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Cannabis use influences disorganized symptoms severity but not transition in a cohort of non-help-seeking individuals at-risk for psychosis from São Paulo, Brazil. Psychiatry Res 2024; 331:115665. [PMID: 38113810 DOI: 10.1016/j.psychres.2023.115665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/21/2023]
Abstract
BACKGROUND Cannabis use is associated with an increased risk of developing a psychotic disorder. However, in individuals with at-risk mental states for psychosis (ARMS) this association is not clear, as well as the impact of cannabis use on symptom severity. The objective of this study was to evaluate the association of cannabis use patterns and ARMS risk status, transition to psychotic and psychiatric disorders, and psychopathology. METHOD A sample of 109 ARMS and 197 control individuals was drawn from the general population. Lifetime, maximum and current amount of cannabis use were assessed with the South Westminster modified questionnaire. Participants were followed-up for a mean of 2.5 years and reassessed for transition to any psychiatric disorder. RESULTS There were no differences between ARMS and controls regarding lifetime use, current amount of use, or maximum amount of cannabis use. There were also no differences between those who transitioned to a psychiatric disorder and those who did not regarding cannabis use variables. In ARMS individuals, cannabis use was significantly related to disorganization symptoms. CONCLUSION The results of this study suggest that cannabis plays a role in the psychopathology of ARMS individuals, leading to more severe symptomatology.
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Assessing evidence supporting cannabis harm reduction practices for adolescents at clinical high-risk for psychosis: a review and clinical implementation tool. Psychol Med 2024; 54:245-255. [PMID: 37882050 DOI: 10.1017/s0033291723002994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
Cannabis use is consistently associated with both increased incidence of frank psychotic disorders and acute exacerbations of psychotic symptoms in healthy individuals and people with psychosis spectrum disorders. Although there is uncertainty around causality, cannabis use may be one of a few modifiable risk factors for conversion to psychotic disorders in individuals with Clinical High Risk for Psychosis (CHR-P) syndromes, characterized by functionally impairing and distressing subthreshold psychotic symptoms. To date, few recommendations beyond abstinence to reduce adverse psychiatric events associated with cannabis use have been made. This narrative review synthesizes existing scientific literature on cannabis' acute psychotomimetic effects and epidemiological associations with psychotic disorders in both CHR-P and healthy individuals to bridge the gap between scientific knowledge and practical mental health intervention. There is compelling evidence for cannabis acutely exacerbating psychotic symptoms in CHR-P, but its impact on conversion to psychotic disorder is unclear. Current evidence supports a harm reduction approach in reducing frequency of acute psychotic-like experiences, though whether such interventions decrease CHR-P individuals' risk of conversion to psychotic disorder remains unknown. Specific recommendations include reducing frequency of use, lowering delta-9-tetrahydrocannabinol content in favor of cannabidiol-only products, avoiding products with inconsistent potency like edibles, enhancing patient-provider communication about cannabis use and psychotic-like experiences, and utilizing a collaborative and individualized therapeutic approach. Despite uncertainty surrounding cannabis' causal association with psychotic disorders, cautious attempts to reduce acute psychosis risk may benefit CHR-P individuals uninterested in abstinence. Further research is needed to clarify practices associated with minimization of cannabis-related psychosis risk.
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Authors' reply to comments on: Recreational cannabis use over time in individuals at clinical high risk for psychosis: Lack of associations with symptom, neurocognitive, functioning, and treatment patterns. Psychiatry Res 2023; 330:115594. [PMID: 37976663 DOI: 10.1016/j.psychres.2023.115594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 11/04/2023] [Indexed: 11/19/2023]
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Recreational cannabis use over time in individuals at clinical high risk for psychosis: Lack of associations with symptom, neurocognitive, functioning, and treatment patterns. Psychiatry Res 2023; 328:115420. [PMID: 37657201 DOI: 10.1016/j.psychres.2023.115420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 07/17/2023] [Accepted: 08/14/2023] [Indexed: 09/03/2023]
Abstract
Recreational cannabis use has recently gained considerable interest as an environmental risk factor that triggers the onset of psychosis. To date, however, the evidence that cannabis is associated with negative outcomes in individuals at clinical high risk (CHR) for psychosis is inconsistent. The present study tracked cannabis usage over a 2-year period and examined its associations with clinical and neurocognitive outcomes, along with medication rates. CHR youth who continuously used cannabis had higher neurocognition and social functioning over time, and decreased medication usage, relative to non-users. Surprisingly, clinical symptoms improved over time despite the medication decreases.
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The impact of early factors on persistent negative symptoms in youth at clinical high risk for psychosis. Front Psychiatry 2023; 14:1125168. [PMID: 37293402 PMCID: PMC10244495 DOI: 10.3389/fpsyt.2023.1125168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 04/18/2023] [Indexed: 06/10/2023] Open
Abstract
Introduction Persistent negative symptoms (PNS) are described as continuing moderate negative symptoms. More severe negative symptoms have been associated with poor premorbid functioning in both chronic schizophrenia and first episode psychosis patients. Furthermore, youth at clinical high risk (CHR) for developing psychosis may also present with negative symptoms and poor premorbid functioning. The aim of this current study was to: (1) define the relationship between PNS and premorbid functioning, life events, trauma and bullying, previous cannabis use, and resource utilization, and (2) to examine what explanatory variables best predicted PNS. Method CHR participants (N = 709) were recruited from the North American Prodrome Longitudinal Study (NAPLS 2). Participants were divided into two groups: those with PNS (n = 67) versus those without PNS (n = 673). A K-means cluster analysis was conducted to distinguish patterns of premorbid functioning across the different developmental stages. The relationships between premorbid adjustment and other variables were examined using independent samples t-tests or chi square for categorical variables. Results There was significantly more males in the PNS group. Participants with PNS had significantly lower levels of premorbid adjustment in childhood, early adolescence, and late adolescence, compared to CHR participants without PNS. There were no differences between the groups in terms of trauma, bullying, and resource utilization. The non-PNS group had more cannabis use and more desirable and non-desirable life events. Conclusion In terms of better understanding relationships between early factors and PNS, a prominent factor associated with PNS was premorbid functioning, in particular poor premorbid functioning in later adolescence.
