No it's not.  That's using a word to make an excuse for one's wrong behavior .  This has nothing to do with morality , it has everything wrong to do with poor life choices.   No one forces you to take more pills than prescribed . People make that choice on their own and using the word disease is nothing more than trying to blame someone or something over which the person has no control.  People who become addicted to drugs have no one to blame but themselves.