Are all mental disorders caused by depression?

No. but some mental disorder are being triggered by depression. 

Clinical depression has been linked to other mental illnesses, such as anxiety disorders, panic disorder, social phobia, and generalized anxiety disorder. Together, depression can lead to mental illness 

of course no ..........................

I leave the answer for the specialties, thanks for the invitation. 

Thanks for the invite I leave the answer for the professionals

wait expert answers for more details