Hello PC1100: I can't give you a definitive answer to your question. Personally I don't believe that either sleeping a lot or sleeping too little causes mental illness. Either one can be a sign that a person is struggling with mental health issues. And certainly being sleep deprived makes mental health issues just all that much worse. But that doesn't mean that sleep, either too much or too little, causes mental illness.

Anyway, I see this is your first post here on PC. So... welcome to PsychCentral… from the Skeezyks! I hope you find the time you spend here to be of benefit.

PsychCentral is a great place to get information as well as support for mental health issues. There are many knowledgeable & caring members here. The more you post, & reply to other members’ posts, the more a part of the community you will become. Plus there are social groups you can join & chat rooms where you’ll be able to connect with other PC members in real time (once your first 5 posts have been reviewed & approved.) Lots of great stuff! So please keep posting!