Maarten Koeter

• PhD
• Academisch Medisch Centrum Universiteit van Amsterdam

Despite the negative impact of lack of insight on the prognosis, general functioning and treatment adherence, the effect of antipsychotic medication on insight has been investigated only in small samples and uncontrolled studies. In this study we examine whether previously reported effects of antipsychotics on insight from uncontrolled studies can...

Introduction: Recent life events are associated with transition to and outcome in psychosis. Childhood trauma and personality characteristics play a role in proneness to adult life events. However, little is known about the relative contribution and interrelatedness of these characteristics in psychotic disorders. Therefore, we investigated whether...

Background: In the Netherlands the Boston psychiatric rehabilitation approach (bpr) is one of the most widely implemented rehabilitation methods. So far, little research has been done on the efficacy of this approach. Aim: To investigate the effect of bpr on the attainment of personal rehabilitation goals, social functioning and empowerment and...

Background: Two recent meta-analyses showed decreased red blood cell (RBC) polyunsaturated fatty acids (FA) in schizophrenia and related disorders. However, both these meta-analyses report considerable heterogeneity, probably related to differences in patient samples between studies. Here, we investigated whether variations in RBC FA are associate...

Objective: Major depressive disorder (MDD) is a burdensome disease that has a high risk of relapse/recurrence. Cognitive reactivity appears to be a risk factor for relapse. It remains unclear, however, whether dysfunctional cognitions alone or the reactivity of such cognitions to mild states of sadness (ie, cognitive reactivity) is the crucial fac...

Background and aims: Between 2000 and 2005 the average percentage of Δ(9) -tetrahydrocannabinol (THC) in marijuana as sold in Dutch coffeeshops has increased substantially; the potency of domestic products (Nederwiet and Nederhasj) has particularly increased. In contrast with imported marijuana, Nederwiet hardly contained any cannabidiol (CBD), a...

Prevention of recurrence is a challenge in the management of major depressive disorder (MDD). The long-term effects of Preventive Cognitive Therapy (PCT) in preventing recurrence in MDD are not known. A RCT comparing the addition of PCT to Treatment As Usual (TAU), versus TAU including patients with recurrent depression who were in remission at ent...

This study aims to (i) assess work functioning in employees returning to work with a major depression in remission, (ii) study the predictors of impaired work functioning. Participants diagnosed with major depressive disorder (MDD), on long term sick leave (mean 27 weeks) and treated in a specialized mental healthcare setting, were selected from an...

Major depressive disorder (MDD) has been associated with low dehydroepiandrosterone-sulphate (DHEAS), - particularly relative to high cortisol - although conflicting findings exist. Moreover, it is unclear whether low DHEAS is only present during the depressive state, or manifests as a trait that may reflect vulnerability for recurrence. Therefore,...

There is a clear need for effective interventions to reduce cannabis use in patients with first-episode psychosis. This follow-up of a randomized trial examined whether an intervention for parents, based on motivational interviewing and interaction skills (Family Motivational Intervention, FMI), was more effective than routine family support (RFS)...

Metabolism of dietary fatty acids (FAs), and its relationship with the hypothalamic-pituitary-adrenal (HPA)-axis, have been found to be altered in major depressive disorder (MDD). Moreover, indications exist that these factors are associated with antidepressant-response. If we better understand these associations, we might identify novel targets fo...

Major depressive disorder (MDD) and bipolar disorder (BD) are difficult to distinguish clinically during the depressed or remitted states. Both mood disorders are characterized by emotion regulation disturbances; however, little is known about emotion regulation differences between MDD and BD. Better insight into these differences would be helpful...

Borderline personality disorder (BPD) and substance use disorders (SUDs) often co-occur, partly because they share risk factors. In this international multicenter study, risk factors for BPD were examined for SUD patients. In total, 1,205 patients were comprehensively examined by standardized interviews and questionnaires on psychiatric diagnosis a...

