Trimbos institute

Utrecht, Netherlands

Trimbos institute

Utrecht, Netherlands
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Brunt T.M.,Netherlands Institute of Mental Health and Addiction | Brunt T.M.,Trimbos Institute | Koeter M.W.,University of Amsterdam | Niesink R.J.M.,Netherlands Institute of Mental Health and Addiction | Van Den Brink W.,University of Amsterdam
Psychopharmacology | Year: 2012

Rationale Most studies on the subjective effects of ecstasy are based on the assumption that the substance that was taken is 3,4- methylenedioxymethamphetamine (MDMA). However, many tablets sold as ecstasy contain other substances and MDMA in varying doses. So far, few attempts have been made to take this into account while assessing subjective effects. Objectives This study aims to link the pharmacological content of tablets sold as ecstasy to the subjective experiences reported by ecstasy users. Methods Self-reported effects on ecstasy tablets were available from 5,786 drug users who handed in their tablets for chemical analysis at the Drug Information and Monitoring System (DIMS) in the Netherlands. Logistic regression was employed to link the pharmacological content of ecstasy tablets to the self-reported subjective effects and compare effects with MDMA to other substances present. Results MDMA showed a strong association with desirable subjective effects, unparalleled by any other psychoactive substance. However, the association of MDMA was dose-dependent, with higher doses (>120 mg/tablet) likely to evoke more adverse effects. The novel psychostimulants mephedrone and p-fluoroamphetamine were considered relatively desirable, whereas meta-chlorophenylpiperazine (mCPP) and p-methoxymethamphetamine (PMMA) were strongly associated with adverse subjective effects. Also, 3,4-methylene- dioxyamphetamine (MDA) and benzylpiper-azine (BZP) were not appreciated as replacement for MDMA. Conclusion Linking the pharmacological content of ecstasy sold on the street to subjective experiences contributes to a better understanding of the wide range of subjective effects ascribed to ecstasy and provides a strong rationale for the prolonged endurance of MDMA as the key ingredient of the ecstasy market. © Springer-Verlag 2011.

Kuntsche E.,Radboud University Nijmegen | Rossow I.,Norwegian Institute for Alcohol and Drug Research | Engels R.,Radboud University Nijmegen | Engels R.,Trimbos Institute
Addiction | Year: 2016

Aim: To address and discuss the weaknesses of age at first drink (AFD) as a concept in alcohol research and prevention. Methods: Narrative literature review. Results: Varying from one sip to the consumption of several full drinks, and sometimes including the specification of particular conditions (e.g. without parental consent), no exact definition and operationalization of AFD was found. Evidence reveals poor test-retest reliability when the same individuals report their AFD two or more times. Theoretical arguments and empirical evidence fail to explain why having one sip or one drink earlier than peers should cause heavier drinking and related problems later in life. Alternative explanations such as self-selection, third variable effects and systematic report bias are not considered in most studies. These shortcomings also make AFD unsuitable as an indicator or marker of underlying problems such as conduct problems and academic failure. Together with unjustified causal inferences, this has led to an over-emphasis on the relevance of postponing AFD as a way to prevent problems later in life. Conclusion: We argue in favour of shifting the focus of alcohol research and prevention away from AFD towards a better understanding of the progression from infrequent, low-quantity drinking to more detrimental drinking patterns and the prevention of associated acute and short-term harm. © 2016 Society for the Study of Addiction.

van Amsterdam J.G.C.,National Institute of Public Health and the Environment RIVM | Brunt T.M.,Trimbos Institute | McMaster M.T.B.,Trimbos Institute | Niesink R.J.M.,Trimbos Institute | Niesink R.J.M.,Open Box
Neuroscience and Biobehavioral Reviews | Year: 2012

In several countries, including the Netherlands, the use of GHB seems to be rising. GHB is regarded by recreational users as an innocent drug without any side effects. Recently, the number of patients in treatment due to GHB addiction sharply increased. In addition, various studies report incidents following risky GHB use or GHB overdosing. Other sedative drugs, like ketamine and alcohol have been shown to result in unintended neurotoxic harm at the level of memory and cognitive function. As outlined in the present review, GHB and ketamine have a common mode of action, which suggests that GHB may also lead to similar neurotoxicity as ketamine. GHB overdosing, as well as binge drinking (and high ketamine doses), induce profound coma which is probably neurotoxic for the brain especially in the maturing brain of young adults. It is therefore advocated to investigate possible long-term neurotoxic effects in recreational GHB users e.g. by studying the residual effects on cognition and memory. © 2012 Elsevier Ltd.

