A relatively large proportion of psychotherapists endorse practicing eclectic or
integrative therapy, drawing from different schools of therapy (Norcross & Alexander,
2019). This tendency towards integrative therapy has been expressed by former president
of the Association of Cognitive and Behavioral Therapies, J. B. Persons, who writes: "We
[clinicians] rarely proceed through a single protocol from beginning to end. Instead, we
use what might be called a mix-and-match strategy, in which we select interventions or
modules from one or even two or more protocols that we believe will be helpful to the
patient" (Persons, 2005, p. 107). Indeed, there has been a growing research and clinical
interest in personalized therapy where treatment components from different therapies are
combined with the aim of targeting the symptomatology and theorized maintenance processes
of the individual patient (Cohen et al., 2021; DeRubeis et al., 2014; Fisher et al.,
2019; Fisher & Boswell, 2016; Hayes et al., 2022; Huibers et al., 2021; Sauer-Zavala et
al., 2022). In addition to this, an increasing number of therapies are designed by
combining components from different treatment models (e.g., modular and process-based
therapies; Barlow et al., 2018; Hofmann & Hayes, 2019; Hofmann et al., 2021). As a
result, patients are likely to be the recipients of several different techniques or
strategies, based on different theoretical models, emphasizing different change
principles. However, the extent to which compatibility exists between different treatment
components remains an underexplored scientific question. The present study aims to fill
this gap.
Combining cognitive behavioral therapies
Cognitive behavioral therapies (CBTs) are among the most well-researched psychological
treatments for anxiety and depressive disorders (Cuijpers, 2017; Cuijpers et al., 2014).
While CBT is often viewed as one of the major schools of psychotherapy, specific CBTs
differ in their rationale and understanding of the key maintaining processes in
psychopathology (Hayes, 2004). A core tenet of traditional CBT, also known as second-wave
CBT, is that psychopathology is maintained by maladaptive or irrational thoughts (Beck,
1976). Thus, a commonly used therapeutic component derived from second-wave CBT is
cognitive restructuring, where the patient is taught to think more realistically about
emotion-evoking situations (Beck et al., 1979; Clark & Beck, 2010). Thus, cognitive
restructuring can be said to target the content of thoughts.
In contrast, newer contemporary or so-called third-wave CBTs such as metacognitive
therapy (MCT), acceptance and commitment therapy (ACT), and mindfulness-based cognitive
therapy (MBCT) target thought processes (Hayes, 2004). A commonly used therapeutic
component across third-wave CBTs involves teaching the patient to meet their experiences
with mindfulness and acceptance rather than attempting to change their form (termed
detached mindfulness in MCT, defusion in ACT, and decentering in MCT; Hayes et al., 2012;
Segal et al., 2002; Wells, 2009). Thus, it can be argued that second- and third-wave CBTs
reflect very different ways of approaching one's inner life.
Despite the differences between second- and third-wave CBTs, treatment components from
each wave are often combined. One example of this is the widely employed Unified Protocol
(UP) which is a transdiagnostic modular cognitive-behavioral treatment for emotional
disorders (e.g., anxiety and depression) (Barlow et al., 2018). In UP, patients are asked
to engage in cognitive restructuring (within the treatment module of cognitive
flexibility) in one module and to practice detached mindfulness (within the treatment
module of mindful emotion awareness) in another (Barlow et al., 2018). Several studies
have documented that UP is an effective treatment for anxiety and depression (Longley &
Gleiser, 2023). However, since the treatment modules in UP are rooted in different
therapeutic traditions with different rationales, an intriguing question remains whether
the treatment modules are in fact compatible. If not, then it is possible that UP is
effective not because but rather despite the combination of the treatment modules
(O'Toole et al., 2024).
Compatibility of components
Regarding the combination of mindful emotion awareness and cognitive flexibility, it is
theoretically plausible that these modules might be incompatible since the technique of
noticing and accepting one's thoughts/emotions (in the module mindful emotion awareness)
could be argued to be in opposition to the technique of actively changing one's thoughts
(in the module cognitive flexibility). This notion is supported by a small study (N=12)
by Gkika and Wells (2015) which investigated the effect of cognitive restructuring and
detached mindfulness in an anxiety-provoking situation in patients with elevated symptoms
of social anxiety. They found that each technique alone reduced symptoms of social
anxiety. However, when combined, a sequencing effect emerged where detached mindfulness
followed by cognitive restructuring, but not the reverse, led to increased anxiety (Gkika
& Wells, 2015). Borlimi et al. (2019) similarly demonstrated a sequencing effect. They
asked non-clinical participants (N=35) to recall an unpleasant experience and apply
either cognitive restructuring or an acceptance technique. Acceptance reduced sympathetic
reactivity (i.e., galvanic skin response) more than cognitive restructuring, and
importantly, the effect was significantly larger when acceptance followed cognitive
restructuring than vice versa (Borlimi et al., 2019).
The studies by Gkika and Wells (2015) and Borlimi et al. (2019) are both laboratory
experimental studies. The question thus remains whether and how their findings can be
generalized to a clinical context with longer duration of each treatment component. Only
one larger intervention study exploring combinatory and sequencing effects exists. In
this study, Brose et al. (2023) investigated the effect of internet-based cognitive
restructuring and behavioral activation on symptoms of depression delivered over 6 weeks.
Individuals with mild to moderate depressive symptoms (N=2,304) were randomized to one of
two treatment arms, one receiving behavioral activation followed by cognitive
restructuring, the other vice versa. The groups had similar dropout rates and showed
similar improvements over time, indicating no incongruency between those two components.
Besides differences in size and setting (experimental vs. actual treatment), the study by
Brose et al. (2023) also differs from the other clinical studies by testing a "cognitive"
component against a "behavioral" component instead of comparing different "cognitive"
components (e.g., cognitive restructuring and detached mindfulness) against each other.
In this case, the rationales may be more consistent with each other.
Taken together, the research findings described above, coupled with results from the few
other available studies of combinatory effects (Dibbets et al., 2012; Woelk et al.,
2022), testify that combining otherwise effective stand-alone treatment components 1)
does not necessarily yield an additive effect, 2) may even sometimes detract from a
positive outcome, and 3) that the combined effect may depend on the order of the
components. Thus, to be able to combine different treatment components for anxiety and
depression effectively, there is a need for intervention studies examining single,
combined, and sequencing effects for treatment components from different therapies that
are often combined. Currently, such research is sparse, thereby motivating the present
study. Moreover, understanding for whom these effects are likely to occur is important
for the appropriate adaptations of therapeutic interventions to fit the needs of the
individual patients (i.e., personalized therapy; Cohen et al., 2021).
Aims and hypotheses
The primary aim of the present study is to explore the effect of combining treatment
components drawn from different CBTs. Thus, we will explore single, combined, and
sequencing effects of two treatment modules (i.e., mindful emotion awareness and
cognitive flexibility). These modules are routinely delivered together in UP for patients
with anxiety disorders or MDD. It is hypothesized that both mindful emotion awareness and
cognitive flexibility, when delivered individually, will be effective in reducing
symptoms of anxiety and depression. The study will take an exploratory stance regarding
combined and sequencing effects and will explore if combined effects are best understood
as non-additive, additive, synergistic or antagonistic (cf. O'Toole et al., 2024).
A secondary aim of the study is to explore possible demographic and clinical moderators
of the effects (e.g., primary diagnosis, baseline cognitive function and symptomatology)
to address the question of what works for whom.