Poster Presentation Australian Diabetes Society and the Australian Diabetes Educators Association Annual Scientific Meeting 2014

Suicidal ideation or non-suicidal self-harm? A mismatch between the DSM-IV criterion and PHQ-9 item nine (#257)

Jessica L Browne 1 2 , Giesje Nefs 3 , Frans Pouwer 3 , Jane Speight 1 2 4
  1. The Australian Centre for Behavioural Research in Diabetes, Diabetes Australia - Vic, Melbourne, VIC, Australia
  2. Centre for Mental Health and Wellbeing Research, School of Psychology, Deakin University, Burwood, VIC, Australia
  3. Center of Research on Psychology in Somatic Diseases, Tilburg University, Tilburg, The Netherlands
  4. AHP Research, Hornchurch, Essex, UK

International guidelines recommend routine screening for emotional distress in people with diabetes so that common problems, including depression, can be detected and treated. The 9-item Patient Health Questionnaire (PHQ-9) is a commonly used tool for this purpose. According to its developers, each item corresponds to a diagnostic criterion for depressive disorder from the Diagnostic and Statistical Manual of Mental Disorders 4th Edition (DSM-IV). We query this claim, as item nine does not assess suicidal ideation alone.

The PHQ-9 asks respondents to indicate the frequency with which they experienced the nine diagnostic symptoms of major depressive disorder over the past fortnight (0=not at all; 3=almost every day; total score range: 0-27). Suicidal ideation is defined in the DSM-IV as “recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation without a specific plan, or a suicide attempt or a specific plan for committing suicide”, however, PHQ-9 item nine wording (“thoughts that you would be better off dead or of hurting yourself in some way”) reveals a mismatch with the diagnostic criterion. The item assesses both thoughts of death/suicide and self-harm, without distinguishing between them, and the latter is not a DSM-IV diagnostic criterion for depression.

This poor wording causes interpretation difficulties, as illustrated by Australian and Dutch Diabetes MILES Study data. PHQ-9 data from these studies (N=7019) demonstrates that 10% (n=701) of participants endorsed item nine (score >0) but, of those, 29% (n=206) were not depressed (PHQ-9 total score <10). It seems that many are responding to the “hurting yourself in some way” portion of the item, and are having non-suicidal thoughts of self-harm (e.g. cutting).

Clinicians need to be aware of the limitations of the PHQ-9 so that these can be accounted for when interpreting patient responses, to minimise over-estimation of depressive symptoms and suicidal ideation.