The most recent version (DSM-5) of the most widely used manual for classifying mental health lists 298 separate conditions, with the implication that these are each discrete, distinct categories. Yet many conditions occur on a spectrum of severity, where, at the mild end the distinction between “normal” and “abnormal” is arbitrary. Furthermore, most people who have one mental health condition have multiple conditions, and there is considerable overlap of symptoms among conditions.
Attempts were made to clarify this diagnostic messiness by suggesting three major factors (Internalizing- depression and anxiety; Externalizing - ADHD, substance abuse, conduct disorder; and Thought Disorders -psychosis) might more accurately capture the variation in mental health conditions. Statistics supported the validity of these dimensions, but even these dimensions show considerable overlap. Mathematical models including an overarching psychopathology, or “p-factor”, in combination with Internalizing, Externalizing, and Thought Disorders provide a better match of the range of expression of mental health conditions.
Genetic, brain research, and psychologic studies all support the existence that such a p-factor exists. But it is possible that the p-factor is more a statistical artifact, rather than reflecting the actual structure of mental health disorders. It may be more a reflection of outcomes or severity of mental health problems than an indication of a common origin.
A p-factor might help explain why so many individuals with ADHD have additional symptoms of depression, anxiety, autism and other mental health conditions. It also suggests that many of our talking and medication therapies may be helpful across multiple conditions rather than only aiding specific ones. Finally, research into ADHD and other conditions should take into account this p-factor when selecting subjects for study, and in interpreting results, and not look at just narrowly defined populations.
References:
Is There a General Factor of Prevalent Psychopathology during Adulthood? (2012)
www.ncbi.nlm.nih.gov/pmc/arti...
The p Factor: One General Psychopathology Factor in the Structure of Psychiatric Disorders? (2014)
www.ncbi.nlm.nih.gov/pmc/arti...
A critical evaluation of the p-factor literature (2024)
www.nature.com/articles/s4415...
The contribution of common genetic risk variants for ADHD to a general factor of childhood psychopathology (2020)
pubmed.ncbi.nlm.nih.gov/29934...
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Psychiatrist, neuroscientist, and author John Kruse, MD, PhD presents practical, actionable, well-researched information about treatment options that scientists and clinicians recommend for adult ADHD and other mental health conditions. Subscribe if you're curious about how neuro-atypical brains can optimize their functioning in our shared, and somewhat strange, world.
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