Cannabis Use, Psychotic Like Experiences and Aberrant Salience in a Sample of Belgian Students

Aberrant salience in cannabis-induced psychosis: a comparative study

Background

Natural Cannabis (NC) and Synthetic Cannabinoids (SCs) use can increase the risk and exacerbate the course of psychotic disorders. These could be influenced by the Aberrant Salience (AS) construct. It refers to an excess of attribution of meaning to stimuli that are otherwise regarded as neutral, thereby transform them into adverse, dangerous, or mysterious entities. This leads the patient to engage in aberrant and consequently incorrect interpretative efforts concerning the normal perception of reality and its relationship with our analytical abilities. AS appears to play a significant role in the onset and perpetuation of psychotic disorders. The internal conflict arising from aberrant attributions of significance leads to delusional thoughts, ultimately culminating in the establishment of a self-sustaining psychosis.

Aims

To examine the differences between psychoses course not associated with cannabis use and those associated with NC-use and SCs-use, in terms of psychotic and dissociative symptoms, AS, global functioning and suicidal ideation.

Methods

A sample of 62 patients with First Episode Psychosis (FEP) was divided into 3 groups: non cannabis users (non-users, N = 20); NC-users or rather Delta-9-tetrahydrocannabinol (THC) users (THC-users, N = 21); SCs-users, commonly referred to as SPICE-users (SPICE-users, N = 20). Each group underwent assessments at the onset of psychotic symptoms, as well as at the 3 months and 6 months marks, utilizing a range of psychopathological scales. These included the Positive and Negative Syndrome Scale (PANSS) for investigating psychotic symptoms, the Global Assessment of Functioning (GAF) scale for assessing overall functioning, the Dissociative Experiences Scale (DES-II) for measuring dissociative symptoms, the Scale for Suicide Ideation (SSI) for evaluating suicidal ideation and the Aberrant Salience Inventory (ASI) scale for gauging AS.

Results

SPICE-users showed more severe and persistent positive symptoms, while negative symptoms were mostly represented among non-users. Non-users showed better recovery than SPICE-users in global functioning. All groups showed a decrease in both ASI scores and subscale scores. SPICE-users exhibited higher global AS scores and less improvement in this aspect compared to other groups.

Conclusion

This study may help understanding the role of AS in both non-substance-related and substance-induced psychosis. This knowledge may lead clinician to a better diagnosis and identify patient-tailored psychopharmacological treatment.

LSD, madness and healing: Mystical experiences as possible link between psychosis model and therapy model

BACKGROUND

For a century, psychedelics have been investigated as models of psychosis for demonstrating phenomenological similarities with psychotic experiences and as therapeutic models for treating depression, anxiety, and substance use disorders. This study sought to explore this paradoxical relationship connecting key parameters of the psychotic experience, psychotherapy, and psychedelic experience.

METHODS

In a randomized, double-blind, placebo-controlled, crossover design, 24 healthy volunteers received 50 μg d-lysergic acid diethylamide (LSD) or inactive placebo. Psychotic experience was assessed by aberrant salience (Aberrant Salience Inventory, ASI), therapeutic potential by suggestibility (Creative Imagination Scale, CIS) and mindfulness (Five Facet Mindfulness Questionnaire, FFMQ; Mindful Attention Awareness Scale, MAAS; Experiences Questionnaire, EQ), and psychedelic experience by four questionnaires (Altered State of Consciousness Questionnaire, ASC; Mystical Experiences Questionnaire, MEQ; Challenging Experiences Questionnaire, CEQ; Ego-Dissolution Inventory, EDI). Relationships between LSD-induced effects were examined.

RESULTS

LSD induced psychedelic experiences, including alteration of consciousness, mystical experiences, ego-dissolution, and mildly challenging experiences, increased aberrant salience and suggestibility, but not mindfulness. LSD-induced aberrant salience correlated highly with complex imagery, mystical experiences, and ego-dissolution. LSD-induced suggestibility correlated with no other effects. Individual mindfulness changes correlated with aspects of aberrant salience and psychedelic experience.

