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1.
J Dual Diagn ; : 1-21, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31647377

RESUMO

Objective: This review discusses the relationship between cannabis use and psychotic, bipolar, depressive, and anxiety disorders, as well as suicide. It summarizes epidemiological evidence from cross-sectional and long-term prospective studies and considers possible etiological mechanisms. Methods: Systematic reviews and methodologically robust studies in the field (from inception to February 2019) were identified using a comprehensive search of Medline, PsychINFO, and Embase and summarized using a narrative synthesis. Results: Consistent evidence, both from observational and experimental studies, has confirmed the important role of cannabis use in the initiation and persistence of psychotic disorders. The size of the effect is related to the extent of cannabis use, with greater risk for early cannabis use and use of high-potency varieties and synthetic cannabinoids. Accumulating evidence suggests that frequent cannabis use also increases the risk for mania as well as for suicide. However, the effect on depression is less clear and findings on anxiety are contradictory with only a few methodologically robust studies. Furthermore, the relationship with common mental disorders may involve reverse causality, as depression and anxiety are reported to lead to greater cannabis consumption in some studies. Pathogenetic mechanisms focus on the effect of tetrahydrocannabinol (THC, the main psychoactive ingredient of cannabis) interacting with genetic predisposition and perhaps other environmental risk factors. Cannabidiol (CBD), the other important ingredient of traditional cannabis, ameliorates the psychotogenic effects of THC but is absent from the high-potency varieties that are increasingly available. Conclusions: The evidence that heavy use of high-THC/low-CBD types of cannabis increases the risk of psychosis is sufficiently strong to merit public health education. Evidence of similar but smaller effects in mania and suicide is growing, but is not convincing for depression and anxiety. There is much current interest in the possibility that CBD may be therapeutically useful.

2.
Psychol Med ; : 1-8, 2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31535606

RESUMO

BACKGROUND: Risk prediction algorithms have long been used in health research and practice (e.g. prediction of cardiovascular disease and diabetes). However, similar tools have not been developed for mental health. For example, for psychotic disorders, attempts to sum environmental risk are rare, unsystematic and dictated by available data. In light of this, we sought to develop a valid, easy to use measure of the aggregate environmental risk score (ERS) for psychotic disorders. METHODS: We reviewed the literature to identify well-replicated and validated environmental risk factors for psychosis that combine a significant effect and large-enough prevalence. Pooled estimates of relative risks were taken from the largest available meta-analyses. We devised a method of scoring the level of exposure to each risk factor to estimate ERS. Relative risks were rounded as, due to the heterogeneity of the original studies, risk effects are imprecisely measured. RESULTS: Six risk factors (ethnic minority status, urbanicity, high paternal age, obstetric complications, cannabis use and childhood adversity) were used to generate the ERS. A distribution for different levels of risk based on simulated data showed that most of the population would be at low/moderate risk with a small minority at increased environmental risk for psychosis. CONCLUSIONS: This is the first systematic approach to develop an aggregate measure of environmental risk for psychoses in asymptomatic individuals. This can be used as a continuous measure of liability to disease; mostly relevant to areas where the original studies took place. Its predictive ability will improve with the collection of additional, population-specific data.

3.
Curr Psychiatry Rep ; 21(10): 100, 2019 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-31522306

RESUMO

PURPOSE OF REVIEW: We review recent developments on risk factors in schizophrenia. RECENT FINDINGS: The way we think about schizophrenia today is profoundly different from the way this illness was seen in the twentieth century. We now know that the etiology of schizophrenia is multifactorial and reflects an interaction between genetic vulnerability and environmental contributors. Environmental risk factors such as pregnancy and birth complications, childhood trauma, migration, social isolation, urbanicity, and substance abuse, alone and in combination, acting at a number of levels over time, influence the individual's likelihood to develop the disorder. Environmental risk factors together with the identification of a polygenic risk score for schizophrenia, research on gene-environment interaction and environment-environment interaction have hugely increased our knowledge of the disorder.

