748 vII. APPLICATIONS  AND  IMPLICATIONS
Somatoform disorders and symptoms may 
ultimately form a fourth higher-  order di -
mension, but data on this issue are quite 
limited (Kotov et al., 2011). One recent pro -
posal offers two additional dimensions— 
detachment and antagonism—  beyond the 
four already mentioned: internalizing, ex -
ternalizing, thought disorder, and somato -
form (Kotov et al., 2017), which are nota -
bly both anchored by personality content. 
Dimensions falling lower in the hierarchy 
have not been as clearly delineated, an issue 
that has received focused attention (Kotov et 
al., 2017) and is not unlike questions about 
lower-order hierarchical structure in person -
ality frameworks. Importantly, personality 
research and constructs play a critical role 
in the developing work on psychopathology 
structure and modeling. In addition to the 
vast knowledge base of constructing, mea -
suring, and analyzing dimensional hierarchi -
cal models in personality research (Markon, 
2009), personality trait associations and 
contributions to various symptoms and dis -
orders form a primary theoretical basis for 
ongoing decisions about characterizing psy -
chopathology structure (Kotov et al., 2017).
These movements also have some ana -
logue in other, relatively recent proposals for 
organizing and guiding psychopathology re -
search. In particular, the National Institute 
of Mental Health has recently promoted the 
Research Domain Criteria (RDoC) frame -
work to guide mental health conceptualiza -
tion and, in particular, research (Cuthbert 
& Insel, 2010, 2013). The RDoC framework 
aims to characterize major dimensions un -
dergirding psychopathology syndromes and 
symptoms, ideally, with established connec -
tions to biological causal factors and mecha -
nisms. The RDoC framework comprises 
negative valence systems, positive valence 
systems, cognitive systems, systems for so -
cial processes, and arousal/regulatory sys -
tems. On some level, a basic description of 
the RDoC framework sounds eerily similar 
to a description of broad-band personality 
models used in psychopathology research: 
a set of dimensional constructs thought to 
undergird mental disorder and cut across ex -
isting diagnostic boundaries in summarizing 
behavior and functioning. Yet the develop -
ment of the RDoC was quite different than, 
say development of the five-  factor model (FFM), as RDoC dimensions were closely 
tied to underlying biology and neuroscience 
constructs. Thus, the RDoC dimensions do 
not cleanly map onto empirically derived 
phenotypic structures such as that of the 
FFM or the dimensional structural models 
of psychopathology we have highlighted 
here (e.g., internalizing–  externalizing). Ad -
ditionally, the coverage of clinical phenom -
ena within the RDoC dimensions is neither 
highly detailed nor comprehensive. None -
theless, this movement is promising in that 
it underscores renewed interest in dimen -
sional approaches in psychopathology, and 
will (we hope) increase acceptance of these 
models in the broader community.
Developmental  Perspectives
Although the development of dimensional 
structural models for psychopathology con -
structs was initially pioneered in child and 
adolescent samples (Achenbach, 1966) and 
only later extended to adults, the research 
trends in personality research have flowed in 
the opposite direction, with much less atten -
tion directed toward understanding person -
ality in youth (Shiner, Chapter 12, this vol -
ume; Soto & Tackett, 2015). Nonetheless, it 
is clear that child personality foreshadows 
the development of psychopathology later in 
life (e.g., Hengartner, Ajdacic-  Gross, Wyss, 
Angst, & Rössler, 2016; Muris & Ollendick, 
2005; Shiner, Masten, & Roberts, 2003). It 
seems likely that research on personality– 
psychopathology relationships in early life 
will increase, following advances in mea -
surement and assessment of early personal -
ity traits (Soto & Tackett, 2015). Despite the 
fact that research on child personality is less 
developed than that for adults, child clini -
cal psychologists have frequently drawn on 
temperament and personality traits to in -
form their understanding of psychological 
disorders and symptoms. Similar to work 
with adults, researchers have drawn on child 
personality and temperament to inform the 
development of structural models and clas -
sification approaches to psychopathology 
(e.g., De Pauw & Mervielde, 2010; Lahey et 
al., 2008; Slobodskaya, 2016).
There are also prominent examples of 
developmental theories of problem behav -