Discussion
Trauma history in patients with anxiety or depressive disorders may
hinder the effects of psychological treatments. We investigated the
effects of trauma on the duration of therapy, applied interventions, and
symptom severity in outpatients receiving naturalistic CBT. Circa half
of the 340 outpatients were classified as having experienced trauma, and
in 79 cases (45.66% of all trauma cases), therapists applied a
trauma-specific intervention.
General treatment characteristics like the number of sessions and the
use of trauma-specific interventions, except for skills training, did
not differ between the groups, indicating that CBT was delivered
similarly to all patients, regardless of trauma history. The overall
severity of depression as well as anxiety was higher among patients with
a trauma history, in line with prior findings (Chu et al., 2013; Fullana
et al., 2019; Hovens et al., 2015; Kuzminskaite et al., 2021; Mandelli
et al., 2015; Nelson et al., 2017). The reduction in symptom severity
throughout treatment and recovery rates were comparable between patients
with and without a trauma history. For anxiety symptoms, this is mainly
in line with the existing literature (Bruce et al., 2013; Trautmann et
al., 2019), while for depressive symptoms, prior studies reported lower
success of a variety of treatments in patients with a trauma history
(Fischer et al., 2018; Miniati et al., 2010; Nanni et al., 2012;
Serbanescu et al., 2020). Previous studies, however, did not investigate
CBT treatments specifically and focused mainly on childhood
interpersonal trauma. Studies showing reduced response to CBT were
conducted mainly in depressed adolescents (Lewis et al., 2010; Waldron,
Howard, & Reinecke, 2019). Differences in the investigated
psychotherapy type and patient age might have contributed to the
diverging results. Our findings are, however, consistent with the
results of a recently published meta-analysis on the effects of
childhood trauma across both pharmacological treatment and
psychotherapy, concluding that evidence-based treatments for depression
are similarly effective for patients with and without a history of
childhood trauma (Kuzminskaite et al., 2022).
To our knowledge, this study is the first to investigates the effects of
trauma history under naturalistic treatment conditions. In addition to
the longer treatment duration (on average 44 sessions) in our study
compared to the abovementioned studies (i.e., less than 20 sessions),
therapists were free to choose therapeutic interventions for each
patient, offering possibilities for personalized treatment. Our results
indicate that among the assessed interventions, therapists independently
from the trauma group most often applied interventions focusing on the
regulation of extreme emotions and coping with maladaptive
cognitive-emotional schemata (schema mode interventions, self-calming
techniques, and skills training) compared to trauma-focused
interventions. However, except for skills training, we did not find
evidence for a specific use of these interventions in patients with a
trauma history. The criteria on which therapists based their choice of
trauma-specific interventions remained unclear. The decision may have
been more bound to the therapist’s therapeutic style rather than the
patient’s characteristics 11Exploratory analyses revealed
significant differences between the therapists in intervention use
irrespective of the patient, \(\chi^{2}\)(59) = 93.76, p =
.003. Therapists, who treated at least 5 different patients, used a
trauma-specific intervention for between 0.00% and 85.71% of their
patients.. Although trauma-related treatments were not necessarily
applied more frequently in patients with a trauma history, exploratory
analyses revealed no differences in symptom severity trajectories
between patients who did or did not receive trauma-specific
interventions, regardless of trauma history. Thus, we did not find
evidence for an efficient personalization of the therapy content based
on the patient’s trauma history. These explorative analyses also suggest
that trauma-specific interventions did not boot symptom reduction in
those patients with an initial higher symptom severity.
While prior studies found more severe long-term consequences of
interpersonal than non-interpersonal trauma (Bridges-Curry & Newton,
2021; Contractor et al., 2018), we did not find any effects when
comparing the interpersonal, non-interpersonal, and no-trauma groups.
This might be due to the relatively small sample size in the
non-interpersonal trauma group (n = 12, 23.12%) and considerable
heterogeneity in the symptom severity trajectories in this group, see
Supplemental Figure 7. As a result of low subgroup sample size and high
within-group variance, we may not have been able to detect between-group
differences. The same might have been accurate for comparing patients
with and without a depression diagnosis as the latter group was
comparatively small (n = 46, 13.53%).