4.
Psychol Med ; : 1-11, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31364523

RESUMO

BACKGROUND: To determine the baseline individual characteristics that predicted symptom recovery and functional recovery at 10-years following the first episode of psychosis. METHODS: AESOP-10 is a 10-year follow up of an epidemiological, naturalistic population-based cohort of individuals recruited at the time of their first episode of psychosis in two areas in the UK (South East London and Nottingham). Detailed information on demographic, clinical, and social factors was examined to identify which factors predicted symptom and functional remission and recovery over 10-year follow-up. The study included 557 individuals with a first episode psychosis. The main study outcomes were symptom recovery and functional recovery at 10-year follow-up. RESULTS: At 10 years, 46.2% (n = 140 of 303) of patients achieved symptom recovery and 40.9% (n = 117) achieved functional recovery. The strongest predictor of symptom recovery at 10 years was symptom remission at 12 weeks (adj OR 4.47; CI 2.60-7.67); followed by a diagnosis of depression with psychotic symptoms (adj OR 2.68; CI 1.02-7.05). Symptom remission at 12 weeks was also a strong predictor of functional recovery at 10 years (adj OR 2.75; CI 1.23-6.11), together with being from Nottingham study centre (adj OR 3.23; CI 1.25-8.30) and having a diagnosis of mania (adj OR 8.17; CI 1.61-41.42). CONCLUSIONS: Symptom remission at 12 weeks is an important predictor of both symptom and functional recovery at 10 years, with implications for illness management. The concepts of clinical and functional recovery overlap but should be considered separately.

5.
Schizophr Res ; 210: 81-88, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31272907

RESUMO

AIMS: Cognitive impairment is a possible indicator of neurodevelopmental impairment, but not all psychotic patients are cognitively compromised. It has been suggested that heavy cannabis use may precipitate psychosis in those who show no such compromise. This study compares two samples of patients with first-episode psychosis and their respective non-psychotic controls, in London (UK) and Palermo (Italy), and examines whether different patterns of cannabis use are reflected in differences in IQ. METHODS: The two studies used the same inclusion/exclusion criteria and instruments. The sample comprised 249 subjects from London (106 patients and 143 controls) and 247 subjects from Palermo (120 patients and 127 controls). ANCOVA was performed with IQ as the dependent variable and city and frequency of cannabis use as predictors. This was then repeated with the case group only, by adjusting for relevant confounders. RESULTS: We found a greater amount of cannabis use in the London sample, compared to Palermo and patients from London had higher IQ than patients from Palermo, a difference that was more significant than that reflected between controls (Fgroup*city(1, 402) = 7.6, p = 0.006). Once corrected for symptomatology and treatment, patients from London who had never used cannabis were similar to patients from Palermo regarding IQ. Thus the higher IQ of patients from London was mainly due to the subgroup of cannabis-using patients (Fcannabis*city(2,145) = 4.6, p = 0.011). CONCLUSIONS: We can speculate that a greater amount of cannabis-use may have contributed by precipitating psychosis in patients with a higher IQ in London but less so in patients from Palermo.

6.
Br J Psychiatry ; : 1-8, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31347480

RESUMO

BACKGROUND: The first episode of psychosis is a critical period in the emergence of cardiometabolic risk.AimsWe set out to explore the influence of individual and lifestyle factors on cardiometabolic outcomes in early psychosis. METHOD: This was a prospective cohort study of 293 UK adults presenting with first-episode psychosis investigating the influence of sociodemographics, lifestyle (physical activity, sedentary behaviour, nutrition, smoking, alcohol, substance use) and medication on cardiometabolic outcomes over the following 12 months. RESULTS: Rates of obesity and glucose dysregulation rose from 17.8% and 12%, respectively, at baseline to 23.7% and 23.7% at 1 year. Little change was seen over time in the 76.8% tobacco smoking rate or the quarter who were sedentary for over 10 h daily. We found no association between lifestyle at baseline or type of antipsychotic medication prescribed with either baseline or 1-year cardiometabolic outcomes. Median haemoglobin A1c (HbA1c) rose by 3.3 mmol/mol in participants from Black and minority ethnic (BME) groups, with little change observed in their White counterparts. At 12 months, one-third of those with BME heritage exceeded the threshold for prediabetes (HbA1c >39 mmol/mol). CONCLUSIONS: Unhealthy lifestyle choices are prevalent in early psychosis and cardiometabolic risk worsens over the next year, creating an important window for prevention. We found no evidence, however, that preventative strategies should be preferentially directed based on lifestyle habits. Further work is needed to determine whether clinical strategies should allow for differential patterns of emergence of cardiometabolic risk in people of different ethnicities.Declaration of interestF.G. has received honoraria for advisory work and lectures or CME activity support from Roche, BMS, Lundbeck, Otsuka, Janssen and Sunovion, is a collaborator on an NHS Innovations project co-funded by Janssen and has a family member with professional links to Lilly and GSK, including shares. R.M.M. has received honoraria for lectures from Lundbeck, Otsuka, Janssen and Sunovian. M.D.F. has received honoraria for lectures from Janssen and Sunovian. Z.A. has received honoraria for advisory work and lectures from Roche, Sanofi, Lilly and Otsuka. O.H. has received investigator-initiated research funding from and/or participated in advisory/speaker meetings organised by Astra-Zeneca, Autifony, Biogen, BMS, Eli Lilly, Heptares, Jansenn, Lundbeck, Lyden-Delta, Otsuka, Servier, Sunovion, Rand and Roche. D.T. has received funding for lectures and research from Janssen, Otsuka, Servier, Lundbeck, Sunovion.

