The Cannabis Pathway to Non-Affective Psychosis may Reflect Less Neurobiological Vulnerability

Association between Cannabis Use Disorder and Mental Health Disorders in the Adolescent Population: A Cohort Study

INTRODUCTION

According to the literature, early initiation to cannabis use and a dependent pattern of use are important risk factors for the development of mental health disorders. However, there are few cohort studies which look at the development of mental health disorders associated with cannabis use among young people with cannabis use disorder (CUD). The aim of the study was to determine the cumulative incidence of mental health disorders and the risk of developing mental health disorders among minors who commenced treatment for CUD in Catalonia during 2015-2019.

METHODS

This was a retrospective fixed cohort study, matched for confounding variables, based on data from the Catalan Health Surveillance System. The exposed cohort comprised young people who entered treatment for CUD during 2015-2019 (n = 948) and who were minors on the date of commencing treatment. Matching was done with a paired cohort (n = 4,737), according to confounding variables. Individuals with a diagnosis of a mental health disorder prior to the study period were excluded. The cumulative incidence was calculated for mental health disorders for the exposed and the paired cohorts and stratified by type of mental disorder. Incidence rate ratios were estimated using the conditional Poisson model with robust variance, stratified by sex.

RESULTS

The cumulative incidence for development of a mental health disorder was 19.6% in the exposed cohort and 3.1% in the paired cohort; with higher incidence among females (females 32.7%; males 15.8%). The exposed cohort had an 8.7 times increased risk of developing a mental health disorder than the paired cohort. The most frequent diagnoses were reaction to severe stress, adjustment disorder, and personality disorders.

CONCLUSION

This study confirmed that the exposed cohort was at increased risk of developing mental health disorders compared to the paired cohort. To date, few studies have analyzed the association between cannabis use and the development of mental health disorders, considering cannabis dependence. Further studies should be undertaken considering CUD. In addition, more studies are needed to understand the factors that determine the development of CUD. Further research in these areas would contribute to the design of prevention strategies aimed at those young individuals with a higher risk of developing cannabis dependence and suffering its consequences.

A Prospective Biopsychosocial Repeated Measures Study of Stress and Dropout from Substance Addiction Treatment

Introduction

This prospective, repeated-measures observational study tested biopsychosocial variables as risk factors for dropping out of inpatient substance addiction treatment. Substance use disorder (SUD) is viewed as a chronic relapsing disease caused by an interaction between biological, psychological, and social factors. However, there is a lack of prospective studies that combine biopsychosocial variables when assessing dropout. The aims of this study were to investigate whether there was 1) An association between biopsychosocial factors and dropping out of inpatient substance addiction treatment, 2) An interaction with SUD diagnosis and cortisol, and 3) Different dropout rates between short-term and long-term institutions.

Materials and Methods

Patients (n = 173) were recruited from two inpatient treatment centers in Norway between 2018 and 2021. The following biopsychosocial variables were measured at four timepoints: ward atmosphere (Ward Atmosphere Scale, WAS), psychological distress (Hopkins Symptom Checklist 10, HSCL-10), motivation (M-scale of the Circumstances, Motivation, Readiness, and Suitability questionnaire), and concentration of salivary cortisol (CORT- nmol/L). Cortisol levels were measured for two consecutive days at each timepoint and calculated by two cortisol indices, daytime cortisol slope (DCS) and area under the curve with respect to the ground (AUC_G). A multivariate logistic regression analysis was performed to find an association between dropout rates and the biopsychosocial variables.

Results

The results suggest a lower dropout odds for patients with high motivation (OR = 0.76, p = 0.022) and patients admitted to short-term treatment (OR = 0.06, p = 0.005). An interaction with stimulant SUD and DCS (OR = 13.74, p = 0.024) also revealed higher dropout odds. No statistical significance was found for psychological distress, WAS, and cortisol AUC_G.

Conclusion

The results support monitoring motivation during treatment and further investigating biopsychosocial variables when assessing dropout risk together with SUD diagnosis.

