Drug induced tonic-clonic seizures?

Recently a friend of mine had an abrupt and violent seizure. I was petrified during it and thought that he was going to die because I could not tell the difference- he had lost all of his color and seemed to almost stop breathing after spitting up white fluids which is what happened when my father died of lung cancer- so I literally thought he had died. But I called the neighbor because I was definitely not thinking clearly and panicking and wanting someone to come in and to tell me what to do- thankfully my friend woke up completely confused, disorientated and sick. He was also extremely agitated and couldn't understand why I was so scared. I stayed with him all night to be sure he was okay, and did research to find out that it was clified as a tonic-clonic seizure (I read each kind and this one had literally all the symptoms- eyes rolling back, violenty shaking, muscles contracting etc. etc.) I know my friend sometimes takes drugs- vicodin or marijuana and I was wondering if this could have caused the seizure? I've never seen anything like that before and was hoping you could tell me- he doesn't have a past history, doesn't have epilepsy and the neighbor (his good friend) said he was caused by not getting enough sleep and dehydration but I'm not buying it. So..is it possible that drugs caused this?