CONCLUSIONS

The LSD state resembles a psychotic experience and offers a tool for healing. The link between psychosis model and therapeutic model seems to lie in mystical experiences. The results point to the importance of meaning attribution for the LSD psychosis model and indicate that psychedelic-assisted therapy might benefit from therapeutic suggestions fostering mystical experiences.

Prevalence and risk factors of self-reported psychotic experiences among high school and college students: A systematic review, meta-analysis, and meta-regression

BACKGROUND

Adolescents are at high risk of incident psychopathology. Fleeting psychotic experiences (PEs) that emerge in young people in response to stress may be warning signs that are missed by research that fails to study stressed populations, such as late high school and college/university students. Our aim in this systematic review was to conduct a meta-analysis that estimates prevalence rates of PEs in students, and to assess whether these rates differ by gender, age, culture, and COVID-19 exposure.

METHOD

We searched nine electronic databases, from their inception until January 31, 2022 for relevant studies. We pooled the estimates using the DerSimonian-Laird technique and random-effects meta-analysis. Our main outcome was the prevalence of self-reported PEs in high school and college/university students. We subsequently analyzed our data by age, gender, population, country, culture, evaluation tool, and COVID-19 exposure.

RESULTS

Out of 486 studies retrieved, a total of 59 independent studies met inclusion criteria reporting 210' 024 students from 21 different countries. Nearly one in four students (23.31%; 95% CI 18.41%-29.05%), reported having experienced PEs (heterogeneity [Q = 22,698.23 (62), p = 0.001] τ²  = 1.4418 [1.0415-2.1391], τ = 1.2007 [1.0205-1.4626], I²  = 99.7%, H = 19.13 [18.59-19.69]). The 95% prediction intervals were 04.01%-68.85%. Subgroup analyses showed that the pooled prevalence differed significantly by population, culture, and COVID-19 exposure.

CONCLUSION

This meta-analysis revealed high prevalence rates of self-reported PEs among teen and young adult students, which may have significance for mental health screening in school settings. An important realization is that PEs may have very different mental health meaning in different cultures.

The role of aberrant salience in the association between cannabis use frequency and psychotic experiences among racial and ethnic minoritized youth

Prior studies have shown cannabis use is correlated with psychotic symptoms, but few have explored potential underlying mechanisms. The present study examined whether aberrant salience explains the association between cannabis use frequency and psychotic experiences (PE) while accounting for the mediating role of anxiety in this association. A US urban undergraduate sample of 816 racial and ethnic minorities contributed data used in linear regression models to determine associations between recent (3 months) cannabis use frequency, aberrant salience, anxiety, positive subscale Prodromal Questionnaire (PQ) items, and distressing positive PQ items. Results from hierarchical linear regression and mediation models using Hayes PROCESS application indicated the association between cannabis use frequency and PE was significantly explained by higher aberrant salience and anxiety. Furthermore, anxiety's indirect association with cannabis use frequency and PE significantly occurred through aberrant salience's indirect association with cannabis use frequency and PE (i.e., serial mediation). A similar pattern emerged for distressing PE. We also found earlier age of cannabis use onset (age 12-14) was associated with a higher number of PE and distressing PE and that this was partially explained by higher aberrant salience. Anxiety's indirect association between earlier age of onset and PE/distressing PE only occurred through aberrant salience (i.e., serial mediation). Aberrant salience may be the part of psychosis proneness most directly connected to why earlier initiation of cannabis use is a risk factor for psychotic disorders. This should be explored further in future longitudinal work with clinical high-risk populations and among minoritized youth.

Aberrant salience in adolescents is related to indicators of psychopathology that are relevant in the prodromal phases of psychosis

AIM

Aberrant salience has been considered as a predisposing factor during prodromal phases of psychosis and in ultra high-risk subjects. Most studies investigated the presence of aberrant salience in general population as a measure of vulnerability to psychosis. This study aimed atinvestigating the level of aberrant salience in a sample of Italian high-school students.

