The Americans with Disabilities Act (ADA) does cover disability due to mental illness, including depression, but this only applies if the treatment a person is receiving is unsuccessful. The accommodations cannot cause undue hardship on an employer, nor is he or she obligated to provide all requests. If you feel you are entitled to accommodations under the ADA, talk to your Human Resources representative to find out how you may be able to modify your work duties or schedule to better manage your depression.