Somatic symptom reporting has a dimensional latent structure: results from taxometric analyses

Area of Science:

• Psychiatry and Psychology
• Medical Sociology
• Clinical Epidemiology

Background:

• Medically unexplained symptoms (MUS) are central to somatoform disorders.
• Current understanding treats MUS as both categorical diagnoses and dimensional symptom reporting.
• The empirical latent structure of MUS remains poorly understood.

Purpose of the Study:

• To investigate the latent structure of somatic symptom reporting.
• To determine if MUS represent a category or a continuum.
• To analyze data using established taxometric methods.

Main Methods:

• Taxometric analyses were applied to somatic symptom reporting data.
• The Patient Health Questionnaire (PHQ)-15 was used in student (N=782, N=2,577) and primary care (N=519) samples.
• Three taxometric methods (MAXEIG, MAMBAC, L-Mode) and simulation data with CCFI were employed.

Main Results:

• All taxometric methods across all three datasets favored a dimensional solution (CCFI<.50).
• Simulated taxonic and dimensional datasets showed substantial differences.
• The study samples were appropriate for taxometric analysis.

Conclusions:

• The latent structure of somatization/somatic symptom reporting, as assessed by the PHQ-15, is dimensional.
• This finding applies to both primary care and student populations.
• Implications for clinical practice, etiology, and pathogenesis models are discussed.