All for one and one for all: Mental disorders in one dimension

By Avshalom Caspi, Terrie E. Moffitt. American Journal of Psychiatry, 2018

773 citations recorded by the source corpus.

In both child and adult psychiatry, empirical evidence has now accrued to suggest that a single dimension is able to measure a person’s liability to mental disorder, comorbidity among disorders, persistence of disorders over time, and severity of symptoms. This single dimension of general psychopathology has been termed "p", because it conceptually parallels a dimension already familiar to behavioral scientists and clinicians: the “g” factor of general intelligence. As the g dimension reflects low-to-high mental ability, the p dimension represents low-to-high psychopathology severity, with thought disorder at the extreme. The dimension of p unites all disorders. It influences present/absent status on hundreds of psychiatric symptoms, which modern nosological systems typically aggregate into dozens of distinct diagnoses, which in turn aggregate into three overarching Externalizing, Internalizing, and Psychotic Experience domains, which finally aggregate into one dimension of psychopathology from low to high: p. Studies show that the higher a person scores on p, the worse that person fares on measures of family history of psychiatric illness, brain function, childhood developmental history, and adult life impairment. A dimension of p may help to account for ubiquitous non-specificity in psychiatry: multiple diagnoses share the same risk factors and biomarkers, and often respond to the same therapies. Here we summarize the history of the uni-dimensional idea, review modern research into p, demystify statistical models, articulate some implications of p for prevention and clinical practice, and outline a transdiagnostic research agenda going forward.

Subfields: Clinical Psychology, Psychiatry and Mental health, Philosophy

View Paper: https://www.semanticscholar.org/paper/36bb3c578d37dadb5233b71ddedc0e8cf9b4d450

How researchers see this paper

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In Clinical Psychology

1. Trevor W. Robbins
2. Naomi P. Friedman
3. Ashley L. Watts
4. I. Waldman
5. Holly E. Poore

In Psychiatry and Mental health

1. Naomi P. Friedman
2. Trevor W. Robbins
3. Ashley L. Watts
4. I. Waldman
5. Holly E. Poore
6. J. Dalley

In Philosophy

1. Trevor W. Robbins
2. Naomi P. Friedman
3. Ashley L. Watts
4. I. Waldman
5. Holly E. Poore

Citations in the corpus

• The role of prefrontal cortex in cognitive control and executive function (2021, background): “That is, its neurobiological underpinnings are not well understood and its psychological interpretation varies [20, 195].”
• Riskier Tests of the Validity of the Bifactor Model of Psychopathology (2019, methodology): “Although research has yet to converge on any one of these explanations, the majority of validation research has proceeded presupposing that the p factor is substantive and meaningful given that it has been established as a correlate of “real-world life outcomes” (Caspi & Moffitt, 2018, p. 835).”
• A new direction to promote the implementation of artificial intelligence in natural clinical settings (2019, background): “For example, Caspi et al. 36 pointed out that among individuals meeting the criteria for one psychiatric disorder in their life time, 66% met the criteria for a second one; of those meeting criteria for two disorders, 53% met the criteria for a third one; of those meeting the criteria for a third di”