Publications by authors named "Robbert-Jan Verkes"

Purpose/background: Antipsychotic polypharmacy (APP) is controversial yet applied in 20% of patients with psychotic disorders. We investigated indications for initiating and continuing APP, including the contribution of unfinished cross-titrations.

Methods/procedures: This 2-month study was part of a prospective study to reduce inappropriate APP in inpatients.

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Background: Antipsychotic polypharmacy (APP) is frequently prescribed for schizophrenia-spectrum disorders. Despite the inconsistent findings on efficacy, APP may be beneficial for subgroups of psychotic patients. This meta-analysis of individual patient data investigated moderators of efficacy and tolerability of APP in adult patients with schizophrenia-spectrum disorders.

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Trauma-focused treatments for post-traumatic stress disorder (PTSD) are effective for many patients. However, relapse may occur when acquired extinction memories fail to generalize beyond treatment contexts. A subgroup of PTSD patients - potentially with substantial exposure to early-life adversity (ELA) - show dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which results in lower cortisol levels.

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Objective: Ibogaine is a hallucinogenic drug that may be used to treat opioid use disorder (OUD). The relationships between pharmacokinetics (PKs) of ibogaine and its metabolites and their clinical effects on side effects and opioid withdrawal severity are unknown. We aimed to study these relationships in patients with OUD undergoing detoxification supported by ibogaine.

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Psychotic depression is a severe and difficult-to-treat subtype of major depressive disorder for which higher rates of treatment-resistant depression were found. Studies have been performed aiming to predict treatment-resistant depression or treatment nonresponse. However, most of these studies excluded patients with psychotic depression.

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Background: Since insomnia and depression are interrelated, improved sleep early in antidepressant pharmacotherapy may predict a positive treatment outcome. We investigated whether early insomnia improvement (EII) predicted treatment outcome in psychotic depression (PD) and examined if there was an interaction effect between EII and treatment type to assess if findings were treatment-specific.

Methods: This study is a secondary analysis of a randomized trial comparing 7 weeks treatment with the antidepressants venlafaxine, imipramine and venlafaxine plus the antipsychotic quetiapine in PD ( n = 114).

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Introduction: Terrorism and violent extremism are major social threats worldwide and are committed not only by men but also by women. Previous research has shown indications of psychopathology, among other personal and contextual factors, as a potential risk factor for perpetrating terrorist and violent extremist crimes. Despite the fact that women have engaged in acts of terrorism and violent extremism throughout history, the vast majority of literature on psychopathology so far has been mainly focused on men with terrorist and violent extremist behavior.

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Article Synopsis
  • Prior research suggested that psychostimulants like methylphenidate might harm creative thinking, but evidence was inconclusive due to small sample sizes and individual differences in response to the drug.
  • A study involving 90 healthy participants examined how methylphenidate affected creative tasks, considering each person's baseline dopamine levels using PET imaging.
  • Findings revealed that methylphenidate negatively impacted certain aspects of divergent creativity in individuals with low dopamine synthesis capacity but could enhance it in those with higher levels, indicating a nuanced effect based on individual differences.
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Individual differences in striatal dopamine synthesis capacity have been associated with working memory capacity, trait impulsivity, and spontaneous eye-blink rate (sEBR), as measured with readily available and easily administered, 'off-the-shelf' tests. Such findings have raised the suggestion that individual variation in dopamine synthesis capacity, estimated with expensive and invasive brain positron emission tomography (PET) scans, can be approximated with simple, more pragmatic tests. However, direct evidence for the relationship between these simple trait measures and striatal dopamine synthesis capacity has been limited and inconclusive.

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Background: Violent offenders with psychopathic tendencies are characterized by instrumental, i.e., planned, callous, and unemotional (aggressive) behavior and have been shown to exhibit abnormal aversive processing.

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Relational security is considered an essential form of security in forensic psychiatric care. Research on relational security is important, but is hampered by the lack of instruments to assess and monitor this concept in clinical practice. Within this current study the psychometric properties of the Dutch version of the See Think Act (STA) scale, an instrument designed to measure relational security as perceived by forensic staff members within secure settings, was studied.

