Psychology is really interesting.
Psychopathology (i.e. mental health) is a part of all psychology A-Levels, but is really only one of the many topics you'll have to study. To be honest, most of the things you learn aren't as attention-grabbing as the type of stuff you've mentioned, but when I was taking it I actually found topics like memory, perception and bio-psychology more interesting.
The best thing to do would be some reading into psychology on your own. If it interests you, you could always do it later down the line at uni (and don't worry - you're not missing out that much IMO. Psychology is great, but the actual A-Level is very little except essay writing, and most of the content is oversimplified for the sake of that).