Background and objectives:
The aim of this study was to test the effects of individual schema therapy (ST)
for patients with chronic depression.
Methods:
Using a multiple-baseline single case series design, patients with chronic major depressive
disorder (
N
¼
25)
fi
rst entered a 6
e
24 weeks baseline phase; this phase functioned as a no-treatment
control condition. Then, patients started a 12 week exploration phase during which symptoms and
underlying schemas were explored; this phase functioned as an attention control condition. Next, pa-
tients received up to 65 sessions of individual ST. The Beck Depression Inventory II (BDI-II) and the Quick
Inventory of Depressive Symptomatology (QIDS) were the primary outcome measures. The BDI-II was
assessed once a week during all phases of the study resulting in 100 repeated assessments per partic-
ipant on average. Mixed regression analysis was used to contrast change in symptoms during the
intervention with change in symptoms during the baseline and exploration control phases.
Results:
When compared to the no-treatment control period, the intervention had a signi
fi
cant, large
effect on depressive symptoms (Cohen's
d
BDI-II
¼
1.30; Cohen's
d
QIDS
¼
1.22). Effects on secondary
continuous outcomes were moderate to large.
Limitations:
The small sample size and lack of a control group.
Conclusions:
These
fi
ndings provide evidence that ST might be an effective treatment for patients with
chronic depression.