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Psychostimulants such as methylphenidate are widely used for their cognitive enhancing effects, but there is large variability in the direction and extent of these effects. We tested the hypothesis that methylphenidate enhances or impairs reward/punishment-based reversal learning depending on baseline striatal dopamine levels and corticostriatal gating of reward/punishment-related representations in stimulus-specific sensory cortex. Young healthy adults (N = 100) were scanned with functional magnetic resonance imaging during a reward/punishment reversal learning task, after intake of methylphenidate or the selective D-receptor antagonist sulpiride.

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Prior laboratory experiments among healthy samples found that training avoidance movements to angry faces may lower anger and aggression, especially people high in trait anger. To enrich this training and make it more suitable for clinical applications, the present researchers developed it into a Virtual Reality Game for Aggressive Impulse Management (VR-GAIME). The current study examined the effects of this training in a randomized controlled trial among forensic psychiatric outpatients with aggression regulation problems (N = 30).

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Abundant evidence shows that early-life stress (ELS) predisposes for the development of stress-related psychopathology when exposed to stressors later in life, but the underlying mechanisms remain unclear. To study predisposing effects of mild ELS on stress sensitivity, we examined in a healthy human population the impact of a history of ELS on acute stress-related changes in corticolimbic circuits involved in emotional processing (i.e.

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Imprisonment may pose a risk for unintended effects such as deterioration of psychiatric symptoms. Therefore, it is pivotal to understand the relation between imprisonment and the course of psychiatric symptoms, but previous studies are inconclusive. The current study followed up the psychiatric symptoms of newly admitted remand prisoners to one Dutch remand prison using the Brief Psychiatric Rating Scale (BPRS) and also studied possible related pre-existing variables.

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Rationale: We constantly need to decide not only which actions to perform, but also how vigorously to perform them. In agreement with an earlier theoretical model, it has been shown that a significant portion of the variance in our action vigor can be explained by the average rate of rewards received for that action. Moreover, this invigorating effect of average reward rate was shown to vary with within-subject changes in dopamine, both in human individuals and experimental rodents.

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Background: Low-grade inflammation occurs in a subgroup of patients with Major Depressive Disorder (MDD) and may be associated with response to antidepressant medications. The Neutrophil to Lymphocyte Ratio (NLR) and total White Blood cell Count (WBC) are markers of systemic inflammation which have not been investigated as predictors for outcome to pharmacotherapy in unipolar depression yet. Moreover, the association between inflammation and treatment response has not been studied in unipolar Psychotic Depression (PD).

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Purpose/background: Antipsychotic polypharmacy (APP) is the concurrent use of more than one antipsychotic by a patient. Multiple antipsychotics are often prescribed, although all relevant guidelines discourage this practice. These recommendations are based on a lack of evidence for effectiveness and an increased risk of serious adverse events with APP.

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The short (S) allele of the serotonin transporter-linked promoter region (5-HTTLPR) polymorphism has been linked to reactive aggression in men, but this association is less consistent in females. Reactive aggression has been particularly described as a result of fear-driven defense to threat, but how this interaction between defensive behavior and aggression is expressed in S-allele carriers remains unknown. In order to explore this interplay between 5-HTTLPR genotype, defensive behavior and reactive aggression, we combined genotyping with objective measures of action tendencies toward angry faces in an approach-avoidance task (AAT) and reactive aggression in the Taylor aggression paradigm (TAP) in healthy females, = 95.

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Reward motivation is known to enhance cognitive control. However, detrimental effects have also been observed, which have been attributed to overdosing of already high baseline dopamine levels by further dopamine increases elicited by reward cues. Aarts et al.

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The cognitive enhancing effects of methylphenidate are well established, but the mechanisms remain unclear. We recently demonstrated that methylphenidate boosts cognitive motivation by enhancing the weight on the benefits of a cognitive task in a manner that depended on striatal dopamine. Here, we considered the complementary hypothesis that methylphenidate might also act by changing the weight on the opportunity cost of a cognitive task, that is, the cost of foregoing alternative opportunity.

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Background: Psychomotor Retardation is a key symptom of Major Depressive Disorder. According to the literature its presence may affect the prognosis of treatment. Aim of the present study is to investigate the prognostic role of Psychomotor Retardation in patients with unipolar Psychotic Depression who are under antidepressant treatment.

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Purpose: Low levels of subjective wellbeing in prisoners may relate to mental health problems and difficulties in reintegration after imprisonment. The development of subjective wellbeing during imprisonment is mostly unclear. The purpose of this paper is to explore this development in a longitudinal study in association with mental disorders and socioeconomic factors.

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