A Systematic Review of the Symptom Profile and Course of Methamphetamine-Associated PsychosisSubstance Use and Misuse

Modern perspectives on psychoses: dissociation, automatism, and temporality across exogenous and endogenous dimensions

Substance use and the emergence of Novel Psychoactive Substances (NPS) present a significant public health challenge and diagnostic dilemma, particularly in the context of psychosis. The increasing availability of psychoactive substances among youth has led to a rise in Substance Use Disorders (SUDs), with profound implications for mental health. This paper explores the psychopathological distinctions between substance-induced psychoses (SIPs) and endogenous psychoses, such as schizophrenia, from a phenomenological perspective. We emphasize three key aspects: dissociation, mental automatism, and temporality, to elucidate the underlying mechanisms of these conditions. Dissociation, as a psychopathological organizer, is central to exogenous psychoses, particularly those triggered by NPS. This phenomenon leads to a fragmentation of consciousness, detachment from reality, and disintegration of identity, distinct from the spaltung observed in endogenous psychoses. The concept of mental automatism, as theorized by De Clerambault, is also explored, highlighting its role in the early stages of exogenous psychoses, where cognitive disruptions precede delusions and hallucinations. Furthermore, the temporal experience in SIPs is characterized by a disconnection from past and future, trapping individuals in an "eternal present." This contrasts with the fragmented temporality observed in schizophrenia, where patients struggle to maintain a coherent narrative of their lives. The phenomenological approach provides critical insights into the clinical differentiation between SIPs and Primary Psychotic Disorders (PPDs), emphasizing the need for targeted interventions that address the specific temporal and cognitive disruptions in substance-induced conditions. In conclusion, this paper underscores the importance of integrating phenomenological psychopathology into clinical practice, particularly in the face of the evolving landscape of substance use and psychosis. Understanding the distinct psychopathological mechanisms underlying SIPs can inform more accurate diagnoses and effective treatments, ultimately improving patient outcomes in the context of this growing public health issue.

Development and validation of a Disorganised Thoughts Scale: a new measure to assess thinking difficulties in the general population

BACKGROUND

Disordered thinking is a condition that can manifest in not only clinical cases (e.g., psychotic disorders), but also the wider general population. However, there is no current method to measure the specific cognitive processes experienced during such a condition. Therefore, this study aimed to develop a new self-report measure, the Disorganised Thoughts Scale (DTS), that can assess disorganised thinking in the general population.

METHODS

To achieve this aim, a survey was developed and shared online with four independent samples, including a sample of Australians in the general population (N = 321) and three samples (N = 200 each) that were controlled for their substance use (i.e., frequent alcohol and cannabis use; non-frequent substance use). Exploratory and confirmatory factor analyses, and reliability analyses, were used to test the internal validity, whilst correlational analyses were implemented to examine the external validity.

RESULTS

The exploratory factor analysis revealed a two-factor structure (10 items each) measuring Positive thought disorder (i.e., accelerated, uncontrollable, and incongruent thinking) and Negative thought disorder (i.e., inhibited, disjointed, and disorientated thinking). This internal structure was confirmed with subsequent confirmatory factor and reliability analyses (α = 0.90 to 0.97) in the three substance-controlled groups. Concurrent validity was also supported, as the DTS exhibited strong correlations with established measures of general cognitive difficulties, specific self-regulatory dysfunctions, and psychopathological symptomology. Finally, the measure was also shown to be significantly higher in cohorts who exhibited a higher degree of psychological distress and who frequently used substances (i.e., alcohol and cannabis).

CONCLUSIONS

Overall, this study provided preliminary evidence to suggest that the DTS is a sound measure of disorganised thought that is linked to psychopathology and substance use in non-clinical populations. The measure could be used in future research which seeks to better understand how thinking effects, and is affected by, various psychological conditions.

"Jail isn't the answer for these inmates": how to respond to methamphetamine use in prisons

PURPOSE

The correctional system continues to face challenges with responding to and managing methamphetamine use among incarcerated individuals. This study aims to uncover what resources and policies could better help correctional workers deal with these challenges. The authors also examined methamphetamine's impact on correctional work and staff well-being.

DESIGN/METHODOLOGY/APPROACH

An online survey was distributed to correctional workers (n = 269) in Manitoba, Canada, featuring questions about their experiences related to methamphetamine use in populations under their care, what supports are needed to adequately address the concern, and the potential effects on self and their occupational responsibilities. Using NVivo software, survey responses were analysed using an emergent theme approach.

FINDINGS

Correctional workers believed policies and protocols for managing methamphetamine use and withdrawal are currently inadequate. Correctional workers reported having monthly contact with incarcerated individuals experiencing methamphetamine withdrawal, posing safety concerns to them and other incarcerated individuals. Respondents proposed more education and training on managing incarcerated people withdrawing from methamphetamines, related to the symptoms of use and withdrawal and how to support persons detoxing. Increased human and material resources were reported as being needed (e.g. more nurses onsite and better screening devices). Respondents also desired more medical intervention, safe living spaces for methamphetamine users and programming to support addiction.

ORIGINALITY/VALUE

The current study unpacks correctional workers' perspectives, support desires and their experiences managing methamphetamine use amongst incarcerated people. The authors discuss the required knowledge to respond to gaps in prison living, re-entry and related policy needs.

Efficacy of probiotic supplements in improving the symptoms of psychosis, anxiety, insomnia, and anorexia due to amphetamine and methamphetamine use: a randomized clinical trial

RATIONALE

Changes in the density and diversity of gut microbiota in chronic use of methamphetamine have been mentioned as contributors to psychotic and anxiety symptoms, sleep problems, and loss of appetite.

