Psychiatrist. A psychiatrist is a medical specialist who focuses on mental health issues, especially through a combination of psychotherapy and psychiatric medication. Psychiatrists usually specialize in the pharmacological aspect of mental health treatment – they’re trained to diagnose diseases and order prescriptions, not necessarily to administer talk therapy themselves. They would work in coordination with differently-trained professionals to provide both sides of the patient’s mental health treatment.
The other options are people who might be involved in mental health support, but who generally wouldn’t have the authority to order a prescription. Youth counselors, mental health counselors, and social workers are usually not qualified to prescribe medications, though they can recommend psychiatrists and help guide patients/clients through the process of regaining mental health.