therapy has huge success rates if the customer believes in it and gives it an honest try. the number one indicator in success rates across therapies is the rapport (kind of like connection, but fancier and a little more complex) between the customer and the provider.
that being said, (cognitive behavioral) therapy tends to be great for specific fear, phobias, panic attacks, compulsive disorders and a few more. it tends to suck for others (add, for instance. but add is usually a misdiagnosis with other factors in play.. IMHO)
this is not medical advise. if you are experience a period where you are unable to enjoy tasks you normally can or your work/personal life are suffering, then you should seek professional help. if you are just feeling a little blue and confused, perhaps an elder relative, community leader, trusted neighbor or spiritual advisor could help. if all else fails.. lose your mind and come to your senses!