OBJECTIVE

In this placebo-controlled clinical trial, we investigated the effect of the probiotic Lactobacillus Acidophilus in improving psychiatric symptoms among hospitalized patients with chronic methamphetamine use along with psychotic symptoms.

METHODS

60 inpatients with a history of more than 3 years of methamphetamine use, were randomly assigned to one of two groups receiving either a probiotic capsule or placebo along with risperidone for 8 weeks based on a simple randomization method. In weeks 0, 4, and 8, patients were evaluated using the Brief Psychiatric Rating Scale (BPRS), Beck Anxiety Inventory (BAI), Pittsburgh Sleep Quality Index (PSQI), Simple Appetite Nutritional Questionnaire (SANQ), and Body Mass Index (BMI).

RESULTS

Compared to the control group, patients receiving probiotics had better sleep quality, greater appetite, and higher body mass index (there were significant interaction effects of group and time at Week 8 in these variables (t = -3.32, B = -1.83, p = .001, d = 0.89), (t = 10.50, B = 2.65, p <.001, d = 1.25) and (t = 3.40, B = 0.76, p <.001, d = 0.30), respectively. In terms of the improvement of psychotic and anxiety symptoms, there was no statistically significant difference between the two groups.

CONCLUSIONS

The use of probiotics was associated with improved sleep quality, increased appetite, and increased body mass index in patients with chronic methamphetamine use. Conducting more definitive clinical trials with larger sample sizes and longer-term follow-up of cases is recommended.

Rethinking Mental Automatism: De Clérambault's Theory in the Age of Novel Psychoactive Drugs: Psychotropic Effects and Synthetic Psychosis

The widespread use of novel psychoactive substances (NPSs)-defined as new narcotic or psychotropic agents not classified under the Single Convention on Narcotic Drugs of 1961 or the Convention on Psychotropic Substances of 1971-poses a significant challenge to contemporary mental health paradigms due to their impact on psychiatric disorders. This study revisits and expands upon the theory of mental automatism as proposed by Gaëtan Gatian de Clérambault, aiming to elucidate the psychopathological mechanisms underlying substance-induced psychoses (SIP) and their distinction from non-induced psychoses (schizophrenia and related disorders). Through a phenomenological and clinical investigation, we explore the relevance of mental automatism in the development of toxic psychoses, drawing upon the historical and contemporary literature. This research highlights the psychopathological distinctions between induced and non-induced psychoses and the transition mechanisms from acute to chronic psychosis states. De Clérambault's theory, supplemented by Janet, Jackson, and Bonhoeffer's contributions, provides a foundational framework for understanding the genesis of SIP. Our findings suggest that NPS consumption, particularly among adolescents and psychiatric patients, significantly correlates with increased risks of SIP, marked by a transition to chronicity influenced by biological lesions triggered by substance use. Furthermore, we propose a comprehensive framework for SIP, integrating mental automatism, psychopathological distinctions, and transition mechanisms. This framework aims to refine diagnostic criteria and therapeutic approaches, addressing gaps in clinical practice and research. The study underscores the need for a nuanced understanding of SIP, advocating for a paradigm shift in psychiatric assessment and treatment approaches to better address the complexities of substance-induced mental health disorders.

Positive and negative symptoms in methamphetamine-induced psychosis compared to schizophrenia: A systematic review and meta-analysis

BACKGROUND

The clinical profiles of methamphetamine-induced psychosis (MIP) and schizophrenia are largely overlapping making differentiation challenging. In this systematic review and meta-analysis, we aim to compare the positive and negative symptoms of MIP and schizophrenia to better understand the differences between them.

STUDY DESIGN

In accordance with our pre-registered protocol (CRD42021286619), we conducted a search of English-language studies up to December 16th, 2022, in PubMed, EMBASE, and PsycINFO, including stable outpatients with MIP and schizophrenia. We used the Newcastle-Ottawa Scale to measure the quality of cross-sectional, case-control, and cohort studies.

STUDY RESULTS

Of the 2052 articles retrieved, we included 12 studies (6 cross-sectional, 3 case-control, and 2 cohort studies) in our meta-analysis, involving 624 individuals with MIP and 524 individuals with schizophrenia. Our analysis found no significant difference in positive symptoms between the two groups (SMD, -0.01; 95%CI, -0.13 to +0.11; p = 1). However, individuals with MIP showed significantly less negative symptoms compared to those with schizophrenia (SMD, -0.35; 95CI%, -0.54 to -0.16; p = 0.01; I2 = 54 %). Our sensitivity analysis, which included only studies with a low risk of bias, did not change the results. However, our meta-analysis is limited by its cross-sectional approach, which limits the interpretation of causal associations. Furthermore, differences in population, inclusion criteria, methodology, and drug exposure impact our findings.

CONCLUSIONS

Negative symptoms are less prominent in individuals with MIP. While both groups do not differ regarding positive symptoms, raises the possibility of shared and partly different underlying neurobiological mechanisms related to MIP and schizophrenia.

The General Neurocognitive Decline in Patients with Methamphetamine Use and Transient Methamphetamine-induced Psychosis is Primarily Determined by Oxidative and AGE-RAGE Stress

BACKGROUND

Chronic Methamphetamine (MA) usage is linked to oxidative and AGE (advanced glycation end products) - RAGE (receptors for AGEs) stress, changes in magnesium, calcium, and copper, increased psychotic symptoms, and neurocognitive deficits. Nevertheless, it is still unclear whether these biological pathways mediate the latter impairments.

OBJECTIVE

This study aimed to investigate the relationships between neurocognition, the aforementioned biomarkers, and psychotic symptoms.

