Substance use in adolescence and psychosis: clarifying the relationship

Investigation of the prevalence and factors influencing tobacco and alcohol use among adolescents in Nigeria: A systematic literature review

The increase in tobacco and alcohol prevalence among Nigerian teenagers necessitates the need to understand the factors influencing use. The aim of this systematic literature review was to synthesis evidence from studies on tobacco and alcohol use among Nigerian adolescents and young adults in order to determine factors influencing tobacco and alcohol use. Six databases MEDLINE, Embase, CINAHL, PsycINFO, PubMed, ScienceDirect, and Google Scholar were used to search for peer-reviewed articles reporting the prevalence and predictors of tobacco and alcohol use among adolescents/youths published between 2010 and 2022. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guided this review. From our search, twelve articles from the 6 geopolitical zones within Nigeria were included. The high prevalence of tobacco and alcohol use among Nigerian adolescents necessitates the need to understand the factors influencing use. A high prevalence rate was recorded among the male gender. Gender, age, and curiosity appear to place adolescents at extra risk for tobacco and alcohol use. Lack of parental monitoring, peer influence, low socio-economic status, low education level, stressful life events, advertisements, availability, and accessibility are factors identified to influence adolescents' alcohol and tobacco use. Alcohol and tobacco use remains a major public health issue as it continues to contribute largely to the growing occurence of diseases globally. Our review showed that adolescents' alcohol and tobacco use behaviour is triggered by various factors on the personal, interpersonal, organisational, community, and policy levels, and these factors are understood to predict or protect against alcohol and tobacco use.

Prevalence and hospital resource usage associated with substance use disorder among hospitalized adolescents in the United States

We sought to determine common characteristics of SUD-related hospitalizations and patterns of discharge diagnoses among adolescents in the United States. Using the 2016 KID, a cross-sectional study was conducted to identify discharge records associated with ICD-10-CM diagnostic codes for SUD. Adolescents between the ages of 13 and 19 were included. SUD and non-SUD groups were compared using the Student's t-test for continuous variables and the χ2 test for categorical variables. A total of 6.7 million hospital discharges were analyzed. A uniform and a standardized coding system were used to identify cases. Subgroup comparative analysis for length of stay, hospital charge, and common discharge diagnoses was performed. A weighted estimate of 94,732 adolescents associated with SUD was discharged from the U.S. hospitals during the study year. Teens with SUD accounted for 510,268 days of inpatient days in the U.S. community hospitals accounting for a total charge of $3,070,948,580. The average LOS for all SUD teens in the U.S. was 5.4 days with a mean charge per discharge of $32,754, indicating higher LOS but a significantly lower mean charge compared to non-SUD teens (4.1 days; $39,657). In 2016, more than 88% of SUD patients had ≥ 3 diagnoses compared to non-SUD patients (76%) (P < 0.0001 for all). The most frequently observed diagnosis associated with teens with SUD was psychoses, depressive neuroses, and alcohol use disorder. With one in ten teenagers found with an SUD, early substance initiation still appears to be an important public health issue. Unfortunately, the health and economic impact of substance use in adolescence on society are huge requiring effective strategies targeted to this population. The concerning data and literature identify a significant need to address prevention, treatment, and recovery services for adolescents throughout the United States.

Understanding Cannabis sativa L.: Current Status of Propagation, Use, Legalization, and Haploid-Inducer-Mediated Genetic Engineering

Cannabis sativa L. is an illegal plant in many countries. The worldwide criminalization of the plant has for many years limited its research. Consequently, understanding the full scope of its benefits and harm became limited too. However, in recent years the world has witnessed an increased pace in legalization and decriminalization of C. sativa. This has prompted an increase in scientific studies on various aspects of the plant’s growth, development, and use. This review brings together the historical and current information about the plant’s relationship with mankind. We highlight the important aspects of C. sativa classification and identification, carefully analyzing the supporting arguments for both monotypic (single species) and polytypic (multiple species) perspectives. The review also identifies recent studies on suitable conditions and methods for C. sativa propagation as well as highlighting the diverse uses of the plant. Specifically, we describe the beneficial and harmful effects of the prominent phytocannabinoids and provide status of the studies on heterologous synthesis of phytocannabinoids in different biological systems. With a historical view on C. sativa legality, the review also provides an up-to-date worldwide standpoint on its regulation. Finally, we present a summary of the studies on genome editing and suggest areas for future research.

Genetic correlation, pleiotropy, and causal associations between substance use and psychiatric disorder

BACKGROUND

Substance use occurs at a high rate in persons with a psychiatric disorder. Genetically informative studies have the potential to elucidate the etiology of these phenomena. Recent developments in genome-wide association studies (GWAS) allow new avenues of investigation.

METHOD

Using results of GWAS meta-analyses, we performed a factor analysis of the genetic correlation structure, a genome-wide search of shared loci, and causally informative tests for six substance use phenotypes (four smoking, one alcohol, and one cannabis use) and five psychiatric disorders (ADHD, anorexia, depression, bipolar disorder, and schizophrenia).

RESULTS

Two correlated externalizing and internalizing/psychosis factor were found, although model fit was beneath conventional standards. Of 458 loci reported in previous univariate GWAS of substance use and psychiatric disorders, about 50% (230 loci) were pleiotropic with additional 111 pleiotropic loci not reported from past GWAS. Of the 341 pleiotropic loci, 152 were associated with both substance use and psychiatric disorders, implicating neurodevelopment, cell morphogenesis, biological adhesion pathways, and enrichment in 13 different brain tissues. Seventy-five and 114 pleiotropic loci were specific to either psychiatric disorders or substance use phenotypes, implicating neuronal signaling pathway and clathrin-binding functions/structures, respectively. No consistent evidence for phenotypic causation was found across different Mendelian randomization methods.

CONCLUSIONS

Genetic etiology of substance use and psychiatric disorders is highly pleiotropic and involves shared neurodevelopmental path, neurotransmission, and intracellular trafficking. In aggregate, the patterns are not consistent with vertical pleiotropy, more likely reflecting horizontal pleiotropy or more complex forms of phenotypic causation.

Impact of Substance Use Disorder on Between-Network Brain Connectivity in Early Psychosis

The Triple Network Model of psychopathology identifies the salience network (SN), central executive network (CEN), and default mode network (DMN) as key networks underlying the pathophysiology of psychiatric disorders. In particular, abnormal SN-initiated network switching impacts the engagement and disengagement of the CEN and DMN, and is proposed to lead to the generation of psychosis symptoms. Between-network connectivity has been shown to be abnormal in both substance use disorders (SUD) and psychosis. However, none have studied how SUD affects connectivity between sub-networks of the DMN, SN, and CEN in early stage psychosis (ESP) patients. In this study, we collected data from 113 ESP patients and 50 healthy controls to investigate the effect of SUD on between-network connectivity. In addition, we performed sub-group analysis by exploring whether past SUD vs current SUD co-morbidity, or diagnosis (affective vs non-affective psychosis) had a modulatory effect. Connectivity between four network-pairs, consisting of sub-networks of the SN, CEN, and DMN, was significantly different between ESP patients and controls. Two patterns of connectivity were observed when patients were divided into sub-groups with current vs past SUD. In particular, connectivity between right CEN and the cingulo-opercular salience sub-network (rCEN-CON) showed a gradient effect where the severity of abnormalities increased from no history of SUD to past+ to current+. We also observed diagnosis-specific effects, suggesting non-affective psychosis patients were particularly vulnerable to effects of substance use on rCEN-CON connectivity. Our findings reveal insights into how comorbid SUD affects between-network connectivity and symptom severity in ESP.

