This study will determine the safety and potential effectiveness of a digital health platform aimed at improving treatment outcomes for patients with depression by assisting physicians with clinical decision making about depression treatment.

Patient Inclusion Criteria:

• diagnosed with major depressive disorder by a physician using DSM-V criteria
• able to provide informed consent
• patients must confirm that they are comfortable being treated for depression by their physician, who may propose a range of treatment options, such as medications or psychotherapies, consistent with best practice guidelines for depression which are included in the application. Physicians will be required, as in usual practice, to explain treatments to patients and patients will be able to give and withdraw consent for treatment in general or for specific treatments as in usual practice.

Patient Exclusion Criteria:

• bipolar disorder of any type
• inability or unwillingness of the individual to give informed consent
• inability to manage patient in an outpatient setting (i.e. imminent suicidality)
• active major depression is not the main condition being treated (i.e. the patient has depressive symptoms in the context of severe substance abuse or a psychotic disorder, but a primary diagnosis of major depressive episode (MDE) cannot be made or would result in inappropriate care).
• inability to use the tool (i.e. patient cannot interface with a mobile phone or computer due to delirium, or another medical condition)* *Note that for patients who do not have access to mobile or desktop devices but are able to use them or to be trained to use them, these will be provided to them at no cost.

Physician Inclusion Criteria:

• any family doctor/primary care physician or psychiatrist accredited in Canada or the USA who treats patients with depression on at least a monthly basis, as well as residents from these specialities supervised by a participating physician
• able to provide informed consent
• comfortable prescribing the range of potential treatments which could have probabilities provided for them by the CDA

No Physician Exclusion Criteria

With participating site and on request. Further sharing will be determined at a later date.

To be determined.

Patient and Rater blinded, Physician partially blinded