Bossong M.G.,University Utrecht | Bossong M.G.,Trimbos Institute | Niesink R.J.M.,Trimbos Institute | Niesink R.J.M.,Open Box
Progress in Neurobiology | Year: 2010

Cannabis use during adolescence increases the risk of developing psychotic disorders later in life. However, the neurobiological processes underlying this relationship are unknown. This review reports the results of a literature search comprising various neurobiological disciplines, ultimately converging into a model that might explain the neurobiology of cannabis-induced schizophrenia. The article briefly reviews current insights into brain development during adolescence. In particular, the role of the excitatory neurotransmitter glutamate in experience-dependent maturation of specific cortical circuitries is examined. The review also covers recent hypotheses regarding disturbances in strengthening and pruning of synaptic connections in the prefrontal cortex, and the link with latent psychotic disorders. In the present model, cannabis-induced schizophrenia is considered to be a distortion of normal late postnatal brain maturation. Distortion of glutamatergic transmission during critical periods may disturb prefrontal neurocircuitry in specific brain areas. Our model postulates that adolescent exposure to Δ9-tetrahydrocannabinol (THC), the primary psychoactive substance in cannabis, transiently disturbs physiological control of the endogenous cannabinoid system over glutamate and GABA release. As a result, THC may adversely affect adolescent experience-dependent maturation of neural circuitries within prefrontal cortical areas. Depending on dose, exact time window and duration of exposure, this may ultimately lead to the development of psychosis or schizophrenia. The proposed model provides testable hypotheses which can be addressed in future studies, including animal experiments, reanalysis of existing epidemiological data, and prospective epidemiological studies in which the role of the dose-time-effect relationship should be central. © 2010 Elsevier Ltd.

Cuijpers P.,VU University Amsterdam | Smit F.,VU University Amsterdam | Smit F.,Trimbos Institute | Bohlmeijer E.,University of Twente | And 3 more authors.
British Journal of Psychiatry | Year: 2010

Background: It is not clear whether the effects of cognitive-behavioural therapy and other psychotherapies have been overestimated because of publication bias. Aims: To examine indicators of publication bias in randomised controlled trials of psychotherapy for adult depression. Method: We examined effect sizes of 117 trials with 175 comparisons between psychotherapy and control conditions. As indicators of publication bias we examined funnel plots, calculated adjusted effect sizes after publication had been taken into account using Duval & Tweedie's procedure, and tested the symmetry of the funnel plots using the Begg & Mazumdar rank correlation test and Egger's test. Results: The mean effect size was 0.67, which was reduced after adjustment for publication bias to 0.42 (51 imputed studies). Both Begg & Mazumbar's test and Egger's test were highly significant (P<0.001). Conclusions: The effects of psychotherapy for adult depression seem to be overestimated considerably because of publication bias.

Van Vugt M.D.,Trimbos Institute | Kroon H.,Trimbos Institute | Delespaul P.A.E.G.,Maastricht University | Mulder C.L.,Rotterdam University
Psychiatric Services | Year: 2012

Objective: This study examined whether employing mental health consumers as consumer-providers in assertive community treatment teams can enhance outcomes for clients with severe mental illness. Methods: In a prospective longitudinal study, presence of consumer-providers and outcomes of 530 clients with severe mental illness in 20 outpatient teams were assessed at baseline and at one-year and two-year follow-ups. Measures included the Health of the Nation Outcome Scales (HoNOS), the Camberwell Assessment of Need Short Assessment Schedule (CANSAS), the Working Alliance Scale, the number of hospital days, and the number of days of homelessness. Multilevel regression was used with the independent variables consumer-provider presence, time of measurement, and their interaction. Results: A positive association was found between consumer-provider presence and improvements in functioning on the HoNOS (p=.020), met needs in relation to personal recovery (p=.044), unmet needs in relation to personal recovery (p=.008), and number of homeless days (p<.001). A negative association was found for consumer-provider presence and the number of hospital days (p=.019). Conclusions: Consumer-providers are important participants in outpatient teams serving clients with severe mental illnesses, although integrating these providers as part of a team is a slow process.

