310 III. DEvELOPMENT
quential adaptive and maladaptive outcomes 
(for a more extensive overview, see De Fruyt, 
De Clercq, & De Bolle, 2017). Consequen -
tial outcomes in adolescence can be roughly 
grouped in outcomes (1) at the level of the in -
dividual adolescent (e.g., well-being or hap -
piness, social skills, self-  esteem, and differ -
ent forms of psychopathology), (2) outcomes 
describing how adolescents relate to their in -
terpersonal environment (e.g., relationships 
with parents, family and peers), and finally 
(3) outcomes that are exhibited in more for -
mally organized contexts, such as behavior 
in class or performance at school (De Fruyt, 
De Clercq, De Clauwé, & Verbeke, 2017).
Individual  Level
There is a broad stream of research under -
scoring the validity of personality dimen -
sions to explain variables at the person 
level, such as happiness and well-being, 
quality-  of-life indices, social skills, and life 
satisfaction across development (DeNeve 
& Cooper, 1998; Steel, Schmidt, & Shultz, 
2008). From a temperamental approach, for 
example, low levels of shyness in childhood 
predicted better social skills in late adoles -
cence (Karevold, Ystrøm, Coplan, Sanson, 
& Mathiesen, 2012). In an extensive meta- 
analysis, Steel et al. (2008) studied links be -
tween personality measures (based on either 
the Big Five or Eysenck’s three dimensions) 
and a broad set of subjective well-being indi -
ces (happiness, life satisfaction, positive af -
fect, negative affect, overall affect, quality of 
life). Neuroticism (negatively) and extraver -
sion (positively) were most strongly associat -
ed with various indicators of subjective well-
being, but agreeableness, conscientiousness, 
and openness also showed positive relation -
ships with well-being outcomes. Together, 
these personality traits explained up to 39% 
of the variance (63% when disattenuated for 
imperfect reliability), underscoring their im -
portance to understand this individual life 
outcome. These meta-  analytic findings also 
generalized to children and adolescents ages 
6–16 (De Bolle, De Clercq, De Fruyt, & 
Benoit, 2008).
Personality traits have been further as -
signed a pivotal role in the understanding of 
adolescents’ identity development. Klimstra, 
Luyckx, Goossens, Teppers, and De Fruyt (2013) described the relationships between 
FFM traits and Luyckx, Goossens, Soenens, 
and Beyers’s (2006) multidimensional model 
of identity formation, and examined what 
FFM traits contribute to identity formation 
processes. This model is an elaboration of 
Marcia’s (1966) identity status paradigm, 
distinguishing five identity dimensions: 
commitment making  (making choices about 
identity-  defining life domains), identifica -
tion with commitment  (feeling confident 
and internalizing choices), exploration in 
breadth  (searching for alternatives), explo -
ration in depth (continuously reflecting on 
these choices), and ruminative exploration  
(individuals getting stuck in the explora -
tion process). Conscientiousness was signifi -
cantly correlated with commitment and the 
two adaptive exploration dimensions (with 
r’s between .25 and .36), whereas agree -
ableness was only slightly correlated with 
all three exploration dimensions, including 
ruminative exploration. Stronger associa -
tions (ranging from .20 to .35) between the 
exploration dimensions and openness were 
observed. Ruminative exploration correlat -
ed more strongly (.29) with neuroticism, and 
neuroticism also correlated with exploration 
in depth (.14) and negatively with identifi -
cation with commitment. Finally, extraver -
sion correlated positively with the first four 
identity dimensions, though negatively with 
ruminative exploration. At the FFM facet 
level, for example, Klimstra et al. (2013) 
found that the associations reported for 
neuroticism and exploration in depth were 
mainly driven by the anxiety facet, whereas 
four FFM neuroticism facets were related to 
ruminative exploration. The negative asso -
ciation between extraversion and rumina -
tive exploration was mainly due to negative 
associations with gregariousness and asser -
tiveness.
Personality traits are also implicated in 
maladaptive outcomes. There is convincing 
evidence that personality traits are substan -
tially related to a broad range of psycho -
pathologies across different developmental 
stages (Mathiesen, Sanson, & Karevold, 
2018; Tackett, 2006). For example, De 
Pauw, Mervielde, Van Leeuwen, and De 
Clercq (2011) examined parent-  rated Child 
Behavior Questionnaire (Putnam & Roth -
bart, 2006) and HiPIC ratings (Mervielde et 