My DD (now 19) was referred for CBT at 17 due to depression. It's done wonders - helped her work out why she reacts the way she does to certain things, and taught her techniques for coping with situations. It does require some self-discipline - i.e. she's taught techniques, but then has to remember to apply them.
Two years ago I thought she's never be able to leave home, go to University etc - now she's off in Spetember . The ADs have undoubtedly helped, but I think the CBT has been invaluable. DD is of the view that everyone should have CBT, regardless of their mental health.