Introduction
Depression and anxiety disorders are among the most frequent mental
disorders in the general population (Jacobi et al., 2014) as well as
among psychotherapy outpatients (Gaebel, Kowitz, Fritze, & Zielasek,
2013; Velten et al., 2018). They carry a high burden of illness
worldwide (GBD 2019 Mental Disorders Collaborators, 2022) and are
associated with high illness costs (König, König, & Konnopka, 2019;
Konnopka & König, 2020).
Lifetime traumatic events including childhood maltreatment (abuse and
neglect) are often risk factors for the onset of a depression or anxiety
disorder (Hovens, Giltay, Spinhoven, Hemert, & Penninx, 2015; Kühn et
al., 2006; Mandelli, Petrelli, & Serretti, 2015; Walsh, McLaughlin,
Hamilton, & Keyes, 2017) and are also predictors of depression and
anxiety severity (Chu, Williams, Harris, Bryant, & Gatt, 2013; Hovens
et al., 2010). Traumatic events can be classified as interpersonal or
non-interpersonal and as single or repeated (Maercker & Augsburger,
2019). Interpersonal and repeated trauma types like childhood
maltreatment and intimate partner violence have robustly been associated
with more severe consequences such as higher posttraumatic stress
disorder (PTSD), depression, and anxiety scores compared to
non-interpersonal types such as traffic accidents and natural disasters
(Bridges-Curry & Newton, 2021; Contractor, Brown, & Weiss, 2018).
Despite long-standing research on the effectiveness of CBT for
depression and anxiety disorders (Carpenter et al., 2018; Hofmann,
Asnaani, Vonk, Sawyer, & Fang, 2012; Tolin, 2010), about 51.5 to 59.0%
of all patients do not respond to treatment (Cuijpers et al., 2021;
Loerinc et al., 2015), calling for a better understanding of mechanisms
involved in the treatment. One promising and cost-efficient way to
identify potential CBT non-responders may lie in assessing and
investigating psychological patient characteristics at the start of
therapy (Kunas, Lautenbacher, Lueken, & Hilbert, 2021).
Childhood maltreatment predicts non-response and non-remission for a
broad range of psychological and medical treatments for depression,
including CBT (Nanni, Uher, & Danese, 2012; Nelson, Klumparendt,
Doebler, & Ehring, 2017). Emotional, physical, and sexual abuse were
related to lower response and higher post-treatment symptom severity for
depressed patients treated with the Cognitive Behavioral Analysis System
of Psychotherapy (CBASP) or Supportive Psychotherapy (Serbanescu et al.,
2020). Emotional abuse in particular predicted less depression-free time
in outpatients one year after psychotherapy (Bausch et al., 2020), while
physical and sexual abuse were more frequently indicated by
psychotherapy non-responders (Fischer et al., 2018). For patients with
an anxiety disorder, the picture is less conclusive. In some studies,
childhood maltreatment in general and more specifically emotional and
physical abuse were linked to low psychotherapy response (Alden, Taylor,
Laposa, & Mellings, 2006; Fischer et al., 2018). Other studies report
no effect of childhood maltreatment (Santacana et al., 2016) or found an
effect only on absolute levels of symptom severity, not on the amount of
decrease (Bruce, Heimberg, Goldin, & Gross, 2013).
Effects of adulthood and non-interpersonal trauma on treatment success
have, to our knowledge, scarcely been investigated. In one study, the
overall effect of exposure-based CBT for panic disorder was similar for
patients with and without trauma history (Trautmann et al., 2019). Only
a subgroup of traumatized female patients, characterized by a specific
genotype and comorbid depressive symptoms, achieved less change in
symptom severity than the non-traumatized controls. Robust evidence on
the effects of adulthood and non-interpersonal trauma on CBT response
rates is missing.
Although negative effects of childhood maltreatment on treatment
response have been demonstrated, questions remain concerning the
relevance of these effects under different delivery conditions of CBT.
Most studies, except for Fischer et al. (2018), investigated the effects
of trauma only for CBT provided under controlled study conditions and
used data from efficacy studies. These studies, while providing a
maximum of experimental control and internal validity, often are not
well transferable to therapies conducted under routine care conditions
in terms of patient characteristics, number of therapy sessions, and
especially the use of treatment manuals (Lincoln & Rief, 2004;
Seligman, 1995; Shadish et al., 1997). Being aware of the trauma history
of a patient gives the therapist the possibility to individually adapt
the treatment by using specific interventions to address the
trauma-related symptoms.
Victims of childhood maltreatment often present a more complex clinical
picture at the start of CBT treatment compared with patients, who did
not suffer childhood maltreatment (Fullana et al., 2019; Norman et al.,
2012). They are more likely to have emotion regulation difficulties
(Bridges-Curry & Newton, 2021) or engage in self-injuring behavior
(Brown et al., 2018; Liu, Scopelliti, Pittman, & Zamora, 2018). These
conditions may complicate the treatment of mental health problems and
are risk factors for low treatment success (Kunas et al., 2021;
Serbanescu et al., 2020; Taylor, Abramowitz, & McKay, 2012). Therapists
might therefore offer skills training (Bohus & Wolf-Arehult, 2016;
Cloitre, Koenen, Cohen, & Han, 2002; Linehan, 1993) to promote emotion
regulation competencies in the early stages of therapy. Furthermore,
childhood maltreatment is linked to an anxious or avoidant attachment
style (Shahab et al., 2021; Widom, Czaja, Kozakowski, & Chauhan, 2018)
and increased problems in intimate partner relationships in adulthood
(Bender et al., 2022; Colman & Widom, 2004; Paradis & Boucher, 2010).
