The P factor in general psychopathology: what is it?

Could it be that all psychiatric disorders have a common element?

The P-factor of psychopathology is a proposal by psychologists Avshalom Caspi and Terrie Moffit, who suggest that psychiatric disorders have a common etiological basis and not a specific or distinct one (as traditionally understood).

In the following we will see where the P-factor hypothesis arises in general psychology and what it proposes. and what it proposes.

Diagnosis in psychiatry: categorical model and dimensional model.

As we know them now, diagnoses in psychiatry have a recent history. This history has been particularly marked by the presence of the North American model of psychiatry, whose highest representative is the American Psychiatric Association. (APA).

Each year, the group of specialists attached to the latter publishes a Diagnostic and Statistical Manual (DSM), which categorizes and describes a series of manifestations known as "mental disorders".

This is relatively recent (it formally began in the early 1950s) and currently constitutes one of the most widely used criteria for understanding and treating these manifestations.. In addition, over time, its criteria have been modified and updated according to the needs produced within the context itself.

One of the most significant and recent changes has occurred under the need to broaden the diagnostic criteria, mainly due to the growing doubts about the specificity of each disorder. In the following paragraphs we will develop in more detail what this change has consisted of.

The categorical model

As we have seen, it was in the second half of the 20th century when the first Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association was published. What was initially consolidated as a compilation of research on psychopathology, soon became one of the diagnostic guidelines for the diagnosis of psychopathology. soon became one of the most widely used diagnostic and clinical guidelines around the world..

At least until the first four versions of this manual, the tendency had been to define clinical entities in a specific and differentiated manner. That is, like physical illnesses, each mental disorder would have its own criteria, symptoms, course criteria, symptoms, course, prevalence, and a particular set of characteristics.. Because of this categorization exercise, it is known as a "categorical model".

However, as time went by, it became increasingly difficult to sustain such a model with the necessary rigor: it became evident that what was defined as a specific mental disorder was closely related to one or more other disorders. This relationship between one and the other was described under the medical term "comorbidity", which means precisely "presence of one or more disorders".which precisely means "presence of one or more diseases or disorders in addition to the primary one".

Not only this, but comorbidity turned out to be sequential, i.e., over time, many diagnoses ended up triggering others. And this was repeated very frequently among people attending psychiatric consultation.

In addition to the above, some studies showed that there were diagnoses with a notable and greater comorbidity than others.. For example, personality disorders had excessively high rates (about 60% of people with personality disorder diagnoses have comorbidity with mood diagnoses).

These figures raised doubts about the specificity of the classifications, and also had obvious clinical consequences: many people, instead of having only one diagnosis, which would allow them to understand and modify their distress, obtained two or more, which could do more harm than good.

In addition, the high rates of comorbidity meant that the decision as to whether it was one disorder or another (and the subsequent psychological and/or pharmacological intervention), far from being based on empirical and objective evidence, fell to the personal judgment of the individual, rested on the personal judgment of the professionalThis issue was increasingly criticized by the community of specialists and those affected.

The dimensional model

The development of the categorical model indicated that it was increasingly difficult to sustain a differentiated way of defining and treating diagnoses in psychiatry. Far from being an entity with distinguishable and particular characteristics, it appeared to be a broad spectrum of manifestations that could hardly be separated from each other, it appeared to be a broad spectrum of manifestations that could hardly be separated from each other..

Consequently, the American Psychiatric Association itself, in its fifth version of the Diagnostic and Statistical Manual, defends the need to create a dimensional model. This would allow diagnoses to be made by means of broad criteria which, in turn, would make it possible to understand the manifestations in a comprehensive manner, would make it possible to understand the manifestations in a multifactorial manner..

This raises an important question for specialists in psychopathology: if, contrary to what we thought, mental disorders are not specific but have a high rate of comorbidity, this probably means that there is a broad phenotypic structure in the genesis of these disorders.

From this point on, different researches set themselves the task of questioning the categorical model as well as investigating and broadening the dimensionality of the diagnosis. One of the most representative in the field of psychopathology is the proposal of the P factor..

The P factor in psychopathology: a common structure in psychiatric diagnoses?

Avshalom Caspi and Terrie Moffit along with their collaborators, published a study in 2014 where they conducted a multifactorial analysis to evaluate a new hypothesis about the underlying structure in 10 common mental disorders among young adults (18-21 years old).

Using data from a previous multidisciplinary health study, the authors examined the structure of psychopathology, considering dimensionality, persistence, coexistence, and sequential comorbidity. dimensionality, persistence, coexistence, and sequential comorbidity of mental disorders over 20 years. of mental disorders over 20 years.

In their research they conclude that mental disorders can be summarized from three general dimensions: internalizing, externalizing and thought disorders..

The first dimension is related to mood diagnoses (such as depression or anxiety), the second is linked to diagnoses of social behavior (such as borderline or antisocial personality) and substance abuse; and the third is related to manifestations of psychosis.

The previous dimensions would be supported by a general element or conditioning factor that contributes significantly to their structuring. This element is called "P Factor" (by analogy to the concept of "G Factor g" in intelligence) and originates from a genetic activity, but also from a family history of depression, anxiety, psychosis, antisocial or substance abuse disorders. of depression, anxiety, psychosis, antisocial disorders or substance abuse. In addition, the same factor may be related to potential risk elements such as a history of maltreatment or abuse during childhood.

To put it another way, the authors believe that the P factor, as a common structuring factor in different psychiatric diagnoses, is related to higher levels of life impairment, greater family history of mental disorders, higher rate of negative histories during life span, and more compromised early brain function.

Thus, it is a common element in the origin, development and absence of disorders, which leads the authors to defend a "transdiagnostic" approach in psychiatry.

Bibliographical references:

• Caspi, A., Houts, R., Belsky, D., Goldman-Mellor, Harrington, H., Israel, S. ... Moffitt, T. (2014). The p Factor: One General Psychopathology Factor in the Structure of Psychiatric Disorders? Clinical Psychology Sici, 2(2): 1190-137.