Characterizing prescription stimulant nonmedical use (NMU) among adults recruited from Reddit

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Adults reporting past 5-year non-oral prescription stimulant NMU were studied.

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Non-oral NMU preferences were snorting (59%) injecting (4%) or smoking (1%).

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Polysubstance use was reported by 79.1% of the sample.

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Route of administration and motivation for prescription stimulant NMU were related.

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Prescription stimulant oral and intranasal NMU was to enhance performance.

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Prescription stimulant intravenous and smoking NMU was to get high.

Objective

Increased prescription stimulant nonmedical use (NMU) is part of a growing polysubstance use landscape. The purpose of the present study was to characterize prescription stimulant NMU among adults reporting past 5-year non-oral prescription stimulant NMU.

Methods

Adults who reported non-oral prescription stimulant NMU within the last 5 years were recruited by banner ads placed on the Reddit website between February and September 2019. Types of prescription stimulants used, routes of administration, preferred routes of administration, motivations for prescription stimulant NMU, concurrent substances used simultaneously during prescription stimulant NMU, illicit substances used and factors impacting prescription stimulant NMU were queried.

Results

Respondents (n = 225) were male (86.2%), non-Hispanic (92.4%), white (78.2%), between 18 and 24 (48.0%) or 25–34 (43.1%) years with some amount of college education (81.3%). Most reported lifetime intranasal (93.8%) or oral use (85.2%). Prescription stimulants were diverted: 64.5% reported the prescription stimulants were given to them by a family or a friend and 10.5% reported that they had stolen these medications from a family or friend. Preferred route of administration was oral use (70.2%). Motivations to use were stratified by route of administration: intranasal (55.6%) or oral (63.0%) use was primarily endorsed as an attempt to enhance performance at work or at school; use by injection (57.1%) or smoking (62.5%) was primarily endorsed to get high. Most of the sample reported concurrent drug use (79.1%) including tobacco (57.3%), marijuana (52.0%), caffeine (47.6%) or alcohol (41.8%), among others. When excluding licit substances, 30.7% reported using 1 illicit substance concurrently with prescription stimulants and 25.3% reported using 2 or more illicit substances concurrently with prescription stimulants. Whether participants would undertake prescription stimulant NMU was determined by their work/school schedules or the location of the NMU (48.9%) whereas the route of administration employed was primarily influenced by the desired feeling or effect (56.9%).

Conclusions

Adults reporting lifetime non-oral prescription stimulant NMU engage in substantial risky behaviors that in addition to alternate routes of administration include polysubstance use, diversion and concurrent substance use.

Adolescent Neurodevelopment and Vulnerability to Psychosis

Adolescence is characterized by significant changes in several domains, including brain structure and function, puberty, and social and environmental factors. Some of these changes serve to increase the likelihood of psychosis onset during this period, while others may buffer this risk. This review characterizes our current knowledge regarding the unique aspects of adolescence that may serve as risk factors for schizophrenia spectrum disorders. In addition, we provide potential future directions for research into adolescent-specific developmental mechanisms that impart vulnerability to psychosis and the possibility of interventions that capitalize on adolescents' unique characteristics. Specifically, we explore the ways in which gray and white matter develop throughout adolescence in typically developing youth as well as in those with psychosis spectrum disorders. We also discuss current views on the function that social support and demands, as well as role expectations, play in risk for psychosis. We further highlight the importance of considering biological factors such as puberty and hormonal changes as areas of unique vulnerability for adolescents. Finally, we discuss cannabis use as a factor that may have a unique impact during adolescent neurodevelopment, and subsequently potentially impact psychosis onset. Throughout, we include discussion of resilience factors that may provide unique opportunities for intervention during this dynamic life stage.

Attenuated Psychotic Symptoms in Adolescents With Chronic Cannabis and MDMA Use

OBJECTIVES

Both substance use, on the one hand, and the first signs of psychosis, on the other, commonly begin in adolescence. Adolescents with substance use disorder (SUD) frequently show recreational use of cannabis and 3,4-methylenedioxymethamphetamine (MDMA). When attenuated psychotic symptoms (APS) occur during the course of SUD, they are commonly attributed to the cannabis use, neglecting the role of other substances abused, such as MDMA in the risk of psychosis.

METHODS

We analyzed retrospective self-reports on APS (Prodromal Questionnaire, PQ-16) and amount of cannabis and MDMA use in n = 46 adolescent psychiatry outpatients with SUD. N = 17 (35%) individuals reported MDMA consume additional to cannabis. Furthermore, we examined the associations of APS with cannabis and MDMA use in stepwise hierarchical regressions while controlling for trauma history, birth complications and gender.

RESULTS

APS were not related to cannabis (B = 0.04, p = 0.842), but to MDMA use (B = 4.88, p = 0.001) and trauma history (B = 0.72, p = 0.001). Gender (B = -0.22, p = 0.767) and birth complications (B = -0.68, p = 0.178) were not associated with APS.

DISCUSSION

Our results indicate that MDMA use additional to cannabis use is associated with APS among adolescent SUD patients. Contrary to our expectations, we did not see an association of cannabis use and APS. We speculate that cannabis increases the risk for psychosis after a longer period of use and in combination with other risk factors, such as trauma history. Clinicians should screen for APS among SUD patients using MDMA and cannabis in order to adapt treatment plans of SUDs. Future research should validate these findings in longitudinal studies including polysubstance use and trauma history.

Problematic Drug Use Among Outpatients With Schizophrenia and Related Psychoses

Background: Problematic drug use is common among psychiatric patients and is linked with poorer course and outcomes of illness. The aim of this study is to assess the prevalence of problematic drug use, and to explore its sociodemographic correlates and associations with health behaviors and outcomes among outpatients with schizophrenia and related psychoses in Singapore. Methods: Data from 397 individuals who were aged 21-65 years and were seeking treatment for schizophrenia and related psychoses in the outpatient clinics of a tertiary psychiatric hospital were analyzed. The Drug Abuse Screening Test (DAST-10) was used to assess problematic drug use. Information on sociodemographics, smoking status, alcohol use, symptoms severity and quality of life were collected. Multivariable logistic regressions were conducted to explore correlates and associations of problematic drug use. Results: The prevalence of problematic drug use was 5.8% (n = 23) in the sample, and 10.6% (n = 42) of the participants reported having problematic drug use and/or problematic alcohol use. More males than females reported having problematic drug use (p = 0.021), and also problematic drug and/or alcohol use (p = 0.004). Significant associations were observed between problematic drug use and smokers with nicotine dependence, and with physical health domain of quality of life. Individuals with greater symptom severity were approximately twice as likely to have problematic drug use and/or alcohol use. Conclusion: While the prevalence of problematic drug use in this sample population is relatively lower compared to other countries, there is a considerable number who might be at risk. Routine screening and close monitoring of drug use is recommended as part of psychiatric assessment, particularly among males and patients with nicotine dependence.

