Summarize this article:

After you have practiced as an RN for 2 years or more, get certified as a psychiatric nurse or psychiatric nurse practitioner with the American Nurses Credentialing Center (ANCC) or equivalent organization in your country. In the U.S., certification is required in many states, and recommended in others.  To qualify for the certification, have the equivalent of 2 years full-time work as a licensed RN. Show that you have completed least 2,000 hours of clinical practice in psychiatric–mental health nursing in the last 3 years. Use your BSN, MSN, or continuing education transcripts to show that you have taken at least 30 hours of continuing education in psychiatric-mental health nursing in the last 3 years. In the United States, requirements for this certification will vary depending on your state. After you have your BSN and RN license, consider pursuing a graduate degree to become either a psychiatric nurse practitioner or clinical nurse specialist. You will be better paid and have more responsibilities. To get an MSN, apply to highly-ranked graduate programs. Then complete a practicum under supervision to earn certification as a specialist in child, adolescent, or adult psychiatric nursing. There are some MSN programs, often called "entry-level," that do not require you to have a BSN as long as you already have an undergraduate degree. These programs typically last 3 years rather than 2. Only 1% of U.S. nurses have a doctoral degree, but it only takes 2-4 years of further study, depending on your program, after you complete your MSN to earn a Doctor of Nursing Practice (DNP) or PhD.  With an advanced degree, you will study how diseases and mental illnesses progress from a clinical point of view. If you are interested in education and research, a doctoral degree will allow you to become a Nurse Educator or a Nurse Researcher.

Summary:
Earn certification as a psychiatric nurse practitioner. Consider pursuing a Masters of Science in Nursing degree. Get your doctorate if you are interested in research and education.