METHODS

We recruited 67 participants, namely 40 patients diagnosed with MA-substance use and 27 healthy controls, and assessed the Brief Assessment of Cognition in Schizophrenia (BACS), symptoms of psychosis, excitation, and formal thought disorders, oxidative toxicity (computed as the sum of myeloperoxidase (MPO), oxidized high-density lipoprotein (HDL), oxidized low-DL, and malondialdehyde), antioxidant defenses (catalase, glutathione peroxidase, total antioxidant capacity, zinc, and HDL), and increased AGEs and RAGEs.

RESULTS

We were able to extract one validated latent vector from the Mini-Mental State Examination score and the BACS test results (including executive functions, verbal fluency, and attention), labeled general cognitive decline (G-CoDe). We found that 76.1% of the variance in the G-CoDe was explained by increased oxidative toxicity, lowered antioxidant defenses, number of psychotic episodes, and MA dose. In patients with MA use, MPO was significantly associated with the GCoDe.

CONCLUSION

The use of MA induced mild cognitive impairments through MA-induced activation of detrimental outcome pathways, including oxidative and AGE-RAGE stress, and suppression of protective antioxidant pathways. Increased MPO, oxidative, and AGE-RAGE stress are new drug targets to prevent neurocognitive deficits and psychosis due to MA use.

Methamphetamine (MA) use and MA-induced psychosis are associated with increasing aberrations in the compensatory immunoregulatory system, interleukin-1α, and CCL5 levels

There are only a few studies reporting on the immunological profiles of methamphetamine (MA) use, MA dependency, or MA-induced psychosis (MAP). This study measured M1 macrophage, T helper (Th)-1, Th-2, growth factor, and chemokine profiles, as well as the immune inflammatory response system (IRS) and compensatory immunoregulatory system (CIRS) in peripheral blood samples from patients with MA use (n = 51), MA dependence (n = 47), and MAP (n = 43) in comparison with controls (n = 32). We discovered that persistent MA use had a robust immunosuppressive impact on all immunological profiles. The most reliable biomarker profile of MA use is the combination of substantial CIRS suppression and a rise in selected pro-inflammatory cytokines, namely CCL27 (CTACK), CCL11 (eotaxin), and interleukin (IL)-1α. In addition, MA dependency is associated with increased immunosuppression, as demonstrated by lower stem cell factor levels and higher IL-10 levels. MAP is related to a significant decrease in all immunological profiles, particularly CIRS, and an increase in CCL5 (RANTES), IL-1α, and IL-12p70 signaling. In conclusion, long-term MA use and dependency severely undermine immune homeostasis, whereas MAP may be the consequence of increased IL-1α - CCL5 signaling superimposed on strongly depleted CIRS and Th-1 functions. The widespread immunosuppression established in longstanding MA use may increase the likelihood of infectious and immune illness or exacerbate disorders such as hepatitis and AIDS. Furthermore, elevated levels of CCL5, CCL11, CCL27, IL-1α, and/or IL-12p70 may play a role in the peripheral (atherosclerosis, cutaneous inflammation, immune aberrations, hypospermatogenesis) and central (neuroinflammation, neurotoxic, neurodegenerative, depression, anxiety, and psychosis) side effects of MA use.

How does a family history of psychosis influence the risk of methamphetamine-related psychotic symptoms: Evidence from longitudinal panel data

AIMS

To determine whether the risk of psychotic symptoms during weeks of methamphetamine use was dependent on, increased by, or independent of having a family history of psychosis.

DESIGN

Secondary analysis of 13 contiguous 1-week periods of data (1370 weeks). A risk modification framework was used to test each scenario.

SETTING

Geelong, Wollongong and Melbourne, Australia.

PARTICIPANTS

Participants in a randomized controlled trial of treatment for methamphetamine dependence (n = 148) who did not have a primary psychotic disorder on enrolment.

MEASUREMENTS

Psychotic symptoms in the previous week were defined as a score of 3+ on any of the Brief Psychiatric Rating Scale items of hallucinations, unusual thought content or suspiciousness. Any (vs no) methamphetamine use in the previous week was assessed using the Timeline Followback method. Self-reported family history of psychosis was assessed using the Diagnostic Interview for Psychosis.

FINDINGS

The risk of psychotic symptoms in the past week was independently associated with methamphetamine use in that week (relative risk [RR] = 2.3, 95% CI = 1.3-4.3) and with having a family history of psychosis (RR = 2.4, 95% CI = 0.9-7.0); the joint risk among participants with a family history of psychosis during weeks when they were using methamphetamine was large (RR = 4.0, 95% CI = 2.0-7.9). There was no significant interaction between a family history of psychosis and methamphetamine use in predicting psychotic symptoms (interaction RR = 0.7 95% CI = 0.3-1.8), but there was a small non-significant excess risk due to the interaction (0.20 95% CI = -1.63 to 2.03).

CONCLUSIONS

Among people dependent on methamphetamine, the relative risk of psychotic symptoms during weeks of methamphetamine use does not appear to be dependent on, or increased by, having a family history of psychosis. However, a family history of psychosis does appear to be an independent risk factor that contributes to the absolute risk of psychotic symptoms in this population.

Methamphetamine dependence in Australia-why is 'ice' (crystal meth) so addictive?