Characterizing Pathways of Non-oral Prescription Stimulant Non-medical Use Among Adults Recruited From Reddit

Objective: Prescription stimulant non-medical use (NMU) is a national predicament. While the risks of prescription stimulant NMU have been considered, less is known about non-oral use. To focus on this gap, a sample of adults with non-oral prescription stimulant NMU within the last 5-years was recruited. The purpose of the present study was to characterize the pathways and substance transitions associated with prescription stimulant NMU and non-oral prescription stimulant NMU in this unique sample of adults. Methods: Adults (n = 225) reporting non-oral prescription stimulant NMU within the last 5 years were recruited to complete an online survey by banner ads placed on the Reddit website between February and September 2019. After completion of the survey, a second study consisting of an in-depth telephone interview was conducted with 23 participants: interviews took place between July and September 2019. Data reported here include substance, route of administration and class transitions, as well as qualitative data from the interviews. Results: Approximately 1 in 5 began their substance use trajectory with prescription stimulants (19.1%). Other than marijuana, most exposures to illicit substances occurred after both initial prescription stimulant NMU and initial non-oral prescription stimulant NMU. The most frequently reported route of administration transition was from oral use to snorting (n = 158, 70.2%), however, other route of administration transitions included oral use to injection drug use (n = 14, 6%). In-depth interviews elaborated upon these transitions and indicated that prescription stimulant NMU was consequential to substance use pathways. Conclusions: Oral prescription stimulant NMU was a precursor to non-oral prescription stimulant NMU. Non-oral prescription stimulant NMU was a precursor to illicit substance use, suggesting that prescription stimulant NMU impacts substance use pathways and revealing opportunities for intervention.

Just what the nurse practitioner ordered: Independent prescriptive authority and population mental health

We examine whether relaxing occupational licensing to allow nurse practitioners (NPs)-registered nurses with advanced degrees-to prescribe medication without physician oversight improves population mental health. Exploiting time-series variation in independent prescriptive authority for NPs from 1990 to 2014, we find that broadening prescriptive authority leads to improvements in self-reported mental health and decreases in mental health-related mortality. These improvements are concentrated in areas that are underserved by physicians and among populations that have difficulty accessing physician-provided care. Our results demonstrate that extending independent prescriptive authority to NPs can help mitigate physician shortages and extend care to disadvantaged populations.

Adolescent Δ9-Tetrahydrocannabinol Exposure and Astrocyte-Specific Genetic Vulnerability Converge on Nuclear Factor-κB-Cyclooxygenase-2 Signaling to Impair Memory in Adulthood

BACKGROUND

Although several studies have linked adolescent cannabis use to long-term cognitive dysfunction, there are negative reports as well. The fact that not all users develop cognitive impairment suggests a genetic vulnerability to adverse effects of cannabis, which are attributed to action of Δ9-tetrahydrocannabinol (Δ⁹-THC), a cannabis constituent and partial agonist of brain cannabinoid receptor 1. As both neurons and glial cells express cannabinoid receptor 1, genetic vulnerability could influence Δ⁹-THC-induced signaling in a cell type-specific manner.

METHODS

Here we use an animal model of inducible expression of dominant-negative disrupted in schizophrenia 1 (DN-DISC1) selectively in astrocytes to evaluate the molecular mechanisms, whereby an astrocyte genetic vulnerability could interact with adolescent Δ⁹-THC exposure to impair recognition memory in adulthood.

RESULTS

Selective expression of DN-DISC1 in astrocytes and adolescent treatment with Δ⁹-THC synergistically affected recognition memory in adult mice. Similar deficits in recognition memory were observed following knockdown of endogenous Disc1 in hippocampal astrocytes in mice treated with Δ⁹-THC during adolescence. At the molecular level, DN-DISC1 and Δ⁹-THC synergistically activated the nuclear factor-κB-cyclooxygenase-2 pathway in astrocytes and decreased immunoreactivity of parvalbumin-positive presynaptic inhibitory boutons around pyramidal neurons of the hippocampal CA3 area. The cognitive abnormalities were prevented in DN-DISC1 mice exposed to Δ⁹-THC by simultaneous adolescent treatment with the cyclooxygenase-2 inhibitor, NS398.

CONCLUSIONS

Our data demonstrate that individual vulnerability to cannabis can be exclusively mediated by astrocytes. Results of this work suggest that genetic predisposition within astrocytes can exaggerate Δ⁹-THC-produced cognitive impairments via convergent inflammatory signaling, suggesting possible targets for preventing adverse effects of cannabis within susceptible individuals.

Cannabis consumption and psychosis or schizophrenia development

OBJECTIVE:

Cannabis consumption produces psychopathology, in some cases psychotic episodes, which are of our interest in this work. However, the relationship between cannabis use and psychosis has not been fully elucidated. The objectives of this work are to (1) review the current state of knowledge on the association of cannabis use with the risk of the development of psychosis or psychotic symptoms in people without schizophrenia and (2) assess the consistency of the hypothesis that cannabis use is associated with increased risk of psychosis in people without schizophrenia.

METHOD:

This work included research done in humans until May 2018 with the keywords 'cannabis' and 'psychosis', published in English and Spanish, in the PubMed database.

RESULTS:

In all, 66 papers were analyzed, of which 23 were cohort trials and 43 were reviews.

CONCLUSION:

Cannabis use doubles the risk of developing psychosis in vulnerable people. There even exists a relationship regarding the dose used and the age of first use. Gene-environment interactions that modulate the association between cannabis use and the presence of psychosis have also been described.

Holistic Management of Schizophrenia Symptoms Using Pharmacological and Non-pharmacological Treatment

Individuals with schizophrenia lead a poor quality of life, due to poor medical attention, homelessness, unemployment, financial constraints, lack of education, and poor social skills. Thus, a review of factors associated with the holistic management of schizophrenia is of paramount importance. The objective of this review is to improve the quality of life of individuals with schizophrenia, by addressing the factors related to the needs of the patients and present them in a unified manner. Although medications play a role, other factors that lead to a successful holistic management of schizophrenia include addressing the following: financial management, independent community living, independent living skill, relationship, friendship, entertainment, regular exercise for weight gained due to medication administration, co-morbid health issues, and day-care programmes for independent living. This review discusses the relationship between different symptoms and problems individuals with schizophrenia face (e.g., homelessness and unemployment), and how these can be managed using pharmacological and non-pharmacological methods. Thus, the target of this review is the carers of individuals with schizophrenia, public health managers, counselors, case workers, psychiatrists, and clinical psychologists aiming to enhance the quality of life of individuals with schizophrenia.

Risk factors in early and late onset schizophrenia

BACKGROUND

This study looks at key risk factors in patients with schizophrenia to identify trends according to age of onset, comparing presentations prior to 26years (youth onset), between 26 and 40years (middle onset), and after 40years of age (late onset).

