Being lazy can cause depression.
When you're lazy you feel unmotivated to do anything and when you're not doing anything to keep you busy you become bored.
That being bored and lazy can then cause depression to set in.
I know when I get lazy and feel like doing nothing that if I lay around or sit around and even watch TV I get depressed.
When I'm feeling lazy and depressed I get in my car and will take a long drive down some old country roads with just myself and I will feel much better.
Sometimes even driving around with my kids and taking my kids to the park or to museums or just going out and doing something helps pull me out of my depression.
Some people are so lazy and do nothing to try to get out of being lazy or depressed and then that can lead to suicidal thoughts or even just other mental and other health issues.