My cousin discovered that one of her sons had got in with a bad lot at school and had been skipping classes to go and sniff solvents.  She and her husband were horrified and could not believe that he would do such a thing.  He is nice polite lad but he is easily led and obviously these other lads have persuaded him that he should do what they say.  He is now in a clinic recovering from substance abuse addiction and is going to be moving schools.  None of their other children have been in trouble and I think it was a big shock for them.