The PHQ-9 is a depression scale used to assess brief depression severity by rating symptoms and functional impairment experienced in the last two weeks. The questionnaire contains a total of 9 questions, and each question is scored on a range from 0-3. The minimum value "0" represents not at all, "1" several days, "2" indicates more than half the days, and the maximum value "3" stands for nearly every day. The total possible range is 0-27. The total number of each 0, 1, 2, 3 is added and multiplied by its value (0=0, 1=1, etc.) to produce a total score generated from the subtotal sum. The PHQ-9 total score is interpreted as follows: 0-4 represents minimal depression, 5-9 as mild depression, 10-14 as moderate depression, 15-19 moderately severe depression, and 20-27 severe depression.