Introduction: The prevalence of ADHD among patients with substance use disorder (SUD) is substantial. This study addressed the following research questions: Are early developmental, temperamental and educational problems overrepresented among SUD patients with ADHD compared to SUD patients without ADHD? Do this comorbid group receive early help for...

Extended-release naltrexone (XRNT), an opioid receptor antagonist, is successfully used in the treatment of opioid dependence. However, naltrexone treatment of opioid-dependent patients may reduce striatal dopamine transporter (DAT) availability and cause depression and anhedonia. The aim of this study is to investigate changes in striatal DAT avai...

AimsTo investigate the temporal pattern of appearance of a new psychoactive substance (4-fluoroamphetamine) on the Dutch drug market, as well as its patterns of use and effects.DesignData from the Drug Information and Monitoring System (DIMS) was used to investigate the emergence of 4-fluoroamphetamine on the Dutch drug market. An online questionna...

Background: There is an increasing interest in cognitive-behavioural therapy (CBT) interventions targeting negative symptoms in schizophrenia. To date, CBT trials primarily focused on positive symptoms and investigated change in negative symptoms only as a secondary outcome. To enhance insight into factors contributing to improvement of negative s...

To examine the consequences and validity of changes in Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 diagnostic criteria for schizophrenia, eg, omission of subtypes, using a large dataset of double-blind, randomized, placebo-controlled schizophrenia trials. Data from 22 short-term efficacy registration trials of second generation an...

Schizophrenia is highly comorbid with cannabis use disorders (CUDs), and this comorbidity is associated with an unfavourable course. Early onset or frequent cannabis use may influence brain structure. A key question is whether comorbid CUDs modulate brain morphology alterations associated with schizophrenia. We used surface-based analysis to measur...

Background Despite the development of various self-management programmes that attempt to ameliorate symptoms of patients with chronic major depressive disorder (MDD), little is known about what these patients perceive as helpful in their struggle during daily live. The present study aims to explore what patients believe they can do themselves to co...

Background Most studies investigating the role of personality as a risk factor for the development of opioid dependence compare dependent opioid users with healthy controls who never used heroin. In order to understand the potential protective role of personality, it is crucial to compare illicit opioid users who never became dependent with depende...

Hypothalamic-pituitary-adrenal (HPA)-axis dysregulation is a prominent finding in more severe Major Depressive Disorder (MDD), and is characterized by increased baseline cortisol levels at awakening (BCL), blunted cortisol awakening response (CAR) and increased area under the cortisol curve (AUC). Selective serotonin reuptake inhibitors (SSRIs) app...

AimOlfactory identification deficits (OIDs) are seen in schizophrenia patients and individuals at increased risk for psychosis but its pathophysiology remains unclear. Although dopaminergic imbalance is known to lie at the core of schizophrenia symptomatology, its role in the development of OIDs has not been elucidated yet. This study investigated...

Generalizability of efficacy results from medication trials across geographic regions is disputed. Geographic differences in factors such as patient characteristics, treatment practices and disease definitions might lead to differences in effect sizes across regions. This study examined geographic variation in efficacy results of schizophrenia tria...

Background / Purpose: Major Depressive Disorder (MDD) has a high risk of relapse (Muller et al. 1999) Cognitive reactivity (CR) represents mood-related change in cognitive processing (Teasdale.1988) CR appears a crucial risk factor for relapse (Segal et al. 2006) CR is efficiently measured by the self-rated Leiden Index of Depression Sensitivi...

Aims: To determine comorbidity patterns in treatment-seeking substance use disorder (SUD) patients with and without adult attention deficit hyperactivity disorder (ADHD), with an emphasis on subgroups defined by ADHD subtype, taking into account differences related to gender and primary substance of abuse. Design: Data were obtained from the cro...

The purpose of the present study was to explore various stakeholder perspectives regarding factors that impede return-to-work (RTW) after long-term sickness absence related to major depressive disorder (MDD). Concept mapping was used to explore employees', supervisors' and occupational physicians' perspectives on these impeding factors. Nine percei...