Eye movements in patients in early psychosis with and without a history of cannabis use

It is unclear whether early psychosis in the context of cannabis use is different from psychosis without cannabis. We investigated this issue by examining whether abnormalities in oculomotor control differ between patients with psychosis with and without a history of cannabis use. We studied four groups: patients in the early phase of psychosis with a history of cannabis use (EPC; n = 28); patients in the early phase of psychosis without (EPNC; n = 25); controls with a history of cannabis use (HCC; n = 16); and controls without (HCNC; n = 22). We studied smooth pursuit eye movements using a stimulus with sinusoidal waveform at three target frequencies (0.2, 0.4 and 0.6 Hz). Participants also performed 40 antisaccade trials. There were no differences between the EPC and EPNC groups in diagnosis, symptom severity or level of functioning. We found evidence for a cannabis effect (χ2 = 23.14, p < 0.001), patient effect (χ2 = 4.84, p = 0.028) and patient × cannabis effect (χ2 = 4.20, p = 0.04) for smooth pursuit velocity gain. There was a large difference between EPC and EPNC (g = 0.76-0.86) with impairment in the non cannabis using group. We found no significant effect for antisaccade error whereas patients had fewer valid trials compared to controls. These data indicate that impairment of smooth pursuit in psychosis is more severe in patients without a history of cannabis use. This is consistent with the notion that the severity of neurobiological alterations in psychosis is lower in patients whose illness developed in the context of cannabis use.

Substance use and symptoms of mental health disorders: a prospective cohort of patients with severe substance use disorders in Norway

BACKGROUND

There is high co-occurrence of substance use disorders (SUD) and mental health disorders. We aimed to assess impact of substance use patterns and sociodemographic factors on mental health distress using the ten-item Hopkins Symptom Checklist (SCL-10) over time.

METHODS

Nested prospective cohort study of 707 participants with severe SUD across nine opioid-agonist-therapy outpatient clinics and low-threshold municipality clinics in Norway, during 2017-2020. Descriptive statistics were derived at baseline and reported by means and standard deviation (SD). A linear mixed model analysis was used to assess the impact of substance use patterns and sociodemographic factors on SCL-10 sum score with beta coefficients with 95% confidence intervals (CI).

RESULTS

Mean (SD) SCL-10 score was 2.2 (0.8) at baseline with large variations across patients. We observed more symptoms of mental health disorders among people with frequent use of benzodiazepines (beta 3.6, CI:2.4;4.8), cannabis (1.3, CI:0.2;2.5), opioids (2.7, CI:1.1;4.2), and less symptoms among people using frequent stimulant use (- 2.7, CI:-4.1;-1.4) compared to no or less frequent use. Females (1.8, CI:0.7;3.0) and participants with debt worries (2.2, CI:1.1;3.3) and unstable living conditions (1.7, CI:0.0;3.3) had also higher burden of mental health symptoms. There were large individual variations in SCL-10 score from baseline to follow-up, but no consistent time trends indicating change over time for the whole group. 65% of the cohort had a mean score > 1.85, the standard reference score.

CONCLUSIONS

People with SUD have a considerable burden of mental health symptoms. We found no association between substance use patterns and change in mental health symptoms over time. This could suggest that the differences observed were indicating flattening of effects or self-medication to a larger degree than medication-related decline in mental health. This call for better individualized mental health assessment and patient care.

Does childhood trauma influence cognitive functioning in schizophrenia? The association of childhood trauma and cognition in schizophrenia spectrum disorders

Childhood trauma (CT) is a risk factor for schizophrenia spectrum disorders (SSDs), and cognitive impairment is a core feature and a vulnerability marker of SSDs. Studies of the relationship between CT and cognitive impairment in SSDs are inconclusive. In addition, few studies have examined differential effects of CT subtypes, e.g. physical, sexual or emotional abuse/neglect, on cognitive functioning. The present study therefore aimed to examine the effects of CT and CT subtypes on cognitive impairment in SSD. Participants (n = 78) with SSDs completed a comprehensive neuropsychological test battery and the Childhood Trauma Questionnaire Short-Form (CTQ-SF). We compared global cognitive performance as well as scores in seven subdomains (verbal abilities, visuospatial abilities, learning, memory, attention/working memory, executive abilities and processing speed) between participants reporting no CT and those reporting CT experiences using independent samples t-tests as well as linear regression analyses to control for possible confounders. CT subtype physical neglect was associated with attention and working memory after controlling for positive and negative psychosis symptoms, years of education, antipsychotics, gender and age, and adjustment of multiple testing. Our results indicate that the observed heterogeneity in cognitive impairment in SSDs, especially attention/working memory abilities, may in part be associated with childhood physical neglect.