METHODS

The early psychosis program at St Vincent's Hospital Melbourne treats patients presenting in the early stages of psychosis between 16 and 65years of age. A database was developed to capture key risk factors in all patients with an eventual diagnosis of schizophrenia (n=225). Risk factor profiles were then generated and compared for patients based on age of onset.

RESULTS

Older age of onset was associated with weaker family history of schizophrenia, lower rates of substance use, better early psychosocial functioning and higher educational achievement. Female preponderance and comorbid physical health problems were particularly notable in the late onset cohort. Later life schizophrenia also showed a relatively greater association with psychosocial factors proximal to psychosis onset, such as unemployment.

DISCUSSION

Clear trends are noticeable with age. Older patients have characteristic differences in their background risk factors compared to youth onset patients, including less hereditary influence and relatively more emphasis on later life risk factors. Identifying the roles of specific risk factors in these distinct age-onset groups can enhance our understanding of underlying aetiology and facilitate service development to meet the needs of each specific age group.

Cannabis Use, Polysubstance Use, and Psychosis Spectrum Symptoms in a Community-Based Sample of U.S. Youth

PURPOSE

To examine how cannabis use and polysubstance use among cannabis users relate to psychosis spectrum (PS) symptoms in a large community-based sample of U.S. youth.

METHODS

Four thousand one hundred seventy-one youths (aged 14-21 years; mean = 16.90 years, SD = 1.85; 55% female) from the Philadelphia Neurodevelopmental Cohort completed assessments of substance use, PS symptoms, and confounding variables (e.g., demographics, comorbid psychopathology, and trauma exposure).

RESULTS

After adjusting for confounds, cannabis use by itself was not associated with increased odds of being classified as "psychosis spectrum." However, cannabis use in combination with tobacco or other substance use was associated with increased odds of PS classification (adjusted odds ratios [ORs] = 1.37-1.76). Follow-up symptom-level analyses revealed that cannabis use in combination with other substances was associated with subclinical positive symptoms (ORs = 1.95 and 2.24) and frequent cannabis use was associated with subclinical negative/disorganized symptoms (OR = 2.14). However, these symptom-level findings were reduced to trends after correction for multiple comparisons. Neither cannabis use nor polysubstance use was associated with threshold delusions or hallucinations.

CONCLUSIONS

After adjusting for important confounds, there was minimal evidence for associations between cannabis use by itself and PS symptoms. More compelling evidence emerged for associations between polysubstance use among cannabis users and PS symptoms. This study highlights the importance of considering polysubstance use and confounds when examining associations between cannabis use and PS symptoms. Further longitudinal research is necessary to determine whether these findings represent causal associations or shared genetic and/or environmental vulnerability for substance use and PS symptoms.

What to make of cannabis and cognition in MS: In search of clarity amidst the haze

Given data showing that cannabis (herbal drug from the Cannabis sativa plant) can impair cognition in healthy subjects, the possibility that it may also do so in people with multiple sclerosis (MS) should be cause for concern. Approximately 20% of people with MS inhale or ingest cannabis for a variety of symptoms, or as a lifestyle choice. In addition, pharmaceutically manufactured cannabis (in capsules or spray) is prescribed most often for pain and spasticity; however, there is a dearth of literature on the cognitive effects of cannabis. Furthermore, methodological limitations introduce a cautionary note when interpreting the data. The evidence, which must therefore be considered preliminary, suggests that smoked cannabis may further compromise information processing speed and memory, with magnetic resonance imaging (fMRI) demonstrating more inefficient patterns of cerebral activation during task performance. The findings related to pharmaceutically manufactured cannabis are equivocal. There is a pressing need for further research to inform clinical opinion, which at present reflects a combination of uncertainty and dogma.

Light alcohol intake during adolescence induces alcohol addiction in a neurodevelopmental model of schizophrenia

Schizophrenia is a mental disorder characterized by a series of positive, negative or cognitive symptoms but with also the particularity of exhibiting a high rate of co-morbid use of drugs of abuse. While more than 80% of schizophrenics are smokers, the second most consumed drug is alcohol, with dramatic consequences on frequency and intensity of psychotic episodes and on life expectancy. Here we investigated the impact of light alcohol intake during adolescence on the subsequent occurrence of alcohol addiction-like behavior in neonatal ventral hippocampal lesion (NVHL) rats, a neurodevelopmental model of schizophrenia. Our findings demonstrated an increased liability to addictive behaviors in adult NVHL rats after voluntary alcohol intake during adolescence. NVHL rats displayed several signs of alcohol use disorder such as a loss of control over alcohol intake and high motivation to consume alcohol, associated with a higher resistance to extinction. In addition, once NVHL rats relapsed, they maintained higher drinking levels than controls. We finally showed that the anti-addictive drug naltrexone is efficient in reducing excessive alcohol intake in NVHL rats. Our results are in accordance with epidemiological studies underlying the particular vulnerability to alcohol addiction after adolescent exposure to alcohol and highlight the fact that schizophrenic subjects may be particularly at risk even after light alcohol consumption. Based on these results, it seems particularly relevant to prevent early onset of alcohol use in at-risk subjects and thus to reduce the incidence of co-morbid alcohol abuse in psychotic patients.

Hemispheric language asymmetry in first episode psychosis and schizotypy: the role of cannabis consumption and cognitive disorganization

Cannabis use has been related to an elevated psychosis risk and attenuated cognitive functioning. Cannabis-related cognitive impairments are also observed in populations along the psychosis dimension. We here investigated whether a potential behavioral marker of the psychosis dimension (attenuated functional hemispheric asymmetry) is even further attenuated in individuals using cannabis (CU) vs those not using cannabis (nCU). We tested 29 patients with first-episode psychosis (FEP; 11 CU) and 90 healthy controls (38 CU) on lateralized lexical decisions assessing left-hemisphere language dominance. In patients, psychotic symptoms were assessed by Positive & Negative Symptom Scale (PANSS). In controls, self-reported schizotypy was assessed (The Oxford-Liverpool Inventory of Feelings and Experiences: O-LIFE). Results indicated that nCU FEP patients had a relative reduced hemispheric asymmetry, as did controls with increasing cognitive disorganization (CogDis) scores, in particular when belonging to the group of nCU controls. Positive, disorganized and negative PANSS scores in patients and negative and positive schizotypy in controls were unrelated to hemispheric asymmetry. These findings suggest that cannabis use potentially balances rather than exacerbates uncommon hemispheric laterality patterns. Moreover, in healthy populations, the potential stabilization of typical hemispheric asymmetry in CU might be most relevant to individuals with elevated CogDis. We discuss the potential beneficial and harmful effects of cannabis use along the psychosis dimension together with propositions for future studies that should account for the mediating role of additional substances (eg nicotine), cannabis composition (eg cannabidiol content), and individual differences (eg physical health, or absence of significant polysubstance use).

Substance use in people at clinical high-risk for psychosis

BACKGROUND

Some high-risk (HR) mental states for psychosis may lack diagnostic specificity and predictive value. Furthermore, psychotic-like experiences found in young populations may act not only as markers for psychosis but also for other non-psychotic psychiatric disorders. A neglected consideration in these populations is the effect of substance misuse and its role in the development of such mental states or its influence in the evolution toward full psychotic presentations. Therefore, the main aim of this study was to thoroughly describe past and current substance use profiles of HR individuals by comparing a consecutive cohort of young people at high risk referred to a population-based early intervention clinical service with a random sample of healthy volunteers (HV) recruited from the same geographical area.