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Neurobehavioral risk factors influence prevalence and severity of hazardous substance use in youth at genetic and clinical high risk for psychosis. Front Psychiatry 2023; 14:1143315. [PMID: 37151981 PMCID: PMC10157227 DOI: 10.3389/fpsyt.2023.1143315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 03/31/2023] [Indexed: 05/09/2023] Open
Abstract
Background Elevated rates of alcohol, tobacco, and cannabis use are observed in both patients with psychotic disorders and individuals at clinical high risk for psychosis (CHR-P), and strong genetic associations exist between substance use disorders and schizophrenia. While individuals with 22q11.2 deletion syndrome (22qDel) are at increased genetic risk for psychosis, initial evidence suggests that they have strikingly low rates of substance use. In the current study, we aimed to directly compare substance use patterns and their neurobehavioral correlates in genetic and clinical high-risk cohorts. Methods Data on substance use frequency and severity, clinical symptoms, and neurobehavioral measures were collected at baseline and at 12-month follow-up visits in two prospective longitudinal cohorts: participants included 89 22qDel carriers and 65 age and sex-matched typically developing (TD) controls (40.67% male, Mage = 19.26 ± 7.84 years) and 1,288 CHR-P youth and 371 matched TD controls from the North American Prodrome Longitudinal Study-2 and 3 (55.74% male; Mage = 18.71 ± 4.27 years). Data were analyzed both cross-sectionally and longitudinally using linear mixed effects models. Results Controlling for age, sex, and site, CHR-P individuals had significantly elevated rates of tobacco, alcohol, and cannabis use relative to TD controls, whereas 22qDel had significantly lower rates. Increased substance use in CHR-P individuals was associated with increased psychosis symptom severity, dysphoric mood, social functioning, and IQ, while higher social anhedonia was associated with lower substance use across all domains at baseline. These patterns persisted when we investigated these relationships longitudinally over one-year. CHR-P youth exhibited significantly increased positive psychosis symptoms, dysphoric mood, social functioning, social anhedonia, and IQ compared to 22qDel carriers, and lower rates of autism spectrum disorder (ASD) compared to 22qDel carriers, both at baseline and at 1 year follow-up. Conclusion Individuals at genetic and CHR-P have strikingly different patterns of substance use. Factors such as increased neurodevelopmental symptoms (lower IQ, higher rates of ASD) and poorer social functioning in 22qDel may help explain this distinction from substance use patterns observed in CHR-P individuals.
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Recommendations for Reducing the Risk of Cannabis Use-Related Adverse Psychosis Outcomes: A Public Mental Health-Oriented Evidence Review. J Dual Diagn 2023; 19:71-96. [PMID: 37450645 DOI: 10.1080/15504263.2023.2226588] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
Objective: Cannabis use is increasingly normalized; psychosis is a major adverse health outcome. We reviewed evidence on cannabis use-related risk factors for psychosis outcomes at different stages toward recommendations for risk reduction by individuals involved in cannabis use. Methods: We searched primary databases for pertinent literature/data 2016 onward, principally relying on reviews and high-quality studies which were narratively summarized and quality-graded; recommendations were developed by international expert consensus. Results: Genetic risks, and mental health/substance use problem histories elevate the risks for cannabis-related psychosis. Early age-of-use-onset, frequency-of-use, product composition (i.e., THC potency), use mode and other substance co-use all influence psychosis risks; the protective effects of CBD are uncertain. Continuous cannabis use may adversely affect psychosis-related treatment and medication effects. Risk factor combinations further amplify the odds of adverse psychosis outcomes. Conclusions: Reductions in the identified cannabis-related risks factors-short of abstinence-may decrease risks of related adverse psychosis outcomes, and thereby protect cannabis users' health.
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Ethnoracial discrimination and the development of suspiciousness symptoms in individuals at clinical high-risk for psychosis. Schizophr Res 2023; 254:125-132. [PMID: 36857950 PMCID: PMC10106391 DOI: 10.1016/j.schres.2023.02.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/31/2023] [Accepted: 02/15/2023] [Indexed: 03/03/2023]
Abstract
BACKGROUND AND HYPOTHESIS While individuals at clinical high-risk (CHR) for psychosis experience higher levels of discrimination than healthy controls, it is unclear how these experiences contribute to the etiology of attenuated positive symptoms. The present study examined the association of perceived discrimination with positive symptoms in a cohort from the North American Prodrome Longitudinal Study (NAPLS2). It predicted that CHR individuals will report higher levels of lifetime and past year perceived discrimination related to their race and ethnicity (ethnoracial discrimination) and that this form of discrimination will be significantly associated with baseline positive symptoms. STUDY DESIGN Participants included 686 CHR and 252 healthy controls. The present study examined data from the perceived discrimination (PD) scale, the Brief Core Schema Scale, and the Scale for the Psychosis-Risk Symptoms. Structural equation modeling was employed to examine whether negative schema of self and others mediated the relation of past year ethnoracial PD to baseline suspiciousness symptoms. RESULTS CHR individuals report higher levels of past year and lifetime PD compared to healthy controls. Lifetime ethnoracial PD was associated with suspiciousness and total positive symptoms. Negative schema of self and others scores partially mediated the relation of past year ethnoracial PD to suspiciousness, one of five positive symptom criteria for CHR. CONCLUSIONS For CHR individuals, past year ethnoracial discrimination was associated with negative beliefs about themselves and others, which was associated with suspiciousness. These findings contribute to an emerging literature characterizing the mechanisms by which discrimination contributes to the positive symptoms characterizing the CHR syndrome.
