Somatic symptom count scores do not identify patients with symptoms unexplained by disease: a prospective cohort study of neurology outpatients

J Neurol Neurosurg Psychiatry. 2015 Mar;86(3):295-301. doi: 10.1136/jnnp-2014-308234. Epub 2014 Jun 16.

Abstract

Objective: Somatic symptoms unexplained by disease are common in all medical settings. The process of identifying such patients requires a clinical assessment often supported by clinical tests. Such assessments are time-consuming and expensive. Consequently the observation that such patients tend to report a greater number of symptom has led to the use of self-rated somatic symptom counts as a simpler and cheaper diagnostic aid and proxy measure for epidemiological surveys. However, despite their increasing popularity there is little evidence to support their validity.

Methods: We tested the score on a commonly used self-rated symptom questionnaire- the Patient Health Questionnaire (PHQ 15) (plus enhanced iterations including an additional 10 items on specific neurological symptoms and an additional 5 items on mental state) for diagnostic sensitivity and specificity against a medical assessment (with 18 months follow-up) in a prospective cohort study of 3781 newly attending patients at neurology clinics in Scotland, UK.

Results: We found 1144/3781 new outpatients had symptoms that were unexplained by disease. The patients with symptoms unexplained by disease reported higher symptoms count scores (PHQ 15: 5.6 (95% CI 5.4 to 5.8) vs 4.2 (4.1 to 4.4) p<0.0001). However, the PHQ15 performed little better than chance in its ability to identify patients with symptoms unexplained by disease. The findings with the enhanced scales were similar.

Conclusions: Self-rated symptom count scores should not be used to identify patients with symptoms unexplained by disease.

Keywords: SOMATISATION DISORDER.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Ambulatory Care
  • Cohort Studies
  • Diagnosis, Differential
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Nervous System Diseases / diagnosis*
  • Nervous System Diseases / psychology
  • Neurologic Examination
  • Predictive Value of Tests
  • Prospective Studies
  • Referral and Consultation
  • Self Report
  • Somatoform Disorders / diagnosis*
  • Somatoform Disorders / psychology
  • Surveys and Questionnaires
  • Young Adult