Background: Available studies vary in their estimated prevalence of attention deficit/hyperactivity disorder (ADHD) in substance use disorder (SUD) patients, ranging from 2 to 83%. A better understanding of the possible reasons for this variability and the effect of the change from DSM-IV to DSM-5 is needed. Methods: A two stage international mu...

Fatty acid (FA)-alterations may mediate the mutual association between Major Depressive Disorder (MDD) and cardiovascular disease (CVD). However, etiology of observed FA-alterations in MDD and CVD remains largely unclear. An interesting candidate may be a mutation in the fatty acid-binding protein 2 (FABP2)-gene, because it regulates dietary FA-upt...

Attention deficit/hyperactivity disorder (ADHD) is an increasingly recognized comorbid condition in subjects with substance use disorders (SUDs). This paper describes the methods and study population of the International ADHD in Substance Use Disorders Prevalence (IASP) study. Objectives of the IASP are to determine the prevalence of ADHD in adult...

BACKGROUND: Self-management appears to be a promising approach in the case of depression, which helps to stimulate patients' autonomy. However, a good and systematic description of the concept self-management from the patients' perspective, to our knowledge, has not yet been performed. OBJECTIVE: To determine: (i) what strategies patients think the...

JANSEN, J.M., J.G. Daams, M.W.J. Koeter, D.J. Veltman, W. van den Brink, and A.E. Goudriaan. Effects of non-invasive neurostimulation on craving: a meta-analysis NEUROSCI BIOBEHAV REV xx(x) XXX-XXX, 2013 - This meta-analysis was conducted to evaluate the available evidence regarding the effects of non-invasive neurostimulation of the dorsolateral p...

Childhood trauma is associated with the onset and recurrence of major depressive disorder (MDD). The thermolabile T variant of the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism (rs1801133) is associated with a limited (oxidative) stress defense. Therefore, C677T MTHFR could be a potential predictor for depressive symptomatology and...

During the past 50 years, workload has shifted from physical to mental demands, and so modern workers are more and more selected on their psychological and mental, rather than their physical, capacities. People with mental health problems, or in more severe cases mental disorders, want to be normal citizens just as much as others do. However, new s...

Background: Internet-based interventions are seen as attractive for harmful users of alcohol and lead to desirable clinical outcomes. Some participants will however not achieve the desired results. In this study, harmful users of alcohol have been partitioned in subgroups with low, intermediate or high probability of positive treatment outcome, us...

Objective: Impaired Theory of Mind (ToM) is found in adults with schizophrenia and is associated with paranoid symptoms. Insecure attachment is proposed to underlie impaired ToM as well as paranoia. Insight into associations between insecure attachment and impaired ToM skills may help clinicians and patients to understand interpersonal difficultie...

Objective: The current study examined whether cognitive reactivity, cognitive extremity reactivity, and mood reactivity following mood provocation predicted relapse in depression over 5.5 years. Additionally, this study was the 1st to examine whether changes in cognitive reactivity and mood reactivity following preventive cognitive therapy (PCT) m...

Alterations in hypothalamic-pituitary-adrenal (HPA)-axis activity and fatty acid (FA)-metabolism have been observed in (recurrent) major depressive disorder (MDD). Through the pathophysiological roles of FAs in the brain and cardiovascular system, a hypothesized relationship between HPA-axis activity and FA-metabolism could form a possible missing...

Background: The number of admissions to addiction treatment centers in the Netherlands for gamma hydroxybutyrate (GHB) dependence is rapidly growing. Until now, treatment seeking GHB users have hardly been studied. This study characterizes inpatients in treatment for GHB dependence in terms of sociodemographics, motives for substance use and reaso...

BACKGROUND: Major depressive disorder (MDD) negatively affects a wide range of work outcomes (absenteeism, work productivity, work limitations). However, the exact longitudinal relationship between depressive symptoms and work outcomes in MDD patients with long-term sickness absence is still unclear. Therefore, the present study aimed to examine th...