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Physical Health in Clinical High Risk for Psychosis Individuals: A Cross-Sectional Study. Brain Sci 2023; 13:brainsci13010128. [PMID: 36672109 PMCID: PMC9857012 DOI: 10.3390/brainsci13010128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/30/2022] [Accepted: 01/09/2023] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND The clinical high risk for psychosis (CHR-P) phase represents an opportunity for prevention and early intervention in young adults, which also could focus on improving physical health trajectories. METHODS We conducted a RECORD-compliant clinical register-based cohort study. The primary outcome was to describe the physical health of assessed CHR-P individuals, obtained via Electronic Health Records at the South London and Maudsley (SLaM) NHS Foundation Trust, UK (January 2013-October 2020). RESULTS The final database included 194 CHR-P subjects (46% female). Mean age was 23.70 ± 5.12 years. Percentage of tobacco smokers was 41% (significantly higher than in the age-matched general population [24%]). We found that 49% of subjects who consumed alcohol had an AUDIT-C (Alcohol Use Disorder Identification Test) score above 5 (hazardous drinking), with an average score of 4.94 (significantly higher than in the general population [2.75]). Investigating diet revealed low fiber intake in most subjects and high saturated fat intake in 10% of the individuals. We found that 47% of CHR-P subjects met the UK recommended physical activity guidelines (significantly lower than in the general population [66%]). Physical parameters (e.g., weight, heart rate, blood pressure) were not significantly different from the general population. CONCLUSIONS This evidence corroborates the need for monitoring physical health parameters in CHR-P subjects, to implement tailored interventions that target daily habits.
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Measurement invariance between online and paper-and-pencil formats of the Launay-Slade Hallucinations scale-extended (LSHS-E) in the Chilean population: Invariance between LSHS-E formats. CURRENT PSYCHOLOGY 2022; 42:1-12. [PMID: 35068905 PMCID: PMC8761522 DOI: 10.1007/s12144-021-02497-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2021] [Indexed: 11/28/2022]
Abstract
Research on the multidimensionality of hallucination-like experiences (HLEs) can contribute to the study of psychotic risk. The Launay-Slade Hallucinations Scale-Extended (LSHS-E) is one of the most widely used tools for research in HLEs, but the correspondence of its paper and online formats has not been established yet. Therefore, we studied the factorial structure and measurement invariance between online and paper-and-pencil versions of LSHS-E in a Chilean population. Two thousand eighty-six completed the online version, and 578 students completed the original paper-and-pencil version. After matching by sex, age, civil status, alcohol and cannabis consumption, and psychiatric treatment received, we selected 543 students from each group. We conducted a confirmatory factor analysis of a four-factor model and a hierarchical model that included a general predisposition to hallucination, explaining the strong relationship between the different types of hallucinations. Both models showed a good fit to the data and were invariant between paper-and-pencil and online versions. Also, the LSHS-E has good reliability in both online and paper-and-pencil formats. This study shows that the online LSHS-E possesses psychometric properties equivalent to the paper-and-pencil version. It should be considered a valuable tool for research of psychosis determinants in the COVID-19 era. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s12144-021-02497-7.
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Lifetime Cannabis Use Is Not Associated With Negative Beliefs About Medication in Patients With First Treatment Psychosis. Front Psychiatry 2022; 13:824051. [PMID: 35422717 PMCID: PMC9001842 DOI: 10.3389/fpsyt.2022.824051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 03/07/2022] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE Cannabis use is common among patients with psychosis, and along with negative beliefs about medication, it has been found to predict poor adherence to antipsychotic drug treatment. Such lack of adherence to antipsychotic drug treatment increases the risk of poor clinical outcomes and relapse in patients with first treatment for psychosis (FTP). However, to date, it is unclear whether cannabis use may be related to negative perceptions about antipsychotic drug treatment. METHODS A cross-sectional sample of 265 FTP patients with schizophrenia spectrum disorder underwent extensive clinical assessments. Three measures of cannabis use were obtained: lifetime, current and meeting diagnostic criteria for abuse or addiction. For the primary analyses we focused on lifetime cannabis use. The Beliefs about Medication Questionnaire (BMQ) was employed to assess the patients' specific concerns and perceptions of antipsychotic medications, as well as general beliefs about pharmacotherapy. The relationship between lifetime cannabis use and BMQ scores was investigated with general linear model (GLM) analyses, controlling for age and sex. RESULTS Patients with lifetime use of cannabis ≥10 times were more likely to be male, younger at the age of onset of psychosis and with higher levels of alcohol use and daily tobacco smoking, as compared to the non-users (p < 0.05). Neither lifetime use of cannabis, current use nor a cannabis abuse diagnosis was associated with negative beliefs about medicines as measured by the BMQ questionnaire. CONCLUSION Use of cannabis is not linked to negative perceptions about antipsychotic medicines in patients with FTP. Other reasons for poor compliance to antipsychotic drug treatment in cannabis users need to be further investigated.
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Abstract
BACKGROUND Evidence suggests that an overlap exists between the neurobiology of psychotic disorders and the effects of cannabinoids on neurocognitive and neurochemical substrates involved in reward processing. AIMS We investigate whether the psychotomimetic effects of delta-9-tetrahydrocannabinol (THC) and the antipsychotic potential of cannabidiol (CBD) are underpinned by their effects on the reward system and dopamine. METHODS This narrative review focuses on the overlap between altered dopamine signalling and reward processing induced by cannabinoids, pre-clinically and in humans. A systematic search was conducted of acute cannabinoid drug-challenge studies using neuroimaging in healthy subjects and those with psychosis RESULTS: There is evidence of increased striatal presynaptic dopamine synthesis and release in psychosis, as well as abnormal engagement of the striatum during reward processing. Although, acute THC challenges have elicited a modest effect on striatal dopamine, cannabis users generally indicate impaired presynaptic dopaminergic function. Functional MRI studies have identified that a single dose of THC may modulate regions involved in reward and salience processing such as the striatum, midbrain, insular, and anterior cingulate, with some effects correlating with the severity of THC-induced psychotic symptoms. CBD may modulate brain regions involved in reward/salience processing in an opposite direction to that of THC. CONCLUSIONS There is evidence to suggest modulation of reward processing and its neural substrates by THC and CBD. Whether such effects underlie the psychotomimetic/antipsychotic effects of these cannabinoids remains unclear. Future research should address these unanswered questions to understand the relationship between endocannabinoid dysfunction, reward processing abnormalities, and psychosis.