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Research on childhood trauma and cognitive impairment in SSDs is inconclusive

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Few studies investigated if CT subtypes (abuse and neglect) could explain the heterogeneity in cognitive impairment in SSDs

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CT subtype physical neglect was associated with impairment in attention/working memory abilities

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The observed heterogeneity in cognitive impairment in SSDs may in part be associated with CT subtypes

Psychosocial characteristics differentiate non-distressing and distressing voices in 10,346 adolescents

Adolescents hearing non-existent voices may be at risk for psychosis, but the prevalence of voice-hearing (VH) in the general population complicates clinical interpretations. Differentiating between VH with and without distress may aid treatment decisions in psychosis services, but understanding the differences between these two phenomena as they present in the normal adolescent population is necessary to validate this differentiation. The present study compared VH with and without distress in 10,346 adolescents in relation to clinical characteristics, known risk factors, predictors and psychosocial moderators of psychosis. A population-based cohort of Norwegian 16-19 years old adolescents completed a comprehensive web-based questionnaire, including two questions from the extended Launay-Slade Hallucinations Scale: (1) I often hear a voice speaking my thoughts aloud and (2) I have been troubled by hearing voices in my head. Adolescents reporting no VH, non-distressing VH or distressing VH were compared on 14 psychosocial and clinical variables. A multinomial regression model showed that non-disturbing voices were predicted by better school grades, social dysfunction, distractibility, affective symptoms and experience of trauma, while the disturbing voices were predicted by the experience of bullying and trauma, perceived negative self-worth and self-efficacy, less family support, dysregulation of activation, distractibility, self-harm and anxiety. Hearing voices without distress versus being distressed by the voices is related to different constellations of psychosocial variables, suggesting that they represent two separate groups of adolescents. The findings validate the emphasis on distress in clinical practice.

Early Substance Use Cessation Improves Cognition-10 Years Outcome in First-Episode Psychosis Patients

Background: Cognitive impairment may be a risk factor for, as well as a consequence of, psychosis. Non-remitting symptoms, premorbid functioning, level of education, and socioeconomic background are known correlates. A possible confounder of these associations is substance use, which is common among patients with psychosis and linked to worse clinical outcomes. Studies however show mixed results for the effect of substance use on cognitive outcomes. In this study, the long-term associations of substance use with cognition in a representative sample of first-episode psychosis patients were examined. Methods: The sample consisted of 195 patients. They were assessed for symptom levels, function, and neurocognition at 1, 2, 5, and 10 years after first treatment. Test scores were grouped into factor analysis-based indices: motor speed, verbal learning, visuomotor processing, verbal fluency, and executive functioning. A standardized composite score of all tests was also used. Patients were divided into four groups based on substance-use patterns during the first 2 years of treatment: persistent users, episodic users, stop-users, and nonusers. Data were analyzed using linear mixed effects modeling. Results: Gender, premorbid academic functioning, and previous education were the strongest predictors of cognitive trajectories. However, on motor speed and verbal learning indices, patients who stopped using substances within the first 2 years of follow-up improved over time, whereas the other groups did not. For verbal fluency, the longitudinal course was parallel for all four groups, while patients who stopped using substances demonstrated superior performances compared with nonusers. Persistent users demonstrated impaired visuomotor processing speed compared with nonusers. Within the stop- and episodic use groups, patients with narrow schizophrenia diagnoses performed worse compared with patients with other diagnoses on verbal learning and on the overall composite neurocognitive index. Discussion: This study is one of very few long-term studies on cognitive impairments in first-episode psychosis focusing explicitly on substance use. Early cessation of substance use was associated with less cognitive impairment and some improvement over time on some cognitive measures, indicating a milder illness course and superior cognitive reserves to draw from in recovering from psychosis.

Prevalence and clinical relevance of interview-assessed psychosis-risk symptoms in the young adult community

BACKGROUND

An efficient indicated prevention of psychotic disorders requires valid risk criteria that work in both clinical and community samples. Yet, ultra-high risk and basic symptom criteria were recently recommended for use in clinical samples only. Their use in the community was discouraged for lack of knowledge about their prevalence, clinical relevance and risk factors in non-clinical, community settings when validly assessed with the same instruments used in the clinic.