METHODS

Aberrant salience was measured with the Aberrant Salience Inventory (ASI) and its association with measures of general psychopathology (Youth Self Report [YSR]) was tested. A sample of 312 high school students (115 boys, 197 girls; age range: 14 to 19) was recruited.

RESULTS

Within the ASI and the YSR, the subscales did associate with each other at medium to large effect size, while the associations of the ASI subscales to the YRS scales had small effect sizes, indicating that the two tools measure different constructs. Latent Class Analysis revealed a distribution of aberrant salience across three classes with the intermediate class corresponding to more than half of the sample (58.3%). The class with the highest endorsement of the ASI items included 101 subjects (32.4%). Greater differences by classes were found in the "increased significance" and the "impending understanding" subscales. Higher aberrant salience was found on the anxious/depressed, the somatic complaints, and the thought problems scales of the YSR.

CONCLUSIONS

Aberrant salience represents a common experience in the adolescent population and is associated with various psychopathological disorders, in particular, thought disorder. Aberrant salience might be involved in proneness to psychosis.

Are psychotic-like experiences related to a discontinuation of cannabis consumption in young adults?

OBJECTIVE

To assess changes in cannabis use in young adults as a function of psychotic-like experiences.

METHOD

Participants were initially recruited at age 14 in high schools for the longitudinal IMAGEN study. All measures presented here were assessed at follow-ups at age 19 and at age 22, respectively. Perceived stress was only assessed once at age 22. Ever users of cannabis (N = 552) gave qualitative and quantitative information on cannabis use and psychotic-like experiences using the Community Assessment of Psychic Experiences (CAPE). Of those, nearly all n = 549 reported to have experienced at least one psychotic experience of any form at age 19.

RESULTS

Mean cannabis use increased from age 19 to 22 and age of first use of cannabis was positively associated with a change in cannabis use between the two time points. Change in cannabis use was not significantly associated with psychotic-like experiences at age 19 or 22. In exploratory analysis, we observed a positive association between perceived stress and the experience of psychotic experiences at age 22.

CONCLUSION

Age of first use of cannabis influenced trajectories of young cannabis users with later onset leading to higher increase, whereas the frequency of psychotic-like experiences was not associated with a change in cannabis use. The observed association between perceived stress and psychotic-like experiences at age 22 emphasizes the importance of stress experiences in developing psychosis independent of cannabis use.

Cannabis Use, Schizotypy and Kamin Blocking Performance

Cannabis use has been associated with increased risk for a first episode of psychosis and inappropriate assignment of salience to extraneous stimuli has been proposed as a mechanism underlying this association. Psychosis-prone (especially schizotypal) personality traits are associated with deficits in associative learning tasks that measure salience allocation. The aim of this study was to examine the relationship between history of cannabis use and Kamin blocking (KB), a form of selective associative learning, in a non-clinical sample. Additionally, KB was examined in relation to self-reported schizotypy and aberrant salience scale profiles. A cross-sectional study was conducted in 307 healthy participants with no previous psychiatric or neurological history. Participants were recruited and tested using the Testable Minds behavioural testing platform. KB was calculated using Oades' "mouse in the house task", performance of which is disrupted in schizophrenia patients. Schizotypy was measured using the Schizotypal Personality Questionnaire (SPQ), and the Aberrant Salience Inventory (ASI) was used to assess self-reported unusual or inappropriate salience. The modified Cannabis Experience Questionnaire (CEQm) was used to collect detailed history of use of cannabis and other recreational drugs. Regression models and Bayesian t-tests or ANOVA (or non-parametric equivalents) examined differences in KB based on lifetime or current cannabis use (frequent use during previous year), as well as frequency of use among those who had previously used cannabis. Neither lifetime nor current cannabis use was associated with any significant change in total or trial-specific KB scores. Current cannabis use was associated with higher Disorganised SPQ dimension scores and higher total and sub-scale values for the ASI. A modest positive association was observed between total KB score and Disorganised SPQ dimension scores, but no relationships were found between KB and other SPQ measures. Higher scores on "Senses Sharpening" ASI sub-scale predicted decreased KB score only in participants who have not engaged in recent cannabis use. These results are discussed in the context of our understanding of the effects of long-term cannabis exposure on salience attribution, as well as inconsistencies in the literature with respect to both the relationship between KB and schizotypy and the measurement of KB associative learning phenomena.

