 35. Personality and Psychopathology  747
depressive disorders (e.g., major depressive 
disorder) and anxiety disorders (e.g., social 
phobia; Naragon-  Gainey, Watson, & Mar -
kon, 2009; Watson et al., 2005). In this 
case, the personality framework argues for 
a different grouping of disorders based on 
their empirical associations with personality 
traits.
In addition to using personality to group 
psychologically similar disorders together, 
personality associations may also point to 
important distinctions between symptoms 
that are grouped together, for example, 
within a given diagnosis. Attention-  deficit/
hyperactivity disorder (ADHD) is a diag -
nosis with many symptoms, often differ -
entiated by symptoms reflecting problems 
with inattention versus problems with hy -
peractivity. Temperament–  trait associations 
indicate that low conscientiousness is par -
ticularly associated with inattentive ADHD 
symptoms, whereas high neuroticism and 
low agreeableness are associated more gen -
erally with hyperactive ADHD symptoms 
(Martel, Nigg, & von Eye, 2009). In this 
case, personality offers empirical validation 
of symptom clustering, while also pointing 
to potential underlying mechanisms and 
pathways through which distinct symptoms 
emerge and develop (Martel et al., 2009).
In addition to informing overall groupings 
of psychopathology structure, the personal -
ity framework can also inform fundamental 
questions about what should be considered 
psychopathology. For example, relational 
aggression  is defined as aggressive acts in -
tended to damage one’s social status or in -
terpersonal relationships. There has been 
some controversy over whether relational 
aggression should be considered a form of 
psychopathology or a normative behavior 
qualitatively distinct from other types of 
aggression or externalizing problems. Per -
sonality associations offer some insight: 
Relational aggression typically shows mod -
erate correlations with neuroticism, (low) 
agreeableness, and (low) conscientiousness, 
a profile virtually identical to that for physi -
cal aggression and many other externaliz -
ing disorders (Burt, Donnellan, & Tackett, 
2012; Tackett, Daoud, et al., 2013). Such 
findings offer support for a common group -
ing between relational aggression and other 
problems classified as psychopathology.Structural Models of Psychopathology
Although hierarchical structural models 
are the historic norm in personality re -
search, they were introduced to the field of 
psychopathology much later—to child psy -
chopathology in the 1960s and 1970s (e.g., 
Achenbach, 1966), then decades later to 
adult psychopathology (e.g., Krueger, 1999). 
Nonetheless, a sizable movement has grown 
to argue for an empirically based approach 
to classifying and organizing symptoms of 
psychopathology (Kotov et al., 2017; Widi -
ger et al., 2019). It is notable that the move 
toward hierarchical structural models of 
psychopathology has been highly informed 
by personality research. The long-  standing 
use of hierarchical structural models to 
characterize personality traits offers a rich 
theoretical and methodological history on 
which psychopathology researchers can 
draw (Markon et al., 2005; Markon, 2009).
Like personality traits, psychopathology 
symptoms exist on the same dimensions as 
normal manifestations of the underlying 
construct, and are therefore most accurately 
conceptualized as continuous (Haslam, Hol -
land, & Kuppens, 2012; Markon & Krueger, 
2005; Widiger & Samuel, 2005). Dimen -
sional hierarchical models are particularly 
useful in organizing psychopathology con -
structs, as they offer an empirical answer to 
problems of co morbidity or co-  occurrence 
of multiple disorders at greater than chance 
levels (Forbes, Tackett, Markon, & Krueger, 
2016; Kessler, Chiu, Demler, & Walters, 
2005; Ormel et al., 2015). A dimensional 
classification retains information about an 
individual’s functioning across all dimen -
sions simultaneously, increasing the amount 
of information about a person’s functioning 
while eliminating problems created by a cat -
egorical system. The concept is likely unsur -
prising to personality researchers, who eas -
ily comprehend what it means for a single 
individual to be high on extraversion, low 
on neuroticism, and average on conscien -
tiousness. The benefits of these models are 
increasingly recognized in psychopathology 
circles.
As noted previously, such empirical ap -
proaches typically characterize three broad 
domains at higher-  order levels: internaliz -
ing, externalizing, and thought problems. 