Australia has one of the highest rates in the world of the use of the crystalline form of methamphetamine, a highly addictive stimulant that is often associated with a chronic, relapsing dependency. Methamphetamine use is associated with both acquisitive and violent offending, which cause substantial personal and societal costs. Whilst the short-term euphoria and stimulation provide a positive reinforcement to methamphetamine use, the aversive states of withdrawing from methamphetamine and the associated craving, which may last up to five weeks into abstinence, underlie the negative reinforcement to continued methamphetamine use. Although many methamphetamine-dependent users experience high levels of psychological distress, it is likely that less than half engage with treatment or support services, and current intervention and treatment programmes have high discontinuation rates. Stigma and discrimination, even from paramedics and health clinicians, are prominent barriers to methamphetamine-dependent users accessing treatment in Australia.

Stimulant and hallucinogenic novel psychoactive substances; an update

INTRODUCTION

The renewed interest in considering a range of stimulants, psychedelics and dissociatives as therapeutics emphasizes the need to draft an updated overview of these drugs' clinical and pharmacological issues.

AREAS COVERED

The focus here was on: stimulants (e.g. amphetamines, methamphetamine, and pseudoephedrine; phenethylamines; synthetic cathinones; benzofurans; piperazines; aminoindanes; aminorex derivatives; phenmetrazine derivatives; phenidates); classical (e.g. ergolines; tryptamines; psychedelic phenethylamines), and atypical (e.g. PCP/ketamine-like dissociatives) psychedelics.Stimulant and psychedelics are associated with: a) increased central DA levels (psychedelic phenethylamines, synthetic cathinones and stimulants); b) 5-HT receptor subtypes' activation (psychedelic phenethylamines; recent tryptamine and lysergamide derivatives); and c) antagonist activity at NMDA receptors, (phencyclidine-like dissociatives).

EXPERT OPINION

Clinicians should be regularly informed about the range of NPS and their medical, psychobiological and psychopathological risks both in the acute and long term. Future research should focus on an integrative model in which pro-drug websites' analyses are combined with advanced research approaches, including computational chemistry studies so that in vitro and in vivo preclinical studies of index novel psychoactives can be organized. The future of psychedelic research should focus on identifying robust study designs to convincingly assess the potential therapeutic benefits of psychedelics, molecules likely to present with limited dependence liability levels.

A qualitative study of people who use methamphetamine during the early COVID-19 pandemic to inform future ED harm reduction strategies

BACKGROUND

Morbidity and mortality rates related to methamphetamine are on the rise. Simultaneously, social-distancing guidelines were issued in March 2020 to decrease transmission of COVID-19. The aim of this study was to explore concerns regarding methamphetamine use during the COVID-19 pandemic and subsequent harm reduction strategies with patients who use methamphetamine to inform emergency department (ED)-based harm reduction approaches.

METHODS

A mixed-methods study of adults residing in Washington with high-risk methamphetamine use and a recent ED visit from April-September 2020 was performed. Participants completed a survey and a semi-structured interview on perceptions and experiences of COVID-19. Descriptive statistics were used for survey responses. Interview transcripts were analyzed and guided by modified grounded theory using an iterative approach to refine the guide and codebook. Interviews were independently coded by 2 investigators and discussed until consensus.

RESULTS

Twenty-five participants completed the survey; 20 participants were interviewed (45% recently used heroin, 40% unstably housed). Thirty-five percent was worried about COVID-19 infection. Three themes emerged from the interviews: (1) increase in meth use, (2) interplay of meth obtention and COVID-19, and (3) interactions with healthcare and social services.

CONCLUSIONS

People who use methamphetamine noted an increase in use along with the social distancing guidelines put in place for COVID-19 and employed a variety of harm reduction profiles when obtaining methamphetamine. Also, the pandemic brought difficulties in accessing care and amplified mistrust in healthcare instructions and public health messages. Based on these qualitative interviews, further work should consider aligning methamphetamine and COVID-19 harm reduction messages and working with trusted community resources to improve harm reduction strategies for methamphetamine use and COVID-19. IRB: Informed Consent by the University of Washington Human Subjects Division (approval number, STUDY00009277).

The prevalence of substance use disorders and associated patterns among patients admitted to a psychiatric hospital in Botswana

OBJECTIVE

Substance use disorders (SUDs) have risen substantially, especially in developing nations, and has become one of the world's most significant public health and socioeconomic challenge. This study aimed to determine the prevalence and patterns of substance use disorders among patients admitted at the main psychiatric hospital, Sbrana Psychiatric Hospital in Botswana.

METHOD

The study design was descriptive cross-sectional, involving patients admitted to a psychiatric hospital. SUDs were assessed using the Alcohol, Smoking, and Substance Involvement Screening Test (ASSIST) v13.0. Bivariate analysis was conducted to determine the association between socio-demographic characteristics and SUDs. Multivariate logistic regression was performed to rule out the effect of confounders.

RESULTS

The final analysis involved one hundred and one (101) participants. Participants ages ranged from 18-60 years with over half (59.4%) being male. Majority of participants (85.1%) had ever used studied substances; with 63.4% found to have substance use disorders. The most frequently used substances were tobacco, cannabis, alcohol and cocaine at 58.4%, 42.6%, 34.7% and 12.8% respectively. SUDs were more common among participants who were male, younger age of 18-35 years, single, tertiary education and unemployed.

CONCLUSIONS

There is a high prevalence of substance use and SUDs among psychiatric patients in Botswana. Structured screening and interventions to manage substance use disorders should be part of routine care at the psychiatric health care facilities in Botswana. Consideration should be given to screening all patients admitted to psychiatric hospitals in Botswana for SUDs using the ASSIST.

