JMIR Publications

ABSTRACT

Background:

Patient Health Questionnaire (PHQ-2) and Insomnia Severity Index (ISI-2) are screening assessments that reflect the past two weeks of experience for depression and insomnia respectively. Retrospective assessment has been associated with reduced accuracy due to recall bias.

Objective:

This study aimed to increase the reliability of the responses by validating the use of PHQ-2 and ISI-2 for daily screening.

Methods:

A total of 167 psychiatric outpatients at the Yongin Severance Hospital (63 males and 104 females), with a mean age of 35.1 years participated in this study. Participants used a mobile application (‘Mental Protector’) for a period of 4 weeks and rated their depressive and insomnia symptoms daily on the modified PHQ-2 and ISI-2 scales. The validation assessments were conducted in two blocks, each with a fortnight response from the participants. The modified version of the PHQ-2 was evaluated against the conventional scales of the Patient Health Questionnaire-9 and the Korean version of the Center for Epidemiologic Studies Depression Scale-Revised.

Results:

According to the sensitivity and specificity analyses, an average score of 3.29 on the modified PHQ-2 was considered valid for screening for depressive symptoms. Likewise, the ISI-2 was evaluated with Insomnia Severity Index, and a mean score of 3.50 was determined as a valid threshold for insomnia symptoms when rated daily.

Conclusions:

This study is one of the first to propose a daily digital screening measure for depression and insomnia delivered through a mobile application. The modified PHQ-2 and ISI-2 were strong candidates for daily screening for depression and insomnia, respectively.