Posttraumatic stress disorder (PTSD) is associated with the occurrence of secondary psychotic features, complicating treatment and resulting in negative outcomes. Some authors have suggested that PTSD with secondary psychotic features (PTSD-SP) is a diagnostic subtype of PTSD or even a separate diagnostic entity. However, other studies suggest that...

Cannabis use is more common in individuals with non-affective psychotic disorder and their siblings compared to healthy controls. As cannabis use is associated with a greater risk to develop psychotic disorder and an adverse outcome in those who already developed psychosis, it is important to know the role of craving in continued cannabis use and r...

Objectives: To evaluate whether adjuvant occupational therapy (OT) can improve the effectiveness of treatment-as-usual (TAU) in sick-listed employees with major depression. Methods: In total, 117 employees sick-listed for a median duration of 4.8 months (IQR=2.6 to 10.1 months) because of major depression were randomised to TAU (n=39) or adjuvan...

Background: Internet interventions with and without therapist support have been found to be effective treatment options for harmful alcohol users. Internet-based therapy (IT) leads to larger and longer-lasting positive effects than Internet-based self-help (IS), but it is also more costly to provide. Objective: To evaluate the cost effectiveness...

To examine whether a simple Visual Analogue Mood Scale (VAMS) is able to predict time to relapse over 5.5-years. 187 remitted recurrently depressed out-patients were interviewed using the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) and the 17-item Hamilton Depression rating scale (HAM-D) to verify remission status (HAM-D <10)...

The purpose of this study was to establish the predictive validity of guidelines for allocating patients to outpatient or inpatient treatment for an alcohol-use disorder. It was hypothesized that patients who were matched to the recommended level of care would have (a) better outcomes than patients treated at a less intensive level of care, and (b)...

Although major depressive disorder (MDD) has substantial negative effects on work outcomes, little is known regarding how to promote a return to work (RTW) after MDD-related sickness absence. The present study aimed to examine predictors across multiple domains for long-term RTW in patients who are sick-listed because of their MDD, and to compare t...

Psychiatric illnesses are under polygenic influence and are associated with interactions between genetic variants and environmental exposures. Gene--environment interactions might not only predict onset of disease, but genetic biomarkers might also help the clinician to select the optimal treatment for patients. However, there is a lack of studies o...

To examine the perspectives of key stakeholders involved in the return-to-work (RTW) process regarding the definition of successful RTW outcome after sickness absence related to common mental disorders (CMD's). A mixed-method design was used: First, we used qualitative methods (focus groups, interviews) to identify a broad range of criteria importa...

Cognitive impairment seems to persist during the euthymic phase of recurrent depression but its relationship with future relapses as with prior course of the disease has to be elucidated. The purpose of this study is to investigate the presence and prognostic value of cognitive dysfunctions for relapse in high risk euthymic patients and to identify...

To investigate what patients themselves think they can contribute to recovery from depression, and what they find to be effective. The patients' perspective is necessary to improve treatment for depression. Qualitative, hypothesis-generating study. The experiences and opinions of 20 patients who had recently recovered from a depressive episode were...

Major Depressive Disorder (MDD) is a highly recurrent disease. Stress-responsive system dysfunction seems to persist after remission. In patients with more chronic and recurrent depressive episodes, state related HPA-axis dysregulation might be a risk factor for prospective recurrence. This study examines the predictive effect of cortisol on consec...

Cannabis use is associated with an earlier age at onset of psychotic illness. The aim of the present study was to examine whether this association is confounded by gender or other substance use in a large cohort of patients with a non-affective psychotic disorder. In 785 patients with a non-affective psychotic disorder, regression analysis was used...

Basic aspects in the handling of fatty acid-data have remained largely underexposed. Of these, we aimed to address three statistical methodological issues, by quantitatively exemplifying their imminent confounding impact on analytical outcomes: (1) presenting results as relative percentages or absolute concentrations, (2) handling of missing/non-de...

Findings on the impact of cannabis use on the course of schizophrenia are inconsistent and not conclusive. 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. Prospective cohort study with assessments of symptoms, confounders and hospitalizatio...