The current study sheds light on applied interventions and treatment
trajectories in naturalistic CBT for depressed or anxious outpatients.
It thereby extends evidence from well-controlled therapy trials by
investigating CBT under routine care conditions. Furthermore, the data
collection from archive files rules out any effects of the scientific
investigation on treatment implementation or results. On the downside,
therapy files did not always provide sufficiently detailed information.
Childhood trauma was assessed through clinical routine data only, and
therapists seldom used validated diagnostic tools to assess trauma
history. Although retrospective trauma assessment is generally reliable
(Kendall-Tackett & Becker-Blease, 2004), it tends to underestimate
childhood trauma (Hardt & Rutter, 2004), especially in clinical records
(Rossiter et al., 2015). Our study might, therefore, have underestimated
the amount of childhood trauma. Furthermore, although interrater
reliability was sufficient for trauma and intervention indices, single
trauma subtypes had low reliabilities and did not allow further analyses
to differentiate the effects of single trauma subtypes. Also, the
effects of childhood and adulthood interpersonal trauma were not
separable because both groups had extreme overlap. Future studies should
encourage therapists to assess trauma history using validated measures,
including trauma duration and age at exposure. Another limitation of our
study was missing post-treatment assessment of symptom severity, which
was not limited to patients who dropped out of therapy. A primary reason
for missing post-treatment assessment presumably was that there were no
special requirements or incentives for therapists concerning
post-treatment diagnostic assessment because of the naturalistic nature
of the therapy setting. We applied Multiple Imputation (Rubin, 1987) to
minimize bias due to missing data. Future studies conducted under
routine care conditions should consider incentives for therapists to
minimize missing data. Concerning the role of the therapist’s choice of
interventions, we could not to investigate the reasons for the
therapist’s decisions. The choice of intervention seemed to depend on
the therapist’s personal style. Therefore, it remains open if a more
targeted application of trauma-specific interventions could help
trauma-exposed patients reach similar symptom levels as unexposed
patients at the end of treatment. Future studies could, therefore,
assess therapist’s reasons for applying certain trauma-specific
interventions and assess the behavioral, emotional, and interpersonal
problems for which each of these interventions is specialized.
Furthermore, a more fine-grained assessment of symptom severity over
time, combined with an assessment of the time interval in which a
particular intervention was applied, would enable an in-depth analysis
of the effects of intervention choice on symptom severity trajectories
in naturalistic CBT.
Conclusion
In summary, our results highlight the frequency of childhood and
adulthood trauma in the outpatient psychotherapy population, even
without a PTSD diagnosis. Therapists should routinely screen for trauma
history at the start of therapy using validated trauma questionnaires,
as trauma history may influence therapeutically relevant characteristics
like emotion regulation (Bridges-Curry & Newton, 2021) and
interpersonal behavior (Shahab et al., 2021; Widom et al., 2018). We
found overall symptom severity higher among trauma-exposed patients than
non-exposed patients. Although patients with interpersonal and
non-interpersonal trauma did improve throughout treatment in our study,
the lack of differences in the relief of symptoms between patients with
and without trauma suggests that other types of interventions might be
necessary to ensure treatment success.
As not all trauma-exposed individuals suffer from long-term consequences
(Glaesmer, Matern, Rief, Kuwert, & Braehler, 2015; Laugharne, Lillee,
& Janca, 2010), assessing domains associated with trauma history and
low therapy success in trauma-exposed patients at the start of treatment
may be promising to identify those needing intensified treatment. These
might be patients with subclinical PTSD symptoms, emotional
dysregulation, interpersonal problems, or early-onset and recurrent
symptoms. Therapists could then tailor interventions to the patient’s
needs, offering, for example, skills training specifically to patients
with (trauma-related) emotional dysregulation and Schema therapy or
CBASP to patients with maladaptive attachment styles and interpersonal
problems. For depressed patients with a trauma history, trauma-focused
interventions like EMDR or Imagery Rescripting may also be effective
(Dominguez, Matthijssen, & Lee, 2021). Modular psychotherapy (Elsaesser
et al., 2022) could be a promising approach to individualized and
evidence-based treatment.