Korte J.,University of Twente | Bohlmeijer E.T.,University of Twente | Cappeliez P.,University of Ottawa | Smit F.,Trimbos Institute | And 2 more authors.
Psychological Medicine | Year: 2012

Background Although there is substantial evidence for the efficacy of life review therapy as an early treatment of depression in later life, its effectiveness in natural settings has not been studied. The present study evaluates an intervention based on life review and narrative therapy in a large multi-site, pragmatic randomized controlled trial (RCT).Method Life review therapy was compared with care as usual. The primary outcome was depressive symptoms; secondary outcomes were anxiety symptoms, positive mental health, quality of life, and current major depressive episode (MDE). To identify groups for whom the intervention was particularly effective, moderator analyses were carried out (on sociodemographic variables, personality traits, reminiscence functions, clinically relevant depressive and anxiety symptoms, and past MDEs).Results Compared with care as usual (n=102), life review therapy (n=100) was effective in reducing depressive symptoms, at post-treatment (d=0.60, B=-5.3, p<0.001), at 3-month follow-up (d=0.50, B=-5.0, p<0.001) and for the intervention also at 9-month follow-up (t=5.7, p<0.001). The likelihood of a clinically significant change in depressive symptoms was significantly higher [odds ratio (OR) 3.77, p<0.001 at post-treatment; OR 3.76, p<0.001 at the 3-month follow-up]. Small significant effects were found for symptoms of anxiety and positive mental health. Moderator analyses showed only two significant moderators, the personality trait of extraversion and the reminiscence function of boredom reduction.Conclusions This study shows the effectiveness of life review therapy as an early intervention for depression in an ecologically valid context, supporting its applicability to a broad target group. The intervention is also effective in reducing anxiety symptoms and strengthening positive mental health. © 2012 Cambridge University Press.

Van Der Zanden R.,Trimbos Institute | Kramer J.,Trimbos Institute | Gerrits R.,Dimence Institute of Mental Health | Cuijpers P.,VU University Amsterdam
Journal of Medical Internet Research | Year: 2012

Background: Depression is a serious mental health problem, whose first onset is usually in adolescence. Online treatment may offer a solution for the current undertreatment of depression in youth. For adults with depressive symptoms, the effectiveness of Internet-based cognitive behavioral therapy has been demonstrated. This study is one of the first randomized controlled trials to investigate the effectiveness online depression treatment for young people with depressive complaints and the first to focus on an online group course. Objective: To evaluate and discuss the effectiveness of a guided Web-based group course called Grip op Je Dip (Master Your Mood [MYM]), designed for young people aged 16 to 25 years with depressive symptoms, in comparison with a wait-listed control group. Methods: We randomly assigned 244 young people with depressive symptoms to the online MYM course or to a waiting-list control condition. The primary outcome measure was treatment outcome after 3 months on the Center for Epidemiologic Studies Depression Scale. Secondary outcomes were anxiety (measured by the Hospital Anxiety and Depression Scale) and mastery (Mastery Scale). We studied the maintenance of effects in the MYM group 6 months after baseline. Missing data were imputed. Results: The MYM group (n = 121) showed significantly greater improvement in depressive symptoms at 3 months than the control group (n = 123) (t 187 = 6.62, P <.001), with a large between-group effect size of d = 0.94 (95% confidence interval [CI] 0.64-1.23). The MYM group also showed greater improvement in anxiety (t 187 = 3.80, P <.001, d = 0.49, 95% CI 0.24-0.75) and mastery (t 187 = 3.36, P =.001, d = 0.44, 95% CI 0.19-0.70). At 12 weeks, 56% (68/121) of the participants in the MYM group and 20% (24/123) in the control group showed reliable and clinically significant change. This between-group difference was significant (χ 2 1 = 35.0, P <.001) and yielded a number needed to treat of 2.7. Improvements in the MYM group were maintained at 6 months. A limitation is the infeasibility of comparing the 6-month outcomes of the MYM and control groups, as the controls had access to MYM after 3 months. Conclusions: The online group course MYM was effective in reducing depressive symptoms and anxiety and in increasing mastery in young people. These effects persisted in the MYM group at 6 months. Trial Registration: Nederlands Trial Register: NTR1694; 1694 (Archived by WebCite at © Rianne van der Zanden, Jeannet Kramer, Rob Gerrits, Pim Cuijpers.

