Increased Belief Instability in Psychotic Disorders Predicts Treatment Response to Metacognitive Training

BACKGROUND AND HYPOTHESIS

In a complex world, gathering information and adjusting our beliefs about the world is of paramount importance. The literature suggests that patients with psychotic disorders display a tendency to draw early conclusions based on limited evidence, referred to as the jumping-to-conclusions bias, but few studies have examined the computational mechanisms underlying this and related belief-updating biases. Here, we employ a computational approach to understand the relationship between jumping-to-conclusions, psychotic disorders, and delusions.

STUDY DESIGN

We modeled probabilistic reasoning of 261 patients with psychotic disorders and 56 healthy controls during an information sampling task-the fish task-with the Hierarchical Gaussian Filter. Subsequently, we examined the clinical utility of this computational approach by testing whether computational parameters, obtained from fitting the model to each individual's behavior, could predict treatment response to Metacognitive Training using machine learning.

STUDY RESULTS

We observed differences in probabilistic reasoning between patients with psychotic disorders and healthy controls, participants with and without jumping-to-conclusions bias, but not between patients with low and high current delusions. The computational analysis suggested that belief instability was increased in patients with psychotic disorders. Jumping-to-conclusions was associated with both increased belief instability and greater prior uncertainty. Lastly, belief instability predicted treatment response to Metacognitive Training at the individual level.

CONCLUSIONS

Our results point towards increased belief instability as a key computational mechanism underlying probabilistic reasoning in psychotic disorders. We provide a proof-of-concept that this computational approach may be useful to help identify suitable treatments for individual patients with psychotic disorders.

Identification of voxel-based texture abnormalities as new biomarkers for schizophrenia and major depressive patients using layer-wise relevance propagation on deep learning decisions

Non-segmented MRI brain images are used for the identification of new Magnetic Resonance Imaging (MRI) biomarkers able to differentiate between schizophrenic patients (SCZ), major depressive patients (MD) and healthy controls (HC). Brain texture measures such as entropy and contrast, capturing the neighboring variation of MRI voxel intensities, were computed and fed into deep learning technique for group classification. Layer-wise relevance was applied for the localization of the classification results. Texture feature map of non-segmented brain MRI scans were extracted from 141 SCZ, 103 MD and 238 HC. The gray level co-occurrence matrix (GLCM) was calculated on a voxel-by-voxel basis in a cube of voxels. Deep learning tested if texture feature map could predict diagnostic group membership of three classes under a binary classification (SCZ vs. HC, MD vs. HC, SCZ vs. MD). The method was applied in a repeated nested cross-validation scheme and cross-validated feature selection. The regions with the highest relevance (positive/negative) are presented. The method was applied on non-segmented images reducing the computation complexity and the error associated with segmentation process.

Classification of first-episode psychosis using cortical thickness: A large multicenter MRI study

Machine learning classifications of first-episode psychosis (FEP) using neuroimaging have predominantly analyzed brain volumes. Some studies examined cortical thickness, but most of them have used parcellation approaches with data from single sites, which limits claims of generalizability. To address these limitations, we conducted a large-scale, multi-site analysis of cortical thickness comparing parcellations and vertex-wise approaches. By leveraging the multi-site nature of the study, we further investigated how different demographical and site-dependent variables affected predictions. Finally, we assessed relationships between predictions and clinical variables. 428 subjects (147 females, mean age 27.14) with FEP and 448 (230 females, mean age 27.06) healthy controls were enrolled in 8 centers by the ClassiFEP group. All subjects underwent a structural MRI and were clinically assessed. Cortical thickness parcellation (68 areas) and full cortical maps (20,484 vertices) were extracted. Linear Support Vector Machine was used for classification within a repeated nested cross-validation framework. Vertex-wise thickness maps outperformed parcellation-based methods with a balanced accuracy of 66.2% and an Area Under the Curve of 72%. By stratifying our sample for MRI scanner, we increased generalizability across sites. Temporal brain areas resulted as the most influential in the classification. The predictive decision scores significantly correlated with age at onset, duration of treatment, and positive symptoms. In conclusion, although far from the threshold of clinical relevance, temporal cortical thickness proved to classify between FEP subjects and healthy individuals. The assessment of site-dependent variables permitted an increase in the across-site generalizability, thus attempting to address an important machine learning limitation.

Attentional salience and the neural substrates of response inhibition in borderline personality disorder

BACKGROUND

Impulsivity is a central symptom of borderline personality disorder (BPD) and its neural basis may be instantiated in a frontoparietal network involved in response inhibition. However, research has yet to determine whether neural activation differences in BPD associated with response inhibition are attributed to attentional saliency, which is subserved by a partially overlapping network of brain regions.

METHODS

Patients with BPD (n = 45) and 29 healthy controls (HCs; n = 29) underwent functional magnetic resonance imaging while completing a novel go/no-go task with infrequent odd-ball trials to control for attentional saliency. Contrasts reflecting a combination of response inhibition and attentional saliency (no-go > go), saliency processing alone (oddball > go), and response inhibition controlling for attentional saliency (no-go > oddball) were compared between BPD and HC.

