Attenuated niacin-induced skin flush response in individuals with clinical high risk for psychosis

Background Im paired sesitwity of he soin Mlush response bo miacin is one of the most rpicated findngs in patents with schizoprenia Howewer.prior studies have usaly focused on postonset psychusis,and ll is knowm about the dinical high-risk(CHR)phase of niacin senstity in psychosis Aims To proftle and compare the miacin flush responsge among CHR individuals(converters and non-coverters)patients with frstepso schinophrenia(FES)and healty controls(HCs).Methods Sensivily 1o ftour concentralions (0.1-0001M)of aqueous methylnicotinate was tested in 105 CHR individuals,57 patients with FES and 52 HCs.CHR individuals were further grouped as converters and non converters according to the 2-year follow-up outcomes.Skin flush response scores were rated on a 4-point scale.Results Of the 105 CHR individuals,21 individuals were lost during the study,leaving 84 CHR individuals;16(19.0%)converted to full psychosis at 2 years of fllow-up.Flush response scores identifed in the CHR samples were characterised as modest degree levels,intermediate between those of HC individuals and patients with FES.The flush responses in the CHR group mimicked the responses observed in the FES group at higher concentrations(0.01 M,0.1 M)and longer time points(15 min,20min);however,these became comparable vith the responses in the HC group at the shorter time points and at lower concentr ations.The converters exhibited lower mean flush response scores than the non-converters.Conclusions Attenuated niacin-induced flushing emerged during the early phase of psychosis.New devices should be developed and verified for objective quantification of skin responses in the CHR population.

Abnormal neural oscillations in clinical high risk for psychosis:a magnetoencephalography method study

Background Neural oscillations directly reflect the rhythmic changes of brain activities during the resting state or while performing specific tasks.Abnormal neural oscillations have been discovered in patients with schizophrenia.However,there is limited evidence available on abnormal spontaneous neural oscillations in clinical high risk for psychosis(CHR-P).The brain signals recorded by the magnetoencephalography(MEG)technique are not to be disrupted by the skull and scalp.Methods In this study,we applied the MEG technique to record the resting-state neural activities in CHR-P.This was followed by a detailed MEG analysis method including three steps:(1)preprocessing,which was band-pass filtering based on the 0.5-60Hz frequency range,removal of 50Hz power frequency interference,and removal of electrocardiography(ECG)and electrooculography(EOG)artefacts by independent component analysis;(2)time-frequency analysis,a multitaper time-frequency transformation based on the Hanning window,and(3)source localisation.an exact low-resolution brain electromagnetic tomography.The method was verified by comparing aparticipant with CHR-P with a healthy control during the MEG recordings with an eyes-closed resting state.Results Experimental results show that the neural oscillations in CHR-P were significantly abnormal in the theta frequency band(4-7Hz)and the delta frequency band(1-3Hz).Also,relevant brain regions were located in the left occipital lobe and left temporo-occipital junction for the theta band and in the right dorsolateral prefrontal lobe and near orbitofrontal gyrus for the delta band.Conclusions Abnormal neural oscillations based on specific frequency bands and corresponding brain sources may become biomarkers for high-risk groups.Further work will validate these characteristics in CHR-P cohorts.

Relationships between selfreflectiveness and clinical symptoms in individuals during pre-morbid and early clinical stages of psychosis

Background Self-reflectiveness,one dimension of cognitive insight,plays a protective role in an individual’s mental state.Both high and low levels of self-reflectiveness have been reported in patients with schizophrenia and individuals at clinical high risk for the illness.Aims This study aimed to explore the relationship patterns between self-reflectiveness and clinical symptoms in individuals during the pre-morbid and early clinical stages of psychosis.Methods A total of 181 subjects,including individuals with attenuated positive symptoms(APS,n=122)and patients with first-episode psychosis(FEP,n=59),completed the Beck Cognitive Insight Scale and were evaluated using the Schedule of Assessment of Insight and Positive and Negative Syndrome Scale.All subjects were classified into three groups according to their level of selfreflectiveness:low level(LSR,n=59),medium level(MSR,n=67)and high level(HSR,n=55).Both linear and nonlinear relationships between self-reflectiveness and clinical symptoms were explored.Results More individuals with APS were classified into the MSR group,while more patients with FEP were classified into the LSR group.The LSR group demonstrated less awareness of illness than the MSR and HSR groups,more stereotyped thinking and poorer impulse control but less anxiety than the MSR group,and lower levels of blunted affect and guilt feelings than the HSR group.The MSR group demonstrated lower stereotyped thinking than the HSR group.Compared to the LSR group,the MSR group had increased selfreflectiveness,improved awareness of illness,decreased stereotyped thinking,and better impulse control,but increased feelings of guilt.The HSR group showed increased stereotyped thinking when compared to the MSR group,but the other variables did not change significantly between these two groups.Overall,self-reflectiveness demonstrated an approximately inverse S-shaped relationship with the awareness of illness,a U-shaped relationship with stereotyped thinking and poor impulse control,and an almost linear relationship with anxiety and guilt feelings.Conclusions Self-reflectiveness demonstrates complex relationships with clinical symptoms and fails to exert significant positive effects when reaching a certain high level.

Euphoric effect induced by zolpidem:a case study of magnetoencephalography

Initially,zolpidem,a non-benzodiazepine hypnotic agent,was considered to have fewer adverse reactions than traditional benzodiazepines.However,after zolpidem was approved for medical use,an increasing number of case reports have described abuse or dependence complications.We were especially interested in the cases of dependence that presented a paradoxical‘euphoric’effect of zolpidem.This article reports the case of a female zolpidem-dependent patient who presented with 6 years of daily use of 400-1400 mg of zolpidem.She reported subjective effects of euphoria,intense craving and the inability to stop drug ingestion.Her diagnoses were zolpidem dependence and a depressive episode induced by substance abuse.To explore the neural mechanisms of the euphoric effect caused by high-dose zolpidem,we performed repeated magnetoencephalography(MEG)recordings.Before undergoing detoxification,her MEG results indicated that cerebellar electrical signal activation increased when taking high zolpidem doses.However,the prefrontal and parietal lobes’electrical signal activity showed a tendency to recover to a normal state as the withdrawal time progressed to completion.This case suggests that the cerebellum plays a role in the euphoria induced by high zolpidem doses and provides clues for further research.