Trace amine-associated receptor 1 (TAAR1) agonism as a new treatment strategy for schizophrenia and related disorders

Schizophrenia remains a major health burden, highlighting the need for new treatment approaches. We consider the potential for targeting the trace amine (TA) system. We first review genetic, preclinical, and clinical evidence for the role of TAs in the aetiopathology of schizophrenia. We then consider how the localisation and function of the trace amine-associated receptor 1 (TAAR1) position it to modulate key brain circuits for the disorder. Studies in rodents using Taar1 knockout (TAAR1-KO) and overexpression models show that TAAR1 agonism inhibits midbrain dopaminergic and serotonergic activity, and enhances prefrontal glutamatergic function. TAAR1 agonists also reduce hyperactivity, attenuate prepulse inhibition (PPI) deficits and social withdrawal, and improve cognitive measures in animal models. Finally, we consider findings from clinical trials of TAAR1 agonists and how this approach may address psychotic and negative symptoms, tolerability issues, and other unmet needs in the treatment of schizophrenia.

Common gray matter loss in the frontal cortex in patients with methamphetamine-associated psychosis and schizophrenia

BACKGROUND AND HYPOTHESIS

Methamphetamine (MA)-associated psychosis has become a public concern. However, its mechanism is not clear. Investigating similarities and differences between MA-associated psychosis and schizophrenia in brain alterations would be informative for neuropathology.

STUDY DESIGN

This study compared gray matter volumes of the brain across four participant groups: healthy controls (HC, n = 53), MA users without psychosis (MA, n = 22), patients with MA-associated psychosis (MAP, n = 34) and patients with schizophrenia (SCZ, n = 33). Clinical predictors of brain alterations, as well as association of brain alterations with psychotic symptoms and attention impairment were further investigated.

STUDY RESULTS

Compared with the HC, the MAP and the SCZ showed similar gray matter reductions in the frontal cortex, particularly in prefrontal areas. Moreover, a stepwise extension of gray matter reductions was exhibited across the MA - MAP - SCZ. Duration of abstinence was associated with regional volumetric recovery in the MAP, while this amendment in brain morphometry was not accompanied with symptom's remission. Illness duration of psychosis was among the predictive factors of regional gray matter reductions in both psychotic groups. Volume reductions were found to be associated with attention impairment in the SCZ, while this association was reversed in the MAP in frontal cortex.

CONCLUSIONS

This study suggested MA-associated psychosis and schizophrenia had common neuropathology in cognitive-related frontal cortices. A continuum of neuropathology between MA use and schizophrenia was tentatively implicated. Illness progressions and glial repairments could both play roles in neuropathological changes in MA-associated psychosis.

Substance use, microbiome and psychiatric disorders

Accumulating evidence from several studies has shown association between substance use, dysregulation of the microbiome and psychiatric disorders such as depression, anxiety, and psychosis. Many of the abused substances such as cocaine and alcohol have been shown to alter immune signaling pathways and cause inflammation in both the periphery and the central nervous system (CNS). In addition, these substances of abuse also alter the composition and function of the gut microbiome which is known to play important roles such as the synthesis of neurotransmitters and metabolites, that affect the CNS homeostasis and consequent behavioral outcomes. The emerging interactions between substance use, microbiome and CNS neurochemical alterations could contribute to the development of psychiatric disorders. This review provides an overview of the associative effects of substance use such as alcohol, cocaine, methamphetamine, nicotine and opioids on the gut microbiome and psychiatric disorders involving anxiety, depression and psychosis. Understanding the relationship between substance use, microbiome and psychiatric disorders will provide insights for potential therapeutic targets, aimed at mitigating these adverse outcomes.

The computational relationship between reinforcement learning, social inference, and paranoia

Theoretical accounts suggest heightened uncertainty about the state of the world underpin aberrant belief updates, which in turn increase the risk of developing a persecutory delusion. However, this raises the question as to how an agent's uncertainty may relate to the precise phenomenology of paranoia, as opposed to other qualitatively different forms of belief. We tested whether the same population (n = 693) responded similarly to non-social and social contingency changes in a probabilistic reversal learning task and a modified repeated reversal Dictator game, and the impact of paranoia on both. We fitted computational models that included closely related parameters that quantified the rigidity across contingency reversals and the uncertainty about the environment/partner. Consistent with prior work we show that paranoia was associated with uncertainty around a partner's behavioural policy and rigidity in harmful intent attributions in the social task. In the non-social task we found that pre-existing paranoia was associated with larger decision temperatures and commitment to suboptimal cards. We show relationships between decision temperature in the non-social task and priors over harmful intent attributions and uncertainty over beliefs about partners in the social task. Our results converge across both classes of model, suggesting paranoia is associated with a general uncertainty over the state of the world (and agents within it) that takes longer to resolve, although we demonstrate that this uncertainty is expressed asymmetrically in social contexts. Our model and data allow the representation of sociocognitive mechanisms that explain persecutory delusions and provide testable, phenomenologically relevant predictions for causal experiments.

Substance-induced psychosis and cognitive functioning: A systematic review

Longitudinal studies of substance-induced psychosis (SIP) suggest that approximately 11-46% of persons will progress to schizophrenia with differential risk of progression depending on the type of substance used. The findings suggest SIP may be a distinct variant of a psychotic disorder, yet SIP is understudied and the disease expression is not well characterized, particularly the cognitive phenotype. There is some evidence for cognitive dysfunction in SIP, but a synthesis of this literature has not been undertaken. We systematically reviewed all empirical research (up to December 31, 2020) that examined cognition in SIP using clinical neuropsychological measures. The cognitive outcomes are summarized by type of SIP (methamphetamine, other stimulants, alcohol, cannabis, undifferentiated). There was evidence for global and domain-specific cognitive dysfunction in SIP compared to controls and non-psychotic persons who use substances. Impairments were of similar magnitude compared to persons with schizophrenia. Delineation of a specific cognitive profile in SIP was precluded by lack of literature with comparable study designs and outcomes. Variation in visual-based cognition may be a distinct feature of SIP, but this requires further investigation. More rigorously controlled studies of cognition in SIP are needed to inform differential diagnosis and identify the unique clinical needs of this population.

