Cited by 367Mental Health Research TopicsAnxiety, Depression, Psychometrics, Treatment, Cognitive ProcessesTreatment of Major Depression

Problematic assumptions have slowed down depression research: Why symptoms, not syndromes are the way forward

Open access
Fried, Eiko I.·2015·Frontiers in Psychology

Abstract

Major depression (MD) is a highly heterogeneous diagnostic category. Diverse symptoms such as sad mood, anhedonia, and fatigue are routinely added to an unweighted sum-score, and cutoffs are used to distinguish between depressed participants and healthy controls. Researchers then investigate outcome variables like MD risk factors, biomarkers, and treatment response in such samples. These practices presuppose that (1) depression is a discrete condition, and that (2) symptoms are interchangeable indicators of this latent disorder. Here I review these two assumptions, elucidate their historical roots, show how deeply engrained they are in psychological and psychiatric research, and document that they contrast with evidence. Depression is not a consistent syndrome with clearly demarcated boundaries, and depression symptoms are not interchangeable indicators of an underlying disorder. Current research practices lump individuals with very different problems into one category, which has contributed to the remarkably slow progress in key research domains such as the development of efficacious antidepressants or the identification of biomarkers for depression. The recently proposed network framework offers an alternative to the problematic assumptions. MD is not understood as a distinct condition, but as heterogeneous symptom cluster that substantially overlaps with other syndromes such as anxiety disorders. MD is not framed as an underlying disease with a number of equivalent indicators, but as a network of symptoms that have direct causal influence on each other: insomnia can cause fatigue which then triggers concentration and psychomotor problems. This approach offers new opportunities for constructing an empirically based classification system and has broad implications for future research.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.3389/fpsyg.2015.00309

Cites

126 of 126 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • From the homogeneity assumption, the comorbidity and heterogeneity problems emerge and limit psychiatric research.

    “From the homo- geneity assumption, the comorbidity (17) and heterogeneity (18,19) problems emerge and limit psychiatric research (20–26).”

    From Methods and challenges for assessing heterogeneity (2020) · cites this paper as [23]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. Grebb J. A. Carlsen A. (2009). “ Introduction and considerations for a brain-based diagnostic system in psychiatry,” in Comprehensive Textbook of Psychiatry eds. Sadock B. Sadock V. Ruiz P. Kaplan H. (Philadelphia: Wolters Kluwer Health/Lippincott Williams) 1– 4.

Cited by

Sorted by citations

Authors
Fried, E. I.
Affiliations
KU Leuven (BE)
Corresponding author
Fried, Eiko I.
Venue
Frontiers in Psychology
Published
2015-03-23
Volume
6
Pages
309-309
ISSN
1664-1078 (ISSN-L)
OpenAlex
W2168432043
Cited by
367
References
126
Citations by year
2026: 25 · 2025: 32 · 2024: 42 · 2023: 57 · 2022: 39 · 2021: 37 · 2020: 35 · 2019: 24 · 2018: 21 · 2017: 22 · 2016: 25 · 2015: 8
FWCI
3.27
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • Frontiers in Psychology (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Lirias (KU Leuven) (submittedVersion, other-oa)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Topics
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Mental Health Research Topics
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Anxiety, Depression, Psychometrics, Treatment, Cognitive Processes
  • Health Sciences › Medicine › Pharmacology › Treatment of Major Depression
Keywords
major depressive disorder, diagnostic heterogeneity, symptom clusters, anhedonia, fatigue, insomnia, biomarkers, antidepressant drug development, anxiety disorders, psychiatric classification, research assumptions

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review