Cannabis use by people with schizophrenia has been found to be associated with family distress and poor clinical outcomes. Interventions to reduce drug use in this patient group have had limited efficacy. This study evaluated the effectiveness of a novel intervention for parents of young adults with recent-onset schizophrenia consisting of family-b...

To investigate the effect of the Boston Psychiatric Rehabilitation (PR) Approach on attainment of personal rehabilitation goals, social functioning, empowerment, needs for care, and quality of life in people with severe mental illness (SMI) in the Netherlands. A 24-month, multicentre, randomized controlled trial was used to compare the results of P...

Identification of potentially modifiable risk factors for recurrence in recurrent depression could provide opportunities to improve preventive interventions. In this study we aimed to examine the predictive value of medically unexplained physical symptoms (MUPS) on time to recurrence in recurrent depression. Additionally, to elucidate pathophysiolo...

Hypothalamic-pituitary-adrenal (HPA)-axis hyperactivity has been observed in (recurrent) major depressive disorder (MDD), although inconsistently and mainly cross-sectional. Longitudinal studies clarifying state-trait issues are lacking. We aimed to determine whether HPA-axis (hyper)activity in recurrent MDD is: (I) reflecting a persistent trait; (...

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. This...

The relationship between cannabis use and cognitive functioning in patients with psychosis has yielded contradictory findings. In individuals at genetic high risk for psychosis, information is sparse. The aim of this study was to assess the association between recency and frequency of cannabis use and cognitive functioning in patients with psychosi...

Vóór de succesvolle inrichting van hostels waren de zogenaamde zorgcentra in Utrecht een belangrijke voorziening voor dakloze verslaafden. Functioneerden deze aanvankelijk vooral als gebruiksruimten en voor de verlening van basale hulp, later kregen zij ook een rol in doorverwijzing naar verdere hulp. Wij onderzochten of de dossiervoering in deze v...

To investigate in heroin-assisted treatment (HAT) compared to methadone maintenance treatment (MMT): the course of heroin craving and illicit heroin use, their mutual association, and their association with multi-domain treatment response. RCTs on the efficacy of 12 months co-prescribed injectable or inhalable HAT compared to 12 months continued or...

This study aims to investigate the most important factors facilitating a return to work after sick leave due to depression from the perspectives of patients, supervisors and occupational physicians. Concept mapping was used to develop a conceptual framework. Using purposive sampling, 32 participants representing Employees, supervisors and occupatio...

Very little is known about the relationship between obsessive-compulsive disorder (OCD) and substance use disorder (SUD). The aim of this study is to compare the co-occurrence of OCD with SUD to the co-occurrence of SUD with other psychiatric disorders in a representative community sample. In order to examine the association of SUD and OCD, logisti...

Problematic alcohol use is the third leading contributor to the global burden of disease, partly because the majority of problem drinkers are not receiving treatment. Internet-based alcohol interventions attract an otherwise untreated population, but their effectiveness has not yet been established. The current study examined the effectiveness of I...

Despite frequent use of subjective adherence measures in patients with schizophrenia as well as other chronic conditions, there are several reports that question the validity of these instruments. Three well known, representative subjective measures are the Medication Adherence Questionnaire (MAQ), the Drug Attitude Inventory (DAI), and the Complia...

Background/Objectives: Major depressive disorder (MDD) is among the medical conditions with the highest negative impact on work outcome. However, little is known regarding evidence-based interventions targeting the improvement of work outcomes in depressed employees. We evaluated the effectiveness of adjuvant occupational therapy in depressed emplo...

To investigate internal consistency and factor structure of a questionnaire measuring learning capacity based on Senge's theory of the five disciplines of a learning organisation: Personal Mastery, Mental Models, Shared Vision, Team Learning, and Systems Thinking. Cross-sectional study. Substance-abuse treatment centres (SATCs) in The Netherlands....

Missing data is a common nuisance in eHealth research: it is hard to prevent and may invalidate research findings. In this paper several statistical approaches to data "missingness" are discussed and tested in a simulation study. Basic approaches (complete case analysis, mean imputation, and last observation carried forward) and advanced methods (e...