Methamphetamine use in the United States: epidemiological update and implications for prevention, treatment, and harm reduction

Recent attention has focused on the growing role of psychostimulants, such as methamphetamine in overdose deaths. Methamphetamine is an addictive and potent stimulant, and its use is associated with a range of physical and mental health harms, overdose, and mortality. Adding to the complexity of this resurgent methamphetamine threat is the reality that the increases in methamphetamine availability and harms are occurring in the midst of and intertwined with the ongoing opioid overdose crisis. Opioid involvement in psychostimulant-involved overdose deaths increased from 34.5% of overdose deaths in 2010 to 53.5% in 2019-an increase of more than 50%. This latest evolution of the nation's overdose epidemic poses novel challenges for prevention, treatment, and harm reduction. This narrative review synthesizes what is known about changing patterns of methamphetamine use with and without opioids in the United States, other characteristics associated with methamphetamine use, the contributions of the changing illicit drug supply to use patterns and overdose risk, motivations for couse of methamphetamine and opioids, and awareness of exposure to opioids via the illicit methamphetamine supply. Finally, the review summarizes illustrative community and health system strategies and research opportunities to advance prevention, treatment, and harm reduction policies, programs, and practices.

Amphetamine-type stimulant use and self-harm: protocol for a systematic review of observational studies

INTRODUCTION

Amphetamine type stimulant (ATS) use and self-harm are both major public health concerns globally. Use of ATS is associated with a range of health and social problems, and has been increasing internationally in the last decade. Self-harm and ATS use share a number of underlying risk factors and occur at elevated rates in marginalised groups with high rates of exposure to trauma. The relationship between self-harm and ATS use is likely complex, and the causal pathway may run in either direction. A comprehensive review, synthesis and analysis of the evidence are warranted to investigate this relationship and inform policy and practice.

METHODS AND ANALYSIS

We will search the Medline, Embase, Cumulative Index to Nursing and Allied Health Literature, PsycINFO and Scopus databases for relevant observational studies published in peer-reviewed journals. The initial search was conducted on 5 February 2021, with a final search expected on 1 February 2022. All studies will be independently screened by two reviewers, first on title and abstract, and then on full-text to determine inclusion in the review. We place no restriction on the population that studies investigate, our exposure of interest is both prescription and illicit ATS use, comparators will be those not currently using ATS, and our primary outcome of interest is the prevalence of self-harm. Data will be extracted using a predesigned template, and pooled prevalence and pooled measures of effect for the association between ATS use and self-harm. If sufficient data are available, we will perform multiple meta-analyses to produce pooled measures of effect for each measure of ATS exposure, as well as different population sub-groups. The Methodological Standard for Epidemiological Research scale will be used to assess study quality, and Egger's test and I² values will be used to assess publication bias and heterogeneity, respectively.

ETHICS AND DISSEMINATION

No ethical approval is required for this review. We will only synthesise information from published studies that were conducted with ethical approval, so no individual participant data will be used. We will disseminate our findings via publication in a peer-reviewed journal, national and international conference presentations, and presentations to stakeholders in the community.

TRIAL REGISTRATION NUMBER

This study has been registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42021226562).

Medial prefrontal cortex Notch1 signalling mediates methamphetamine-induced psychosis via Hes1-dependent suppression of GABAB1 receptor expression

Methamphetamine (METH), a widely abused stimulant drug, induces psychosis in approximately half of abusers; this effect is becoming a major concern for society. Although the Notch1 signalling pathway has been shown to play a part in the pathogenesis of some psychiatric disorders, its role in METH-induced psychosis (MIP) is still unknown. Here, the METH-induced locomotor sensitization model in rodents is considered to represent the underlying neurochemical changes driving psychoses. We found that the Notch1 signalling was downregulated in the medial prefrontal cortex (mPFC) in sensitized mice. Direct genetic and pharmacological manipulations of Notch1 signalling bidirectionally altered METH-induced locomotor sensitization and other MIP-related behaviours through governing neuronal activity in the mPFC. Moreover, Notch1 signalling negatively regulated GABA_B1 receptor expression in the mPFC of METH-sensitized mice through Hes1, a transcriptional repressor in Notch1 signalling. Further, we show that Hes1 can directly bind to the GABA_B1 receptor promoter. Notably, pharmacological regulation of the GABA_B receptor in the mPFC reversed the changes in METH-induced locomotor sensitization caused by the dysfunction of Notch1 signalling. Together, our findings uncover a previously unrecognised Notch1-Hes1-GABA_B1 receptor-dependent mechanism involved in regulating mPFC neuronal activity and behavioural phenotypes in MIP. Our work provides mechanistic insight into the aetiology and pathophysiology of MIP.