7.
Schizophr Bull ; 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31361020

RESUMO

Psychotic patients with a lifetime history of cannabis use generally show better cognitive functioning than other psychotic patients. Some authors suggest that cannabis-using patients may have been less cognitively impaired and less socially withdrawn in their premorbid life. Using a dataset comprising 948 patients with first-episode psychosis (FEP) and 1313 population controls across 6 countries, we examined the extent to which IQ and both early academic (Academic Factor [AF]) and social adjustment (Social Factor [SF]) are related to the lifetime frequency of cannabis use in both patients and controls. We expected a higher IQ and a better premorbid social adjustment in psychotic patients who had ever used cannabis compared to patients without any history of use. We did not expect such differences in controls. In both patients and controls, IQ was 3 points higher among occasional-users than in never-users (mean difference [Mdiff] = 2.9, 95% CI = [1.2, 4.7]). Both cases and control daily-users had lower AF compared to occasional (Mdiff = -0.3, 95% CI = [-0.5; -0.2]) and never-users (Mdiff = -0.4, 95% CI = [-0.6; -0.2]). Finally, patient occasional (Mdiff = 0.3, 95% CI = [0.1; 0.5]) and daily-users (Mdiff = 0.4, 95% CI = [0.2; 0.6]) had better SF than their never-using counterparts. This difference was not present in controls (Fgroup*frequency(2, 2205) = 4.995, P = .007). Our findings suggest that the better premorbid social functioning of FEP with a history of cannabis use may have contributed to their likelihood to begin using cannabis, exposing them to its reported risk-increasing effects for Psychotic Disorders.

8.
Am J Psychiatry ; 176(10): 811-819, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31256609

RESUMO

OBJECTIVE: Schizophrenia is associated with a marked cognitive impairment that is widely believed to remain stable after illness onset. Yet, to date, 10-year prospective studies of cognitive functioning following the first episode with good methodology are rare. The authors examined whether schizophrenia patients experience cognitive decline after the first episode, whether this decline is generalized or confined to individual neuropsychological functions, and whether decline is specific to schizophrenia. METHODS: Participants were from a population-based case-control study of patients with first-episode psychosis who were followed prospectively up to 10 years after first admission. A neuropsychological battery was administered at index presentation and at follow-up to patients with a diagnosis of schizophrenia (N=65) or other psychoses (N=41) as well as to healthy comparison subjects (N=103). RESULTS: The schizophrenia group exhibited declines in IQ and in measures of verbal knowledge and of memory, but not processing speed or executive functions. Processing speed and executive function impairments were already present at the first episode and remained stable thereafter. The magnitude of declines ranged between 0.28 and 0.66 standard deviations. Decline in measures of memory was not specific to schizophrenia and was also apparent in the group of patients with other psychoses. Healthy individuals with low IQ showed no evidence of decline, suggesting that a decline is specific to psychosis. CONCLUSIONS: Patients with schizophrenia and other psychoses experience cognitive decline after illness onset, but the magnitude of decline varies across cognitive functions. Distinct mechanisms consequent to the illness and/or psychosocial factors may underlie impairments across different cognitive functions.