METHODS

We compared alcohol and substance use profiles of sixty help-seeking HR individuals and 60 healthy volunteers (HV). In addition to identification of abuse/dependence and influence on psychotic-like experiences, differences between HR individuals and HV were assessed for gender, ethnicity, occupational status, age of lifetime first substance use, prevalence and frequency of substance use.

RESULTS

There were no cases of substance use disorder or dependence in either groups. HR individuals were significantly younger than HV when they first started to use substances (p = 0.014). The prevalence of overall HR substance use was similar to that of HV. Although HR individuals reported less cannabinoid use than HV currently (15% vs. 27%), and more in the past (40% vs. 30%), the differences were not statistically significant (p = 0.177 & 0.339 respectively). Current frequency of use was significantly higher for HR individuals than HV for alcohol (p = 0.001) and cannabinoids (p = 0.03). In this sample, only 5% of HR individuals converted to psychosis over a two-year follow-up.

CONCLUSIONS

Certain profiles of substance use could potentially play a significant part in the evolution of HR presentations. Therefore, substance use may well represent a clinical domain that requires further emphasis and more detailed consideration in future studies.

Alcohol and Relatively Pure Cannabis Use, but Not Schizotypy, are Associated with Cognitive Attenuations

Elevated schizotypy relates to similar cognitive attenuations as seen in psychosis and cannabis/polydrug use. Also, in schizotypal populations cannabis and polydrug (including licit drug) use are enhanced. These cognitive attenuations may therefore either be a behavioral marker of psychotic (-like) symptoms or the consequence of enhanced drug use in schizotypal populations. To elucidate this, we investigated the link between cognitive attenuation and cannabis use in largely pure cannabis users (35) and non-using controls (48), accounting for the potential additional influence of both schizotypy and licit drug use (alcohol, nicotine). Cognitive attenuations commonly seen in psychosis were associated with cannabis and alcohol use, but not schizotypy. Future studies should therefore consider (i) non-excessive licit substance use (e.g., alcohol) in studies investigating the effect of cannabis use on cognition and (ii) both enhanced illicit and licit substance use in studies investigating cognition in schizotypal populations.

Substance use in clinical high risk for psychosis: a review of the literature

AIM

In the literature, there is evidence suggesting an association between substance use and psychosis. However, little is known about substance use in those who may be in the pre-psychotic phase, that is, those who are putatively prodromal are considered to be at clinical high risk (CHR) of developing psychosis.

METHODS

We conducted a review of publications measuring patterns and rates of substance use in CHR for psychosis individuals and the effects on the transition to psychosis.

RESULTS

Of 5527 potentially relevant research papers, 10 met inclusion criteria of CHR subjects and specifically mentioned substance use in the sample. The results of these studies varied. Cannabis, alcohol and tobacco/nicotine were reported as the most commonly used substances. There was limited information on the changes in patterns of use over time. Two out of the ten studies found a significant association between the use of substances and subsequent transition to psychosis. In one of these studies, substance abuse was a predictor of psychosis when included as a variable in a prediction algorithm. In the other study, the abuse of cannabis and nicotine was associated with transition to psychosis.

CONCLUSIONS

We found limited evidence to suggest that increased rates of substance use may be associated with transition to psychosis. However, further prospective research examining the association between substance use and transition to psychosis is required before any firm conclusions can be made.

Predictors of methamphetamine psychosis: history of ADHD-relevant childhood behaviors and drug exposure

The goal of this study was to extend our previous research that reported a significant association between Attention Deficit Hyperactivity Disorder (ADHD)-relevant childhood behaviors and the frequency of methamphetamine (MA)-induced psychotic symptoms in an expanded sample. 190 participants who met DSM-IV criteria for MA dependence were administered the Methamphetamine Experience Questionnaire that assessed MA-induced psychosis. Data related to MA exposure, comorbid drug use, education, familial psychiatric history and assessments of ADHD-relevant childhood behaviors as measured by the Wender Utah Rating Scale (WURS) were collected. Although WURS scores did not differ between 145 MAP+ and 45 MAP- subjects, MAP+ subjects with higher WURS scores were significantly more likely to report more frequent psychosis. Although mean daily MA dosage did not differ between the MAP+ and MAP- subjects, MAP+ subjects who consumed larger doses of MA were significantly more likely to experience frequent psychosis. These data suggest that ADHD-relevant childhood behaviors may interact with MA exposure to reflect a neurobiological vulnerability related to the emergence of frequent MA-induced psychotic symptoms. These results may elucidate factors that contribute to the psychiatric sequelae of MA abuse.

Does Cannabidiol Protect Against Adverse Psychological Effects of THC?

The recreational use of cannabis can have persistent adverse effects on mental health. Delta-9-tetrahydrocannabinol (THC) is the main psychoactive constituent of cannabis, and most, if not all, of the effects associated with the use of cannabis are caused by THC. Recent studies have suggested a possible protective effect of another cannabinoid, cannabidiol (CBD). A literature search was performed in the bibliographic databases PubMed, PsycINFO, and Web of Science using the keyword "cannabidiol." After removing duplicate entries, 1295 unique titles remained. Based on the titles and abstracts, an initial selection was made. The reference lists of the publications identified in this manner were examined for additional references. Cannabis is not a safe drug. Depending on how often someone uses, the age of onset, the potency of the cannabis that is used and someone's individual sensitivity, the recreational use of cannabis may cause permanent psychological disorders. Most recreational users will never be faced with such persistent mental illness, but in some individuals cannabis use leads to undesirable effects: cognitive impairment, anxiety, paranoia, and increased risks of developing chronic psychosis or drug addiction. Studies examining the protective effects of CBD have shown that CBD can counteract the negative effects of THC. However, the question remains of how the laboratory results translate to the types of cannabis that are encountered by real-world recreational users.

Deconstructing sub-clinical psychosis into latent-state and trait variables over a 30-year time span

BACKGROUND

Our aim was to deconstruct the variance underlying the expression of sub-clinical psychosis symptoms into portions associated with latent time-dependent states and time-invariant traits.

METHODS

We analyzed data of 335 subjects from the general population of Zurich, Switzerland, who had been repeatedly measured between 1979 (age 20/21) and 2008 (age 49/50). We applied two measures of sub-clinical psychosis derived from the SCL-90-R, namely schizotypal signs (STS) and schizophrenia nuclear symptoms (SNS). Variance was decomposed with latent state-trait analysis and associations with covariates were examined with generalized linear models.

RESULTS

At ages 19/20 and 49/50, the latent states underlying STS accounted for 48% and 51% of variance, whereas for SNS those estimates were 62% and 50%. Between those age classes, however, expression of sub-clinical psychosis was strongly associated with stable traits (75% and 89% of total variance in STS and SNS, respectively, at age 27/28). Latent states underlying variance in STS and SNS were particularly related to partnership problems over almost the entire observation period. STS was additionally related to employment problems, whereas drug-use was a strong predictor of states underlying both syndromes at age 19/20. The latent trait underlying expression of STS and SNS was particularly related to low sense of mastery and self-esteem and to high depressiveness.

