Amsterdam Institute for Addiction Research

Amsterdam, Netherlands

Amsterdam Institute for Addiction Research

Amsterdam, Netherlands
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Amsterdam J.V.,Laboratory for Health Protection Research | Opperhuizen A.,Laboratory for Health Protection Research | Brink W.V.D.,University of Amsterdam | Brink W.V.D.,Amsterdam Institute for Addiction Research
Regulatory Toxicology and Pharmacology | Year: 2011

In 2007, the Minister of Health of the Netherlands requested the CAM (Coordination point Assessment and Monitoring new drugs) to assess the overall risk of magic mushrooms. The present paper is an updated redraft of the review, written to support the assessment by CAM experts. It summarizes the literature on physical or psychological dependence, acute and chronic toxicity, risk for public health and criminal aspects related to the consumption of magic mushrooms. In the Netherlands, the prevalence of magic mushroom use was declining since 2000 (last year prevalence of 6.3% in 2000 to 2.9% in 2005), and further declined after possession and use became illegal in December 2008.The CAM concluded that the physical and psychological dependence potential of magic mushrooms was low, that acute toxicity was moderate, chronic toxicity low and public health and criminal aspects negligible. The combined use of mushrooms and alcohol and the quality of the setting in which magic mushrooms are used deserve, however, attention. In conclusion, the use of magic mushrooms is relatively safe as only few and relatively mild adverse effects have been reported. The low prevalent but unpredictable provocation of panic attacks and flash-backs remain, however, a point of concern. © 2011 Elsevier Inc.


van Amsterdam J.,University of Amsterdam | Nabben T.,University of Amsterdam | van den Brink W.,University of Amsterdam | van den Brink W.,Amsterdam Institute for Addiction Research
Regulatory Toxicology and Pharmacology | Year: 2015

Nitrous oxide (N2O; laughing gas) is clinically used as a safe anesthetic (dentistry, ambulance, childbirth) and appreciated for its anti-anxiety effect. Since five years, recreational use of N2O is rapidly increasing especially in the dance and festival scene. In the UK, N2O is the second most popular recreational drug after cannabis. In most countries, nitrous oxide is a legal drug that is widely available and cheap. Last month prevalence of use among clubbers and ravers ranges between 40 and almost 80 percent. Following one inhalation, mostly from a balloon, a euphoric, pleasant, joyful, empathogenic and sometimes hallucinogenic effect is rapidly induced (within 10 s) and disappears within some minutes. Recreational N2O use is generally moderate with most users taking less than 10 balloons of N2O per episode and about 80% of the users having less than 10 episodes per year. Side effects of N2O include transient dizziness, dissociation, disorientation, loss of balance, impaired memory and cognition, and weakness in the legs. When intoxicated accidents like tripping and falling may occur. Some fatal accidents have been reported due to due to asphyxia (hypoxia). Heavy or sustained use of N2O inactivates vitamin B12, resulting in a functional vitamin B12 deficiency and initially causing numbness in fingers, which may further progress to peripheral neuropathy and megaloblastic anemia. N2O use does not seem to result in dependence. Considering the generally modest use of N2O and its relative safety, it is not necessary to take legal measures. However, (potential) users should be informed about the risk of vitamin B12-deficiency related neurological and hematological effects associated with heavy use. © 2015 Elsevier Inc.


Brunt T.M.,Trimbos Institute Netherlands Institute of Mental Health and Addiction | van Amsterdam J.G.C.,National Institute of Public Health and the Environment RIVM | van Amsterdam J.G.C.,Amsterdam Institute for Addiction Research | van den Brink W.,University of Amsterdam | van den Brink W.,Amsterdam Institute for Addiction Research
Current Pharmaceutical Design | Year: 2014

A growing body of evidence shows that gamma-hydroxybutyric acid (GHB) is an addictive substance. Its precursors gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD) show the same properties and may pose even more risks due to different pharmacoki-netics. There are indications that problematic GHB use is increasing in the European Union. This review investigates the existing literature on the neurochemistry of GHB and its precursors, their acute toxicity, addiction potential and withdrawal, the proposed molecular mechanism underlying addiction and the treatment of withdrawal and addiction. Current evidence shows that GHB and its precursors are highly addictive, both in humans and animals, probably through a GABAB receptor related mechanism. Severity of withdrawal symptoms can be considered as a medical emergency. Recent studies suggest that benzodiazepines are not very effective, showing a high treatment resistance, whereas detoxification with pharmaceutical GHB proved to be successful. However, relapse in GHB use is frequent and more research is warranted on relapse prevention. This might aid medical practitioners in the field and improve general understanding of the severity of addiction to GHB, GBL and 1,4-BD. © 2014 Bentham Science Publishers.