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Cannabis use, polysubstance use, and psychosis prodrome among first-degree relatives of patients with schizophrenia. JOURNAL OF SUBSTANCE USE 2021. [DOI: 10.1080/14659891.2021.1989510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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A latent class analysis of psychiatric symptom profiles associated with past-month methamphetamine use. Psychiatry Res 2021; 298:113760. [PMID: 33548691 DOI: 10.1016/j.psychres.2021.113760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 01/23/2021] [Indexed: 11/29/2022]
Abstract
We explored latent psychiatric symptom profiles associated with methamphetamine use, and examined how these corresponded to diagnoses of schizophrenia (SZ) and methamphetamine-associated psychosis (MAP). We assessed psychiatric symptoms among 160 people who had used methamphetamine in the past month. Psychiatric symptoms were defined as a score of 4+ on Brief Psychiatric Rating Scale (BPRS) items. Diagnoses were made using the Composite International Diagnostic Interview (CIDI). Participants were defined as having MAP if they met symptom criteria for SZ, but symptoms were considered to be always the result of substance use. Latent class analysis identified three classes. Class one (44% of participants) had a low probability of most BPRS symptoms; 4% met criteria for SZ, 51% for MAP. Class two (31% of participants) had a higher probability hallucinations and suspiciousness (37-46%); 72% met criteria for MAP, and 7% for SZ. Class three (25% of participants) had the highest probability for all positive psychotic symptoms (hallucinations, suspiciousness, grandiosity, unusual thought content; 32-82%), and reported activation, conceptual disorganisation, and tension (35% met criteria for SZ and 17% for MAP). We found three distinct classes of psychiatric symptom profiles, two of which showed partial alignment with diagnostic constructs of SZ and MAP.
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Cannabis use in adolescence and risk of psychosis: Are there factors that moderate this relationship? A systematic review and meta-analysis. Subst Abus 2021; 42:527-542. [DOI: 10.1080/08897077.2021.1876200] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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A Retrospective Study of the Clinical Characteristics Associated with Alcohol and Cannabis use in Early Phase Psychosis. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2020; 65:426-435. [PMID: 32013556 PMCID: PMC7265604 DOI: 10.1177/0706743720905201] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Alcohol and cannabis misuse are common in patients with early phase psychosis (EPP); however, research has tended to focus primarily on cannabis misuse and EPP outcomes, with a relative lack of data on alcohol misuse. This retrospective cross-sectional EPP study investigated the relationship between cannabis, alcohol, and cannabis combined with alcohol misuse, on age, gender, psychotic, depressive and anxiety symptom severity, and social/occupational functioning, at entry to service. METHODS Two-hundred and sixty-four EPP patients were divided into 4 groups based on substance use measured by the Alcohol, Smoking and Substance Involvement Screening Test: (1) no to low-level cannabis and alcohol misuse (LU), (2) moderate to high alcohol misuse only (AU), (3) moderate to high cannabis misuse only (CU), and (4) moderate to high alcohol and cannabis misuse (AU + CU). RESULTS We found significant between group differences in age (with the AU group being the oldest and AU + CU group the youngest) as well as gender (with the CU group having the highest percentage of men). There were also group differences in positive psychotic symptoms (lowest in AU group), trait anxiety (highest in AU + CU group), and social/occupational functioning (highest in AU group). Further regression analyses revealed a particularly strong relationship between AU + CU group and trait anxiety (3-fold increased odds of clinical trait anxiety for combined misuse of alcohol and cannabis compared to non/low users). CONCLUSIONS This study demonstrates the unique demographic and clinical characteristics found in the EPP population at entry to care associated with alcohol and cannabis misuse both separately and in combination. This work highlights the importance of including the assessment of alcohol misuse in addition to cannabis misuse in future treatment guidelines and research.
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Telepsychotherapy with Youth at Clinical High Risk for Psychosis: Clinical Issues and Best Practices during the COVID-19 Pandemic. JOURNAL OF PSYCHOTHERAPY INTEGRATION 2020; 30:304-331. [PMID: 34305369 PMCID: PMC8297958 DOI: 10.1037/int0000211] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Early detection and prevention of psychosis has become an international priority. Much of this work has focused on youth presenting with attenuated symptoms of psychosis-those at Clinical High Risk for psychosis (CHR)-given their elevated probability of developing the full disorder in subsequent years. Individuals at CHR may be prone to exacerbated psychological distress during the COVID-19 pandemic and its subsequent physical isolation measures, due to heightened stress sensitivity and comorbid mental health problems. Telepsychotherapy holds promise for reaching this population, especially during the current COVID-19 outbreak. However, there are limited evidence-based guidelines or interventions for use of telepsychotherapy with this population. In this paper, we review common clinical issues for individuals at CHR and how they might be exacerbated by the COVID-19 pandemic; best practices for treatment and adaptations for telepsychotherapy for individuals at CHR; and highlight real clinical issues that we are currently experiencing in a United States-based specialized CHR clinic as we conduct telepsychotherapy via videoconferencing. We conclude with questions for those in the field to contemplate, as well as potential challenges and benefits in using telepsychotherapy with individuals at CHR and their families.
