BackgroundDespite statistical evidence of a general factor of psychopathology (i.e.,p-factor), there is little agreement about what thep-factor represents. Researchers have proposed five theories: dispositional negative emotionality (neuroticism), impulsive responsivity to emotions (impulsivity), thought dysfunction, low cognitive functioning, and impairment. These theories have primarily been inferred from patterns of loadings of diagnoses onp-factors with different sets of diagnoses included in different studies. Researchers who have directly examined these theories ofphave examined a subset of the theories in any single sample, limiting the ability to compare the size of their associations with ap-factor.MethodsIn a sample of adults (N= 1833,Mage= 34.20, 54.4% female, 53.3% white) who completed diagnostic assessments, self-report measures, and cognitive tests, we evaluated statisticalp-factor structures across modeling approaches and compared the strength of associations among thep-factor and indicators of each of these five theories.ResultsWe found consistent evidence of thep-factor's unidimensionality across one-factor and bifactor models. Thep-factor was most strongly and similarly associated with neuroticism (r= .88), impairment (r= .88), and impulsivity (r= .87), χ2(1)s < .15,ps > .70, and less strongly associated with thought dysfunction (r= .78), χ2(1)s > 3.92,ps < .05, and cognitive functioning (r= −.25), χ2(1)s > 189.56,ps < .01.ConclusionsWe discuss a tripartite definition ofpthat involves the transaction of impulsive responses to frequent negative emotions leading to impairment that extends and synthesizes previous theories of psychopathology.