Cannabis for medical and scientific purposes: the Colombian landscape

The Colombian government, through Law 1787 of 2016, has created a regulatory framework that allows its citizens to have a safe and informed access to cannabis and its derivatives for medical and scientific purposes. Our country joins others in their efforts to legalize cannabis-derived substances for therapeutic purposes, as many jurisdictions have recognized the potential these products have in the treatment of certain medical conditions. This paper describes the current medical cannabis outlook in Colombia, compares the different medical cannabis supply systems in other parts of the world, summarizes the evidence related to the potential therapeutic benefits and potential risks of using cannabis for medical purposes.

Post-secondary students with symptoms of psychosis: A mixed-methods systematic review

Post-secondary students are at a heightened risk of psychosis, yet little is known about this population. The aim of this study was to conduct a mixed-methods systematic review of psychosis among post-secondary students, including student characteristics, overall prevalence, risk factors, interventions, and their reported experiences. Procedures were modelled on the Joanna Briggs Institute approach, while PRISMA guided conduct and reporting. A librarian created a systematic search of nine databases, and quality was assessed using JBI Critical Appraisal Tools. We pooled and analysed data according to objectives and recorded data using synthesis tables and narrative summaries. 26 articles published between 2006 and 2018 are included. The average age of participants was 21 years, and most identified as female and Caucasian. The prevalence of psychosis was often measured in a way that limited comparison across studies. Risk factors associated with symptoms of psychosis included substance use, depression, and younger age. Other risk factors trending towards a relationship included racial discrimination and anxiety. Protective factors included self-esteem and self-concept clarity. Five interventions were studied, with mixed results, and only three studies reported on the experience of students. While five promising interventions are identified, inadequate testing and replication limit confidence in their effectiveness and there is a notable deficit in qualitative evidence exploring the experiences of these students. Integrating knowledge on risk factors, interventions, and experiences of students with psychosis will help tailor and facilitate their health care while protecting their right to education.

Cognitive biases in individuals with psychotic-like experiences: A systematic review and a meta-analysis

A prior meta-analyze using behavioral tasks demonstrated that individuals with subclinical delusional ideations jump to conclusion (JTC). The major aim of our systematic review and meta-analyses was to highlight the relationship between cognitive biases and psychotic-like experiences (PLEs) when both are assessed by self-reports measures. In accordance with PRISMA guidelines, four electronic databases were searched. A total of 669 studies were identified, 39 articles met inclusion criteria for the systematic review and 27 for the random effects meta-analysis on healthy and UHR samples investigating cognitive biases (JTC, aberrant salience (ASB), attention to threat (ATB), externalizing bias (ETB), belief inflexibility (BIB), personalizing bias, aggression bias and need for closure). Effect size estimates were calculated using Pearson's correlation coefficients (r). In samples including both healthy and Ultra High Risk (UHR) individuals, positive psychotic-like experiences (PPLEs) were positively associated with ATB (r_s = 0.38), ETB (r_s = 0.35), BIB (r_s = 0.19), JTC (r_s = 0.10), and personalizing (r_s = 0.24). In community samples, PPLEs were positively associated with ASB (r_s = 0.62), ATB (r_s = 0.34), ETB (r_s = 0.36), BIB (r_s = 0.18), JTC (r_s = 0.11). In addition, negative PLEs were positively associated with ATB (r_s = 0.28), ETB (r_s = 0.37), BIB (r_s = 0.19) and ASB (r_s = 0.18). In UHR samples, positive associations were established between PPLEs and ATB (rs = 0.47), ETB (rs = 0.34), personalizing (r_s = 0.36) and the aggression bias (r_s = 0.35). Our results support cognitive models of psychosis considering the role of cognitive biases in the onset and the maintenance of psychotic symptoms. Cognitive interventions targeting cognitive biases could potentially prevent transition to psychosis in youth reporting PLEs and in UHR.