CONCLUSIONS

Although most psychosis symptoms are transient and episodic in nature, the variability in their expression is predominantly caused by stable traits. Those time-invariant and rather consistent effects are particularly influential around age 30, whereas the occasion-specific states appear to be particularly influential at ages 20 and 50.

Convergence of genetic and environmental factors on parvalbumin-positive interneurons in schizophrenia

Schizophrenia etiology is thought to involve an interaction between genetic and environmental factors during postnatal brain development. However, there is a fundamental gap in our understanding of the molecular mechanisms by which environmental factors interact with genetic susceptibility to trigger symptom onset and disease progression. In this review, we summarize the most recent findings implicating oxidative stress as one mechanism by which environmental insults, especially early life social stress, impact the development of schizophrenia. Based on a review of the literature and the results of our own animal model, we suggest that environmental stressors such as social isolation render parvalbumin-positive interneurons (PVIs) vulnerable to oxidative stress. We previously reported that social isolation stress exacerbates many of the schizophrenia-like phenotypes seen in a conditional genetic mouse model in which NMDA receptors (NMDARs) are selectively ablated in half of cortical and hippocampal interneurons during early postnatal development (Belforte et al., 2010). We have since revealed that this social isolation-induced effect is caused by impairments in the antioxidant defense capacity in the PVIs in which NMDARs are ablated. We propose that this effect is mediated by the down-regulation of PGC-1α, a master regulator of mitochondrial energy metabolism and anti-oxidant defense, following the deletion of NMDARs (Jiang et al., 2013). Other potential molecular mechanisms underlying redox dysfunction upon gene and environmental interaction will be discussed, with a focus on the unique properties of PVIs.

A comprehensive review of auditory verbal hallucinations: lifetime prevalence, correlates and mechanisms in healthy and clinical individuals

Over the years, the prevalence of auditory verbal hallucinations (AVHs) have been documented across the lifespan in varied contexts, and with a range of potential long-term outcomes. Initially the emphasis focused on whether AVHs conferred risk for psychosis. However, recent research has identified significant differences in the presentation and outcomes of AVH in patients compared to those in non-clinical populations. For this reason, it has been suggested that auditory hallucinations are an entity by themselves and not necessarily indicative of transition along the psychosis continuum. This review will examine the presentation of auditory hallucinations across the life span, as well as in various clinical groups. The stages described include childhood, adolescence, adult non-clinical populations, hypnagogic/hypnopompic experiences, high schizotypal traits, schizophrenia, substance induced AVH, AVH in epilepsy, and AVH in the elderly. In children, need for care depends upon whether the child associates the voice with negative beliefs, appraisals and other symptoms of psychosis. This theme appears to carry right through to healthy voice hearers in adulthood, in which a negative impact of the voice usually only exists if the individual has negative experiences as a result of their voice(s). This includes features of the voices such as the negative content, frequency, and emotional valence as well as anxiety and depression, independently or caused by voices presence. It seems possible that the mechanisms which maintain AVH in non-clinical populations are different from those which are behind AVH presentations in psychotic illness. For example, the existence of maladaptive coping strategies in patient populations is one significant difference between clinical and non-clinical groups which is associated with a need for care. Whether or not these mechanisms start out the same and have differential trajectories is not yet evidenced. Future research needs to focus on the comparison of underlying factors and mechanisms that lead to the onset of AVH in both patient and non-clinical populations.

Adolescent bullying, cannabis use and emerging psychotic experiences: a longitudinal general population study

BACKGROUND

Using longitudinal and prospective measures of psychotic experiences during adolescence, we assessed the risk of developing psychosis in three groups showing low, increasing and elevated psychotic experiences associated with bullying by peers and cannabis use in a UK sample of adolescents. Method Data were collected by self-report from 1098 adolescents (mean age 13.6 years; 60.9% boys) at five separate time points, equally separated by 6 months, across a 24-month period. General growth mixture modelling identified three distinct trajectories of adolescents reporting psychotic experiences: elevated, increasing and low.

RESULTS

Controlling for cannabis use, bullying by peers significantly predicted change in psychotic experiences between Time 2 and Time 5 in adolescents belonging to the increasing group. No effect was found for the elevated or low groups. Controlling for bullying, an earlier age of cannabis use and cannabis use more than twice significantly predicted change in psychotic experiences in adolescents belonging to the increasing group. Cannabis use at any age was significantly associated with subsequent change in psychotic experiences in the low group. Reverse causal associations were examined and there was no evidence for psychotic experiences at Time 1 predicting a subsequent change in cannabis use between Times 2 and 5 in any trajectory group.

CONCLUSIONS

Bullying by peers and cannabis use are associated with adolescents' reports of increasing psychotic experiences over time. Further research into the longitudinal development of psychosis in adolescence and the associated risk factors would allow for early intervention programmes to be targeted more precisely.

Inferring about individual drug and schizotypy effects on cognitive functioning in polydrug using mephedrone users before and after clubbing

OBJECTIVE

Mephedrone has been recently made illegal in Europe, but little empirical evidence is available on its impact on human cognitive functions. We investigated acute and chronic effects of mephedrone consumption on drug-sensitive cognitive measures, while also accounting for the influence of associated additional drug use and personality features.

METHOD

Twenty-six volunteers from the general population performed tasks measuring verbal learning, verbal fluency and cognitive flexibility before and after a potential drug-taking situation (pre-clubbing and post-clubbing at dance clubs, respectively). Participants also provided information on chronic and recent drug use, schizotypal (Oxford-Liverpool Inventory of Feelings and Experiences) and depressive symptoms (Beck Depression Inventory), sleep pattern and premorbid IQ.

RESULTS

We found that (i) mephedrone users performed worse than non-users pre-clubbing and deteriorated from the pre-clubbing to the post-clubbing assessment; (ii) pre-clubbing cannabis and amphetamine (not mephedrone) use predicted relative cognitive attenuations; (iii) post-clubbing, depression scores predicted relative cognitive attenuations; and (iv) schizotypy was largely unrelated to cognitive functioning, apart from a negative relationship between cognitive disorganisation and verbal fluency.

CONCLUSION

Results suggest that polydrug use and depressive symptoms in the general population negatively affect cognition. For schizotypy, only elevated cognitive disorganisation showed potential links to a pathological cognitive profile previously reported along the psychosis dimension.

Caregiver causal attributions in youth psychosis

AIM

Caregiver causal attributions influence patient and caregiver reactions to psychosis. The current study describes common caregiver causal attributions about psychosis onset in youth, including a subset of first-episode psychosis patients, and the patient and caregiver characteristics that influence these attributions. It also examines if caregiver views are affected by contact with youth mental health services.

METHODS

Fifty-one caregivers of 50 youth patients with a diagnosed Diagnostic and statistical manual of mental disorders, fourth edition (DSM-IV) psychotic disorder were interviewed about their causal attributions. Patient and caregiver demographic and clinical predictors were also collected.