11.
Schizophr Bull ; 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31206164

RESUMO

BACKGROUND: Cognitive impairment is a clinically important feature of schizophrenia. Polygenic risk score (PRS) methods have demonstrated genetic overlap between schizophrenia, bipolar disorder (BD), major depressive disorder (MDD), educational attainment (EA), and IQ, but very few studies have examined associations between these PRS and cognitive phenotypes within schizophrenia cases. METHODS: We combined genetic and cognitive data in 3034 schizophrenia cases from 11 samples using the general intelligence factor g as the primary measure of cognition. We used linear regression to examine the association between cognition and PRS for EA, IQ, schizophrenia, BD, and MDD. The results were then meta-analyzed across all samples. A genome-wide association studies (GWAS) of cognition was conducted in schizophrenia cases. RESULTS: PRS for both population IQ (P = 4.39 × 10-28) and EA (P = 1.27 × 10-26) were positively correlated with cognition in those with schizophrenia. In contrast, there was no association between cognition in schizophrenia cases and PRS for schizophrenia (P = .39), BD (P = .51), or MDD (P = .49). No individual variant approached genome-wide significance in the GWAS. CONCLUSIONS: Cognition in schizophrenia cases is more strongly associated with PRS that index cognitive traits in the general population than PRS for neuropsychiatric disorders. This suggests the mechanisms of cognitive variation within schizophrenia are at least partly independent from those that predispose to schizophrenia diagnosis itself. Our findings indicate that this cognitive variation arises at least in part due to genetic factors shared with cognitive performance in populations and is not solely due to illness or treatment-related factors, although our findings are consistent with important contributions from these factors.

12.
PLoS One ; 14(6): e0218478, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31188887

RESUMO

[This corrects the article DOI: 10.1371/journal.pone.0093955.].

14.
Schizophr Res ; 209: 88-97, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31113746

RESUMO

BACKGROUND: Psychosis is a condition influenced by an interaction of environmental and genetic factors. Gene expression studies can capture these interactions; however, studies are usually performed in patients who are in remission. This study uses blood of first episode psychosis patients, in order to characterise deregulated pathways associated with psychosis symptom dimensions. METHODS: Peripheral blood from 149 healthy controls and 131 first episode psychosis patients was profiled using Illumina HT-12 microarrays. A case/control differential expression analysis was performed, followed by correlation of gene expression with positive and negative syndrome scale (PANSS) scores. Enrichment analyses were performed on the associated gene lists. We test for pathway differences between first episode psychosis patients who qualify for a Schizophrenia diagnosis against those who do not. RESULTS: A total of 978 genes were differentially expressed and enriched for pathways associated to immune function and the mitochondria. Using PANSS scores we found that positive symptom severity was correlated with immune function, while negative symptoms correlated with mitochondrial pathways. CONCLUSIONS: Our results identified gene expression changes correlated with symptom severity and showed that key pathways are modulated by positive and negative symptom dimensions.

15.
Biol Psychiatry ; 86(2): 120-130, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31097295

RESUMO

BACKGROUND: The 5'-nucleotidase, cytosolic II gene (NT5C2, cN-II) is associated with disorders characterized by psychiatric and psychomotor disturbances. Common psychiatric risk alleles at the NT5C2 locus reduce expression of this gene in the fetal and adult brain, but downstream biological risk mechanisms remain elusive. METHODS: Distribution of the NT5C2 protein in the human dorsolateral prefrontal cortex and cortical human neural progenitor cells (hNPCs) was determined using immunostaining, publicly available expression data, and reverse transcriptase quantitative polymerase chain reaction. Phosphorylation quantification of adenosine monophosphate-activated protein kinase (AMPK) alpha (Thr172) and ribosomal protein S6 (Ser235/Ser236) was performed using Western blotting to infer the degree of activation of AMPK signaling and the rate of protein translation. Knockdowns were induced in hNPCs and Drosophila melanogaster using RNA interference. Transcriptomic profiling of hNPCs was performed using microarrays, and motility behavior was assessed in flies using the climbing assay. RESULTS: Expression of NT5C2 was higher during neurodevelopment and was neuronally enriched in the adult human cortex. Knockdown in hNPCs affected AMPK signaling, a major nutrient-sensing mechanism involved in energy homeostasis, and protein translation. Transcriptional changes implicated in protein translation were observed in knockdown hNPCs, and expression changes to genes related to AMPK signaling and protein translation were confirmed using reverse transcriptase quantitative polymerase chain reaction. The knockdown in Drosophila was associated with drastic climbing impairment. CONCLUSIONS: We provide an extensive neurobiological characterization of the psychiatric risk gene NT5C2, describing its previously unknown role in the regulation of AMPK signaling and protein translation in neural stem cells and its association with Drosophila melanogaster motility behavior.