Diviani N.,University of Amsterdam | Van Den Putte B.,University of Amsterdam | Van Den Putte B.,Trimbos Institute | Giani S.,University of Amsterdam | Van Weert J.C.M.,University of Amsterdam
Journal of Medical Internet Research | Year: 2015

Background: Recent years have witnessed a dramatic increase in consumer online health information seeking. The quality of online health information, however, remains questionable. The issue of information evaluation has become a hot topic, leading to the development of guidelines and checklists to design high-quality online health information. However, little attention has been devoted to how consumers, in particular people with low health literacy, evaluate online health information. Objective: The main aim of this study was to review existing evidence on the association between low health literacy and (1) people's ability to evaluate online health information, (2) perceived quality of online health information, (3) trust in online health information, and (4) use of evaluation criteria for online health information. Methods: Five academic databases (MEDLINE, PsycINFO, Web of Science, CINAHL, and Communication and Mass-media Complete) were systematically searched. We included peer-reviewed publications investigating differences in the evaluation of online information between people with different health literacy levels. Results: After abstract and full-text screening, 38 articles were included in the review. Only four studies investigated the specific role of low health literacy in the evaluation of online health information. The other studies examined the association between educational level or other skills-based proxies for health literacy, such as general literacy, and outcomes. Results indicate that low health literacy (and related skills) are negatively related to the ability to evaluate online health information and trust in online health information. Evidence on the association with perceived quality of online health information and use of evaluation criteria is inconclusive. Conclusions: The findings indicate that low health literacy (and related skills) play a role in the evaluation of online health information. This topic is therefore worth more scholarly attention. Based on the results of this review, future research in this field should (1) specifically focus on health literacy, (2) devote more attention to the identification of the different criteria people use to evaluate online health information, (3) develop shared definitions and measures for the most commonly used outcomes in the field of evaluation of online health information, and (4) assess the relationship between the different evaluative dimensions and the role played by health literacy in shaping their interplay.

Van der Pol P.,Trimbos Institute | Liebregts N.,University of Amsterdam | de Graaf R.,Trimbos Institute | Korf D.J.,University of Amsterdam | And 2 more authors.
Drug and Alcohol Dependence | Year: 2013

Background: Frequent cannabis users are at high risk of dependence, still most (near) daily users are not dependent. It is unknown why some frequent users develop dependence, whereas others do not. This study aims to identify predictors of first-incidence DSM-IV cannabis dependence in frequent cannabis users. Methods: A prospective cohort of frequent cannabis users (aged 18-30, n= 600) with baseline and two follow-up assessments (18 and 36 months) was used. Only participants without lifetime diagnosis of DSM-IV cannabis dependence at baseline (n= 269) were selected. Incidence of DSM-IV cannabis dependence was established using the Composite International Diagnostic Interview version 3.0. Variables assessed as potential predictors of the development of cannabis dependence included sociodemographic factors, cannabis use variables (e.g., motives, consumption habits, cannabis exposure), vulnerability factors (e.g., childhood adversity, family history of mental disorders or substance use problems, personality, mental disorders), and stress factors (e.g., life events, social support). Results: Three-year cumulative incidence of cannabis dependence was 37.2% (95% CI. = 30.7-43.8%). Independent predictors of the first incidence of cannabis dependence included: living alone, coping motives for cannabis use, number and type of recent negative life events (major financial problems), and number and type of cannabis use disorder symptoms (impaired control over use). Cannabis exposure variables and stable vulnerability factors did not independently predict first incidence of cannabis dependence. Conclusions: In a high risk population of young adult frequent cannabis users, current problems are more important predictors of first incidence cannabis dependence than the level and type of cannabis exposure and stable vulnerability factors. © 2013 Elsevier Ireland Ltd.

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