Van Amsterdam J.,National Health Research Institute | Van Den Brink W.,University of Amsterdam | Van Den Brink W.,Amsterdam Institute for Addiction Research
Journal of Psychopharmacology | Year: 2013

The aim of this paper is to create awareness of the negative health impact and economic burden and benefits associated to alcohol consumption. Worldwide about two billion people consume alcohol. Low intake of alcohol has a minor protective cardiovascular effect. On the other hand, even moderate alcohol consumption appears to be weakly, but significantly, associated to a limited number of chronic diseases. Alcohol causes a considerable economic burden to society due to the high absolute number of alcohol consumers. As such, alcohol abuse is more harmful for public health and society than illicit drug use. Some 3.7% of alcohol consumers (worldwide 76 million people) have an alcohol use disorder leading to 60-70% of the societal costs related to alcohol. Therefore, policy measures should, in addition to regulatory measures to reduce alcohol use, aim at closing the treatment gap and improving treatment effectiveness of people with an alcohol use disorder. The key message is that policy-makers unjustifiably focus on the harm of illicit drugs, whereas they underestimate the harm of alcohol use. Policy makers should therefore consider alcohol to be at least as harmful as illicit drugs and invest more in prevention and harm reduction strategies for alcohol abuse and dependence. © The Author(s) 2013.


Van Amsterdam J.,Amsterdam Institute for Addiction Research | Nutt D.,Imperial College London | Van Den Brink W.,University of Amsterdam
Journal of Psychopharmacology | Year: 2013

New psychoactive drugs (NPDs, new psychoactive substances) enter the market all the time. However, it takes several months to ban these NPDs and immediate action is generally not possible. Several European countries and drug enforcement officers insist on a faster procedure to ban NPDs. Introduction of generic legislation, in which clusters of psychotropic drugs are banned in advance, has been mentioned as a possible solution. Here we discuss the pros and cons of such an approach. First, generic legislation could unintentionally increase the expenditures of enforcement, black market practices, administrative burden and health risks for users. Second, it may have a negative impact on research and the development of new treatments. Third, due to the complexity of generic legislation, problems in the enforcement are anticipated due to lack of knowledge about the chemical nomenclature. Finally, various legal options are already available to ban the use, sale and trade of NPDs. We therefore conclude that the currently used scientific benefit-risk evaluation should be continued to limit the adverse health effects of NPDs. Only in emergency cases, where fatal incidents (may) occur, should this approach be overruled. © The Author(s) 2013.


Mantione M.,University of Amsterdam | Van De Brink W.,University of Amsterdam | Van De Brink W.,Amsterdam Institute for Addiction Research | Schuurman P.R.,University of Amsterdam | Denys D.,University of Amsterdam
Neurosurgery | Year: 2010

OBJECTIVE: Smoking and overeating are compulsory habits that are difficult to stop. Several studies have shown involvement of the nucleus accumbens in these and other addictive behaviors. In this case report, we describe a patient who quit smoking and lost weight without any effort, and we review the underlying mechanisms of action. CLINICAL PRESENTATION: A 47-year-old woman presented with chronic treatment-refractory obsessive-compulsive disorder, nicotine dependence, and obesity. INTERVENTION: The patient was treated with deep brain stimulation of the nucleus accumbens for obsessive-compulsive disorder. Unintended, effortless, and simultaneous smoking cessation and weight loss were observed. CONCLUSION: This study supports the idea of compulsivity with common circuitry in the processing of diverse rewards and suggests that deep brain stimulation of the nucleus accumbens could be a possible treatment of patients with a dependency not responding to currently available treatments. Copyright © 2010 by the Congress of Neurological Surgeons.


Tuithof M.,Netherlands Institute of Mental Health and Addiction | ten Have M.,Netherlands Institute of Mental Health and Addiction | van den Brink W.,Amsterdam Institute for Addiction Research | Vollebergh W.,University Utrecht | de Graaf R.,Netherlands Institute of Mental Health and Addiction
Drug and Alcohol Dependence | Year: 2012

Background: Much is unclear about the association between attention-deficit/hyperactivity disorder (ADHD) and alcohol use (disorder). Research on this subject is hindered by the role of conduct disorder (CD). We investigate whether (1) childhood ADHD is associated with higher prevalence and earlier onset of alcohol initiation, regular alcohol use and alcohol use disorder (AUD) (2) CD mediates or modifies this association. Methods: Data were derived from the baseline assessment of the Netherlands Mental Health Survey and Incidence Study-2, a general population study. ADHD and CD were assessed among respondents aged 18-44 (n= 3309). ADHD, CD, and alcohol use (disorder) were assessed using the Composite International Diagnostic Interview 3.0. Results: Lifetime prevalence was 2.9% for ADHD, 5.6% for CD, 94.3% for alcohol initiation, 85.7% for regular alcohol use and 19.0% for AUD; mean ages of onset were 6.7, 11.5, 14.8, 16.7 and 19.2 years, respectively. After correction for gender and age, ADHD was associated with a higher prevalence of all three stages of alcohol use, but not with earlier onset of these stages. The association between ADHD and prevalence of AUD was fully explained by a mediating role of CD. CD did not modify the associations between ADHD and prevalence and onset of alcohol use (disorder). Conclusions: The mediating role of CD in the association between ADHD and AUD suggests a developmental pathway from ADHD to CD and subsequent AUD. Early interventions in children with ADHD may prevent CD and subsequent onset of AUD. © 2011 Elsevier Ireland Ltd.


