Aberrant Salience among Young Healthy Postgraduate University Students: The Role of Cannabis Use, Psychotic-Like Experiences, and Personality

Cannabis use and psychotic-like experiences: A systematic review of biological vulnerability, potency effects, and clinical trajectories

Epidemiological data have provided evidence that psychotic-like experiences (PLEs) occur in the general population without clinical impairment. According to the psychosis continuum hypothesis, PLEs are subject to multiple risk factors. This review synthesizes current research on biological, substance use-related, and environmental risk factors for PLEs in non-clinical populations. PubMed/Medline and Scopus databases were searched for peer-reviewed studies published until January 2024 investigating risk factors for PLEs in non-clinical samples. Following PRISMA guidelines, 38 full-text articles were analyzed after title/abstract and full-text screening (PROSPERO registration ID: N 1001,807). Four main risk factor categories emerged. Biological vulnerabilities included specific metabolic profiles, genetic predisposition, and neurobiological alterations. Substance use patterns, particularly high-potency cannabis, showed significant associations with PLEs, with evidence for bidirectional relationships. Socio-demographic factors revealed influences of digital media use, ethnic density, and gender differences. Outcome studies demonstrated associations between PLEs and consequences including suicidal behavior and cognitive impairments. Findings suggest a complex interplay between multiple risk factors in PLE development. More attention should be paid to the interaction between biological vulnerabilities and environmental factors, as these experiences may represent important markers for mental health outcomes. A comprehensive assessment approach and proactive early intervention strategies are essential for the timely identification and management of at-risk individuals. Our findings support a multifactorial model where genetic vulnerabilities, cannabis use patterns, and socio-environmental factors influence PLE trajectories. The bidirectional cannabis-PLE relationship suggests self-regulatory mechanisms that could inform preventive interventions. Early identification of PLEs in young cannabis users represents a crucial opportunity for targeted clinical interventions.

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.