RESULTS

Compared to HC, BPD showed less activation in the combined no-go > go contrast in the right posterior inferior and middle-frontal gyri, and less activation for oddball > go in left-hemispheric inferior frontal junction, frontal pole, superior parietal lobe, and supramarginal gyri. Crucially, BPD and HC showed no activation differences for the no-go > oddball contrast. In BPD, higher vlPFC activation for no-go > go was correlated with greater self-rated BPD symptoms, whereas lower vlPFC activation for oddball > go was associated with greater self-rated attentional impulsivity.

CONCLUSIONS

Patients with BPD show frontoparietal disruptions related to the combination of response inhibition and attentional saliency or saliency alone, but no specific response inhibition neural activation difference when attentional saliency is controlled. The findings suggest a neural dysfunction in BPD underlying attention to salient or infrequent stimuli, which is supported by a negative correlation with self-rated impulsiveness.

Long-term rates of remission and late psychotic transition of individuals at risk for psychosis

Introduction

In the growing research field of early psychosis detection in patients with an at risk mental state (ARMS), most studies focus on the transition to frank psychosis. However, the majority of ARMS patients do not go on to develop frank psychosis and reported transition rates are declining. Little is known about the long-term outcome of these non-transitioned patients (ARMS-NT).

Objectives

To investigate in preliminary analyses the long-term outcome of ARMS-NT patients with respect to persistence of ARMS signs and symptoms and the rates of late psychotic transition.

Methods

The ongoing study “FePsy-BHS-NT” follows up ARMS-NT without transition during at least the first two years for up to 15 years after their initial assessment. ARMS status is ascertained with the Basel Screening Instrument for Psychosis (BSIP). ARMS remission is defined as the absence of attenuated psychotic symptoms or brief limited intermittent psychotic symptoms for at least 12 consecutive months.

Results

In this preliminary sample of 51 ARMS-NT, the majority of patients (70.6%) have remitted from their at risk mental state, 13.7% remain at risk and 15.7% have made a late psychotic transition during the course of long-term follow up (median = 5.75, range 4–11 years after initial assessment).

Conclusions

The considerable rates of ARMS persistence and late psychotic transition indicate that longer follow-up durations than commonly recommended should be contemplated in ARMS patients. Potential predictors of favorable long-term clinical outcome, as well as psychosocial, neurocognitive and other outcomes of ARMS-NT patients will be further evaluated in the present study.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Acute LSD effects on response inhibition neural networks

BACKGROUND

Recent evidence shows that the serotonin 2A receptor (5-hydroxytryptamine2A receptor, 5-HT2AR) is critically involved in the formation of visual hallucinations and cognitive impairments in lysergic acid diethylamide (LSD)-induced states and neuropsychiatric diseases. However, the interaction between 5-HT2AR activation, cognitive impairments and visual hallucinations is still poorly understood. This study explored the effect of 5-HT2AR activation on response inhibition neural networks in healthy subjects by using LSD and further tested whether brain activation during response inhibition under LSD exposure was related to LSD-induced visual hallucinations.

METHODS

In a double-blind, randomized, placebo-controlled, cross-over study, LSD (100 µg) and placebo were administered to 18 healthy subjects. Response inhibition was assessed using a functional magnetic resonance imaging Go/No-Go task. LSD-induced visual hallucinations were measured using the 5 Dimensions of Altered States of Consciousness (5D-ASC) questionnaire.

RESULTS

Relative to placebo, LSD administration impaired inhibitory performance and reduced brain activation in the right middle temporal gyrus, superior/middle/inferior frontal gyrus and anterior cingulate cortex and in the left superior frontal and postcentral gyrus and cerebellum. Parahippocampal activation during response inhibition was differently related to inhibitory performance after placebo and LSD administration. Finally, activation in the left superior frontal gyrus under LSD exposure was negatively related to LSD-induced cognitive impairments and visual imagery.

CONCLUSION

Our findings show that 5-HT2AR activation by LSD leads to a hippocampal-prefrontal cortex-mediated breakdown of inhibitory processing, which might subsequently promote the formation of LSD-induced visual imageries. These findings help to better understand the neuropsychopharmacological mechanisms of visual hallucinations in LSD-induced states and neuropsychiatric disorders.

Long-term reduction of seclusion and forced medication on a hospital-wide level: Implementation of an open-door policy over 6 years

BACKGROUND

Psychiatric inpatient treatment is increasingly performed in settings with locked doors. However, locked wards have well-known disadvantages and are ethically problematic. In addition, recent data challenges the hypothesis that locked wards provide improved safety over open-door settings regarding suicide, absconding and aggression. Furthermore, there is evidence that the introduction of an open-door policy may lead to short-term reductions in involuntary measures. The aim of this study was to assess if the introduction of an open-door policy is associated with a long-term reduction of the frequency of seclusion and forced medication.

