How to tell my parents I want to see a therapist?

I have been depressed for over a year. I ran away from home last year after christmas and my parents did nothing about it. I cut myself, and self diagnosed myself with social phobia. My parents don't know about any of this [except for running away] and I really dont want to tell them. I try to tell them stuff but they think they can help me and fix it on their own but they can't. I have told my mom I think I am dyslexic but she shook it off like i never even said anything to her. All my parents care about is themselves. My brother attempted suicide, ran away from home and quit school. My other brother smokes and drinks. AND MY PARENTS THINK THEIR KIDS ARE FINE AND HAPPY. They think we dont have a clue what pain is because we are so young. But I can feel pain. And it hurts. I have nobody I can trust or cares about me. I'm pretty sure even if I did tell my parents about all this they would just ignore it.. please help I really don't know what to do and it is pushing me over the edge..