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Editorial: Brain Mediators of the Cannabis-Prodromal Psychosis Connection. J Am Acad Child Adolesc Psychiatry 2020; 59:592-594. [PMID: 31634567 DOI: 10.1016/j.jaac.2019.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/24/2019] [Accepted: 10/14/2019] [Indexed: 01/03/2023]
Abstract
The article by Yu and Jia et al.1 in this issue of the Journal investigates the role of a subregion of the parahippocampal gyrus called the right uncus ("hook") as a possible mediator of the known increase of psychotic-like experiences (PLEs) due to the consumption of cannabinoids (ie, cannabis).2 The authors chose a pattern of plausible inference worthy of pursuit. Cannabis continues to be one of the most widely used drugs globally, only behind alcohol, caffeine, and tobacco; 188 million people used cannabis worldwide in 2017.3 In January 2019, the WHO's Expert Committee on Drug Dependence (ECDD)4 recommended that cannabis be no longer classified as a Schedule IV drug (its medical potential is now deemed to outweigh its abuse potential). It should be noted that cannabidiol (CBD) is a non-psychoactive component of cannabis that has medicial uses in reducing pain and inflammation, controlling epileptic seizures, and possibly even treating mental illness and addiction.5 As more world governments legalize cannabis for recreational use, and owing to the widening availability of higher tetrahydrocannabinol content variants of cannabis, the number of cannabis users is increasing rapidly, which in turn increases the number of people having PLEs worldwide. Schizophrenia is one of the top 15 leading causes of disability worldwide.6 The estimated prevalence of schizophrenia and related psychotic disorders in the United States in 2005 ranged from 0.25% to 0.64%7; a meta-analysis a decade later found the lifetime prevalence worldwide to be 0.48% with interquartile range 0.34% to 0.85%.8 The high variability of sampling domains, diagnostic criteria, data availability and analytic methods employed preclude reliable estimates of incidence and prevalence increases of schizophrenia at present.
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Cannabis use in individuals at clinical high-risk for psychosis: a comprehensive review. Soc Psychiatry Psychiatr Epidemiol 2020; 55:527-537. [PMID: 31796983 DOI: 10.1007/s00127-019-01810-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/28/2019] [Indexed: 12/16/2022]
Abstract
PURPOSE The objectives of this review were to understand the prevalence of cannabis use and how cannabis is associated with transition to psychosis, symptoms, cognition, trauma and family history in clinical high risk (CHR) for psychosis individuals. METHOD A systematic literature review was conducted to find studies that examined cannabis use in CHR individuals, with no limitations on the geographical area, and included publications up to November 2018. Studies were screened for inclusion based on detailed criteria, and data were extracted on cannabis use and associated outcomes. A quantitative synthesis by meta-analysis was performed where appropriate, otherwise, a qualitative synthesis was conducted. RESULTS Overall, 36 studies met inclusion criteria with an average age of 20.1 years and 58.4% males. Prevalence of lifetime cannabis use was 48.7%, whereas current cannabis use was 25.8% and the prevalence of cannabis use disorder/abuse or dependence was 14.9% across the studies. All cannabis use results had statistically significant heterogeneity ranging from 75.7 to 92.8%. The most commonly reported association with cannabis use was transition to psychosis, although the pooled relative risk (RR) was not statistically significant (RR = 1.11, 95% confidence interval = 0.89-1.37). For all other outcomes including symptoms, cognition, trauma, and family history, the evidence was limited, and therefore, the results were synthesized qualitatively. CONCLUSION Almost half of CHR individuals have ever used cannabis. However, cannabis use has not been thoroughly researched regarding frequency and dose of use, and how other factors, such as symptoms, are associated with cannabis in CHR individuals.
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Factors Moderating the Association Between Cannabis Use and Psychosis Risk: A Systematic Review. Brain Sci 2020; 10:brainsci10020097. [PMID: 32059350 PMCID: PMC7071602 DOI: 10.3390/brainsci10020097] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/07/2020] [Accepted: 02/10/2020] [Indexed: 12/11/2022] Open
Abstract
Increasing evidence indicates a relationship between cannabis use and psychosis risk. Specific factors, such as determinants of cannabis use or the genetic profile of cannabis users, appear to moderate this association. The present systematic review presents a detailed and up-to-date literature overview on factors that influence the relationship between cannabis use and psychosis risk. A systematic search was performed according to the PRISMA guidelines in MEDLINE and Embase, and 56 studies were included. The results show that, in particular, frequent cannabis use, especially daily use, and the consumption of high-potency cannabis are associated with a higher risk of developing psychosis. Moreover, several genotypes moderate the impact of cannabis use on psychosis risk, particularly those involved in the dopamine function, such as AKT1. Finally, cannabis use is associated with an earlier psychosis onset and increased risk of transition in individuals at a clinical high risk of psychosis. These findings indicate that changing cannabis use behavior could be a harm reduction strategy employed to lower the risk of developing psychosis. Future research should aim to further develop specific biomarkers and genetic profiles for psychosis, thereby contributing to the identification of individuals at the highest risk of developing a psychotic disorder.
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[Cannabis use in subjects at ultra high risk for psychosis]. Presse Med 2019; 48:1229-1236. [PMID: 31732360 DOI: 10.1016/j.lpm.2019.09.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 07/10/2019] [Accepted: 09/23/2019] [Indexed: 11/30/2022] Open
Abstract
Cannabis use is widespread among people at ultra-high risk (UHR) for psychosis. The causal link as well as the temporal link between cannabis use and further occurrence of psychosis in UHR people remain inconclusive. Current science data supported an increased risk of transition to psychosis in cannabis users who are genetically predisposed to psychosis. This risk would be even greater in the presence of a family history of psychosis, in case of a strong use and an early onset use. Several models have been cited to explain the link between cannabis use and the subsequent onset of psychosis or prepsychotic states: cannabis-induced modifications of some brain structures, a dysregulation of the hypothalamic-pituitary axis and an alteration of normal neurological development via the endocannabinoid system. Cannabis represents a modifiable risk for psychosis. Current interventions aim to reduce or stop the cannabis use in order to reduce the risk of transition to psychosis.
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The psychosis risk timeline: can we improve our preventive strategies? Part 2: adolescence and adulthood. BJPSYCH ADVANCES 2019. [DOI: 10.1192/bja.2019.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARYCurrent understanding of psychosis development is relevant to patients' clinical outcomes in mental health services as a whole, given that psychotic symptoms can be a feature of many different diagnoses at different stages of life. Understanding the risk factors helps clinicians to contemplate primary, secondary and tertiary preventive strategies that it may be possible to implement. In this second article of a three-part series, the psychosis risk timeline is again considered, here focusing on risk factors more likely to be encountered during later childhood, adolescence and adulthood. These include environmental factors, substance misuse, and social and psychopathological aspects.LEARNING OBJECTIVES:After reading this article you will be able to:
•understanding the range of risk factors for development of psychotic symptoms in young people and adults•understand in particular the association between trauma/abuse and subsequent psychosis•appreciate current evidence for the nature and strength of the link between substance misuse and psychosis.DECLARATION OF INTEREST:None.
