If someone is underaged, would they be allowed to prescribe anti-depressants without consulting the parents?

Confusing question: One must be a physician (and thus of age) to prescribe antidepressants. If you're asking a different question instead -- for an underage child to be prescribed antidepressants, at least one parent or guardian would have to sign a consent for treatment. The child needs to have some one available to help in case of emergency, and to care for him/her at home during the treatment.