sleep aid, while others enjoy the sedative and euphoric effects it provides as a result of