In the last few decades we've witnessed a
dramatic rise in the number of DSM mental disorders. DSM1, published in 1952, included 128 mental
disorders; DSM5, published in 2013, includes 541 mental disorders (Blashfield
et al, 2014). There is a high degree of
comorbidity between mental disorders (comorbidity means a person having two
disorders or more at the same time). Comorbidity
rates in psychiatry roughly obey the 50% rule: half of the people who meet
diagnostic criteria for one disorder also meet diagnostic criteria for a second
disorder concurrently; half of the people with two disorders meet criteria for
a third disorder, etc.
There is also sequential comorbidity (a person overcomes
one disorder and then has a second disorder).
For example, longitudinal studies show that general anxiety disorder
(GAD) and depression are sequentially tied:
a person who has one of them at any point in time has a higher risk of
developing the second one in the future (Caspi et al, 2014).
This high comorbidity means that there may be a
simpler structure to psychopathology than the one arising from the current
diagnostic criteria that identify a lot of distinct and different disorders.
Albert
Einstein wrote: "The supreme goal of all theory is to make the irreducible
basic elements as simple and as few as possible without having to surrender the
adequate representation of a single datum of experience." (Carroll,
2017).
Clinicians realize that many disorders have
common dimensions/factors (these broad factors are parallel to the broad
abilities in the CHC model). Researchers
identify two broad factors typical of childhood disorders: internalizing (anxiety, depression, phobias)
and externalizing (aggression, antisocial behavior, hyperactivity-impulsivity). We are familiar with these dimensions from
the Achenbach questionnaire. Externalizing
disorders usually begin in childhood and affect boys more than girls, while
internalizing disorders appear more towards adolescence and are more typical of
girls. Some scholars find that internalizing subsumes two lower-order
factors: distress (major
depression, generalized anxiety, dysthymia) and fear (agoraphobia,
social phobia, specific phobia).
Externalizing and internalizing continue to characterize personality
throughout life. In adults some
researchers add an additional broad factor:
thought disorders. This factor
correlates 0.6 with internalizing (Caspi et al, 2014).
Externalizing and externalizing correlate
0.4-0.6, but researchers treat them as two separate broad factors. Are they really so, or are they two extremes
of the same dimension? Intuitively we
feel that a person who has high externalizing will tend to be low in
internalizing and vice versa. It's possible that the positive
and significant correlation between internalizing and externalizing indicates
the existence of a superordinate common factor, a general psychopathology
factor (p, analogous to g, general intelligence). As g reflects the correlation between broad
cognitive abilities, p might express the correlation, the common variance,
between different dimensions of psychopathology (Caspi et al, 2014).
I have
reservations about the name "general psychopathology factor". What's the use of emphasizing
pathology? According to this formulation, the higher a person's p, the poorer
his mental health. Beyond the bad
feeling this evokes, the p factor correlates negatively with g. It might have been better to name this
general factor on the positive side, say a "general mental health
factor", h.
One more
thing: I think there is room for
unification:
a. A
unification between conceptualizations of the broad factors of psychopathology (internalizing,
externalizing, thought disorders) and conceptualizations of personality (for
example, the BIG5 model). Internalizing may
be linked to Neuroticism (and also to Agreeableness and Conscienciousness); Externalizing
may be linked to Extraversion and to Openness to experience, and a thought
disorder factor may also be linked to the Openness factor (at its
extreme). As will be seen later, the
broad factors of psychopathology affect and are affected by the BIG5.
B. A unification between conceptualizations of
personality/psychopathology and conceptualizations of cognitive abilities. I think personality includes both traits, broad
factors of psychopathology and cognitive. The tight linkage between
conscientiousness and executive functions attests that.
The studies discussed below examined three
possible models of mental health/psychopathology in children, adolescents and
adults:
A. a model of several correlated broad
factors (internalizing, externalizing and, in adults, thought disorders). Each factor expresses the common variance
(the common element) of the mental disorders that are mapped to it. This model is presented in figure 1.
Figure 1: a model of several correlated
broad factors
B. a bifactor model, that sees
psychopathology as having two aspects: 1) several broad factors (internalizing,
externalizing and, in adults, maybe also thought disorders). Each factor expresses the common variance
(the common element) of the mental disorders that are mapped to it. 2) a
general psychopathology factor – that expresses the common variance of all
mental disorders. This model is
presented in figure 2.
Figure 2: a bifactor model
C. a model with one general psychopathology
factor that expresses the common variance of all mental disorders. This model is presented in figure 3.
Figure 3: a model with one general psychopathology
factor
In a previous post we
discussed distinctions between such models as related to cognitive abilities.
Research
with children: The three models were compared by Martel et al in 2017. Brazilian families were screened at schools
on the registry day (the average age of the children was 9 and the average age
of the parents was 35). Out of about
8000 families the researchers identified about 1500 families with high risk for
mental disorders and 950 families with no such risk. The parents were asked about symptoms of depression,
mania, phobias, anxiety, panic, OCD, psychosis, addictions, ODD and CD in one
or more of the child's first degree relatives. The child's psychopathology
symptoms (panic attacks, phobias, anxiety, eating disorders, depression, PTSD,
OCD, CD, ODD, ADHD and ASD) were assessed with interviews and questionnaires
given to the parents.
