 38. Personality Interventions  797
types and multiple assessment methods, was 
lasting after therapy ended (2+ months), and 
was effective regardless of age. Furthermore, 
both clinical and nonclinical samples, using 
quasi- and truly experimental designs found 
evidence for a robust effect (Roberts et al., 
2017).
Emotional stability and extraversion 
showed the most marked change in response 
to intervention. Agreeableness and conscien -
tiousness changed more modestly, and open -
ness appeared not to change. The findings 
for these traits are to be expected given that 
emotional stability includes components of 
anxiety and depression, often explicit tar -
gets of therapy. Because reducing compo -
nents of neuroticism is often an objective 
of therapy, it is possible that the observed 
changes are due to short-term elevations 
brought on by what lead people into therapy 
to begin with, the onset of a depressive epi -
sode, for example. In other words, therapy 
may merely bring people back to a baseline 
levels of traits rather than meaningfully alter 
personality.
Much like therapy, eating disorders and 
substance use disorder (SUD) treatment can 
be seen as an intervention to change per -
sonality, though with a more explicit focus 
to modify health behaviors. In their meta- 
analysis, Roberts et al. (2017) found that 
treatment for both eating disorders and sub -
stance use was modestly effective for chang -
ing personality, but that, in general, these 
effects were smaller compared to other types 
of treatment. Moreover, when accounting 
for small study effects, they found no chang -
es in personality for eating disorder treat -
ment.
For SUDs, changes in impulsivity are 
thought to be an important mechanism 
toward effective SUD treatment, as sub -
stance use behaviors are strongly linked to 
impulsivity-  related constructs (Littlefield & 
Sher, 2014) such as conscientiousness, neu -
roticism, and extraversion. Consistent with 
this idea, participation in Alcoholics Anony -
mous (AA), is associated with decreases in 
impulsivity across a 16-year time period, 
with longer participation associated with 
greater declines in impulsivity (Bloningen, 
Timko, Moos, & Moos, 2009). Similarly, 
impulsivity facets assessed via behavioral 
measures and traditional questionnaires showed changes in response to SUD treat -
ment over a 4-week time span (Littlefield et 
al., 2015). Passive longitudinal designs also 
draw a link between decreases in alcohol 
use and decreases in impulsivity (Littlefield, 
Sher, & Wood, 2009).
Interventions for SUDs may end up chang -
ing personality by creating a positive psy -
chosocial support network, coping skills, 
increased structure, and a framework for 
tackling negative patterns of thoughts and 
behaviors (Bloningen, Timko, & Moos, 
2013). Consistent with this, decreases in im -
pulsivity following AA predict fewer legal 
problems, fewer drinking problems, more so -
cial support, and more frequent use of adap -
tive coping skills (Bloningen et al., 2013).
Psychopharmacological  Interventions
Therapeutic interventions can also take the 
form of a pill rather than, or in addition 
to, therapy. Little work has systematically 
examined whether psychopharmacological 
interventions need to be paired with thera -
py or which drugs are effective, but meta- 
analytic findings suggest that psychophar -
macological interventions are associated 
with changes in personality (Roberts et al., 
2017). For example, DeFruyt, Van Leeuwen, 
Bagby, Rolland, and Rouillon (2006) found 
that individuals treated with a combination 
of either tianeptine or fluoxetine, along with 
therapy, showed greater extraversion, open -
ness to experience, agreeableness, and con -
scientiousness following treatment. Similar -
ly, in a sample of depressed individuals, use 
of cognitive therapy and medication (selec -
tive serotonin reuptake inhibitors [SSRIs]) 
were associated with changes in neuroti -
cism and extraversion compared to a con -
trol group (Tang et al., 2009). Most inter -
estingly, changes in depression were shown 
to be the result of changes in neuroticism, 
and long-term relapse in depression was ex -
plained by changes in neuroticism, such that 
people who decreased the most on neuroti -
cism were the least likely to experience a re -
lapse. In a similar study, both pharmacologi -
cal intervention (antidepressant) and therapy 
(cognitive-  behavioral) were associated with 
declines in neuroticism and increases in con -
scientiousness in a large sample of depressed 
patients (Spittlehouse et al., 2010).