The Major Depression Inventory (MDI) is a self-report mood questionnaire developed by the World Health Organization.
The instrument was constructed by a team led by Professor Per Bech, a psychiatrist based at Frederiksborg General Hospital in Denmark.
[1] The MDI differs from many other self-report inventories, such as the Beck Depression Inventory (BDI), because it is able to generate an ICD-10 or DSM-IV diagnosis of clinical depression in addition to an estimate of symptom severity.
[2][3] Unlike many other similar instruments, the MDI is available free of charge and can be downloaded from the internet with a full manual and scoring instructions.
This makes it an attractive option in epidemiological population surveys.