The model
most fitting with the childrens', the fathers' and the mothers' data was the
bi-factor model that contained a general psychopathology factor and three broad
factors: fear, distress and externalizing. Fear and distress were highly correlated
(0.861). P explained most of the
children and adults' item variance.
There was a significant correlation between the
mother's p and the child's p as well as between the father's p and the child's p. There was a significant correlation between
the mother's p and the child's distress and fear factors. The same was true in respect to the
father. The mother's externalizing
factor was significantly related to the child's p and to the child's
externalizing factor. The father's
externalizing factor was related to the child's externalizing factor, and negatively
related to the child's fear factor. All
correlations were 0.33 and below.
Research
with adolescents was done in 2015 by Patalay et al (one of the researchers was Peter
Fonagy). The researchers gathered data
from about 23500 children aged 11-13, in 7th and 8th
grades, from 200 schools in Britain.
After a year the mental state of about 10300 of the children was
re-assessed. In addition to that, about
7500 children who were in 8th grade at the time of the first
assessment had taken a national achievement test a year and a half later. Thus the researchers were able to assess the
influence of psychopathology on achievement.
It should be noted that the group of children who were reassessed and
who took the achievement test contained less boys and less children of lower
SES.
During both assessment times the children
filled two computerized questionnaires ('Me and My school'; Strengths and
Difficulties Questionnaire SDQ).
In this
study too, model B, the bifactor model (seen in figure 4) best explained the
data. Model A with
only two broad factors (internalizing and externalizing) fit the data almost as
well. In model A, the correlation
between internalizing and externalizing was 0.45, while in model B, the
bifactor model, the correlation between internalizing and externalizing was
small and negative (-0.16). This is
reasonable, since after accounting for p, each of these broad factors expresses
only its unique aspect. Consequently the correlation between them is
significantly lowered. The p factor was
correlated 0.3 with internalizing and 0.22 with externalizing.
Figure 4: the bi-factor model,
Patalay et al, 2015.
The p factor predicted psychopathology, future internalizing
and externalizing and future academic achievement. Both externalizing and internalizing factors
from model A predicted future psychopathology and future academic
achievement. The size of the effect of
the P factor in predicting future psychopathology was large; externalizing and
internalizing had a small to moderate
effect size in the prediction of future psychopathology.
A study
with adults was done by Avshalom Caspi, Terrie Moffitt and their colleagues in
2014. They used data from a longitudinal
study, the Dunedin study, which follows about 1000 people born in Dunedin, New
Zealand. These people were repeatedly
assessed since the age of 3 (they were last assessed at the age of 38). The data brought here were gathered when the
participants were 21,26,32 and 38 years old.
At each assessment period the participants were
asked about symptoms they had during the past year (symptoms of alcoholism,
drug abuse, conduct disorder, depression, general anxiety disorder,
fears/phobias, OCD, mania and symptoms of schizophrenia). The researchers also asked whether during the
period between assessments the participants took psychiatric medicine or were
in psychiatric hospitalization.
in this
study too, the model that best explained the data was the bi-factor model, with
a general psychopathology factor and two broad factors (internalizing and
externalizing). Model A, which had three
broad factors (internalizing, externalizing and thought disorders) fitted the
data almost as well.
The p factor was extracted in all ages
(21,26,32, and 38). The correlation
between the p factor and externalizing was 0.637; the correlation between the p
factor and internalizing was 0.917 (!).
Another broad factor, thought disorders, had a near perfect correlation
(0.997) with p, which attests to their being almost identical.
According to Caspi and his colleagues, "Any individual
who carries a strong General Psychopathology liability might, if their disorder
grows severe enough, experience psychotic thought processes, whatever the
presenting diagnosis; that is, unwanted irrational thoughts are not just for
the formal psychoses. Cognitive behavioral therapies aimed at correcting
patients’ inaccurate thoughts are among the most effective treatments for a
wide variety of disorders. The clinical literature is replete with discussion
of disordered thought processes in the context of affective disorders, anxiety
disorders, eating disorders, autism, posttraumatic stress disorder, somatoform
disorders, dissociative disorders, identity disorders, personality disorders,
and substance disorders. Most chapters of the DSM mention thought symptoms. Indeed, in general,
the only disorders lacking prominent focus on disordered thought in their symptom
criteria are disorders of childhood".
Caspi et al found a positive correlation (0.3)
between externalizing and internalizing in model A, but a negative correlation
(0.47-) between these two factors in model B.
The positive correlation in model is and
indication of the general psychopathology factor. After accounting for p, people who tend
towards externalizing behaviors (for example, drug abuse or antisocial
behavior) tend less towards internalizing behaviors (depression, anxiety) and vice
versa.
Men leaned more towards externalizing and women
leaned towards internalizing. There was
no difference between the sexes in thought disorders. In model B there were no differences between
the sexes in the tendency towards general psychopathology.
