Reading focus
Syllabus: How Should We Classify Psychopathology?
Track how the measurement choices create the symptom profiles being counted.
Why you’re reading it. Use empirical heterogeneity to ask what information a broad diagnostic category retains and loses.
A question to consider. Two people share a diagnosis but few measured symptoms. What would that observation establish about the category, and what causal conclusion would require additional evidence?
Why this reading
People given the same diagnosis can report markedly different combinations of symptoms. This analysis makes that diversity visible and asks what a diagnostic grouping conceals when researchers treat its members as interchangeable.
Before you read
Heterogeneity means variation within a group. A symptom profile records a combination rather than just a total. Converting graded responses into present/absent indicators makes the threshold part of the measurement.
Read for
- Track how questionnaire responses become symptom profiles and how severity restrictions change the comparison.
- Distinguish observed diversity from conclusions about the number or nature of underlying causes.
Consider afterwards
- How could changing the threshold alter the apparent number of profiles?
- Could one causal process produce several symptom patterns? What would discriminate that account from several distinct processes?
Editorial context
The study uses selected STAR*D outpatients and thresholded questionnaire responses; profile counts depend on those choices. Its historical claim that NIMH would fund only a neurobiological approach should be read alongside Morris et al.’s clarification: NIMH did not stop funding research based on existing diagnoses.