Does cannabis use predict psychometric schizotypy via aberrant salience?

Cannabis can induce acute psychotic symptoms in healthy individuals and exacerbate pre-existing psychotic symptoms in patients with schizophrenia. Inappropriate salience allocation is hypothesised to be central to the association between dopamine dysregulation and psychotic symptoms. This study examined whether cannabis use is associated with self-reported salience dysfunction and schizotypal symptoms in a non-clinical population. 910 University students completed the following questionnaire battery: the cannabis experience questionnaire modified version (CEQmv); schizotypal personality questionnaire (SPQ); community assessment of psychic experience (CAPE); aberrant salience inventory (ASI). Mediation analysis was used to test whether aberrant salience mediated the relationship between cannabis use and schizotypal traits. Both frequent cannabis consumption during the previous year and ASI score predicted variation across selected positive and disorganised SPQ subscales. However, for the SPQ subscales 'ideas of reference' and 'odd beliefs', mediation analysis revealed that with the addition of ASI score as a mediating variable, current cannabis use no longer predicted scores on these subscales. Similarly, cannabis use frequency predicted higher total SPQ as well as specific Positive and Disorganised subscale scores, but ASI score as a mediating variable removed the significant predictive relationship between frequent cannabis use and 'odd beliefs', 'ideas of reference', 'unusual perceptual experiences', 'odd speech', and total SPQ scores. In summary, cannabis use was associated with increased psychometric schizotypy and aberrant salience. Using self-report measures in a non-clinical population, the cannabis-related increase in selected positive and disorganised SPQ subscale scores was shown to be, at least in part, mediated by disturbance in salience processing mechanisms.

Terminology and assessment tools of psychosis: A systematic narrative review

AIM

Phenomena within the psychosis continuum that varies in frequency/duration/intensity have been increasingly identified. Different terms describe these phenomena, however there is no standardization within the terminology. This review evaluated the definitions and assessment tools of seven terms - (i) 'psychotic experiences'; (ii) 'psychotic-like experiences'; (iii) 'psychotic-like symptoms'; (iv) 'attenuated psychotic symptoms'; (v) 'prodromal psychotic symptoms'; (vi) 'psychotic symptomatology'; and (vii) 'psychotic symptoms'.

METHODS

EMBASE, MEDLINE, and CINAHL were searched during February-March 2019. Inclusion criteria included 1989-2019, full text, human, and English. Papers with no explicit definition or assessment tool, duplicates, conference abstracts, systematic reviews, meta-analyses, or no access were excluded.

RESULTS

A total of 2238 papers were identified and of these, 627 were included. Definitions and assessment tools varied, but some trends were found. Psychotic experiences and psychotic-like experiences were transient and mild, found in the general population and those at-risk. Psychotic-like symptoms were subthreshold and among at-risk populations and non-psychotic mental disorders. Attenuated psychotic symptoms were subthreshold but associated with distress, risk, and help-seeking. Prodromal psychotic symptoms referred to the prodrome of psychotic disorders. Psychotic symptomatology included delusions and hallucinations within psychotic disorders. Psychotic symptoms was the broadest term, encompassing a range of populations but most commonly involving hallucinations, delusions, thought disorder, and disorganization.

DISCUSSION

A model for conceptualizing the required terms is proposed and future directions needed to advance this field of research are discussed.