Cognition in Mindfulness: Negativity and Depression

Depression is highly prevalent and is ranked by the WHO as the number one
contributor to disability worldwide. The highly recurrent nature of the disorder contributes
greatly to the burden of Major Depressive Disorder (MDD) and with every new depressive
episode, outcome prospective worsen. Mindfulness Based Cognitive Therapy (MBCT) is an
effective treatment to reduce relapse rates and (residual) symptoms that contribute to
recurrence in MDD. However, the mechanisms underlying this MBCT-induced effect are far
from clear.
Elucidating these mechanisms will provide insight in the existing individual differences in
effectiveness of MBCT. Consequently, this insight will help to improve effectiveness of
treatment and possibly even personalize treatment regimes.
One likely candidate that could play a major role in the positive effects of MBCT on
depressive symptoms, is repetitive negative thinking (RNT or depressive rumination). Here,
we will investigate individual levels of RNT before, during and after MBCT by using a selfreport questionnaire. We will use this information to assess whether MBCT reduces MDD
symptoms through its effect on RNT. In other words, we will assess whether RNT mediates
the effect of MBCT on MDD symptoms. In addition, we will assess whether pre-treatment
levels of RNT on the individual level, predict treatment outcome. Thus, we ask whether
baseline levels of RNT moderate the effect of MBCT on an individual level.
Thus, we will assess the mediating and moderating role of RNT in the effect of MBCT on
MDD.
In addition (secondary), we will explore which exact processes of RNT are altered by MBCT
and when this change occurs. Therefore, we will ask participants to fill in short-self report
measures after each session of MBCT. This will give us information about the temporal order
of change in RNT and depressive symptoms. However, self-report questionnaires can only
provide limited information. We will therefore also use experimental tasks to further
investigate the exact processes of RNT that are modified by MBCT. First of all, we will use a
behavioural task (breathing focus task) to assess the repetitive nature of ruminative thoughts.
Furthermore, we will focus on important aspects of cognitive control putatively related to RNT. We will measure emotional working memory processing and behavioural inhibition, before and after MBCT with two innovative behavioural tasks. We will use this
behavioural data to assess whether emotional working memory and inhibition are indeed (1) related to RNT and MDD, (2) are changed by MBCT and (3) whether these changes are indeed related to clinical effects of MBCT.
In toto, these findings will shed light on the psychological and cognitive working mechanisms
through which MBCT sorts its clinical effect.

Our objectives thereby are the following:
1. Replicate beneficial effects of MBCT on depressive symptoms and RNT in patients with
recurrent or chronic major depression.
2. Test moderating and mediating effects of RNT:
2.1.1. Does rumination mediate the effect of MBCT on depressive symptoms in
recurrent depressed and chronic depressed patients?
2.1.2. Does RNT at baseline moderate the effect of MBCT versus treatment as usual
on depressive symptoms in patients with moderate to severe depressive
symptoms?
3. Assess the influence of MBCT on a behavioural measure of RNT focused on the
intrusiveness of negative thoughts (breathing focus task).
4. Explore the timing of change in RNT during MBCT by using repeated self-report measures
after each session of MBCT.
5. Assess the relation between cognitive control (operationalized by working memory and
inhibition) on the one hand and RNT and depressive symptoms on the other.
6. Assess whether MBCT changes cognitive control in patients with crMDD.
7. Assess whether (changes in) cognitive control moderate and/or mediate the effect of
MBCT on depressive symptoms.

Study design: Controlled trial with sampling based on date of regular clinical assessment
procedure and start of treatment groups: Patients with crMDD will get assigned to one of two
groups, based on the date of intake. Group 1 will perform measurements once before, during
and once after MBCT treatment, whereas group 2 will perform measurements once before,
once during and once after an 8 weeks waiting period. Group 2 will receive MBCT after this
waiting period, where they will also have measurements during and once after the MBCT.
Note that with this procedure we do not interfere with current clinical practice, i.e. if patients
have to wait > 2 months for the next MBCT group they will be invited to participate in group 2,
if they have to wait < 2 months they will be allocated to group 1.

Additionally, healthy controls will be tested, necessary for benchmarking the innovative cognitive control tasks.

Primary hypothesis:
The effects of MBCT on depressive symptoms will be mediated by RNT in patients following MBCT compared with waitlist

Group 1: Baseline, weekly measures after each MBCT session, halfway trough MBCT, after completing MBCT
Group 2: Baseline, halfway trough TAU/waitlist, after TAU/waitlist, weekly measures during TAU/waitlist and after each MBCT session, halfway through MBCT, after MBCT

Participants will follow Mindfulness based cognitive therapy (MBCT). MBCT is a group program that teaches formal and informal mindfulness practices. It is an 8-week program of weekly sessions of two and a half-hour with one full retreat day (6 hours), and daily home practice (about 45 min/day). Core components include practices of the body
scan, sitting meditation, walking meditation and mindful movement. It has an attitudinal
framework of kindness, curiosity and willingness to be present, which are embodied in the
teacher.