Such interpersonal problems may affect the therapeutic relationship,
which poses a key factor for successful therapy (Flückiger, Del Re,
Wampold, & Horvath, 2018; Weck, Grikscheit, Jakob, Höfling, &
Stangier, 2015), for example, by lowering relationship quality or
raising difficulties in building a trustful working alliance (Alden et
al., 2006). Consequently, interpersonal problems might mediate the link
between childhood maltreatment and low therapy response. Supporting this
notion, meta-analytic evidence points towards lower therapy success in
patients with insecure attachment styles (Levy, Kivity, Johnson, &
Gooch, 2018). Elements of schema therapy (Young, Klosko, & Weishaar,
2006), developed specifically for patients with challenging
interpersonal behavior and a history of childhood maltreatment, might be
applied to overcome problems in the therapeutic relationship and even
modify dysfunctional attachment styles. Regarding persistent depressive
disorder, deficits in social cognition, more specifically the phenomenon
of preoperational thinking (McCullough, 2000, 2006), has been proposed
as a mediator between childhood trauma and chronic, treatment-resistant
depression (McCullough Jr., 2003; Struck, Gärtner, Kircher, &
Brakemeier, 2021). Following McCullough (2006), maltreated and
early-onset chronically depressed patients have difficulties in
recognizing the effects they have on their interaction partners. They
therefore cannot use the feedback obtained during interactions with
their therapists to correct maladaptive assumptions and behaviors
(McCullough, 2006). Supporting its relevance for treatment outcome,
preoperational thinking is correlated with childhood maltreatment and a
chronic course of depression (Klein et al., 2020) and can predict the
course of depression over two years (Sondermann et al., 2020).
Therapists might implement CBASP interventions like Disciplined Personal
Involvement (McCullough, 2000) to reduce preoperational thinking and
promote interpersonal learning. Regarding anxiety disorders, impaired
extinction learning in trauma victims might contribute to low therapy
success. Extinction of conditioned fear appears to be a key mechanism of
exposure therapy for anxiety disorders (Craske et al., 2008; Craske,
Treanor, Conway, Zbozinek, & Vervliet, 2014). It is the laboratory
analog of exposure therapy (Barlow, 2002), during which a new safety
memory trace is formed and can inhibit fear (Milad & Quirk, 2012).
However, extinction learning may be impaired in patients with an anxiety
disorder (Duits et al., 2015). Alterations in extinction learning
observed in victims of childhood trauma aged 6-11 years might contribute
to impaired extinction learning during adulthood (Marusak et al., 2021).
There is also experimental evidence that supports impaired extinction
learning following stress exposure in healthy adults (Klinke, Fiedler,
Lange, & Andreatta, 2020) and in stress-exposed rodents (Knox et al.,
2012; Wilber, Southwood, & Wellman, 2009; Yamamoto et al., 2008).
Hence, trauma-exposed patients might experience slower or less robust
extinction learning and, in parallel, profit less during exposure
therapy (Maren & Holmes, 2016). They might, therefore, need a more
extended treatment duration to compensate for slower learning.
These possibilities to individualize and intensify treatment in the
naturalistic context might buffer adverse effects of trauma on treatment
success observed in highly manualized therapy settings. Additionally, in
the case of trauma-related avoidance behavior and hyperarousal,
therapists might apply trauma-focused techniques (Neuner, 2012) and
self-calming techniques (Reddemann, 2010) to treat these PTSD-like
symptoms. To date, it remains open to what extent therapists under
naturalistic treatment conditions apply trauma-specific interventions
and unspecific intensification of therapy for traumatized patients.
Furthermore, it is currently unknown if and how applying these measures
affects treatment response.
Taken together, patients suffering from anxiety or depression, who
additionally experienced trauma, seem to be at risk for non-response and
non-remission in CBT treatment as these patients are more likely to
present a complex clinical picture, have difficulties in the therapeutic
relationship and possibly show reduced sensitivity to important CBT
change mechanisms. Current evidence points towards more severe effects
of interpersonal and childhood trauma compared to non-interpersonal and
adulthood trauma. Still, the role of different trauma subtypes and the
characteristics of the naturalistic therapy setting remain unclear. The
present study aims to investigate treatment trajectories for depression
and anxiety symptoms of patients with and without a trauma history in a
naturalistic CBT context. It will distinguish between different trauma
subtypes and test the role of the diagnostic group and trauma-specific
therapy modifications as potential moderators of treatment success. We
expect therapists to adapt treatment for patients with a trauma history
by offering longer and intensified therapies and using trauma-specific
interventions (Hypothesis 1). We also expect higher overall levels of
symptom severity in the trauma group (Hypothesis 2a) and less decrease
in symptom severity throughout therapy (Hypothesis 2b), especially for
depressed patients (Hypothesis 2c). Furthermore, we expect the effect of
trauma on symptom severity and decrease in symptom severity to be more
pronounced in patients with a history of childhood trauma and
interpersonal trauma in contrast to adulthood trauma and
non-interpersonal trauma only (Hypothesis 3). Regarding the
individualization of treatment in the naturalistic context, we expect to
find more improvement in symptom severity for traumatized patients if
trauma-specific therapy techniques were used (Hypothesis 4).