The purpose of this study was to assess the predictive validity of guidelines for allocating outpatients with an alcohol-use disorder to different levels of care in routine alcohol outpatient treatment facilities. It was hypothesized that patients matched to the recommended level of care would have (a) better outcomes than patients treated at a les...

The aim of this study is to assess the influence of early and late compliance of acamprosate on attendance and abstinence duration in the treatment of alcohol dependence. Individual patient data of 2,305 patients from 11 randomized controlled trials comparing acamprosate (n = 1,128) with placebo (n = 1,177) were used to predict early and late compl...

Background Depressive disorders are highly prevalent in primary care (PC) and are associated with considerable functional impairment and increased health care use. Research has shown that many patients prefer psychological treatments to pharmacotherapy, however, it remains unclear which treatment is most optimal for depressive patients in primary c...

Major depressive disorder is among the medical conditions with the highest negative impact on work outcome. However, little is known regarding evidence-based interventions targeting the improvement of work outcomes in depressed employees. In this paper, the design of a randomized controlled trial is presented in order to evaluate the effectiveness...

Drug policy makers continuously face a changing pattern of drug use, i.e. new drugs appear on the market, the popularity of certain drugs changes or drugs are used in another way or another combination. For legislative purposes, drugs have mostly been classified according to their addictive potency. Such classifications, however, lack a scientific...

The Patient Health Questionnaire-9 (PHQ-9) has been widely used in research and clinical settings. To be able to attribute differences in PHQ-9 scores between groups with different cultural backgrounds to differences in the level of depression, the instrument has to possess measurement invariance. Data from the Apollo-D study were used. We used two...

Depression is a disease with high recurrence rates. Identifying predictors of recurrence and their relative importance in patients with recurrent depression is important for a better understanding of the course of this disease. This type of knowledge can be used to optimize and tailor preventive strategies of recurrence. In this study, we examined...

To present and evaluate a measurement tool for assessing characteristics of people with drug and/or alcohol problems for triage and evaluation in treatment. Measurements in the Addictions for Triage and Evaluation (MATE) is composed of 10 modules, selected on the basis of a detailed set of specifications. Conceptually, the MATE was constructed acco...

This paper illustrates the process of constructing, selecting and applying simple measures in order to empirically derive patterns of course of psychotic episodes in schizophrenia. Data were collected with a composite instrument constructed for a multi-centre, follow-up randomized controlled trial of adherence therapy for people with schizophrenia....

Major depressive disorder (MDD) was projected to rank second on a list of 15 major diseases in terms of burden in 2030. A crucial part of the treatment of depression is the prevention of relapse/recurrence in high-risk groups, ie, recurrently depressed patients. The long-term preventive effects of group cognitive therapy (CT) in preventing relapse/...

Studies reporting ecstasy-induced serotonin-toxicity and (neuro)psychological dysfunctions have been conducted in young adults. Little is known about ecstasy effects later in life, when serotonin levels and cognition decrease as a consequence of normal ageing. This study aimed to assess whether harmful effects of ecstasy only add to or also interac...

Attention to caregiver consequences has been mainly restricted to caregivers of patients with schizophrenia. The few studies done in depression were conducted on small samples and/or with non-validated instruments. Caregiver consequences in depression and schizophrenia were measured with the validated Involvement Evaluation Questionnaire (IEQ). IEQ...

Little is known about Autism Spectrum Disorder (ASD) in adults, especially not about ASD with co-morbid Substance Use Disorder (SUD). We wanted to examine how adults with ASD compare to adults with ADHD on prevalence and risk factors for co-morbid SUD, and on disability levels associated with SUD. We stratified 123 treatment seeking adults with ASD...

Acamprosate and naltrexone are effective medications in the treatment of alcoholism. However, effect sizes are modest. Pharmacogenomics may improve patient-treatment-matching and effect sizes. It is hypothesized that naltrexone exerts its effect through genetic characteristics associated with the dopaminergic/opioidergic positive reinforcement syst...