Patient Health Questionnaire - PHQ-9

Technical Manual

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond

Created: January 02, 2021

Last Modified: January 10, 2025 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script implements a computerized version of the Patient Health Questionnaire (PHQ-9) by Kroenke et al (2001).

References

Kroenke, K., Spitzer, R. L., & Williams, J. B. W. (2001). The PHQ-9 - Validity of a brief depression severity measure. Journal of General Internal Medicine, 16, 606-613.

Duration

0.5 minutes

Description

9 4-point Likert scale items, self-report

Summary Data

File Name: phq_9_summary.iqdat

Data Fields

NameDescription
inquisit.version Inquisit version number
computer.platform Device platform: win | mac |ios | android
computer.touch 0 = device has no touchscreen capabilities; 1 = device has touchscreen capabilities
computer.hasKeyboard 0 = no external keyboard detected; 1 = external keyboard detected
startDate Date the session was run
startTime Time the session was run
subjectId Participant ID
groupId Group number
sessionId Session number
elapsedTime Session duration in ms
completed 0 = Test was not completed
1 = Test was completed
dePressedMoodOrAnhedonia 1 = at least one answer for q1 (anhedonia) or q2 (depressed mood)
was a '2' or a '3 (>= more than half the days)
0 = otherwise
depressionSymptonsCounter Counts the number of '2' or '3' responses (>= more than half the days)
for q1-q8 as well as any response other than 0 for q9
Major Depression if
1. 'DepressedMoodOrAnhedonia' = 1 AND
2. DepressionSymptonsCounter >= 5
Other Depression if
1. 'DepressedMoodOrAnhedonia' = 1 AND
2. 2 <= DepressionSymptonsCounter < 5
phq9SeverityScore Total Score (adds up all valid response values from q1-q9; range: 0-27)
1-4 Minimal depression
5-9 Mild depression
10-4 Moderate depression
15-19 Moderately severe depression
20-27 Severe depression

Raw Data

File Name: phq_9.iqdat

Data Fields

NameDescription
date Date the session was run
time Time the session was run
subject Participant ID
group Group number
session Session number
build Inquisit version number
q*_response Response given (in assigned values)
Scale: q1-q9: 0 (Not at all) - 3 (Nearly every day)
Scale: q10: 0 (Not difficult at all) - 3 (Extremely difficult)
scale: q1-q9: 0 (Not at all) - 3 (Nearly every day)
q*_latency How much time (in ms) the participant spent on the surveyPage with this particular
question (the last time this particular surveyPage was visited)

Parameters

The procedure can be adjusted by setting the following parameters.

NameDescriptionDefault
pageInstructions The instructions presented to participants