Van Dijk D.,Robert Bosch GmbH | Koeter M.W.J.,University of Amsterdam | Koeter M.W.J.,Amsterdam Institute for Addiction Research | Hijman R.,University Utrecht | And 2 more authors.
Schizophrenia Research | Year: 2012

Background: Findings on the impact of cannabis use on the course of schizophrenia are inconsistent and not conclusive. Aims: To study the effect of cannabis use on the course of schizophrenia taking into account the effects of the quantity of cannabis use and important confounders. Methods: Prospective cohort study with assessments of symptoms, confounders and hospitalizations at baseline, 6. month and 12. month follow up. Results: In a representative cohort of 145 male patients with schizophrenia, 68 (46.9%) used cannabis. Mean age at onset of schizophrenia in cannabis using patients was significantly lower than in non-cannabis using patients. No other cross-sectional demographic or clinical differences were observed between users and non-users. In a series of longitudinal analyses, cannabis use was not associated with differences in psychopathology, but relapse in terms of the number of hospitalizations was significantly higher in cannabis using patients compared to non-cannabis using patients. Conclusions: Patients with schizophrenia using cannabis are more frequently hospitalized than non-cannabis using patients but do not differ with respect to psychopathology. Possible explanations for these findings are discussed. © 2012 Elsevier B.V.


Cousijn J.,University of Amsterdam | Cousijn J.,Amsterdam Institute for Addiction Research | Goudriaan A.E.,University of Amsterdam | Goudriaan A.E.,Amsterdam Institute for Addiction Research | Wiers R.W.,University of Amsterdam
Addiction | Year: 2011

Aims Repeated drug exposure can lead to an approach-bias, i.e. the relatively automatically triggered tendencies to approach rather that avoid drug-related stimuli. Our main aim was to study this approach-bias in heavy cannabis users with the newly developed cannabis Approach Avoidance Task (cannabis-AAT) and to investigate the predictive relationship between an approach-bias for cannabis-related materials and levels of cannabis use, craving, and the course of cannabis use. Design, settings and participants Cross-sectional assessment and six-month follow-up in 32 heavy cannabis users and 39 non-using controls. Measurements Approach and avoidance action-tendencies towards cannabis and neutral images were assessed with the cannabis AAT. During the AAT, participants pulled or pushed a joystick in response to image orientation. To generate additional sense of approach or avoidance, pulling the joystick increased picture size while pushing decreased it. Craving was measured pre- and post-test with the multi-factorial Marijuana Craving Questionnaire (MCQ). Cannabis use frequencies and levels of dependence were measured at baseline and after a six-month follow-up. Findings Heavy cannabis users demonstrated an approach-bias for cannabis images, as compared to controls. The approach-bias predicted changes in cannabis use at six-month follow-up. The pre-test MCQ emotionality and expectancy factor were associated negatively with the approach-bias. No effects were found on levels of cannabis dependence. Conclusions Heavy cannabis users with a strong approach-bias for cannabis are more likely to increase their cannabis use. This approach-bias could be used as a predictor of the course of cannabis use to identify individuals at risk from increasing cannabis use. © 2011 The Authors, Addiction © 2011 Society for the Study of Addiction.


Van Amsterdam J.,University of Amsterdam | Nutt D.,Imperial College London | Phillips L.,The London School of Economics and Political Science | Van Den Brink W.,University of Amsterdam | Van Den Brink W.,Amsterdam Institute for Addiction Research
Journal of Psychopharmacology | Year: 2015

Background: The present paper describes the results of a rating study performed by a group of European Union (EU) drug experts using the multicriteria decision analysis model for evaluating drug harms. Methods: Forty drug experts from throughout the EU scored 20 drugs on 16 harm criteria. The expert group also assessed criteria weights that would apply, on average, across the EU. Weighted averages of the scores provided a single, overall weighted harm score (range: 0-100) for each drug. Results: Alcohol, heroin and crack emerged as the most harmful drugs (overall weighted harm score 72, 55 and 50, respectively). The remaining drugs had an overall weighted harm score of 38 or less, making them much less harmful than alcohol. The overall weighted harm scores of the EU experts correlated well with those previously given by the UK panel. Conclusion: The outcome of this study shows that the previous national rankings based on the relative harms of different drugs are endorsed throughout the EU. The results indicates that EU and national drug policy measures should focus on drugs with the highest overall harm, including alcohol and tobacco, whereas drugs such as cannabis and ecstasy should be given lower priority including a lower legal classification. © The Author(s) 2015.

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