16.
Asian J Psychiatr ; 43: 125-131, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31132542

RESUMO

AIM: People with psychotic disorders have increased premature mortality in comparison with the general population, with high rates of cigarette use a contributing factor. We aimed to describe the prevalence of cigarette use and nicotine dependence (ND) in first episode psychosis (FEP), and established psychosis; and to investigate associations between clinical symptoms and ND. METHODOLOGY: Smoking and clinical data were collected from two cohorts: 181 people with FEP recruited as part of the Physical Health and Substance Use Measures in First Onset Psychosis (PUMP) study and from 432 people with established psychosis recruited as part of the Improving physical health and reducing substance use in psychosis randomised controlled trial (IMPaCT RCT). RESULTS: The prevalence of cigarette smoking was 78% in FEP and 62% in established psychosis. Forty nine percent (n = 60) of smokers in the FEP cohort and 69% (n = 183) of smokers with established psychosis were highly nicotine dependent. Being a highly nicotine dependent smoker was significantly associated with higher PANSS positive symptom scores (F = 5.480 p = 0.004), and with decreased scores on the Rosenberg self-esteem scale (F = 3.261, p = 0.039) in established psychosis. There was no diagnostic specificity identified in relation to smoking or ND in both groups. CONCLUSION: High rates of cigarette usage and nicotine dependence are problems from the early stages of psychosis. ND is higher in people with established psychosis. Smoking cessation strategies as part of comprehensive management of psychotic disorders at every stage require further development and evaluation.

17.
Psychol Med ; : 1-11, 2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31057129

RESUMO

BACKGROUND: Reducing hospitalisation and length of stay (LOS) in hospital following first episode psychosis (FEP) is important, yet reliable measures of these outcomes and their moderators are lacking. We conducted a systematic review and meta-analysis to investigate the proportion of FEP cases who were hospitalised after their first contact with services and the LOS in a hospital during follow-up. METHODS: Studies were identified from a systematic search across major electronic databases from inception to October 2017. Random effects meta-analyses and meta-regression analyses were conducted. RESULTS: 81 longitudinal studies encompassing data for 23 280 FEP patients with an average follow-up length of 7 years were included. 55% (95% CI 50.3-60.5%) of FEP cases were hospitalised at least once during follow-up with the pooled average LOS of 116.7 days (95% CI 95.1-138.3). Older age of illness onset and being in a stable relationship were associated with a lower proportion of people who were hospitalised. While the proportion of hospitalised patients has not decreased over time, LOS has, with the sharpest reduction in the latest time period. The proportion of patients hospitalised during follow-up was highest in Australia and New Zealand (78.4%) compared to Europe (58.1%) and North America (48.0%); and lowest in Asia (32.5%). Black ethnicity and longer duration of untreated psychosis were associated with longer LOS; while less severe psychotic symptoms at baseline were associated with shorter LOS. CONCLUSION: One in two FEP cases required hospitalisation at least once during a 7-year follow-up with an average length of hospitalisation of 4 months during this period. LOS has declined over time, particularly in those countries in which it was previously longest.

18.
eNeuro ; 6(2)2019.
Artigo em Inglês | MEDLINE | ID: mdl-31001576

RESUMO

Language difficulties have been reported in children and adolescents who were born very preterm (<32 weeks' gestation) and associated with an atypical lateralization of language processing, i.e., increased right-hemispheric engagement. This study used functional magnetic resonance imaging (fMRI) and spherical deconvolution tractography to study the hemodynamic responses associated with verbal fluency processing (easy and hard letter trials) and verbal fluency-related white matter fiber tracts in 64 very preterm born adults and 36 adult controls (mean age: 30 years). Tractography of the arcuate fasciculus (AF) and frontal aslant tract (FAT) was performed. Tracts were quantified in terms of mean volume, hindrance modulated orientational anisotropy, and lateralization, assessed using a laterality index (LI) to indicate hemispheric dominance. During verbal fluency fMRI, very preterm participants displayed decreased hemodynamic response suppression in both the Easy > Rest and Hard > Rest conditions, compared to controls, in superior temporal gyrus (STG), insula, thalamus, and sensorimotor cortex, particularly in the right hemisphere. At the whole-group level, decreased hemodynamic response suppression in the right sensorimotor cortex was associated with worse on-line performance on the hard letter trials. Increased left-laterality in the AF was present alongside increased right hemispheric hemodynamic response suppression in controls. When only right-handed participants were considered, decreased hemodynamic response suppression in the right STG during hard letter trials was related to weaker left and right FAT white matter integrity in the preterm group only. These results show that verbal fluency is affected by altered functional lateralization in adults who were born very preterm.