Links to
the BIG5
In Caspi et al's study, each of the three factors from model A was significantly associated
with low Agreeableness, low Conscientiousness, and
high Neuroticism. General
Psychopathology was distinctly characterized by high Neuroticism and low
Agreeableness and Conscientiousness. High- p individuals experience
difficulties in regulation/control when dealing with others, the environment,
and the self.
Individuals
who score high on a liability to Externalizing disorders, net of a tendency
toward General Psychopathology, have poorer impulse control (low
Conscientiousness); can be aggressive, rude, and manipulative (low
Agreeableness); but also evoke and enjoy social attention and appear to be
sensitive to potential rewards (high Extraversion). In contrast, individuals
who score high on a liability to Internalizing style disorders, net of General
Psychopathology, are more easily distressed (high Neuroticism) and tend to
refrain from actively approaching, engaging, or exploring their environment
(low Extraversion), although they tend to be agreeable.
Links to intelligence:
Adults with higher levels of p
scored lower on an IQ test than their age peers with lower levels of p. Adults with higher levels of p fared less well
on tests requiring attention, concentration, mental control, visual-perceptual
speed, and visual-motor coordination. People who knew them well said that
individuals with high levels of p experienced cognitive problems in their
everyday lives.
General insights:
Studies with children, adolescents and adults show the existence of a bifactorial
structure of psychopathology/mental health.
The structure includes a general psychopathology factor and two broad
factors (internalizing and externalizing).
Parent maltreatment in
childhood raises the risk for a high p. Impaired
language development and cognitive development in childhood, poor executive
functions and poor impulse control in childhood are risk factors for a high p
in adulthood. A family history of psychiatric
disorders also raises the risk for higher general psychopathology.
The p factor influences the
BIG5 traits and is influenced by them. The
p factor is related to lower general intelligence.
Caspi et al write: "there
could be a developmental progression of severity in psychopathology. Many
individuals manifest a brief episode of an individual disorder, a smaller
subset of individuals progress to develop a persistent Internalizing or
persistent Externalizing syndrome, whereas only a very few individuals progress
to the extreme elevation of p, ultimately emerging with a psychotic condition
most likely during late adolescence or adulthood".
"Such a developmental
progression would require …that brief episodes of single disorders are
widespread in the population, which is …supported by research. A developmental progression also would
require that individuals who manifest psychosis have an extensive prior history
of many other disorders, which has been reported. In addition, a developmental
progression would anticipate that when individuals are followed long enough,
those with the most severe liability to psychopathology will tend to move in
and out of diagnostic categories. Today’s patient with schizophrenia was
yesterday’s boy with conduct disorder or girl with social phobia… This
developmental progression hypothesis is consistent with evidence that
sequential comorbidity is the rule rather than the exception and that
individuals experiencing sequentially comorbid disorders also exhibit more
severe psychopathology".
"…Parallels can be drawn with immuno-deficiencies in physical
health. Immunocompromised individuals are more susceptible to infections.
Identifying the immunodeficiency rather than just observing the expressed
symptoms is crucial to the long-term management and treatment of individuals
with these immune deficits. Similarly, the general psychopathology factor
places the emphasis on considering the individual’s inherent propensity for
psychopathology, rather than simply focusing on diagnostic categories and
symptoms. The existence of a general psychopathology factor or deficit suggests
that individuals with greater propensity (or higher general psychopathology)
are more likely to experience psychopathology no matter what, with
environmental factors and life events perhaps serving only as moderators and
triggers of the expression of specific disorders". Identifying
the p factor, even in children, may help to give the child preemptive
interventions, like parental guidance and assistance in building emotional
regulation skills.
Blashfield, R. K., Keeley, J. W.,
Flanagan, E. H., & Miles, S. R. (2014). The Cycle of Classification: DSM-I Through DSM-5. Annu.
Rev. Clin. Psychol, 10, 25-51.
Caspi, A., Houts, R. M., Belsky, D. W.,
Goldman-Mellor, S. J., Harrington, H., Israel, S., ... & Moffitt, T. E.
(2014). The p factor: one
general psychopathology factor in the structure of psychiatric
disorders?. Clinical Psychological Science, 2(2),
119-137.
Carroll, S. (2017). The big picture: on the origins of
life, meaning, and the universe itself. Penguin.
Martel, M. M., Pan, P. M., Hoffmann, M.
S., Gadelha, A., do Rosário, M. C., Mari, J. J., ... & Rohde, L. A. (2017).
A general psychopathology
factor (P factor) in children: Structural model analysis and external
validation through familial risk and child global executive function. Journal
of abnormal psychology, 126(1), 137. https://pdfs.semanticscholar.org/ce68/6315f65d19842a226063d861d4a80b213cce.pdf
Patalay, Praveetha, Peter
Fonagy, Jessica Deighton, Jay Belsky, Panos Vostanis, and Miranda Wolpert. "A general psychopathology
factor in early adolescence." The British Journal of
Psychiatry 207, no. 1 (2015): 15-22.
https://cloudfront.escholarship.org/dist/prd/content/qt40f4m10p/qt40f4m10p.pdf