METHODS

Using semi-structured telephone interviews with established psychosis-risk instruments, we studied the prevalence of psychosis-risk symptoms and criteria, their clinical relevance (using presence of a non-psychotic mental disorder or of functional deficits as proxy measures) and their risk factors in a random, representative young adult community sample (N=2683; age 16-40 years; response rate: 63.4%).

RESULTS

The point-prevalence of psychosis-risk symptoms was 13.8%. As these mostly occurred too infrequent to meet frequency requirements of psychosis-risk criteria, only 2.4% of participants met psychosis-risk criteria. A stepwise relationship underlay the association of ultra-high risk and basic symptoms with proxy measures of clinical relevance, this being most significant when both occurred together. In line with models of their formation, basic symptoms were selectively associated with age, ultra-high risk symptoms with traumatic events and lifetime substance misuse.

CONCLUSIONS

Psychosis-risk criteria were uncommon, indicating little risk of falsely labelling individuals from the community at-risk for psychosis. Besides, both psychosis-risk symptoms and criteria seem to possess sufficient clinical relevance to warrant their broader attention in clinical practice, especially if ultra-high risk and basic symptoms occur together.

Heavy cannabis use prior psychosis in schizophrenia: clinical, cognitive and neurological evidences for a new endophenotype?

Cannabis use is associated with an increased risk of schizophrenia, and is considered to impact late neurodevelopment. Neurological soft signs (NSS) associated with schizophrenia are considered as markers of early neurodevelopmental impairment. Our study examines the association between heavy cannabis use before the onset of psychosis and clinical, neuropsychological and neurological symptoms, including NSS. In a cross-sectional study, we consecutively included 61 patients with schizophrenia (34 reporting heavy cannabis use before the onset of psychosis and 27 not reporting such use), in the setting of a University Hospital and a Medical Center. Symptoms assessment and substance use disorder were evaluated with the Diagnostic Interview for Genetic Studies. NSS were assessed with the Neurological Evaluation Scale. Psychopathology was assessed with the Positive and Negative Symptom Scale. All patients underwent a battery of neurocognitive tests evaluating attention, memory and executive functions domains. Patients with heavy cannabis use before the onset of psychosis showed significantly less NSS (p < 0.05), less negative symptoms (p < 10^-3) and a better cognitive functioning in different domains [median reaction time (p = 0.03), episodic memory (p = 0.04), visuoconstructive praxs (p = 0.03) than their non-heavy user counterparts]. Confounding effects of alcohol and tobacco were taken into account. Age and gender were not statistically different between the two groups (p = 0.70 and p = 0.16, respectively). Our study supports the clinical, neuropsychological and neurological specificity associated with the heavy use of cannabis before the onset of schizophrenia. Patients with heavy cannabis use before the onset of schizophrenia may exhibit later neurodevelopmental impairment than those who do not report such use. Schizophrenia associated with heavy cannabis use could represent a specific phenotype.

Neurological soft signs in Tunisian patients with first-episode psychosis and relation with cannabis use

BACKGROUND

Neurological soft signs (NSS) are minor non-localizing neurological abnormalities that are conceptualized as neurodevelopmental markers that mediate the biological risk for psychosis. We aimed to explore the relationship between NSS and cannabis use, an environmental risk factor of psychosis.

METHODS

This was a cross-sectional study in consecutively admitted patients hospitalized for first-episode psychosis. NSS were assessed by the NSS scale (23 items exploring motor coordination, motor integrative function, sensory integration, involuntary movements or posture, quality of lateralization). Presence of NSS was defined as a NSS scale total score ≥9.5. Cannabis use was ascertained with the cannabis subsection in the Composite International Diagnostic Interview.

RESULTS

Among 61 first-episode psychosis patients (mean age = 28.9 ± 9.4 years; male = 86.9%, antipsychotic-naïve = 75.4%), the prevalence of current cannabis use was 14.8% (heavy use = 8.2%, occasional use = 6.6%). NSS were present in 83.6% of the sample (cannabis users = 66.7% versus cannabis non-users = 85.5%, p = 0.16). The mean total NSS score was 15.3 ± 6.7, with a significant lower total NSS score in cannabis users (11.2 ± 5.6 versus 16.0 ± 6.7, p = 0.048). Differences were strongest for the "motor coordination" (p = 0.06) and "involuntary movements" (p = 0.07) sub-scores.