RESULTS

Caregivers most highly endorsed substance use, genetics, negative peer influences and school stress as individual causes. These findings were consistent across the total sample. Principal components analysis derived three causal categories. Caregivers most frequently endorsed a biological and substance use lifestyle causal category, followed by psychological vulnerability and stress-reactivity causal categories. There was evidence that caregiver and patient factors, as well as contact with youth mental health services, influenced the causal attributions caregivers made about the onset of psychosis.

CONCLUSION

Caregivers of youth with psychosis are making causal attributions that are consistent with current aetiological theories of psychosis in youth. The study showed that caregivers are particularly cognizant of genetic and substance use factors in the development and maintenance of psychosis. However, youth mental health services may need to particularly focus on increasing caregiver understanding of the dynamics of stress factors as symptoms, and not causes, of psychosis early in the illness course.

A validation of cognitive biomarkers for the early identification of cognitive enhancing agents in schizotypy: a three-center double-blind placebo-controlled study

A number of compounds aimed at improving cognition in schizophrenia have failed to demonstrate efficacy in Phase 2 clinical trials. Translational studies using biomarkers in surrogate populations, such as schizotypy, could be used to assess the efficacy of novel compounds. In this study, we aimed to validate the sensitivity and inter-site reliability of cognitive biomarkers (working memory (N-back), spatial working memory (SWM) and verbal fluency (VF) tasks) to detect the schizotypy phenotype and its reversal by psychotropic drugs. Healthy volunteers scoring high or average on a schizotypal personality measure (122 in each group) were randomized to receive a single dose of risperidone, amisulpride, nicotine or placebo in a double-blind, between-subject design. We found evidence for a poorer performance on N-back and VF tasks in the high schizotypy group, replicating previous research. This effect was counteracted by amisulpride on N-back: it improved working memory in high schizotypy group but impaired the controls. A similar pattern was seen in SWM and VF. We interpret this finding in the light of the dopamine enhancing action of amisulpride when given in low doses. In contrast, risperidone impaired both groups and nicotine had a beneficial effect for the low baseline performers only. These effects were consistent across sites. These data demonstrates the utility of biomarkers in detecting the effect of schizotypy and its reversal by drugs that enhance dopamine and cholinergic function. Studies using similar design could help the early assessment of potential of compounds designed to improve cognition in schizophrenia.

Psychiatric co-morbidity and substance use disorders: treatment in parallel systems or in one integrated system?

Psychiatric co-morbidity among substance users refers to the simultaneous presence of at least another psychiatric disorder in a person diagnosed with a substance use disorder. Co-morbid patients represent a substantial number of people in treatment and present greater disorder severity from both the clinical and social perspectives than those people diagnosed with only one type of disorder. We present an overview of the current state of the art concerning the choice of site of treatment, the kind of intervention, the length of such treatment, and future goals, aiming to establish a more effective intervention, and finally so as to further improve clinical outcomes.

Linking substance use with symptoms of subclinical psychosis in a community cohort over 30 years

AIMS

The aim of the study was to examine the temporal associations between substance use and subclinical psychosis symptoms.

DESIGN

Data from a prospective community study sampled within a single cohort over 30 years (1978-2008) were analysed with discrete-time hazard models.

SETTING

General population-based sample.

PARTICIPANTS

At initial sampling in 1978 males (n = 292) were 19 and females (n = 299) were 20 years old.

MEASUREMENTS

Two psychosis syndromes representing 'schizotypal signs' and 'schizophrenia nuclear symptoms' and various substance use variables including cannabis, alcohol, tobacco and multiple-drug use (i.e. cannabis combined with other drugs).

FINDINGS

In bivariate analyses, schizotypal signs were predominantly associated with regular cannabis use in adolescence (OR = 2.29, 95% CI 1.32-3.97). Schizophrenia nuclear symptoms were mainly related to alcohol (OR = 1.84, 95% CI 1.00-3.38) and multiple-drug use (OR = 2.35, 95% CI 1.38-4.02) during adolescence. Multivariate analyses showed that, in particular, regular cannabis use during adolescence was associated with the occurrence of subsequent schizotypal symptoms over a 30-year period (OR = 2.60, 95% CI; 1.59-4.23), whereas multiple-drug use in adolescence was associated predominantly with schizophrenia nuclear symptoms (OR = 1.75, 95% CI 1.01-3.03). Alcohol misuse was only slightly associated with the onset of such symptoms.

CONCLUSIONS

A significant portion of the occurrence of subclinical psychosis symptoms in adulthood can be attributed to excessive cannabis and multiple-drug use during adolescence. This is in line with the hypothesis that long-term sensitization of dopaminergic brain receptors plays a role in developing psychotic symptoms.

Environmental Risk and Protective Factors and Their Influence on the Emergence of Psychosis

Environmental risk and protective factors in schizophrenia play a significant role in the development and course of the disorder. The following article reviews the current state of evidence linking a variety of environmental factors and their impact on the emergence of psychotic disorders. The environmental factors include pre- and perinatal insults, stress and trauma, family environment, and cannabis use. The review of evidence is followed by case examples and clinical applications to facilitate the integration of the evidence into clinical practice.

Correlates to the variable effects of cannabis in young adults: a preliminary study

BACKGROUND

Cannabis use can frequently have adverse affects in those that use it and these can be amplified by various characteristics of an individual, from demographic and environmental variations to familial predisposition for mental illnesses.

METHODS

The current study of 100 individuals, who were cannabis users during their adolescence and may still be users, was a survey of the self perceived effects of cannabis and their correlates. A reliable family member was also interviewed for determination of family history of various major mental illnesses and substance use.

RESULTS

As many as 40% of cannabis users had paranoid feelings (suspiciousness) when using cannabis, although the most frequent effect was feeling relaxed (46%). Having a familial background for mental illnesses such as depression or schizophrenia did not determine the effects of cannabis nor its pattern of use, although the number of subjects with such a history was small. An age at which an individual began using cannabis did have an effect on how heavily it was used and the heavier the cannabis use, the more likely the individual was also to have had psychotic symptoms after use. There were no sex differences in effects of cannabis. These results are tempered by the reliance on self-report for many of the variables ascertained.

CONCLUSION

Cannabis can frequently have negative effects in its users, which can be amplified by certain demographic and/or psychosocial factors. Thus, users with a specific profile may be at a higher risk of unpleasant effects from cannabis use and caution should be noted when cannabis is administered to young people for medicinal purposes.

Stressing schizotypy: the modulating role of stress-relieving behaviours and intellectual capacity on functional hemispheric asymmetry

Relative cognitive impairments are common along the schizophrenia spectrum reflecting potential psychopathological markers. Yet stress, a vulnerability marker in schizophrenia (including its spectrum), is likewise related to cognitive impairments. We investigated whether one such cognitive marker (attenuated functional hemispheric asymmetry) during stressful life periods might be linked to individuals' schizotypal features or rather to individuals' stress-related experiences and behaviours. A total of 58 students performed a left hemisphere dominant (lateralised lexical decisions) and right hemisphere dominant (sex decisions on composite faces) task. In order to account for individual differences in stress sensitivity we separated participants into groups of high or low cognitive reserve according to their average current marks. In addition, participants filled in questionnaires on schizotypy (short O-LIFE), perceived stress, stress response, and a newly adapted questionnaire that enquired about potential stress compensation behaviour (elevated substance use). The most important finding was that enhanced substance use and cognitive disorganisation contributed to a right and left hemisphere shift in language dominance, respectively. We discuss that (i) former reports on right hemisphere shifts in language dominance with positive schizotypy might be explained by an associated higher substance use and (ii) cognitive disorganisation relates to unstable cognitive functioning that depend on individuals' life circumstances, contributing to published reports on inconsistent laterality-schizotypy relationships.

