Well, you sure gave us a doozy of a question: there are so many variables to consider. Do you have any psych experience? Is it a for-profit or non-profit facility? Is is connected with one of the psychiatric hospital chains? What kind of patients are there--geriatric, adolescent, dual diagnosis, voluntary, involuntary?, etc. etc. You might think it's not so important, but it makes a big difference whether the facility is located in an urban or suburban area, or out in the "boonies"
I have 25 years experience as a psych nurse, in a variety of settings, and I can tell you off the top of my head that 3 weeks is not a perfect orientation. I didn't feel comfortable in psych, as a new graduate, for about 6 months--there is so much to learn and to put into practice without having to think about it. I didn't feel fully competent and accustomed to psych until I had about 2 years experience.
I'm sorry I can't be of more help in such a short response, but if you'd like to ask me more questions, feel free to email me. And remember, the number one thing to always have foremost in your mind is SAFETY, SAFETY, SAFETY!! Go by the book for all security issues like having backup plans, searches, suicide checks, contraband,etc, or you will eventually regret it.
Dave Dunn, RN