METHOD

In this 6-year, hospital-wide, longitudinal, observational study, we examined the frequency of seclusion and forced medication in 17,359 inpatient cases admitted to the Department of Adult Psychiatry, Universitäre Psychiatrische Kliniken (UPK) Basel, University of Basel, Switzerland. In an approach to enable a less restrictive policy, six previously closed psychiatric wards were permanently opened beginning from August 2011. During this process, a systematic change towards a more patient-centered and recovery-oriented care was applied. Statistical analysis consisted of generalized estimating equations (GEE) models.

RESULTS

In multivariate analyses controlling for potential confounders, the implementation of an open-door policy was associated with a continuous reduction of seclusion (from 8.2 to 3.5%; η_p²=0.82; odds ratio: 0.88) and forced medication (from 2.4 to 1.2%; η_p²=0.70; odds ratio: 0.90).

CONCLUSION

This underlines the potential of the introduction of an open-door policy to attain a long-term reduction in involuntary measures.

Increased thalamic resting-state connectivity as a core driver of LSD-induced hallucinations

OBJECTIVE

It has been proposed that the thalamocortical system is an important site of action of hallucinogenic drugs and an essential component of the neural correlates of consciousness. Hallucinogenic drugs such as LSD can be used to induce profoundly altered states of consciousness, and it is thus of interest to test the effects of these drugs on this system.

METHOD

100 μg LSD was administrated orally to 20 healthy participants prior to fMRI assessment. Whole brain thalamic functional connectivity was measured using ROI-to-ROI and ROI-to-voxel approaches. Correlation analyses were used to explore relationships between thalamic connectivity to regions involved in auditory and visual hallucinations and subjective ratings on auditory and visual drug effects.

RESULTS

LSD caused significant alterations in all dimensions of the 5D-ASC scale and significantly increased thalamic functional connectivity to various cortical regions. Furthermore, LSD-induced functional connectivity measures between the thalamus and the right fusiform gyrus and insula correlated significantly with subjective auditory and visual drug effects.

CONCLUSION

Hallucinogenic drug effects might be provoked by facilitations of cortical excitability via thalamocortical interactions. Our findings have implications for the understanding of the mechanism of action of hallucinogenic drugs and provide further insight into the role of the 5-HT_2A -receptor in altered states of consciousness.

Longitudinal alterations in motivational salience processing in ultra-high-risk subjects for psychosis

BACKGROUND

Impairments in the attribution of salience are thought to be fundamental to the development of psychotic symptoms and the onset of psychotic disorders. The aim of the present study was to explore longitudinal alterations in salience processing in ultra-high-risk subjects for psychosis.

METHOD

A total of 23 ultra-high-risk subjects and 13 healthy controls underwent functional magnetic resonance imaging at two time points (mean interval of 17 months) while performing the Salience Attribution Test to assess neural responses to task-relevant (adaptive salience) and task-irrelevant (aberrant salience) stimulus features.

RESULTS

At presentation, high-risk subjects were less likely than controls to attribute salience to relevant features, and more likely to attribute salience to irrelevant stimulus features. These behavioural differences were no longer evident at follow-up. When attributing salience to relevant cue features, ultra-high-risk subjects showed less activation than controls in the ventral striatum at both baseline and follow-up. Within the high-risk sample, amelioration of abnormal beliefs over the follow-up period was correlated with an increase in right ventral striatum activation during the attribution of salience to relevant cue features.

CONCLUSIONS

These findings confirm that salience processing is perturbed in ultra-high-risk subjects for psychosis, that this is linked to alterations in ventral striatum function, and that clinical outcomes are related to longitudinal changes in ventral striatum function during salience processing.

Impact of polygenic schizophrenia-related risk and hippocampal volumes on the onset of psychosis

Alterations in hippocampal volume are a known marker for first-episode psychosis (FEP) as well as for the clinical high-risk state. The Polygenic Schizophrenia-related Risk Score (PSRS), derived from a large case-control study, indicates the polygenic predisposition for schizophrenia in our clinical sample. A total of 65 at-risk mental state (ARMS) and FEP patients underwent structural magnetic resonance imaging. We used automatic segmentation of hippocampal volumes using the FSL-FIRST software and an odds-ratio-weighted PSRS based on the publicly available top single-nucleotide polymorphisms from the Psychiatric Genomics Consortium genome-wide association study (GWAS). We observed a negative association between the PSRS and hippocampal volumes (β=-0.42, P=0.01, 95% confidence interval (CI)=(-0.72 to -0.12)) across FEP and ARMS patients. Moreover, a higher PSRS was significantly associated with a higher probability of an individual being assigned to the FEP group relative to the ARMS group (β=0.64, P=0.03, 95% CI=(0.08-1.29)). These findings provide evidence that a subset of schizophrenia risk variants is negatively associated with hippocampal volumes, and higher values of this PSRS are significantly associated with FEP compared with the ARMS. This implies that FEP patients have a higher genetic risk for schizophrenia than the total cohort of ARMS patients. The identification of associations between genetic risk variants and structural brain alterations will increase our understanding of the neurobiology underlying the transition to psychosis.

