What Is The Treatment For Grand Mal Seizure?

My daughter is 18 and currently in university. Last week she had what I believe was a grand mal seizure. This was the first time and we haven't had any thing like this happen in our family. She had a ct scan and blood work - all normal. She does have an appt with a neurologist this week - but I can't stop reading and thinking about it. Why does this happen to a healthy girl? She was up late the night before and had a few drinks the night before also. Thoughts on test results and why this happens?