hi.. i have understood your concerns and worries for your son.. the issues of girlfriend and rejection from the loved person are big issues to handle for a person who is actually cares a lot for loved one.. because the all symptoms of depression and worthlessness are because the rejection in love, i ll suggest you to go for counselling and psychotherapy.. when your son will talk about the issues and feelings attached to it, he will gradually came out of the depression and he will himself find the solution.. counselling and psychotherapy will guide him in a proper direction.. apart from this if his depression is severe, then in my opinion u shud give him antidepressant medications, which will show its effect within next one month and raise his mood from the depressed one to euthymic and normal one.. drugs i am suggesting are: tablet. prozac [fluoxetine 20 mg] once in the morning after the breakfast tablet. ambien [zolpidem 10 mg] at bed time for disturbed sleep. u can decrease the dose according to his sleep.. motivate him and u shud talk to him about his plans and future perspective, try to engage him in exercise, hobbies and outing with the friends, keep away him from the addictive drugs.. i hope u ll find this advice helpful..best luck