CONCLUSIONS

This study demonstrated a negative association between cannabis use and NSS, especially regarding motor discoordination. This finding supports the hypothesis that a strong environmental risk factor, such as cannabis, may contribute to the onset of psychosis even in the presence of lower biological and genetic vulnerability, as reflected indirectly by lower NSS scores. Nevertheless, additional studies are needed that explore this interaction further in larger samples and considering additional neurobiological and environmental risk factors.

Traditional marijuana, high-potency cannabis and synthetic cannabinoids: increasing risk for psychosis

Epidemiological evidence demonstrates that cannabis use is associated with an increased risk of psychotic outcomes, and confirms a dose-response relationship between the level of use and the risk of later psychosis. High-potency cannabis and synthetic cannabinoids carry the greatest risk. Experimental administration of tetrahydrocannabinol, the active ingredient of cannabis, induces transient psychosis in normal subjects, but this effect can be ameliorated by co-administration of cannabidiol. This latter is a constituent of traditional hashish, but is largely absent from modern high-potency forms of cannabis. Argument continues over the extent to which genetic predisposition is correlated to, or interacts with, cannabis use, and what proportion of psychosis could be prevented by minimizing heavy use. As yet, there is not convincing evidence that cannabis use increases risk of other psychiatric disorders, but there are no such doubts concerning its detrimental effect on cognitive function. All of the negative aspects are magnified if use starts in early adolescence. Irrespective of whether use of cannabis is decriminalized or legalized, the evidence that it is a component cause of psychosis is now sufficient for public health messages outlining the risk, especially of regular use of high-potency cannabis and synthetic cannabinoids.

Cannabis and development of dual diagnoses: A literature review

BACKGROUND

The use of cannabis has garnered more attention recently with ongoing efforts at marijuana legalization. The consequences of cannabis use are not clearly understood and remain a concern.

OBJECTIVES

To review the acute and persistent effects of cannabis use and associations with psychiatric disorders.

METHODS

Using Pubmed and PsychInfo, we conducted a narrative review of the literature on cannabis and psychiatric comorbidity using the keywords cannab*, marijuana, schizo*, psychosis, mood, depression, mania, bipolar, and anxiety.

RESULTS

There is substantial evidence of cannabis use leading to other illicit drug use and of an association between cannabis use and psychosis. A few reports suggest an association with bipolar disorder while the association with depression and anxiety disorders is mixed.

CONCLUSIONS

Whenever an association is observed between cannabis use and psychiatric disorders, the relationship is generally an adverse one. Age at the time of cannabis use appears to be an important factor with stronger associations observed between adolescent onset cannabis use and later onset of psychiatric disorders. Additional studies taking into account potential confounds (such as withdrawal symptoms, periods of abstinence, and other substance use) and moderators (such as age of initiation of cannabis use, the amount and frequency of drug use, prior history of childhood maltreatment, and gender) are needed to better understand the psychiatric consequences of cannabis use.

Cannabinoids and Schizophrenia: Risks and Therapeutic Potential

A convergence of evidence shows that use of Cannabis sativa is associated with increased risk of developing psychotic disorders, including schizophrenia, and earlier age at which psychotic symptoms first manifest. Cannabis exposure during adolescence is most strongly associated with the onset of psychosis amongst those who are particularly vulnerable, such as those who have been exposed to child abuse and those with family histories of schizophrenia. Schizophrenia that develops after cannabis use may have a unique clinical phenotype, and several genetic polymorphisms may modulate the relationship between cannabis use and psychosis. The endocannabinoid system has been implicated in psychosis both related and unrelated to cannabis exposure, and studying this system holds potential to increase understanding of the pathophysiology of schizophrenia. Anandamide signaling in the central nervous system may be particularly important. Δ(9)-Tetrahydrocannabinol in cannabis can cause symptoms of schizophrenia when acutely administered, and cannabidiol (CBD), another compound in cannabis, can counter many of these effects. CBD may have therapeutic potential for the treatment of psychosis following cannabis use, as well as schizophrenia, possibly with better tolerability than current antipsychotic treatments. CBD may also have anti-inflammatory and neuroprotective properties. Establishing the role of CBD and other CBD-based compounds in treating psychotic disorders will require further human research.