The influence of negative emotions on decision making in women with Bulimia Nervosa and Binge Eating Disorder.

Recent research demonstrated impairments in the decision making abilities of
patients with Bulimia Nervosa (BN) and Binge Eating Disorder (BED). The
findings indicate that they focus on short-term rewards and seem to ignore
long-term consequences. BN and BED are both characterized by binge eating
episodes that have been typified as behaviours with short-term gains and
long-term negative consequences. Furthermore, patients suffering from these
disorders have an impulsive personality and as a consequence, they frequently
behave in an impulsive manner (bingeing) especially following negative events.
It has been shown that binge episodes are often preceded by negative emotions.
It is therefore reasonable to assume that the negative emotions cause patients
to behave more impulsively (to reduce the negative emotions) and thereby
increasing the likelihood of a binge episode. An important difference between
the two disorders is that BN patients compensate their bingeing in an attempt
to repair the negative consequences, while BED patients do not. This
compensatory behaviour also has negative long-term consequences. It can
therefore be expected that BN patients may even respond stronger to negative
emotions by behaving more impulsively than BED patients. However, these ideas
have so far not been tested.

The current study aims to examine the influence of negative emotions on
decision making abilities in patients with a binge-eating related disorder.
There are three primary hypotheses: both patients groups (BN and BED) will show
decision making impairments in comparison to a healthy control group, and this
will become stronger after experiencing negative emotions in comparison with a
neutral condition, and finally BN patients will show stronger impairments after
experiencing negative emotions than BED patients.

The study consists of three distinct groups and in each group a negative
emotion induction will be conducted among half of the participants by means of
a film fragment. This negative fragment has been used in previous studies with
BN and BED patients and has no longterm consequences. The other half of
participants will watch a neutral film fragment and will therefore not
experience negative emotions. Subsequently, participants are asked to perform
the Iowa Gambling Task. This task has also been used previously in BN and BED
patients and is also not considered a burden. Prior to the emotion induction,
questionnaires will be administered to measure several relevant personality
characteristics and after the task, eating disorder severity will be measured.

This study will only take place onetime. Therefore the burden is relatively
small. All participants are asked to fill in some questionnaires which can be
considered a small burden. Subsequently, half of the participants will
experience negative emotions as a result of watching a film fragment, and the
other half will not experience negative emotions. This procedure to evoke
negative emotions has been used very frequently by other researchers (e.g.,
Jakobs et al., 1999; Macht & Mueller, 2007) and specifically also by BN and BED
patients in a specialized clinic in The Netherlands (Ursula Centre Eating
Disorders, in press). Moreover, this film fragment has also been used by AN
patients in Rintveld Centre Eating Disorders and the study was approved by the
Ethical Committee of the UMCU (Zonnevylle-Bender et al., 2005). More
importantly, no negative consequences were experienced as a result of this
procedure. Near the end of the study, participants will perform the Iowa
Gambling Task which is a card game that been used several times before in
patients with BN and BED as well as in other psychiatric disorders (e.g., OCD,
depression, schizophrenia). Often, patients find this game amusing to play. The
entire procedure is considered safe.
Prior to the study, participants are ensured that their treatment will not be
influenced in any way by participating in the study and they are told that they
can stop participating at any time without providing a reason. At the end of
the study, participants will be thoroughly debriefed and will be asked to fill
in an evaluation form. They are instructed that they can contact the
researchers or the therapist anytime in case of question or any inconveniences
as a result of the study.