So you're right, it's imperative that there is close monitoring of patients. The way that's done is by asking patients how they're feeling and what is going on, and monitoring their symptoms. Some will use rating scales to help monitor those risks. But it really does require regular follow-up to do that.
In terms of the antidepressants themselves, some people feel an increase in impulsivity. That can include self-harm acts and other things. Again, you have to adequately warn patients about that ahead of time. Let them know what the side effects are to the medication they're taking. I would hope every doctor who prescribes medication does that with their patients.