The biology of mental pain: a systematic review to map the different expressions, definitions, hypotheses, experimental paradigms, investigation methods and candidate biomarkers of mental pain in human subjects
Bibliographic record
Abstract
Introduction Mental pain is a transdiagnostic symptom, predictive of suicide and reported as a critical outcome by patients. A previous systematic review of epidemiological and clinical research has shown a lack of consensual definition of mental pain in clinical research and high heterogeneity across the different measurement instruments of mental pain. Up today there is no systematic review synthetizing all published biological investigations on mental pain. Objectives This study aims to map the field of biological investigations of mental pain in human to identify what and how biomarkers are investigated with a meta-research approach, by providing a critical appraisal of the terms and definitions of mental pain, the studies’ hypotheses, the experimental paradigms used to induce or mimic mental pain and the measurement instruments used to measure mental pain. Methods We conducted a systematic review (compliant with PRISMA guidelines) of all primary research reporting to investigate candidate biomarkers of mental pain in human subjects as stated by the authors. We searched from inception to June 23rd, 2022, the 3 databases MEDLINE, Web of Science and EMBASE. We extracted the study characteristics (e.g., year of publication, population, etc.), the terms used for meaning mental pain, the definition of mental pain, the method to induce mental pain and its rational, the hypotheses and aims, the measurement instruments of mental pain, the candidate biomarkers, and their method of investigation. We performed descriptive statistics of the sample’s characteristics and the extracted data, a qualitative analysis of the definitions, hypothesis, aims and experimental paradigms, and a data visualization linking candidate biomarkers, experimental paradigms, and their investigation methods. Results The search retrieved 5685 papers of which we included 72 primary research publications constituting 78 distinct research studies. Only 37.5% of studies reported a definition of mental pain. 11.5% of studies did not show a measurement instrument of mental pain. The Cyberball (a social exclusion paradigm) was the most frequently used paradigm in experimental studies (62.7%). The cingulate cortex was the most frequently investigated biomarker category (15.3% of all candidate biomarkers), with fMRI as the most frequent investigation method (53.7% of all investigation methods). Conclusions The field of biological investigations on mental pain shows a marked heterogeneity of definitions, terms, hypotheses, experimental paradigms, and measurement instruments, with an over-representation of the construct of social pain and the Cyberball. These could compromise the comparison and combination of studies results in evidence synthesis and their translation into clinical practice. Disclosure of Interest None Declared
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.026 | 0.099 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.014 | 0.013 |
| Bibliometrics | 0.025 | 0.022 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.005 | 0.006 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".