Effects of cortisol administration on craving in heroin addicts

Heroin dependence is a severe and chronically relapsing substance use disorder with limited treatment options. Stress is known to increase craving and drug-taking behavior, but it is not known whether the stress hormone cortisol mediates these stress effects or whether cortisol may rather reduce craving, for example, by interfering with addiction memory. The aim of the present study was to determine the effects of cortisol administration on craving in heroin-dependent patients and to determine whether the effects depend on the daily dose of heroin consumption. We used a double-blind, placebo-controlled, cross-over study in 29 heroin-dependent patients in a stable heroin-assisted treatment setting. A single oral dose of 20 mg of cortisol or placebo was administered 105 min before the daily heroin administration. The primary outcome measure was cortisol-induced change in craving. Secondary measures included anxiety, anger and withdrawal symptoms. For the visual analog scale for craving, we found a significant interaction (P = 0.0027) between study medication and heroin-dose group (that is, daily low, medium or high dose of heroin). Cortisol administration reduced craving in patients receiving a low dose of heroin (before heroin administration: P = 0.0019; after heroin administration: P = 0.0074), but not in patients receiving a medium or high dose of heroin. In a picture-rating task with drug-related pictures, cortisol administration did not affect the ratings for the picture-characteristic craving in all the three heroin-dose groups. Cortisol also did not significantly affect secondary outcome measures. In conclusion, a single administration of cortisol leads to reduced craving in low-dose heroin addicts. The present findings might have important clinical implications with regard to understanding stress effects and regarding treatment of addiction.

BDNF Val66Met polymorphism and hippocampal volume in neuropsychiatric disorders: A systematic review and meta-analysis

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a neurotrophin involved in neurogenesis and synaptic plasticity in the central nervous system, especially in the hippocampus, and has been implicated in the pathophysiology of several neuropsychiatric disorders. Its Val66Met polymorphism (refSNP Cluster Report: rs6265) is a functionally relevant single nucleotide polymorphism affecting the secretion of BDNF and is implicated in differences in hippocampal volumes.

METHODS

This is a systematic meta-analytical review of findings from imaging genetic studies on the impact of the rs6265 SNP on hippocampal volumes in neuropsychiatric patients with major depressive disorder, anxiety, bipolar disorder or schizophrenia.

RESULTS

The overall sample size of 18 independent clinical cohorts comprised 1695 patients. Our results indicated no significant association of left (Hedge's g=0.08, p=0.12), right (g=0.07, p=0.22) or bilateral (g=0.07, p=0.16) hippocampal volumes with BDNF rs6265 in neuropsychiatric patients. There was no evidence for a publication bias or any demographic, clinical, or methodological moderating effects. Both Val/Val homozygotes (g=0.32, p=0.004) and Met-carriers (g=0.20, p=0.004) from the patient sample had significantly smaller hippocampal volumes than the healthy control sample with the same allele. The magnitude of these effects did not differ between the two genotypes.

CONCLUSION

This meta-analysis suggests that there is no association between this BDNF polymorphism and hippocampal volumes. For each BDNF genotype, the hippocampal volumes were significantly lower in neuropsychiatric patients than in healthy controls.

Neuroanatomical markers of genetic liability to psychosis and first episode psychosis: a voxelwise meta-analytical comparison

OBJECTIVES

To address at a meta-analytical level the neuroanatomical markers of genetic liability to psychosis and a of first episode of psychosis.

METHODS

Fifteen voxel-based morphometry (VBM) studies of antipsychotic-naive subjects at genetic high-risk (HR) for psychosis or with a first-episode psychosis (FEP) were included in a Signed Differential Mapping (SDM) meta-analysis. Publication bias was assessed with funnel plots and Egger's intercept. Heterogeneity was assessed with Q statistics and I (2) index.

RESULTS

The database comprised 458 HR and 206 antipsychotic-naïve FEP subjects, matched with controls. Gray matter (GM) reductions as compared to controls, were observed in the left parahippocampal gyrus and in the bilateral anterior cingulate gyrus in the HR group, and in the right superior temporal gyrus, in the left insula and in the left cerebellum in the FEP group. Further GM decreases were observed in the FEP group as compared to the HR group in the left anterior cingulate, in the right precuneus, in the left cerebellum and in the right superior temporal gyrus. Limitations. The cross-sectional nature of the included studies prevented the comparison of high risk subjects who later did or did not develop a psychotic episode. Other caveats are based on the methodological heterogeneity across individual imaging studies.

CONCLUSIONS

GM reductions in the anterior cingulate are markers of genetic liability to psychosis while reductions in the superior temporal gyrus and cerebellum can be interpreted as markers of a first onset of the illness.