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What prevents youth at clinical high risk for psychosis from engaging in physical activity? An examination of the barriers to physical activity. Schizophr Res 2018; 201:400-405. [PMID: 29907494 PMCID: PMC6252130 DOI: 10.1016/j.schres.2018.06.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 06/08/2018] [Accepted: 06/08/2018] [Indexed: 01/09/2023]
Abstract
BACKGROUND Exercise has increasingly been proposed as a healthful intervention prior to and after the onset of psychosis. There is some evidence to suggest that youth at clinical high risk (CHR) for psychosis are less physically active and report more barriers to engaging in exercise; however, there has been relatively limited empirical work documenting this phenomenon, and to date, relationships between physical activity, barriers, and clinical phenomenology have been unclear. METHODS CHR (N = 51) and healthy control (N = 37) participants completed a structured clinical interview assessing attenuated psychotic symptoms and substance use, and an exercise survey that assessed current exercise practices, perceived physical fitness, and barriers related to engaging in exercise. RESULTS CHR youth engaged in less physical activity, exhibited lower perception of fitness, and endorsed more barriers related to motivation for exercise. The CHR group showed significant negative correlations where lower perceptions of fitness were associated with increased negative, disorganized, and general symptoms. Decreased frequency of activity was related to more barriers of motivation. Interestingly, greater symptomatology in the CHR group was associated with more barriers of self-perception and motivation for engaging in exercise. However, findings suggested a nuanced relationship in this area; for example, increased physical activity was associated with increased substance use. CONCLUSIONS The results of the current study support the notion that sedentary behavior is common in CHR youth, and more broadly, provide an impetus to target motivation through supervised exercise and fitness tracking to promote the health and well-being of CHR individuals.
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Impact of comorbid cannabis use on outcome in first episode psychosis. Early Interv Psychiatry 2018; 12:848-855. [PMID: 27592556 DOI: 10.1111/eip.12377] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/26/2016] [Accepted: 06/12/2016] [Indexed: 11/29/2022]
Abstract
AIM Comorbid cannabis abuse is common in patients with early psychosis. Little is known about the effect of stopping cannabis use on positive, negative and depressive symptoms. Few studies have controlled for multiple substance use that may mask the specific role that cannabis plays in symptom outcomes. The aim of this study was to investigate whether course and level of cannabis use negatively impacted early psychosis patient symptom profiles (positive, negative and depressive symptoms) over 24 months. METHODS One hundred and ninety-two patients admitted to an early psychosis intervention programme in a naturalistic setting were followed across three time periods: initial presentation, 12 and 24 months. Patients' clinical characteristics (substance use, positive/negative symptoms and depressive symptoms) were assessed at each time period. RESULTS There were no significant associations found between cannabis abuse and positive and negative symptoms. Continuation and discontinuation of cannabis use were not significant for cannabis or any other substance when compared to positive and negative symptoms. There was a significant interaction between cannabis and alcohol for depressive symptoms, where depressive symptoms were significantly higher in patients who abused cannabis without co-occurring alcohol abuse when compared to non-cannabis using patients. CONCLUSION The current study findings indicate a complex interaction between cannabis and alcohol use in a sample of early psychosis patients across 24 months. More research is needed into the association between ceasing cannabis use and long-term outcome for early psychosis patients. Of particular importance is the interaction between level of cannabis and alcohol use as it is related to symptom outcome in early psychosis patients.
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Are cannabis-using and non-using patients different groups? Towards understanding the neurobiology of cannabis use in psychotic disorders. J Psychopharmacol 2018; 32:825-849. [PMID: 29591635 PMCID: PMC6058406 DOI: 10.1177/0269881118760662] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A substantial body of credible evidence has accumulated that suggest that cannabis use is an important potentially preventable risk factor for the development of psychotic illness and its worse prognosis following the onset of psychosis. Here we summarize the relevant evidence to argue that the time has come to investigate the neurobiological effects of cannabis in patients with psychotic disorders. In the first section we summarize evidence from longitudinal studies that controlled for a range of potential confounders of the association of cannabis use with increased risk of developing psychotic disorders, increased risk of hospitalization, frequent and longer hospital stays, and failure of treatment with medications for psychosis in those with established illness. Although some evidence has emerged that cannabis-using and non-using patients with psychotic disorders may have distinct patterns of neurocognitive and neurodevelopmental impairments, the biological underpinnings of the effects of cannabis remain to be fully elucidated. In the second and third sections we undertake a systematic review of 70 studies, including over 3000 patients with psychotic disorders or at increased risk of psychotic disorder, in order to delineate potential neurobiological and neurochemical mechanisms that may underlie the effects of cannabis in psychotic disorders and suggest avenues for future research.
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Abstract
BACKGROUND The association between cannabis use and the risk of psychosis has been studied extensively but the temporal order still remains controversial. Aims To examine the association between cannabis use in adolescence and the risk of psychosis after adjustment for prodromal symptoms and other potential confounders. METHOD The sample (n = 6534) was composed of the prospective general population-based Northern Finland Birth Cohort of 1986. Information on prodromal symptoms of psychosis and cannabis use was collected using questionnaires at age 15-16 years. Participants were followed up for ICD-10 psychotic disorders until age 30 years using nationwide registers. RESULTS The risk of psychosis was elevated in individuals who had tried cannabis five times or more (hazard ratio, (HR) = 6.5, 95% CI 3.0-13.9). The association remained statistically significant even when adjusted for prodromal symptoms, other substance use and parental psychosis (HR = 3.0, 95% CI 1.1-8.0). CONCLUSIONS Adolescent cannabis use is associated with increased risk of psychosis even after adjustment for baseline prodromal symptoms, parental psychosis and other substance use. Declaration of interest None.
