Registered nurses who seek additional education and obtain a masters or doctoral degree can become advanced practice nurses in the specialty (Psychiatric-Mental Health Clinical Nurse Specialists or Psychiatric Nurse Practitioners). After post-master's supervised clinical practice, they can become certified as specialists in adult, or child and adolescent psychiatric-mental health nursing. In addition to the functions performed at the basic level, these advanced practice nurses assess, diagnose, and treat psychiatric disorders and potential mental health problems. They provide the full range of primary mental health care services to individuals, families, groups and communities, function as psychotherapists, and in some states they have the authority to prescribe medications. Psychiatric-mental health nurses in advanced practices are qualified to practice independently to offer direct care services in settings such as agencies, communities, homes, hospitals, and offices. Some psychiatric-mental health clinical nurse specialists practice consultation/liaison nursing, delivering mental health services to physically ill patients or consultation to staff in general medical settings.