The association of the BDNF Val66Met polymorphism and the hippocampal volumes in healthy humans: a joint meta-analysis of published and new data

BACKGROUND

The brain-derived neurotrophic factor (BDNF) Val66Met polymorphism (refSNP Cluster Report: rs6265) is a common and functionally relevant single nucleotide polymorphism (SNP). The gene itself, as well as the SNP rs6265, have been implicated in hippocampal learning and memory. However, imaging genetic studies have produced controversial results about the impact of this SNP on hippocampal volumes in healthy subjects.

METHODS

We examined the association between the rs6265 polymorphism and hippocampal volume in 643 healthy young subjects using automatic segmentation and subsequently included these data in a meta-analysis based on published studies with 5298 healthy subjects in total.

RESULTS

We found no significant association between SNP rs6265 and hippocampal volumes in our sample (g=0.05, p=0.58). The meta-analysis revealed a small, albeit significant difference in hippocampal volumes between genotype groups, such that Met-carriers had slightly smaller hippocampal volumes than Val/Val homozygotes (g=0.09, p=0.04), an association that was only evident when manual (g=0.22, p=0.01) but not automatic tracing approaches (g=0.04, p=0.38) were used. Studies using manual tracing showed evidence for publication bias and a significant decrease in effect size over the years with increasing sample sizes.

CONCLUSIONS

This study does not support the association between SNP rs6265 and hippocampal volume in healthy individuals. The weakly significant effect observed in the meta-analysis is mainly driven by studies with small sample sizes. In contrast, our original data and the meta-analysis of automatically segmented hippocampal volumes, which was based on studies with large samples sizes, revealed no significant genotype effect. Thus, meta-analyses of the association between rs6265 and hippocampal volumes should consider possible biases related to measuring technique and sample size.

Do subjects at clinical high risk for psychosis differ from those with a genetic high risk?--A systematic review of structural and functional brain abnormalities

Introduction:

Pre-psychotic and early psychotic characteristics are investigated in the high-risk (HR) populations for psychosis. There are two different approaches based either on hereditary factors (genetic high risk, G-HR) or on the clinically manifested symptoms (clinical high risk, C-HR). Common features are an increased risk for development of psychosis and similar cognitive as well as structural and functional brain abnormalities.

Methods:

We reviewed the existing literature on longitudinal structural, and on functional imaging studies, which included G-HR and/or C-HR individuals for psychosis, healthy controls (HC) and/or first episode of psychosis (FEP) or schizophrenia patients (SCZ).

Results:

With respect to structural brain abnormalities, vulnerability to psychosis was associated with deficits in frontal, temporal, and cingulate regions in HR, with additional insular and caudate deficits in C-HR population. Furthermore, C-HR had progressive prefrontal deficits related to the transition to psychosis.

With respect to functional brain abnormalities, vulnerability to psychosis was associated with prefrontal, cingulate and middle temporal abnormalities in HR, with additional parietal, superior temporal, and insular abnormalities in C-HR population. Transition-to-psychosis related differences emphasized prefrontal, hippocampal and striatal components, more often detectable in C-HR population.

Multimodal studies directly associated psychotic symptoms displayed in altered prefrontal and hippocampal activations with striatal dopamine and thalamic glutamate functions.

Conclusion:

There is an evidence for similar structural and functional brain abnormalities within the whole HR population, with more pronounced deficits in the C-HR population. The most consistent evidence for abnormality in the prefrontal cortex reported in structural, functional and multimodal studies of HR population may underlie the complexity of higher cognitive functions that are impaired during HR mental state for psychosis.

Volumetric changes in the basal ganglia after antipsychotic monotherapy: a systematic review

Introduction:

Exposure to antipsychotic medication has been extensively associated with structural brain changes in the basal ganglia (BG). Traditionally antipsychotics have been divided into first and second generation antipsychotics (FGAs and SGAs) however, the validity of this classification has become increasingly controversial. To address if specific antipsychotics induce differential effects on BG volumes or whether volumetric effects are explained by FGA or SGA classification, we reviewed longitudinal structural magnetic resonance imaging (MRI) studies investigating effects of antipsychotic monotherapy.

Material and Methods:

We systematically searched PubMed for longitudinal MRI studies of patients with schizophrenia or non-affective psychosis who had undergone a period of antipsychotic monotherapy. We used specific, predefined search terms and extracted studies were hand searched for additional studies.

Results:

We identified 13 studies published in the period from 1996 to 2011. Overall six compounds (two classified as FGAs and four as SGAs) have been investigated: haloperidol, zuclophentixol, risperidone, olanzapine, clozapine, and quetiapine. The follow-up period ranged from 3-24 months.

Unexpectedly, no studies found that specific FGAs induce significant BG volume increases. Conversely, both volumetric increases and decreases in the BG have been associated with SGA monotherapy.

Discussion:

Induction of striatal volume increases is not a specific feature of FGAs. Except for clozapine treatment in chronic patients, volume reductions are not restricted to specific SGAs.

