Clinical trial NCT00279604: INCA - Intervention and Neuropsychology in Cannabis Abuse
Official title: Targeted Interventions in Cannabis Abuse: Focus on Decision Making (INCA)
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Marijuana Abuse
Lead sponsor: University Hospital, Bonn
Sponsor class: OTHER
Collaborators: name: German Federal Ministry of Education and Research
First posted: 2006-01-19
Enrollment: 160
Sex: ALL
Minimum age (years): 16
Maximum age (years): 36
Standard ages: CHILD
ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: INCA (Intervention and Neuropsychology of Cannabis Abuse) is a study combining two research goals. One is to study efficacy of a short intervention the 'Problem Profile Intervention', which utilizes individual feedback from a 'substance problem check-up'. Subjects will randomly receive the 'Problem Profile Intervention' or the WHO Brief Intervention, a brief intervention, which has been shown to be efficacious. Currently efficiency studies are under way. The WHO Brief Intervention has been translated into German by our group. In contrast to most other cannabis intervention studies the current study is focussed on cannabis abusers not so much cannabis-dependent subjects. A total of 160 subjects are to be recruited. Half of them will randomly receive either the Problem Profile Intervention or the WHO Brief Intervention (active control). A total of 25% of subjects from each group will be placed on a 3 months waiting list before receiving the intervention (inactive control). Intervention outcome will be assessed three months, six month and 12 months after the intervention. We hypothesize cannabis use to be reduced by 25% by the 'Problem Profile Intervention'. The second aim of the study is to study mechanism of substance abuse. Initial results from own studies and data from other groups point to executive cognitive functions as a subtle but important factor that can be compromised in cannabis users (Verdejo-Garcia et al., 2004; Garavan and Stout, 2005). Using an fMRI-study, we intend to examine a subgroup of our subjects on a specific aspect of executive functioning that has recently received major interest in drug research: Decision-making capability, or risk-taking behaviour, respectively (e.g. Ernst and Paulus, 2005).


Eligibility criteria: Inclusion Criteria:

* ASSIST-Score for cannabis consume ≥ 4 ≤ 26
* german mother tongue (or comparable level)

Exclusion Criteria:

* major current psychiatric disorder (e.g. psychosis)
* addiction to other illegal drugs or alcohol
* recent or current intravenous drug use
* CNS-affecting medication
* current psychotherapy, other treatment for substance use disorder

exclusion criteria for fMRI-part:

* left-handedness
* medication (birth control pill, thyroid gland hormones possible)
* internistic illnesses (hypertension, diabetes, diseases of lungs)
* metallic implants (cardiac pacemaker, ferromagnetic object implanted through surgical intervention or accident, large-area tattoos)
* history of serious trauma
* claustrophobia
* gestation

Primary outcomes:
measure: Cannabis consumption,
measure: motivational change
Secondary outcomes:
measure: ASSIST-Score
Other outcomes:
Locations:
city: Bonn
country: Germany
facility: Friedrich-Wilhelms-University, Department of Psychiatry
state: NRW
city: Essen
country: Germany
facility: University of Essen, Department of Psychiatry and Psychotherapy
state: NRW
Study officials:
affiliation: University of Bonn, Department of Psychiatry
name: Christian G Schuetz, MD MPH
role: PRINCIPAL_INVESTIGATOR
References: