40-Hz Auditory Steady-State Responses Characterize Circuit Dysfunctions and Predict Clinical Outcomes in Clinical High-Risk for Psychosis Participants: A Magnetoencephalography Study.

BACKGROUND: This study aimed to examine whether 40-Hz auditory steady-state responses (ASSRs) are impaired in participants at clinical high-risk for psychosis (CHR-P) and predict clinical outcomes. METHODS: Magnetoencephalography data were collected during a 40-Hz ASSR paradigm for a group of 116 CHR-P participants, 33 patients with first-episode psychosis (15 antipsychotic-naïve), a psychosis risk-negative group (n = 38), and 49 healthy control subjects. Analysis of group differences of 40-Hz intertrial phase coherence and 40-Hz amplitude focused on right Heschl's gyrus, superior temporal gyrus, hippocampus, and thalamus after establishing significant activations during 40-Hz ASSR stimulation. Linear regression and linear discriminant analyses were used to predict clinical outcomes in CHR-P participants, including transition to psychosis and persistence of attenuated psychotic symptoms (APSs). RESULTS: CHR-P participants and patients with first-episode psychosis were impaired in 40-Hz amplitude in the right thalamus and hippocampus. In addition, patients with first-episode psychosis were impaired in 40-Hz amplitude in the right Heschl's gyrus, and CHR-P participants in 40-Hz intertrial phase coherence in the right Heschl's gyrus. The 40-Hz ASSR deficits were pronounced in CHR-P participants who later transitioned to psychosis (n = 13) or showed persistent APSs (n = 34). Importantly, both APS persistence and transition to psychosis were predicted by 40-Hz ASSR impairments, with ASSR activity in the right hippocampus, superior temporal gyrus, and middle temporal gyrus correctly classifying 69.2% individuals with nonpersistent APSs and 73.5% individuals with persistent APSs (area under the curve = 0.842), and right thalamus 40-Hz activity correctly classifying 76.9% transitioned and 53.6% nontransitioned CHR-P participants (area under the curve = 0.695). CONCLUSIONS: Our data indicate that deficits in gamma-band entrainment in the primary auditory cortex and subcortical areas constitute a potential biomarker for predicting clinical outcomes in CHR-P participants.

The introduction of mindfulness groups to a psychiatric rehabilitation in-patient setting: a feasibility study.

BACKGROUND: Patients within psychiatric rehabilitation services have multiple, complex and enduring difficulties, and are frequently described as 'treatment resistant'. This group have diagnoses of major mental health conditions, most commonly schizophrenia, often alongside a history of complex trauma, co-morbid alcohol/ substance misuse, and cognitive impairment. There is no known effective medical treatment other than Clozapine in this patient group, however, there is preliminary evidence that mindfulness can help individuals with psychosis by improving their ability to cope with stressful internal experiences. This study aimed to determine if mindfulness practice groups are an acceptable therapeutic intervention in an in-patient rehabilitation setting. The study also aimed to monitor the well-being of those who participated. METHODS: Mindfulness practice groups were offered three times weekly on a 15-bedded rehabilitation ward in a psychiatric hospital over 5 months, and weekly in a second ward over an 18 month period. The sessions were delivered by Clinical Psychologists in accordance with adaptations for a psychosis population. Attendance data were gathered on both wards and additional measures of well-being were collected on one ward. Qualitative interviews were conducted with a sample of patients, group facilitators, and staff, to provide supplementary information about the acceptability of the intervention. RESULTS: In both wards around two thirds (65, 67%) of in-patients attended at least one group and smaller proportion (around a third) went on to attend regularly. There was no discernible impact on well-being using the Warwick-Edinburgh well-being scale. Qualitative interviews suggested a number of benefits to individuals attending as well as the potential for groups to enhance the therapeutic culture within wards. CONCLUSIONS: Clinical guidelines suggest that all patients with a diagnosis of psychosis should have access to psychological therapies, but delivering psychological therapy within an in-patient rehabilitation setting can be challenging. This preliminary feasibility study suggests that mindfulness practice groups are an acceptable intervention, and that further research to look at the effectiveness of mindfulness for symptoms of treatment-resistant psychosis is both possible and merited.

Animal-assisted therapy for schizophrenia and related disorders: A systematic review.

Animal-assisted therapy (AAT) is increasingly researched as a potential treatment for physical and mental illness, including schizophrenia. The aim of the current paper is to systematically review randomised controlled trials (RCTs) to assess the effectiveness of AAT for schizophrenia and related disorders. We searched PubMed, PsycINFO, CINAHL, EMBASE, The Cochrane Library, CAB Abstracts, and Web of Science for RCTs of AAT for schizophrenia and related disorders. Primary outcomes were mental state and behaviour, clinical global response, and quality of life and wellbeing. Studies were eligible if they were RCTs that had compared AAT, or other animal-assisted intervention, to any control group using any participants with a clinical diagnosis of schizophrenia (or related disorder), regardless of age, gender, setting, or severity and duration of illness. Seven studies were identified for the review. Meta-analysis was not possible due to heterogeneity of studies, including marked differences in outcome measures and interventions. Five out of seven studies included symptoms as an outcome measure, with one reporting improvements in negative symptoms and one study reporting improvements in positive and emotional symptoms. The remaining studies reported no significant effects of AAT. Three studies included quality of life as an outcome measure but did not find any significant effects. Two studies did, however, report improvements in various measures of self-view. The use of AAT for schizophrenia remains inconclusive and there is currently not enough evidence to draw any firm conclusions due to heterogeneity of studies, risk of bias, and small samples. Rigorous, large-scale RCTs are needed to assess the true impact of AAT on schizophrenia.

Acute ketamine dysregulates task-related gamma-band oscillations in thalamo-cortical circuits in schizophrenia.

Hypofunction of the N-methyl-d-aspartate receptor (NMDAR) has been implicated as a possible mechanism underlying cognitive deficits and aberrant neuronal dynamics in schizophrenia. To test this hypothesis, we first administered a sub-anaesthetic dose of S-ketamine (0.006 mg/kg/min) or saline in a single-blind crossover design in 14 participants while magnetoencephalographic data were recorded during a visual task. In addition, magnetoencephalographic data were obtained in a sample of unmedicated first-episode psychosis patients (n = 10) and in patients with chronic schizophrenia (n = 16) to allow for comparisons of neuronal dynamics in clinical populations versus NMDAR hypofunctioning. Magnetoencephalographic data were analysed at source-level in the 1-90 Hz frequency range in occipital and thalamic regions of interest. In addition, directed functional connectivity analysis was performed using Granger causality and feedback and feedforward activity was investigated using a directed asymmetry index. Psychopathology was assessed with the Positive and Negative Syndrome Scale. Acute ketamine administration in healthy volunteers led to similar effects on cognition and psychopathology as observed in first-episode and chronic schizophrenia patients. However, the effects of ketamine on high-frequency oscillations and their connectivity profile were not consistent with these observations. Ketamine increased amplitude and frequency of gamma-power (63-80 Hz) in occipital regions and upregulated low frequency (5-28 Hz) activity. Moreover, ketamine disrupted feedforward and feedback signalling at high and low frequencies leading to hypo- and hyper-connectivity in thalamo-cortical networks. In contrast, first-episode and chronic schizophrenia patients showed a different pattern of magnetoencephalographic activity, characterized by decreased task-induced high-gamma band oscillations and predominantly increased feedforward/feedback-mediated Granger causality connectivity. Accordingly, the current data have implications for theories of cognitive dysfunctions and circuit impairments in the disorder, suggesting that acute NMDAR hypofunction does not recreate alterations in neural oscillations during visual processing observed in schizophrenia.

Use of novel psychoactive substances by inpatients on general adult psychiatric wards.

OBJECTIVES: Non-illicit alternatives to controlled drugs, known as novel psychoactive substances (NPS), have recently risen to prominence. They are readily available, with uncertain pharmacology and no widely available assay. Given that psychiatric patients are at risk of comorbid substance abuse, we hypothesised that NPS use would be present in the psychiatric population, and sought to determine its prevalence and investigate the characteristics of those who use these drugs with a retrospective review of discharge letters. SETTING: General adult inpatient wards of a psychiatric hospital in a Scottish city. PARTICIPANTS: All adult inpatients (18-65) discharged from general psychiatric wards between 1 July 2014 and 31 December 2014. Of the 483 admissions identified, 46 were admissions for maintenance electroconvulsive therapy (ECT) and were excluded. Of the remaining 437 admissions, 49 discharge letters were unobtainable, leaving 388 admissions to analyse. PRIMARY OUTCOME MEASURE: The mention, or lack thereof, of NPS use in discharge letters was our planned primary outcome measure and was also the primary outcome measure we used in our analysis. RESULTS: NPS use was identified in 22.2% of admissions, contributing to psychiatric symptoms in 59.3%. In comparison to non-users, NPS users were younger (p<0.01), male and more likely to have a forensic history ((p<0.001) for both). The diagnosis of drug-induced psychosis was significantly more likely in NPS users (p<0.001, OR 18.7, 95% CI 8.1 to 43.0) and the diagnosis of depression was significantly less likely (p<0.005, OR 0.133, CI 0.031 to 0.558). Use of cannabis was significantly more likely in NPS users (p<0.001, OR 4.2, CI 2.5 to 7.1), as was substitute opiate prescribing (p<0.001, OR 3.7, CI 1.8 to 7.4). CONCLUSIONS: NPS use was prevalent among young, male psychiatric inpatients, in particular those with drug-induced psychosis and often occurred alongside illicit drug use.

The application of nonlinear Dynamic Causal Modelling for fMRI in subjects at high genetic risk of schizophrenia.

Nonlinear Dynamic Causal Modelling (DCM) for fMRI provides computational modelling of gating mechanisms at the neuronal population level. It allows for estimations of connection strengths with nonlinear modulation within task-dependent networks. This paper presents an application of nonlinear DCM in subjects at high familial risk of schizophrenia performing the Hayling Sentence Completion Task (HSCT). We analysed scans of 19 healthy controls and 46 subjects at high familial risk of schizophrenia, which included 26 high risk subjects without psychotic symptoms and 20 subjects with psychotic symptoms. The activity-dependent network consists of the intra parietal cortex (IPS), inferior frontal gyrus (IFG), middle temporal gyrus (MTG), anterior cingulate cortex (ACC) and the mediodorsal (MD) thalamus. The connections between the MD thalamus and the IFG were gated by the MD thalamus. We used DCM to investigate altered connection strength of these connections. Bayesian Model Selection (BMS) at the group and family level was used to compare the optimal bilinear and nonlinear models. Bayesian Model Averaging (BMA) was used to assess the connection strengths with the gating from the MD thalamus and the IFG. The nonlinear models provided the better explanation of the data. Furthermore, the BMA analysis showed significantly lower connection strength of the thalamocortical connection with nonlinear modulation from the MD thalamus in high risk subjects with psychotic symptoms and those who subsequently developed schizophrenia. These findings demonstrate that nonlinear DCM provides a method to investigate altered connectivity at the level of neural circuits. The reduced connection strength with thalamic gating may be a neurobiomarker implicated in the development of psychotic symptoms. This study suggests that nonlinear DCM could lead to new insights into functional and effective dysconnection at the network level in subjects at high familial risk.

Relationship between gyrification and functional connectivity of the prefrontal cortex in subjects at high genetic risk of schizophrenia.

Measures of cortical folding ('gyrification') and connectivity are both reported to be disrupted in schizophrenia. There are also reports that increases in prefrontal gyrification may be predictive of subsequent illness in individuals at familial risk of the disorder. Such measures therefore have important potential clinical relevance. The nature of the relationship between cortical morphology and underlying connectivity is however unclear. In the current study we sought to explore the relationship between measures of gyrification and functional connectivity in a cohort of individuals at high genetic risk for the disorder. The theoretical background is based on the hypothesis that increased gyrification index (GI) in the prefrontal cortex may reflect increased short range regional connectivity. The cohort comprised 68 young unaffected relatives of schizophrenia patients and 21 healthy controls. Cortical folding was assessed using an automated Gyrification Index method (A-GI). Participants performed the Hayling sentence completion paradigm in the scanner and measures of functional connectivity were assessed using a correlation based approach. In the high risk subjects significant positive associations were found between prefrontal GI and prefrontal lateral-medial connectivity, while a negative correlation was found between prefrontal GI and prefrontal-thalamic connectivity. These associations indicate that measures describing morphological features of the brain surface relate to measures of underlying functional connectivity in the high risk subjects. Correlations in high risk people were more pronounced than in control subjects. We suggest our previous finding of increased prefrontal gyrification may therefore relate to increased local short range prefrontal connectivity and reduced long range connectivity.

Impact of cannabis use on thalamic volume in people at familial high risk of schizophrenia.

BACKGROUND: No longitudinal study has yet examined the association between substance use and brain volume changes in a population at high risk of schizophrenia. AIMS: To examine the effects of cannabis on longitudinal thalamus and amygdala-hippocampal complex volumes within a population at high risk of schizophrenia. METHOD: Magnetic resonance imaging scans were obtained from individuals at high genetic risk of schizophrenia at the point of entry to the Edinburgh High-Risk Study (EHRS) and approximately 2 years later. Differential thalamic and amygdala-hippocampal complex volume change in high-risk individuals exposed (n = 25) and not exposed (n = 32) to cannabis in the intervening period was investigated using repeated-measures analysis of variance. RESULTS: Cannabis exposure was associated with bilateral thalamic volume loss. This effect was significant on the left (F = 4.47, P = 0.04) and highly significant on the right (F= 7.66, P= 0.008). These results remained significant when individuals using other illicit drugs were removed from the analysis. CONCLUSIONS: These are the first longitudinal data to demonstrate an association between thalamic volume loss and exposure to cannabis in currently unaffected people at familial high risk of developing schizophrenia. This observation may be important in understanding the link between cannabis exposure and the subsequent development of schizophrenia.

Correlations between fMRI activation and individual psychotic symptoms in un-medicated subjects at high genetic risk of schizophrenia.

BACKGROUND: It has been proposed that different types of psychopathology in schizophrenia may reflect distinguishable pathological processes. In the current study we aimed to address such associations in the absence of confounders such as medication and disease chronicity by examining specific relationships between fMRI activation and individual symptom severity scores in un-medicated subjects at high genetic risk of schizophrenia. METHODS: Associations were examined across two functional imaging paradigms: the Hayling sentence completion task, and an encoding/retrieval task, comprising encoding (at word classification) and retrieval (old word/new word judgement). Symptom severity was assessed using the positive and negative syndrome scale (PANSS). Items examined were hallucinations, delusions, and suspiciousness/persecution. RESULTS: Associations were seen in the anterior middle temporal gyrus in relation to hallucination scores during the sentence completion task, and in the medial temporal lobe in association with suspiciousness/persecution scores in the encoding/retrieval task. Cerebellar activation was associated with delusions and suspiciousness/persecution scores across both tasks with differing patterns of laterality. CONCLUSION: These results support a role for the lateral temporal cortex in hallucinations and medial temporal lobe in positive psychotic symptoms. They also highlight the potential role of the cerebellum in the formation of delusions. That the current results are seen in un-medicated high risk subjects indicates these associations are not specific to the established illness and are not related to medication effects.