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Acute effects of smoked marijuana in marijuana smokers at clinical high-risk for psychosis: A preliminary study. Psychiatry Res 2017; 257:372-374. [PMID: 28803095 PMCID: PMC5890804 DOI: 10.1016/j.psychres.2017.07.070] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 06/08/2017] [Accepted: 07/30/2017] [Indexed: 11/20/2022]
Abstract
Marijuana use is associated with psychosis, but its effects are understudied in individuals with preexisting risk for psychotic disorders. This preliminary study examined the acute psychological and physiological effects of smoked marijuana (0.0% or 5.5% Δ9-THC) in marijuana users at clinical high-risk (CHR; n = 6) to develop a psychotic disorder, and those not at risk (n = 6), under controlled laboratory conditions. CHR marijuana users exhibited temporary increases in psychotic-like states and decreases in neurocognitive performance during marijuana intoxication but control marijuana smokers did not. These findings, if replicated, may support a psychotogenic role for marijuana in CHR individuals.
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Prevalence and Correlates of Cannabis Use in Outpatients with Serious Mental Illness Receiving Treatment for Alcohol Use Disorders. Cannabis Cannabinoid Res 2017; 2:133-138. [PMID: 28861513 PMCID: PMC5569619 DOI: 10.1089/can.2017.0006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Introduction: People with serious mental illness (SMI) use cannabis more than any other illicit drug. Cannabis use is associated with increased psychotic symptoms and is highly comorbid with alcohol use disorders (AUDs). Despite the national trend toward decriminalization, little is known about the prevalence, correlates, and impact of cannabis use on those with SMI receiving treatment for substance use disorders, a group at high risk for the negative effects of cannabis use. Methods: In this secondary data analysis, cannabis use prevalence, correlates, and impact on treatment outcomes were examined in 121 adults with cooccurring SMI and AUDs receiving outpatient addiction treatment in a randomized trial of contingency management (CM) for alcohol. Prevalence and frequency of cannabis use were calculated across the 7-month study period using self-report and urine tests. Cannabis users were compared with nonusers by SMI diagnosis, psychiatric symptoms, medical problems, legal problems, and HIV-risk behavior. The relationship between cannabis use and longest duration of alcohol abstinence in participants randomized to CM (n=40) was assessed. Results: Fifty-seven (47%) of participants submitted at least one cannabis-positive urine sample during the study. Out of the 2834 total samples submitted, 751 (27%) were positive for cannabis. Cannabis users were 2.2 times more likely to submit an alcohol-positive sample, and 2.5 times more likely to submit a cocaine-positive sample at baseline, relative to noncannabis users (p=0.01). Cannabis users were more likely to engage in risky sexual behavior (p=0.01) and to report being homeless (p=0.03) than nonusers. When controlling for pretreatment alcohol use, the relationship between comorbid cannabis use and alcohol abstinence during CM was not significant (p=0.77). Conclusion: Rates of comorbid cannabis use were high in this sample of adults with SMI and AUDs. Cannabis use was correlated with recent alcohol and cocaine use, risky sexual behavior, and homelessness, but not with alcohol abstinence during CM.
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Cannabis use and symptom severity in individuals at ultra high risk for psychosis: a meta-analysis. Acta Psychiatr Scand 2017; 136:5-15. [PMID: 28168698 PMCID: PMC5484316 DOI: 10.1111/acps.12699] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/09/2017] [Indexed: 02/07/2023]
Abstract
OBJECTIVE We aimed to assess whether individuals at ultra high risk (UHR) for psychosis have higher rates of cannabis use and cannabis use disorders (CUDs) than non-UHR individuals and determine whether UHR cannabis users have more severe psychotic experiences than non-users. METHOD We conducted a meta-analysis of studies reporting cannabis use in the UHR group and/or positive or negative symptoms among UHR cannabis users and non-users. Logit event rates were calculated for cannabis use, in addition to odds ratios to assess the difference between UHR and controls. Severity of clinical symptoms in UHR cannabis users and non-users was compared using Hedges' g. RESULTS Thirty unique studies were included (UHR n = 4205, controls n = 667) containing data from cross-sectional and longitudinal studies, and randomised control trials. UHR individuals have high rates of current (26.7%) and lifetime (52.8%) cannabis use, and CUDs (12.8%). Lifetime use and CUDs were significantly higher than controls (lifetime OR: 2.09; CUD OR: 5.49). UHR cannabis users had higher rates of unusual thought content and suspiciousness than non-users. CONCLUSION Ultra high risk individuals have high rates of cannabis use and CUDs, and cannabis users had more severe positive symptoms. Targeting substance use during the UHR phase may have significant benefits to an individual's long-term outcome.
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Deconstructing Vulnerability for Psychosis: Meta-Analysis of Environmental Risk Factors for Psychosis in Subjects at Ultra High-Risk. Eur Psychiatry 2016; 40:65-75. [DOI: 10.1016/j.eurpsy.2016.09.003] [Citation(s) in RCA: 184] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 09/13/2016] [Accepted: 09/15/2016] [Indexed: 01/13/2023] Open
Abstract
AbstractBackgroundSubjects at ultra high-risk (UHR) for psychosis have an enhanced vulnerability to develop the disorder but the risk factors accounting for this accrued risk are undetermined.MethodSystematic review of associations between genetic or environmental risk factors for psychosis that are widely established in the literature and UHR state, based on comparisons to controls.ResultsForty-four studies encompassing 170 independent datasets and 54 risk factors were included. There were no studies on association between genetic or epigenetic risk factors and the UHR state that met the inclusion criteria. UHR subjects were more likely to show obstetric complications, tobacco use, physical inactivity, childhood trauma/emotional abuse/physical neglect, high perceived stress, childhood and adolescent low functioning, affective comorbidities, male gender, single status, unemployment and low educational level as compared to controls.ConclusionsThe increased vulnerability of UHR subjects can be related to environmental risk factors like childhood trauma, adverse life events and affective dysfunction. The role of genetic and epigenetic risk factors awaits clarification.
