The Cornell Scale for Depression in Dementia (CSDD) was specifically developed to assess signs and symptoms of major depression in patients with dementia. Because some of these patients may give unreliable reports, the CSDD uses a comprehensive interviewing approach that derives information from the patient and the informant.

Information is elicited through two semi-structured interviews; an interview with an informant and an interview with the patient. Based on these interviews, the interviewer can score the CSDD by assigning a preliminary score to each item of the scale on the basis of the informant’s report in the “Informant” column. The next step is for the rater to interview the patient using the Cornell scale items as a guide.

The interviews focus on depressive symptoms and signs occurring during the week preceding the interview. Many of the items during the patient interview can be filled after direct observation of the patient. If there are discrepancies in ratings generated from the informant and the patient interviews, the rater should re-interview both the informant and the patient to resolve the discrepancies.

The final ratings of the CSDD items represent the rater’s clinical impression rather than the responses of the informant or the patient. The CSDD takes approximately 20 minutes to administer.

Each item is rated for severity on a scale of 0-2 (0=absent, 1=mild or intermittent, 2=severe). The item scores are added. Scores above 10 indicate a probable major depression. Scores above 18 indicate a definite major depression. Scores below 6 as a rule are associated with absence of significant depressive symptoms.