The current review adds brain structural support to the notion that antipsychotics should no longer be classified as either FGAs or SGAs. Future clinical MRI studies should strive to elucidate effects of specific antipsychotic drugs.

Cannabis use and cognitive functions in at-risk mental state and first episode psychosis

BACKGROUND

Meta-analyses suggest that schizophrenia patients with a history of cannabis use have less impaired cognitive functioning compared to patients without cannabis use.

AIMS

The objective of this study was to assess the association between recency and frequency of cannabis use and cognitive functioning in at-risk mental state for psychosis (ARMS) and first episode psychosis (FEP) individuals.

METHODS

One hundred thirty-six participants completed a cognitive test battery and were assessed for current and past cannabis use. Analyses of covariance models were applied to evaluate the main effects of cannabis use and patient group (ARMS vs. FEP) as well as their interactions on cognitive functioning.

RESULTS

No differences were observed in cognitive performance between current, former, and never users, and there were no significant interactions between cannabis use and patient group. Furthermore, within the group of current cannabis users, the frequency of cannabis use was not significantly associated with cognitive functioning.

CONCLUSION

The results of the present study do not support the notion that FEP patients and ARMS individuals with a history of cannabis use have less impaired cognitive functioning compared to those without cannabis use.

Progressive brain changes in schizophrenia related to antipsychotic treatment? A meta-analysis of longitudinal MRI studies

Context

Antipsychotic treatment is the first-line treatment option for schizophrenia. Individual studies suggested they can significantly affect brain structure and account for progressive brain changes observed during the illness.

Objectives

To quantitatively examine the effect of antipsychotics as compared to illness related factors on progressive brain changes in schizophrenia.

Data sources

Electronic databases were searched until April 2012. All magnetic resonance imaging studies reporting progressive brain changes in schizophrenia subjects and antipsychotic exposure were retrieved.

Study selection

30 longitudinal MRI studies with antipsychotic administration in schizophrenia patients met the inclusion criteria.

Data extraction

Brain volumes before and after antipsychotic exposure, duration of illness, severity of psychotic symptoms as well as demographic, clinical, and methodological variables were extracted from each publication, or obtained directly from its authors.

Data synthesis

The overall sample was of 1046 schizophrenia patients and 780 controls for a median duration of follow-up of 72.4 weeks. At baseline, patients showed significant whole brain volume reductions and enlarged lateral ventricle (LV) volumes compared to controls. No baseline volumetric abnormalities were detected in the gray matter volumes (GMV), white matter volumes, cerebrospinal fluid and caudate nucleus. Longitudinally, there were progressive GMV decreases and LV enlargements in patients but not in controls. The GMV decreases were inversely correlated with cumulative exposure to antipsychotic treatments, while no effects were observed for duration of illness or illness severity.

Conclusions

Schizophrenia is characterized by progressive gray matter volume decreases and lateral ventricular volume increases. Some of these neuroanatomical alterations may be associated with antipsychotic treatment.

[Prediction of psychosis by stepwise multilevel assessment--the Basel FePsy (Early Recognition of Psychosis)-Project]

BACKGROUND

We have conducted various studies in Basel with the aim of improving the methods for the early detection of psychosis (Früherkennung von Psychosen, FePsy).

METHODS

From 1.3.2000 to 29.2.2004 234 individuals were screened using the Basel Screening Instrument for Psychosis (BSIP). 106 patients were identified as at risk for psychosis; out of these 53 remained in follow-up for up to 7 years (mean 5.4 years). The assessments were done with a specifically developed instrument for history taking, various scales for the psychopathology, assessments of neuropsychology and fine motor functioning, clinical and quantitative EEG, MRI of the brain, laboratory etc.

RESULTS

Based on the BSIP alone, a relatively reliable prediction was possible: 21 (39.6%) of the individuals identified as at risk developed psychosis within the follow-up time. Post-hoc prediction could be improved to 81% by weighting psychopathology and including neuropsychology. Including the other domains obviously allows further improvements of prediction.

CONCLUSIONS

The risk for psychosis should be assessed in a stepwise procedure. In a first step, a clinically oriented screening should be conducted. If an at-risk status is found, further assessments in various domains should be done in a specialised centre.

Acute effects of a single, oral dose of d9-tetrahydrocannabinol (THC) and cannabidiol (CBD) administration in healthy volunteers

RATIONALE

Animal and humans studies suggest that the two main constituents of cannabis sativa, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) have quite different acute effects. However, to date the two compounds have largely been studied separately.

OBJECTIVE

To evaluate and compare the acute pharmacological effects of both THC and CBD in the same human volunteers.

METHODS

A randomised, double-blind, cross-over, placebo controlled trial was conducted in 16 healthy male subjects. Oral THC 10 mg or CBD 600 mg or placebo was administered in three consecutive sessions, at one-month interval. Physiological measures and symptom ratings were assessed before, and at 1, 2 and 3 hours post drug administration. The area under the curve (AUC) between baseline and 3 hours, and the maximum absolute change from baseline at 2 hours were analysed by one-way repeated measures analysis of variance, with drug condition (THC or CBD or placebo) as the factor.