Substance-Induced Psychoses: An Updated Literature Review

Background: On the current psychopharmacological panorama, the variety of substances able to provoke an episode of acute psychosis is rapidly increasing. Such psychotic episodes are classified according to the major category of symptoms: positive, negative, or cognitive psychotic episodes. On one hand, the abuse of methamphetamines, cannabis, and cocaine plays a big role in increasing the incidence of episodes resembling a psychotic disorder. On the other hand, the progress in terms of pharmacodynamics knowledge has led to the synthesis of new drugs, such as cannabinoids and cathinone's, which have rapidly entered into the common pool of abusers' habits. Regarding these newly synthesized substances of abuse, further clinical studies are needed to understand their psychogenic properties. The topic of this review is complicated due to the frequent abuse of psychotomimetic drugs by patients affected by psychotic disorders, a fact that makes it extremely difficult to distinguish between an induced psychosis and a re-exacerbation of a previously diagnosed disorder. Methods: The present narrative review summarizes results from clinical studies, thus investigating the psychotogenic properties of abused substances and the psychotic symptoms they can give rise to. It also discusses the association between substance abuse and psychosis, especially with regards to the differential diagnosis between a primary vs. a substance-induced psychotic disorder. Findings: Our findings support the theory that psychosis due to substance abuse is commonly observed in clinical practice. The propensity to develop psychosis seems to be a function of the severity of use and addiction. Of note, from a phenomenological point of view, it is possible to identify some elements that may help clinicians involved in differential diagnoses between primary and substance-induced psychoses. There remains a striking paucity of information on the outcomes, treatments, and best practices of substance-induced psychotic episodes.

Cross-sectional study comparing cognitive function in treatment responsive versus treatment non-responsive schizophrenia: evidence from the STRATA study

BACKGROUND

70%-84% of individuals with antipsychotic treatment resistance show non-response from the first episode. Emerging cross-sectional evidence comparing cognitive profiles in treatment resistant schizophrenia to treatment-responsive schizophrenia has indicated that verbal memory and language functions may be more impaired in treatment resistance. We sought to confirm this finding by comparing cognitive performance between antipsychotic non-responders (NR) and responders (R) using a brief cognitive battery for schizophrenia, with a primary focus on verbal tasks compared against other measures of cognition.

DESIGN

Cross-sectional.

SETTING

This cross-sectional study recruited antipsychotic treatment R and antipsychotic NR across four UK sites. Cognitive performance was assessed using the Brief Assessment of Cognition in Schizophrenia (BACS).

PARTICIPANTS

One hundred and six participants aged 18-65 years with a diagnosis of schizophrenia or schizophreniform disorder were recruited according to their treatment response, with 52 NR and 54 R cases.

OUTCOMES

Composite and subscale scores of cognitive performance on the BACS. Group (R vs NR) differences in cognitive scores were investigated using univariable and multivariable linear regressions adjusted for age, gender and illness duration.

RESULTS

Univariable regression models observed no significant differences between R and NR groups on any measure of the BACS, including verbal memory (ß=-1.99, 95% CI -6.63 to 2.66, p=0.398) and verbal fluency (ß=1.23, 95% CI -2.46 to 4.91, p=0.510). This pattern of findings was consistent in multivariable models.

CONCLUSIONS

The lack of group difference in cognition in our sample is likely due to a lack of clinical distinction between our groups. Future investigations should aim to use machine learning methods using longitudinal first episode samples to identify responder subtypes within schizophrenia, and how cognitive factors may interact within this.

TRAIL REGISTRATION NUMBER

REC: 15/LO/0038.

Brain dysfunction of methamphetamine-associated psychosis in resting state: Approaching schizophrenia and critical role of right superior temporal deficit

Methamphetamine (MA)-associated psychosis (MAP) is highly debilitating and common among individuals who use the drug, yet the underlying neural mechanism is not clear. This study compared brain functions between patients with MAP and those with schizophrenia during resting state and investigated the effect of brain alteration on the association between MA use and psychosis in patients with MAP. Three groups, including 24 patients with MAP, 17 with schizophrenia in first-episode (SCZ) and 31 healthy controls (HCs), were included after receiving a resting-state functional MRI scan. The severity of psychosis was assessed with Positive and Negative Syndrome Scale (PANSS). Imaging data were analysed using regional homogeneity (ReHo) to measure individual's brain function. Compared with the HC subjects, the MAP and SCZ groups had significantly lower ReHo in the cortical regions including left postcentral cortex, right superior temporal gyrus and right rolandic operculum, while had higher ReHo in the left putamen, with brain dysfunctions being more pronounced in the SCZ group. Among the MAP subjects, a mediating effect of ReHo in the right superior temporal gyrus was found on the association between MA use frequency and PANSS positive score. MAP and schizophrenia had a common trend of brain alteration, with the dysfunction being more pronounced in schizophrenia. This finding implicated that MAP might be a condition with neuropathology approaching schizophrenia. The observed critical role of right superior temporal deficit between MA use and psychosis proposed a potential target for interventions.

N-acetylcysteine (NAC) for methamphetamine dependence: A randomised controlled trial

BACKGROUND

Methamphetamine dependence is a significant global health concern for which there are no approved medications. The cysteine prodrug, N-acetylcysteine (NAC), has been found to ameliorate glutamate dysregulation in addiction, and to reduce craving for methamphetamine and other drugs. We evaluated the efficacy and safety of NAC as a pharmacotherapy for methamphetamine dependence.

METHODS

A parallel double-blind randomised placebo-controlled trial of people dependent on methamphetamine recruited from Geelong, Melbourne and Wollongong, Australia, between July 2018 and December 2019. Participants were randomised to receive either 12 weeks of oral NAC (2400 mg/day) or matched placebo, delivered as a take-home medication. The primary outcome was methamphetamine use, measured in two ways: (a) change in days of use in the past 4 weeks from baseline to weeks 4, 8 and 12, assessed using the Timeline Followback; and (b) methamphetamine-positive oral fluid samples taken weekly. Analyses were intention-to-treat and based on imputed data. Secondary outcomes were craving, severity of dependence, withdrawal severity and psychiatric symptoms (depression, suicidality, hostility and psychotic symptoms). Significance levels were p < 0.025 for primary outcomes and p < 0.01 for secondary outcomes. Adverse events were compared between groups by system organ class. The study was prospectively registered, ACTRN12618000366257.

