Neurocognitive predictors of treatment outcome in cocaine patients: the role of cognitive control

One of the major challenges in substance dependence treatment is to improve
treatment outcome. Dropout rates in detoxification clinics for illicit drugs
are about 50% within the first month. Currently, there is insufficient
knowledge about the factors influencing this outcome. Recent advances in
clinical and cognitive neuroscience might give us better measures to predict
treatment outcome. In the present study we will focus on the role of cognitive
control. More specifically, we propose to examine two indices of
(neuro)cognitive control associated with cocaine addiction: reduced error
processing and reduced attentional control. We will measure the
neurophysiological correlates of these mechanisms using Event Related
Potentials (ERPs; error processing) and eye-tracker (attentional control). More
specifically, we are interested in a decreased Error-Related Negativity (ERN)
as neurophysiological indices of reduced error-processing and increased visual
fixation to drug related stimuli as behavioral measure of reduced attentional
control. In order to assess these (neuro)cognitive parameters participants will
carry out an Eriksen flanker task (for the error-processing study) and a
picture task with drug related and neutral stimuli (for the attentional control
task) during the first week of their detoxification.
In addition, participants will perform a cocaine Stroop task in the fMRI
scanner. We will examine differences in brain activity between cocaine
dependent patients and controls on the Stroop task, an index of attentional
control in the presence of cocaine cues.

The main goal of the study is to examine the predictive value for treatment
outcome of
neurophysiological indices of two aspects of cognitive control in abstinent
cocaine dependent patients: Error-processing and attentional control
(respectively assessed with ERPs, eye-tracker and fMRI).

All patients will be recruited from the detoxification department of the
addiction treatment center BoumanGGZ in Rotterdam. The participants will be
assessed at Erasmus University Rotterdam, department of Psychology (ERP and
eye-tracker assessment) and Erasmus MC (fMRI assessment). We will collect the
baseline variables race, age, education, gender, medical problems (Addiction
Severity Index; ASI), and psychopathology (ASI), and drug use variable (ASI).
In addition, in order to assess the actual decreased Error-Related Negativity
and increased visual fixation/attention to drug related stimuli we will compare
the baseline findings to healthy control groups. Most importantly, after one
month we will assess whether patients completed the detoxification treatment
(treatment compliance) and after 3 months we will assess treatment outcome
(relapse rates) by means of a structured interview and urine analysis. We will
examine the predictive value of the neurophysiological and behavioral indices
of cognitive control for both treatment compliance and relapse rates.

fMRI is an invasive measurement. The apparatus that is being used consists
(among other things) of a strong magnet. This magnet pulls metal objects.
Therefore it is important that during participation there are no metal objects
in and around the human body. The participant will be alerted about this.