To bastardize Forrest Gump: "Psych is like a box of chocolates, you never know what you're gonna get."
That being said, while working in outpatient psych services (not as a nurse) at a CMHC that had a 12-bed inpatient unit, our outpatient unit had the occasional moment of excitement, usually from someone who missed their depot Halperidol. Even when I was working as a liaison between outpatient and inpatient, whenever I was on "on the unit" in inpatient, I never felt concerned about my safety. Even among the clients that were cranky, coming down/off of something, or had anger issues, most were decent people just having a crap go of things. Among the involuntary admits there were very, very few cases of clients assaulting staff. We had good staff in place, good training on therapeutic options, and good protocols in place for de-escalation.
I cannot say the same for when I was working as an aide in LTC with alzheimer's clients right out of high school back in the mid 90's... I would get the crap beat out of me regularly on the night shift by a client who thought I was her teenage daughter sneaking in the house. In comparison with the CHMC, we had less training on how to deal with the psych issues and how to successfully de-escalate clients, and I feel this made for a less safe environment for both clients and staff.
There's always a risk of being hurt by clients wherever you work - that's life. However, proper training, situational awareness, being able to engage in therapeutic communication, and utilizing de-escalation techniques will serve you well on psych... or in any unit.