FORMULA
Addition of the selected points; points assigned in this table.

FACTS & FIGURES
QIDS Scoring Information:

Collect responses to all questions.
Use the highest score on any 1 of the 4 sleep symptoms (items 1 to 4).
Use the highest score on any 1 of the 4 weight symptoms (items 6 to 9).
Use the highest score on either of the 2 psychomotor symptoms (items 15 and 16).
There will be one score for each of the nine depression symptoms.
Add the scores of the of the 14 items as instructed above pertaining to the 9 depression symptoms (sleep, mood, weight, concentration, guilt, suicidal ideation, interest, fatigue and psychomotor changes) to obtain the total score. Total scores range from 0-27.
Score interpretation:

The higher the score, the more severe the depression.
Scores ≤5 indicate no depression.
Scores of 6-10 indicate mild depression.
Scores of 11-15 indicate moderate depression.
Scores of 16-20 indicate severe depression.
Scores ≥21 indicate very severe depression.
LITERATURE
ORIGINAL/PRIMARY REFERENCE
Research Paper
Rush AJ, Giles DE, Schlesser MA, Fulton CL, Weissenburger JE, Burns CT. The Inventory of Depressive Symptomatology (IDS): Preliminary findings. Psychiatry Research. 1986; 18:65-87.
Research Paper
Rush AJ, Trivedi MH, Ibrahim HM, Carmody TJ, Arnow B, Klein DN, Markowitz JC, Ninan PT, Kornstein S, Manber R, Thase ME, Kocsis JH, Keller MB. The 16-item Quick Inventory of Depressive Symptomatology (QIDS) Clinician Rating (QIDS-C) and Self-Report (QIDS-SR): A psychometric evaluation in patients with chronic major depression. Biological Psychiatry. 2003; 54:573-583.