Negative affectivity as a transdiagnostic factor in patients with common mental disorders

Area of Science:

• Psychological Medicine
• Clinical Psychology
• Psychotherapy Research

Background:

• Increasing use of screening and monitoring systems in psychotherapy.
• Debate on the necessity of multi-item questionnaires for outcome measurement.
• Need for empirical research to guide the selection of assessment instruments.

Purpose of the Study:

• Investigate the latent factor structure of a multi-dimensional outcome measurement strategy.
• Examine if routinely used instruments (PHQ-9, GAD-7, WSAS) assess empirically distinct dimensions.
• Analyze data from English Improving Access to Psychological Therapies (IAPT) services.

Main Methods:

• Factor analyses and structural equation modeling.
• Utilized 11,939 intake assessments from outpatients (2008-2010).
• Assessed PHQ-9 (depression), GAD-7 (anxiety), and WSAS (functional impairment).

Main Results:

• Instruments primarily assess one general dimension.
• Some items of GAD-7 and WSAS capture unique variance beyond the general dimension.
• Disorder-specific factor scores were predicted by patient diagnostic categories.

Conclusions:

• Supports multi-dimensional assessment in primary care populations.
• Highlights the importance of transdiagnostic factors as treatment targets.
• Acknowledges limitations including missing data and brief diagnostic measures.