19.
Lancet Psychiatry ; 6(5): 427-436, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30902669

RESUMO

BACKGROUND: Cannabis use is associated with increased risk of later psychotic disorder but whether it affects incidence of the disorder remains unclear. We aimed to identify patterns of cannabis use with the strongest effect on odds of psychotic disorder across Europe and explore whether differences in such patterns contribute to variations in the incidence rates of psychotic disorder. METHODS: We included patients aged 18-64 years who presented to psychiatric services in 11 sites across Europe and Brazil with first-episode psychosis and recruited controls representative of the local populations. We applied adjusted logistic regression models to the data to estimate which patterns of cannabis use carried the highest odds for psychotic disorder. Using Europe-wide and national data on the expected concentration of Δ9-tetrahydrocannabinol (THC) in the different types of cannabis available across the sites, we divided the types of cannabis used by participants into two categories: low potency (THC <10%) and high potency (THC ≥10%). Assuming causality, we calculated the population attributable fractions (PAFs) for the patterns of cannabis use associated with the highest odds of psychosis and the correlation between such patterns and the incidence rates for psychotic disorder across the study sites. FINDINGS: Between May 1, 2010, and April 1, 2015, we obtained data from 901 patients with first-episode psychosis across 11 sites and 1237 population controls from those same sites. Daily cannabis use was associated with increased odds of psychotic disorder compared with never users (adjusted odds ratio [OR] 3·2, 95% CI 2·2-4·1), increasing to nearly five-times increased odds for daily use of high-potency types of cannabis (4·8, 2·5-6·3). The PAFs calculated indicated that if high-potency cannabis were no longer available, 12·2% (95% CI 3·0-16·1) of cases of first-episode psychosis could be prevented across the 11 sites, rising to 30·3% (15·2-40·0) in London and 50·3% (27·4-66·0) in Amsterdam. The adjusted incident rates for psychotic disorder were positively correlated with the prevalence in controls across the 11 sites of use of high-potency cannabis (r = 0·7; p=0·0286) and daily use (r = 0·8; p=0·0109). INTERPRETATION: Differences in frequency of daily cannabis use and in use of high-potency cannabis contributed to the striking variation in the incidence of psychotic disorder across the 11 studied sites. Given the increasing availability of high-potency cannabis, this has important implications for public health. FUNDING SOURCE: Medical Research Council, the European Community's Seventh Framework Program grant, São Paulo Research Foundation, National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) at South London and Maudsley NHS Foundation Trust and King's College London and the NIHR BRC at University College London, Wellcome Trust.


Assuntos
Abuso de Maconha/epidemiologia , Transtornos Psicóticos/epidemiologia , Adulto , Brasil/epidemiologia , Estudos de Casos e Controles , Europa (Continente)/epidemiologia , Feminino , Humanos , Incidência , Masculino , Abuso de Maconha/complicações , Pessoa de Meia-Idade , Razão de Chances , Transtornos Psicóticos/etiologia , Adulto Jovem
20.
Schizophr Bull ; 2019 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-30809667

RESUMO

Despite the high level of interest in the use of machine learning (ML) and neuroimaging to detect psychosis at the individual level, the reliability of the findings is unclear due to potential methodological issues that may have inflated the existing literature. This study aimed to elucidate the extent to which the application of ML to neuroanatomical data allows detection of first episode psychosis (FEP), while putting in place methodological precautions to avoid overoptimistic results. We tested both traditional ML and an emerging approach known as deep learning (DL) using 3 feature sets of interest: (1) surface-based regional volumes and cortical thickness, (2) voxel-based gray matter volume (GMV) and (3) voxel-based cortical thickness (VBCT). To assess the reliability of the findings, we repeated all analyses in 5 independent datasets, totaling 956 participants (514 FEP and 444 within-site matched controls). The performance was assessed via nested cross-validation (CV) and cross-site CV. Accuracies ranged from 50% to 70% for surfaced-based features; from 50% to 63% for GMV; and from 51% to 68% for VBCT. The best accuracies (70%) were achieved when DL was applied to surface-based features; however, these models generalized poorly to other sites. Findings from this study suggest that, when methodological precautions are adopted to avoid overoptimistic results, detection of individuals in the early stages of psychosis is more challenging than originally thought. In light of this, we argue that the current evidence for the diagnostic value of ML and structural neuroimaging should be reconsidered toward a more cautious interpretation.

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