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Letter to the Editor: Disentangling cause and effect in the relationship between cannabis and psychosis: are we there yet? Psychol Med 2016; 46:3061-3062. [PMID: 27452108 DOI: 10.1017/s0033291716001434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
BACKGROUND Previous research has established the relationship between cannabis use and psychotic disorders. Whether cannabis use is related to transition to psychosis in patients at ultra-high risk (UHR) for psychosis remains unclear. The present study aimed to review the existing evidence on the association between cannabis use and transition to psychosis in UHR samples. METHOD A search of PsychInfo, Embase and Medline was conducted from 1996 to August 2015. The search yielded 5559 potentially relevant articles that were selected on title and abstract. Subsequently 36 articles were screened on full text for eligibility. Two random-effects meta-analyses were performed. First, we compared transition rates to psychosis of UHR individuals with lifetime cannabis use with non-cannabis-using UHR individuals. Second, we compared transition rates of UHR individuals with a current DSM-IV cannabis abuse or dependence diagnosis with lifetime users and non-using UHR individuals. RESULTS We found seven prospective studies reporting on lifetime cannabis use in UHR subjects (n = 1171). Of these studies, five also examined current cannabis abuse or dependence. Lifetime cannabis use was not significantly associated with transition to psychosis [odds ratio (OR) 1.14, 95% confidence interval (CI) 0.856-1.524, p = 0.37]. A second meta-analysis yielded an OR of 1.75 (95% CI 1.135-2.710, p = 0.01), indicating a significant association between current cannabis abuse or dependence and transition to psychosis. CONCLUSIONS Our results show that cannabis use was only predictive of transition to psychosis in those who met criteria for cannabis abuse or dependence, tentatively suggesting a dose-response relationship between current cannabis use and transition to psychosis.
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Abstract
LEARNING OBJECTIVES After participating in this activity, learners should be better able to: ABSTRACT The psychosis prodrome, or period of clinical and functional decline leading up to acute psychosis, offers a unique opportunity for identifying mechanisms of psychosis onset and for testing early-intervention strategies. We summarize major findings and emerging directions in prodromal research and provide recommendations for clinicians working with individuals suspected to be at high risk for psychosis. The past two decades of research have led to three major advances. First, tools and criteria have been developed that can reliably identify imminent risk for a psychotic disorder. Second, longitudinal clinical and psychobiological data from large multisite studies are strengthening individual risk assessment and offering insights into potential mechanisms of illness onset. Third, psychosocial and pharmacological interventions are demonstrating promise for delaying or preventing the onset of psychosis in help-seeking, high-risk individuals. The dynamic psychobiological processes implicated in both risk and onset of psychosis, including altered gene expression, cognitive dysfunction, inflammation, gray and white matter brain changes, and vulnerability-stress interactions suggest a wide range of potential treatment targets and strategies. The expansion of resources devoted to early intervention and prodromal research worldwide raises hope for investigating them. Future directions include identifying psychosis-specific risk and resilience factors in children, adolescents, and non-help-seeking community samples, improving study designs to test hypothesized mechanisms of change, and intervening with strategies that, in order to improve functional outcomes, better engage youth, address their environmental contexts, and focus on evidence-based neurodevelopmental targets. Prospective research on putatively prodromal samples has the potential to substantially reshape our understanding of mental illness and our efforts to combat it.
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Abstract
Interest in the relationship between cannabis use and psychosis has increased dramatically in recent years, in part because of concerns related to the growing availability of cannabis and potential risks to health and human functioning. There now exists a plethora of scientific articles addressing this issue, but few provide a clear verdict about the causal nature of the cannabis-psychosis association. Here, we review recent research reports on cannabis and psychosis, giving particular attention to how each report provides evidence relating to two hypotheses: (1) cannabis as a contributing cause and (2) shared vulnerability. Two primary kinds of data are brought to bear on this issue: studies done with schizophrenic patients and studies of first-episode psychosis. Evidence reviewed here suggests that cannabis does not in itself cause a psychosis disorder. Rather, the evidence leads us to conclude that both early use and heavy use of cannabis are more likely in individuals with a vulnerability to psychosis. The role of early and heavy cannabis use as a prodromal sign merits further examination, along with a variety of other problem behaviors (e.g., early or heavy use of cigarettes or alcohol and poor school performance). Future research studies that focus exclusively on the cannabis-psychosis association will therefore be of little value in our quest to better understand psychosis and how and why it occurs.
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Evaluating the relationship between cannabis use and IQ in youth and young adults at clinical high risk of psychosis. Psychiatry Res 2015; 230:878-84. [PMID: 26626949 PMCID: PMC5037441 DOI: 10.1016/j.psychres.2015.11.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 11/12/2015] [Accepted: 11/13/2015] [Indexed: 11/28/2022]
Abstract
Among people with psychosis, those with a history of cannabis use show better cognitive performance than those who are cannabis naïve. It is unknown whether this pattern is present in youth at clinical high risk (CHR) of psychosis. We evaluated relationships between IQ and cannabis use while controlling for use of other substances known to impact cognition in 678 CHR and 263 healthy control (HC) participants. IQ was estimated using the Vocabulary and Block Design subtests of the Wechsler Abbreviated Scale of Intelligence. Drug and alcohol use severity and frequency were assessed with the Alcohol and Drug Use Scale, and we inquired participants' age at first use. CHR were further separated into early and late age at onset of cannabis use sub-groups, and low-, moderate- and high-frequency sub-groups. No significant differences in IQ emerged between CHR or HC cannabis users vs. non-users, or between use frequency groups. CHR late-onset users showed significantly higher IQ than CHR early-onset users. Age at onset of cannabis use was significantly and positively correlated with IQ in CHR only. Results suggest that age at onset of cannabis may be a more important factor for IQ than use current use or use frequency in CHR.
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