Neurocognitive and neuroimaging factors explaining differences in drug use in at-risk cannabis users.

To date very little is known about factors that predict the course of drug use
and transition of drug use into drug abuse and dependence in the general
population. At the same time knowledge about these factors is crucial for the
development of effective prevention strategies. Cannabis is the most commonly
used illegal drug in most countries and progression into use of other illegal
drugs is frequently observed. Few investigations, however, have addressed the
possible predictors of the trajectory of cannabis use and the potential
progression into other drug use. It is suggested that addictive behaviour
develops due to an imbalance between an approach-oriented motivational system
and a regulatory executive system. This view is supported by an abundance of
studies evidencing diminished neurocognitive functions and underlying altered
patterns of brain activity related to both the motivational system and
regulatory executive system in substance dependent populations compared to
normal controls. These observed diminished neurocognitive functions and the
underlying altered patterns of brain activity have been shown important
predictors for relapse and treatment outcome in substance dependent
populations. So far, however, the role of these different neurocognitive and
neuroimaging factors in the development of addiction remains largely
suggestive. To what extend they are involved in the course of drug use and the
possible transition into dependence is not known.

We aim at investigating the role of different neurocognitive and neuroimaging
factors in the course of drug use in at-risk cannabis-users. We intend to
delineate how (1) decision making (2) working memory, (3) cue-reactivity, (4)
the underlying abnormal brain responses during performance of these tasks, and
(5) structural connectivity relate to the course of marijuana use in at-risk
cannabis users, in a longitudinal, prospective fMRI study.

The participants will be subjected to questionnaires and standardised
diagnistic interviews. Further, neurocognitive tasks will be performed,
functional and structural MRI scans will be recorded, a DTI scan will be
recorded, and urine will be tested onces for drug trails. There will be a
follow-up interview after both 3 and 6 months.

This research requires 6 hours of each participant (e.g. one 4h part at the
AMC, a pre-screening of max 1h, and 2 follow-up interviews by phone of each max
30 minutes) and can be considered non-invasive. There are no known risks of
undergoing MRI. We consider the new knowledge about the development of
addiction and the course of drug-use resulting from this research of great
importance. The focus of this project will be factors involved in the
development of addiction and therefore it is of direct concern for the
development of new treatments and prevention strategies of addiction.