Stress Illness Screening (2)

In the last post we saw four questions (PHQ – 4) that screen for anxiety and depression.  These are described in the reference below (1).  However, to document that screening questions achieve their intended goals and are scientifically valid, it is not enough merely to come up with what sound like reasonable questions.

The authors validated their questions by several means.  Using data from 2149 primary care patients they first determined that response to the PHQ-4 matched-up well with results from longer versions (the PHQ-9 for depression and the GAD-7 for anxiety).  They also found that PHQ-4 responses were predictive of scores on the Medical Outcomes Study Short-Form General Health Survey (the SF-20) which breaks down a person’s functioning into six different dimensions (Social, Physical and Role Functioning, Mental and General Health and Bodily Pain).  They also documented that the questions separated individuals with anxiety (12.1%) from those with depression (4.4%) though many had both (8.5%).  Adding these figures shows that 25% of the sample had positive screens, emphasizing the need for this tool in daily practice.  Finally, the authors showed that higher PHQ-4 scores were associated with a greater number of disability days and physician visits in the prior 3 months.  They also cite a prior paper (2) supporting the concept that a score totaling 3 or more from the two anxiety questions is a good screen for post-traumatic stress disorder as well.

In their discussion the authors take care to remind us of two important points:

  • A positive screen with the PHQ-4 is not diagnostic but merely an indication for further inquiry.
  • To achieve good outcomes, screening must be accompanied by systems of care that monitor treatment adherence and response and enable the clinician to adjust therapy or consult with experts as needed.

1. Kroenke K et al.  An Ultra-Brief Screening Scale for Anxiety and Depression: The PHQ-4.  Psychosomatics 50:6.  Nov-Dec 2009.

2. Kroenke K et al.  Anxiety disorders in primary care: prevalence, impairment , comorbidity and detection.  Ann Intern Med 2007; 146: 317-325.

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