Klonopin can be a depressant. I used to take it and I’d be depressed for the next 2 days.

There’s also a side effect called rebound anxiety, but I’m not sure if it’s an experience of comparing the returning anxiety to the (Klonopin-induced) non-anxious state or whether the metabolization of Klonopin creates more anxiety.

Either way, it is helpful to have for panic attacks, despite that side effect.