The next edition of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-5) - used around the world to classify mental disorders - will include a new category of somatic symptom disorder.
But Allen Frances, Chair of the current (DSM-IV) task force warns that the DSM-5 definition of somatic symptom disorder "may result in inappropriate diagnoses of mental disorder and inappropriate medical decision making."
The new category will extend the scope of mental disorder classification by eliminating the requirement that somatic symptoms must be "medically unexplained" he explains. In DSM-5, the focus shifts to "excessive" responses to distressing, chronic, somatic symptoms with associated "dysfunctional thoughts, feelings, or behaviours."
His concern is supported by the results of the DSM-5 field trial study. Somatic symptom disorder captured 15% of patients with cancer or heart disease and 26% with irritable bowel syndrome or fibromyalgia, and had a very high false-positive rate of 7% among health people in the general population.
He points out that, previous DSM criteria "have always included reminders to clinicians to rule out other explanations before concluding that any mental disorder is present. But his suggestions to the DSM-5 work group that similar reminders should be included this time were rejected."
Every diagnostic decision is a delicate balancing act between definitions that will result in too much versus too little diagnosis - the DSM-5 work group "chose a remarkably sensitive definition that is also remarkably non-specific," warns Frances.
This, he argues "reflected a consistent bias throughout DSM-5 to expand the boundaries of psychiatric diagnosis with what I believe was insufficient attention to the risks of the ensuing false positive mislabeling."
"The DSM-5 diagnosis of somatic symptom disorder is based on subjective and difficult to measure cognitions that will enable a "bolt-on" diagnosis of mental disorder to be applied to all medical conditions, irrespective of cause," he adds.
"Clinicians are best advised to ignore this new category. When a psychiatric diagnosis is needed for someone who is overly worried about medical problems the more benign and accurate diagnosis is adjustment disorder."