Question about Straterra?

My friends 15 year old son has been on Straterra & Paxil for awhile now. Last Thursday night he got irriatated at some girls bothering him and got very angry. He calmed down Mom took him home and he went nuts, Saying he was going to kill them he was sitting in her driveway with a bagfulful of hammers etc. saying he was going to get them etc. and that she better drive him there .He completely snapped. He is normally a mellow kid . We've heard Straterra can give horrible side effects such as this anyone else experience anything like this? She had to call the Deputies as she was scared he would hurt himself.