What is the difference between a social worker, a professional counselor, a psychologist, a psychiatrist and a nurse practitioner?

Social workers, professional counselors, psychologists, and psychiatrists are all fully trained mental health professionals, licensed by the state, and experienced in a range of mental health treatment modalities. Clinical social workers, professional counselors, and psychologists have all received graduate degrees in the mental health field. Psychologists are now required to have a PhD but some who practice may have a master’s level degree.