The tech giant's partnership with the University of California, Los Angeles was unveiled by the research college and is set to take place over three years, commencing this week.
It will see a study into how sleep, physical activity, heart rate and more can affect a person's mental health.
Participants will download and app onto their Apple device, which will track data, and they will also have a Beddit sleep monitor and an Apple Watch, to add further data.
Amid the Covid-19 pandemic, the study will be carried out remotely and they will check in with the participants - which will eventually expand to 3,000 - via video conference and by tracking the data.
Dr. Nelson Freimer, the study's principal investigator on the study, will provide vital information on future care for sufferers of clinical depression.
He explained: "This collaboration, which harnesses UCLA's deep research expertise and Apple's innovative technology, has the potential to transform behavioural health research and clinical care.
"Current approaches to treating depression rely almost entirely on the subjective recollections of depression sufferers. This is an important step for obtaining objective and precise measurements that guide both diagnosis and treatment."
The study will be extended into 2021, and all the way through to 2023.
Apple is set to "analyse the data only after they are coded and stripped of names and other contact information."
The company previously joined forces with the Stanford Medicine on the Apple Watch Heart Study.
Whilst just last year, they launched three new studies via the Research app called Women's Health, Heart and Movement, and the Hearing Study.