Pothead is not a term to be used lightly. You cannot start calling yourself a pothead until others do first. Its like a pothead rule man.
Potheads only smoke pot. Maybe a little shrooms but no hard drugs. If a pothead does a hard drug they move into the term "druggie" which is almost a complete opposite from pothead. Potheads are cool, druggies are quite lame.
"Tim is such a pothead, yet he gets on the High honors every Semester."
Pothead: "Yeah sure, you wanna smoke a bowl?"
John: "I dunno man, my throat's been kinda sore lately."
Pothead: "Oh that's ok, a bowl will fix that."
John: "Really? Well I've got this Government test tomorrow too, so I probably shouldn't smoke."
Pothead: "Pot makes studying easier. You'll enjoy the subject more!"
John: "You're full of shit. Next you'll tell me weed can fix my chronic back pain and I should get high before visiting my grandma in the nursing home."
Pothead: "I'm glad you understand now. Got a lighter?"
Pot heads should not be confused with occasional smokers who are still able to function and fulfill their responsibilities and obligations.