RESULTS

Relative to both placebo and CBD, administration of THC was associated with anxiety, dysphoria, positive psychotic symptoms, physical and mental sedation, subjective intoxication (AUC and effect at 2 hours: p < 0.01), an increase in heart rate (p < 0.05). There were no differences between CBD and placebo on any symptomatic, physiological variable.

CONCLUSIONS

In healthy volunteers, THC has marked acute behavioural and physiological effects, whereas CBD has proven to be safe and well tolerated.

Neuroimaging in cannabis use: a systematic review of the literature

BACKGROUND

We conducted a systematic review to assess the evidence for specific effects of cannabis on brain structure and function. The review focuses on the cognitive changes associated with acute and chronic use of the drug.

METHOD

We reviewed literature reporting neuroimaging studies of chronic or acute cannabis use published up until January 2009. The search was conducted using Medline, EMBASE, LILACS and PsycLIT indexing services using the following key words: cannabis, marijuana, delta-9-tetrahydrocannabinol, THC, cannabidiol, CBD, neuroimaging, brain imaging, computerized tomography, CT, magnetic resonance, MRI, single photon emission tomography, SPECT, functional magnetic resonance, fMRI, positron emission tomography, PET, diffusion tensor MRI, DTI-MRI, MRS and spectroscopy.

RESULTS

Sixty-six studies were identified, of which 41 met the inclusion criteria. Thirty-three were functional (SPECT/PET/fMRI) and eight structural (volumetric/DTI) imaging studies. The high degree of heterogeneity across studies precluded a meta-analysis. The functional studies suggest that resting global and prefrontal blood flow are lower in cannabis users than in controls. The results from the activation studies using a cognitive task are inconsistent because of the heterogeneity of the methods used. Studies of acute administration of THC or marijuana report increased resting activity and activation of the frontal and anterior cingulate cortex during cognitive tasks. Only three of the structural imaging studies found differences between users and controls.

CONCLUSIONS

Functional neuroimaging studies suggest a modulation of global and prefrontal metabolism both during the resting state and after the administration of THC/marijuana cigarettes. Minimal evidence of major effects of cannabis on brain structure has been reported.

Opposite Neural Effects of the Main Psychoactive Ingredients of Cannabis- Neural Basis for Potential Therapeutic Effects of Cannabidiol

There is considerable interest in the therapeutic potential of Cannabidiol (CBD), the second most abundant component of Cannabis. While delta-9-THC, the main psychoactive ingredient of cannabis, impairs memory and induces anxiety and psychotic symptoms acutely and increases the risk of psychotic disorders in regular cannabis users, CBD does not impair memory, may have anxiolytic and possibly antipsychotic effects. Hence, we compared directly the acute neural effects of these two active ingredients of cannabis, by combining pharmacological challenge with fMRI. Using a double-blind, repeated measures design and oral challenge with 10mg of delta-9-THC, 600mg of CBD or placebo in 15 healthy volunteers, we examined whether delta-9-THC and CBD have opposing effects on the neural substrates of verbal memory and fear processing and whether they also have opposing effects on the neural substrates of anxiety and psychotic symptoms induced by delta-9-THC. Delta-9-THC induced anxiety and psychotic symptoms acutely while there was a trend for a reduction in anxiety but no change in psychotic symptoms with CBD. During the memory task, delta-9-THC attenuated and CBD increased activation in the striatum bilaterally. Effect of delta-9-THC on striatal activation was inversely correlated with the psychotic symptoms induced by it concomitantly. During the processing of fearful faces, delta-9-THC increased and CBD attenuated activation in the amygdala and these effects correlated with their anxiogenic and anxiolytic effects respectively. These opposing effects of CBD on the key neural substrates for psychotic symptoms and anxiety induced by delta-9-THC may suggest its possible therapeutic role in countering these conditions.

Neurofunctional Effects of Cannabis on Response Inhibition

Background:

This study examined the effect of Delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) on brain activation during a motor inhibition task.

Methods:

Functional magnetic resonance imaging and behavioural measures were recorded while 15 healthy volunteers performed a Go/No-Go task following administration of either THC or CBD or placebo in a double-blind, pseudo-randomized, placebo-controlled repeated measures within-subject design.

Results:

Relative to placebo, THC attenuated activation in the right inferior frontal and the anterior cingulate gyrus. In contrast, CBD deactivated the left temporal cortex and insula. These effects were not related to changes in anxiety, intoxication, sedation, and psychotic symptoms.

Conclusions:

These data suggest that THC attenuates the engagement of brain regions that mediate response inhibition. CBD modulated function in regions not usually implicated in response inhibition.