Evaluation of secondary school teachers' knowledge about psychosis: a contribution to early detection

AIMS

We sought to evaluate secondary school teachers' knowledge about psychosis and their level of interest in this topic given the key role they may be able to play in the early detection of psychosis.

METHODS

A questionnaire survey of 268 secondary school teachers from eight secondary schools within the Azienda Sanitaria Locale Rome/E and Rome/A catchment areas (two of the five city health districts) in Rome. Teachers were asked to complete the Italian version Esperienza e Conoscenza delle Difficoltò Sociali ed Emotive dei Giovani of the Knowledge and Experience of Social Emotional Difficulties among Young people self-report questionnaire that investigates the diagnosis, age of onset, aetiology, prognosis and treatment of psychosis. They were also asked about their experience with pupils with possible psychosis.

RESULTS

Most of teachers were able to recognize psychotic symptoms from a case vignette. Approximately 25% of the teachers had experienced a pupil with possible symptoms of psychosis. However, teachers displayed little awareness of psychiatric community services available for young people.

CONCLUSIONS

Our study shows that teachers may play an important role in early detection and psychosis prevention strategies. The teachers also displayed a keen interest in gaining a deeper knowledge of early psychotic signs and in cooperating closely with a mental health specialist to obtain guidance and support when faced with serious mentally ill pupils.

Adolescent exposure to cannabis as a risk factor for psychiatric disorders

Adolescence represents a critical period for brain development and the endocannabinoid system plays a crucial role in the regulation of neuronal refinement during this period. Cannabis is the most consumed drug among adolescent people and its heavy use may affect maturational refinement by disrupting the regulatory role of the endocannabinoid system. In animals, adolescent cannabinoid exposure has been reported to cause long-term impairment in specific components of learning and memory and to differentially affect emotional reactivity with milder effects on anxiety behaviour and more pronounced effects on depression-like behaviour. Moreover, adolescent exposure to cannabinoids might represent a risk factor for developing psychotic-like symptoms at adulthood. Also epidemiological studies suggest that heavy adolescent cannabis use may increase the risk of cognitive abnormalities, psychotic illness, mood disorders and other illicit substance use later in life. In conclusion, the available data point to the hypothesis that heavy cannabis use in adolescence could increase the risk of developing psychiatric disorders, especially in people who already have a vulnerability to develop a psychiatric syndrome. Only few papers have investigated the neurobiological substrates of this vulnerability, thus further studies are needed to clarify the molecular mechanisms underlying the effect of cannabis on the adolescent brain.

Putative diffusion tensor neuroimaging endophenotypes in schizophrenia: a review of the early evidence

Although schizophrenia has a high heritability, the genetic effects conferring diathesis to schizophrenia are thought to be complex and underlain by multifactorial polygenic inheritance. ‘Endophenotypes’, or ‘intermediate phenotypes’, are narrowed constructs of genetic risk that are assumed to be more proximal to the gene effects in the disease pathway than clinical phenotypes. A current aim in schizophrenia research is to identify promising putative endophenotypes for use in molecular genetics studies. Recently, much of the focus has been on neurocognitive, conventional T1-weighted structural MRI, functional MRI and electrophysiological endophenotypes. Diffusion tensor imaging has emerged as another important structural neuroimaging modality in the aim to identify abnormalities in brain connectivity and diffusivity in schizophrenia, and abnormalities detected via this method may be promising candidate endophenotypes. In this article, we present the first comprehensive review of the early evidence that qualifies diffusion tensor abnormalities as potentially appropriate endophenotypes of schizophrenia.

Persistence and outcome of auditory hallucinations in adolescence: a longitudinal general population study of 1800 individuals

BACKGROUND

Auditory hallucinations are common in adolescents. However, it has been suggested that not the presence of low-grade psychotic experiences per se, but rather the level of persistence and associated clinical complications over time may lead to psychotic illness. The current paper investigated, in a large representative sample of adolescents, to what degree hallucinations persist, and whether persistence of hallucinations increases the risk of developing secondary delusional ideation and affective dysregulation.

METHODS

Data were derived from a general health screening of all 1912 adolescents living in the Maastricht area. Baseline assessment was in the second grade of secondary school (T0) and follow-up occurred 2 years later (T1). Questions included the psychosis screening questions (Poulton et al., 2000), the SDQ assessing general psychopathology and a question assessing depression.

RESULTS

Five percent of adolescents reported hallucinations at T0 and 27% of these hallucinations were still present 2 years later. Hallucinations at T0 were associated with increased levels of depressed mood and general psychopathology at T1, and the degree of persistence of hallucinations was associated with a progressively greater risk for T1 delusional ideation as well as increased levels of follow-up depressed mood and general psychopathology.

CONCLUSION

Although hallucinations in adolescents are a common and mainly transitory phenomenon, the persistence rate over time is far from negligible, and associated with clinical deterioration.

Pre-morbid Conduct Disorder symptoms are associated with cannabis use among individuals with a first episode of psychosis

BACKGROUND

Early cannabis use has consistently been associated with an increased risk for the later development of psychosis. Studies suggest that Conduct Disorder (CD) is more common amongst young people who later go on to develop psychosis. CD has been associated with greater and earlier cannabis use in general population samples. Based on this evidence, we hypothesised that among patients experiencing their first episode of psychosis, the presence of CD symptoms prior to age 15 would be associated with cannabis use.

METHOD

102 patients experiencing a first episode of psychosis were interviewed to assess CD symptoms prior to age 15 and use of cannabis and other substances.

RESULTS

The number of CD symptoms was significantly associated with lifetime cannabis use (odds ratio=5.41 (1.76-16.57), p=0.03) and with first use of cannabis before age 14 (odds ratio=1.46 (1.12-1.92), p=0.006), after controlling for stimulant/hallucinogen use and level of education.

CONCLUSIONS

Among patients experiencing a first episode of psychosis, CD symptoms were significantly associated with use of cannabis and with use by age 14. Among individuals vulnerable for psychosis, CD symptoms may independently increase the likelihood of cannabis use which in turn increases the risk of psychosis.

The environment and schizophrenia

Psychotic syndromes can be understood as disorders of adaptation to social context. Although heritability is often emphasized, onset is associated with environmental factors such as early life adversity, growing up in an urban environment, minority group position and cannabis use, suggesting that exposure may have an impact on the developing 'social' brain during sensitive periods. Therefore heritability, as an index of genetic influence, may be of limited explanatory power unless viewed in the context of interaction with social effects. Longitudinal research is needed to uncover gene-environment interplay that determines how expression of vulnerability in the general population may give rise to more severe psychopathology.