The internalizing and externalizing dimensions of psychopathology have been shown to
effectively identify groups that are at higher risk for experiencing certain forms of
psychopathology. Many studies have shown that chronic physical health conditions are a
risk factor for psychological distress, yet there has been very little research examining the
association between chronic physical health conditions and dimensional models of
psychopathology to date. In the present study we examined the factor structure of
internalizing and externalizing symptoms in a sample of adults with postural orthostatic
tachycardia syndrome (POTS; n =172) and in a sample of adults without any chronic
illness diagnoses (n = 199). Confirmatory factor analyses suggested that psychological
distress in individuals with POTS can be effectively characterized by an internalizing
dimension composed of distress and fear subcomponents as well as an externalizing
dimension. Tests of measurement invariance allowed for the examination of latent means,
which showed that individuals with POTS tend to have higher scores on the internalizing
dimension and lower scores on the externalizing dimension than healthy controls.
Regression analyses suggested that within the sample of people with POTS, those who
were more accepting of their illness and had higher health related quality of life tended to
have lower scores on the internalizing dimension. Findings suggest that individuals with
POTS are at heightened risk for experiencing internalizing symptoms of psychopathology. A dimensional conceptualization of psychopathology seems like an
effective way to identify symptoms of psychopathology that are separate from symptoms
of autonomic nervous system dysfunction.