[The Basel Screening Instrument for Psychosis (BSIP): development, structure, reliability and validity]

BACKGROUND

Early detection of psychosis is of growing clinical importance. So far there is, however, no screening instrument for detecting individuals with beginning psychosis in the atypical early stages of the disease with sufficient validity. We have therefore developed the Basel Screening Instrument for Psychosis (BSIP) and tested its feasibility, interrater-reliability and validity.

AIM

Aim of this paper is to describe the development and structure of the instrument, as well as to report the results of the studies on reliability and validity.

METHOD

The instrument was developed based on a comprehensive search of literature on the most important risk factors and early signs of schizophrenic psychoses. The interraterreliability study was conducted on 24 psychiatric cases. Validity was tested based on 206 individuals referred to our early detection clinic from 3/1/2000 until 2/28/2003.

RESULTS

We identified seven categories of relevance for early detection of psychosis and used them to construct a semistructured interview. Interrater-reliability for high risk individuals was high (Kappa .87). Predictive validity was comparable to other, more comprehensive instruments: 16 (32 %) of 50 individuals classified as being at risk for psychosis by the BSIP have in fact developed frank psychosis within an follow-up period of two to five years.

CONCLUSIONS

The BSIP is the first screening instrument for the early detection of psychosis which has been validated based on transition to psychosis. The BSIP is easy to use by experienced psychiatrists and has a very good interrater-reliability and predictive validity.

The Basel early-detection-of-psychosis (FEPSY)-study--design and preliminary results

Early detection and therapy of schizophrenic psychoses have become broadly accepted aims in psychiatry, recently even in very early stages of the disorder when clear diagnostic criteria are not yet fulfilled. However, reliable and widely applicable methods do not yet exist. This study aims at contributing to the improvement of the early assessment of psychosis.

METHOD

Individuals potentially at risk are identified by a newly developed stepwise screening procedure. Identified subjects are then examined extensively and followed-up for at least 5 years to detect actual transition to psychosis.

RESULTS

Of 50 subjects who have been followed up for 1-5 years by now, 16 have progressed to frank psychosis, 12 of them during the first 12 months of follow-up.

CONCLUSION

At this stage, our approach seems to be promising for the early detection of psychosis. Further results from this ongoing study will hopefully permit us to optimize the assessment procedure.

Early detection and treatment of schizophrenia: how early?

OBJECTIVE

Whereas early detection and therapy of schizophrenic psychoses until some time ago concentrated on frank schizophrenia, during the last years some centres have also started to treat patients even before a clear diagnosis could be established. This paper attempts to discuss if and when this is justified in the light of recent research.

METHOD

Mini review of literature.

RESULTS

The rationale for early detection and treatment of schizophrenia is based on several observations: diagnosis and treatment of schizophrenia are often seriously delayed. Consequences of the disease are severe already in the early undiagnosed phase of the disorder and early treatment seems to improve the course of the disease. It can therefore be stated quite safely that patients should be treated as early as possible. However, the question of how early has not been sufficiently answered up to now.

CONCLUSION

We are at the moment in an ethical dilemma between either diagnosing and treating this disorder too late or too early. The only way and prerequisite for solving this dilemma is a more reliable identification of individuals at risk and the beginning disease process.

Chronisch subdurales H�matom bei einem Patienten mit Verdacht auf Prodromalstadium einer Schizophrenie

A patient showing "prodromal symptoms" of suspected psychosis was referred to our clinic specialized in early recognition of schizophrenia where an MRI brain scan showed a chronic subdural hemorrhage. Based on this case, it will be shown that organic brain disease, in addition to incipient schizophrenia, needs to be considered in patients with marked personality changes, social withdrawal, aggressiveness, and suspiciousness. Diagnosis of the first episode and prodromal stage of schizophrenia should include-apart from the case history as well as the psychopathological and physiological findings-certain obligatory medical examinations (EEG, cCT, or MRI) in order to identify possible organic causes and avoid misdiagnoses.

Neuropsychological and neurophysiological findings in individuals suspected to be at risk for schizophrenia: preliminary results from the Basel early detection of psychosis study - Früherkennung von Psychosen (FEPSY)

OBJECTIVE

Our study aims to establish a scientific basis for the very early detection of patients at risk for schizophrenia during the nonspecific prodromal phase of the disorder and to predict its outbreak.

METHOD

A multidomain approach is used. After screening, approved psychopathological, neurophysiological, neuropsychological and neuroradiological investigations are used to assess a sample of individuals suspected to be at risk for schizophrenia.

RESULTS

Neuropsychological and fine motor functioning tests as well as eye movement measurements showed statistically significant differences (P<0.01) between individuals suspected to be at risk for schizophrenia and healthy controls.

CONCLUSION

Individuals suspected to be at risk for schizophrenia show specific impairments in various investigations including neuropsychological and fine motor functioning tests as well as eye movement measurements. A set of methods sensitive to even subtle changes in normal functioning may prove useful in predicting the subsequent outbreak of schizophrenia.