Answer: The Beck depression index is a short psychiatric self-report exam that measures depression.
The Beck depression index, or Beck depression inventory, was first developed by American psychotherapist Aaron Beck in the early 1960s. He is regarded as the father of modern cognitive therapy, the school of thought that supports the idea that thoughts and behaviors are closely related, and that a person is able to overcome behavioral difficulties by identifying and changing thoughts or emotions that lead to the undesirable behavior. This assessment method was revolutionary since it shifted professional opinion on the cause of depression from the Freudian model of psychodynamics to an internally produced state.
The original Beck depression inventory (BDI) was first developed in 1961. The exam currently administered is the second revision of the exam, the BDI-II, which was developed in 1996. The BDI-II is consistent with the criteria put forward in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) for their definition of Major Depressive Disorder as revised by the American Psychiatric Association.
The exam itself consists of 21 questions. The questions ask the patient to recall how they felt over the past two weeks. Questions themselves are given a value from 0 to 3, and higher scores mean a greater feeling of depression. The test itself asks about happiness, optimism, pleasure, irritability, appearance, weight loss, and changes in sleep patterns. The test is very quick, and can be completed in 5 minutes.
The BDI is effective at diagnosing depression. High scores on the Beck depression inventory also correlate closely with a diagnosis of Major Depression as observed by interview when conducted by a trained clinician. There is also a very high correlation between scores when the test is retaken, indicating that scores on the BDI-II are measuring an underlying recurrent thought rather than a temporary mood.
Since the BDI is a self-reported exam, scores can be artificially inflated or deflated. It is easy for the subject to disguise his actual diagnosis intentionally by answering untruthfully or without reflection. Self-report scores may also be sensitive to the placebo effect. Also, the questions ask the person to compare their current feelings with some previous time period, which may be difficult to recall. Many of the feelings assessed on the BDI may change gradually, possibly making it difficult for a person to remember their past feelings.