Is inactivity caused by depression or laziness?
Yes, im lazy right now and im just answering questions.
Both, and vice versa.
Inactivity is caused by both depression and laziness.
It's a triangle. Each one causes the other to occur.
Either or, or both.
It can be either or some other problem, too. I'm inactive at times because I have a problem that makes walking painful and sometimes I don't want to.
It could be both.