How much college do you need to be a nurse in mental hospital?

To become a registered nurse (RN) working in a mental hospital, you need at least an Associate Degree in Nursing (ADN) or a Bachelor of Science in Nursing (BSN). While an ADN is sufficient to become licensed, many hospitals, especially those with more complex cases, prefer or require a BSN. An ADN typically takes 2 years, while a BSN takes 4 years. After completing your degree, you must pass the NCLEX-RN licensing exam to practice.