RESULTS

Participants (N = 153; 59% male, mean [SD] age 38 [8]) were randomised to placebo (n = 77) or NAC (n = 76). Both groups had a median (IQR) of 24 (15-28) days of methamphetamine use in the 4 weeks prior to baseline. Both groups significantly reduced methamphetamine use (mean [SE] reduction of 7.3 [1.2]) days for placebo, 6.8 [1.2] for NAC) but NAC did not reduce days of methamphetamine use more than placebo (group difference of 0.5 days, 97.5% CI -3.4-4.3). There was no significant effect of NAC on methamphetamine-positive oral fluid samples (placebo 79%, NAC 76%; mean difference -2.6, 97.5% CI -12.6-7.4). NAC did not significantly reduce craving, severity of dependence, withdrawal, suicidality, depression, hostility or psychotic symptoms relative to placebo. Adverse events did not differ significantly between placebo and NAC groups.

INTERPRETATION

These findings suggest that take-home oral NAC has no significant effect on methamphetamine use or most clinically related outcomes amongst people who are dependent on the drug.

Cognitive insight, medication adherence and methamphetamine cessation in people enrolled in a pharmacotherapy trial for methamphetamine use

BACKGROUND

The current study examined correlates of cognitive insight in people enrolled in a methamphetamine pharmacotherapy trial; whether cognitive insight at the start of the trial predicted medication adherence and reductions in methamphetamine use during the trial; and, whether insight would remain stable over the trial or improve with reductions in methamphetamine use.

METHODS

A subset of people enrolled in a 12-week randomised placebo-controlled pharmacotherapy trial for methamphetamine dependence completed the Beck Cognitive Insight Scale, comprising subscales for Self-Reflection and Self-Certainty, at baseline (n = 152) and at week 12 (n = 79). Medication adherence was expressed as the percentage of non-missed doses measured using eCAP™ technology. Methamphetamine use days were assessed using the Timeline Followback.

RESULTS

At baseline, greater Self-Reflection was correlated with more severe methamphetamine withdrawal, and hostility, whereas Self-Certainty was correlated with less education and longer duration of methamphetamine use. No relationship was found between BCIS subscales at baseline and medication adherence (Self-Reflection b[SE] = -0.73 [0.43] p = .09; Self-Certainty b[SE] = -0.31 [0.48] p = .52,). Neither BCIS subscale was predictive of reduced methamphetamine use at 12 weeks (Self-Reflection b[SE] = 0.001 [0.01] p = .95 Self-Certainty b[SE] = -0.003 [0.01], p = .74). Self-Reflection decreased over the trial (t = 3.42, p = .001) but this was unrelated to change in methamphetamine use (Self-Reflection, b[SE] = -1.68 [1.16] p = .15) Change in methamphetamine use was found to be a significant predictor of Self-Certainty at 12 weeks (b [SE] = -2.71 [1.16] p = .02).

CONCLUSIONS

We found no evidence that cognitive insight predicted medication adherence or methamphetamine reduction in people engaged in this trial. Ongoing or increased methamphetamine use predicted increased Self-Certainty at 12 weeks.

Adverse childhood experiences and stimulant use disorders among adults in the United States

Recent data indicate a resurgence of stimulant use and harms in the United States; thus, there is a need to identify risk factors to inform development of effective prevention strategies. Prior research suggests adverse childhood experiences (ACEs) are common among individuals using stimulants and may be an important target for prevention. National Epidemiological Survey on Alcohol and Related Conditions was used to estimate prevalence of ACEs among U.S. adults using amphetamine-type stimulants (ATS), cocaine, or both. Multivariable logistic regression examined associations between ACEs and stimulant use and use disorders. Among adults reporting lifetime ATS use, 22.1% had ≥4 ACEs, 24.9% had 2-3 ACEs, 22.4% had 1 ACE, 30.6% reported no ACEs. Among adults with lifetime ATS use disorder, 29.3% reported ≥4 ACEs, 28.7% reported 2-3 ACEs, 21.6% reported 1 ACE, and 20.4% reported no ACEs. Multivariable logistic regression found a significant relationship between number of ACEs and stimulant use and use disorders. In conclusion, we found a strong relationship between increasing ACE exposures and stimulant use and use disorders. Advancing comprehensive strategies to prevent ACEs and treating underlying trauma among those using stimulants holds great promise to reduce stimulant use and its health and social consequences in the United States.

A latent class analysis of psychiatric symptom profiles associated with past-month methamphetamine use

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.

Prevalence of Substance Use among Psychotic Patients and Determining Its Strongest Predictor

Objective: Although comorbidity of psychotic disorders and substance use can lead to increase in mortality, less is known about the outbreak and predictors. Psychotic patients tend to be overlooked during assessment; hence, the possibility of an undertreated or missed condition such as increasing substance use. This investigation aimed to measure the prevalence of substance use in psychotic patients and to survey the powerful predictors.

Method: In a 1-year cross-sectional study, 311 psychotic patients were assessed using the Structured Interview Based on DSM-5 for diagnostic confirmation as well as questions surveying prevalence and possible predictors of substance use.

Results: Prevalence of substance use among psychotic patients was 37.9%. Several variables were identified as factors associated with drug abuse among the psychotic patients. These included male gender, younger age, being currently homeless, a history of imprisonment, and having family history of drug use. The strongest predictors of substance use, however, were family history of drug use, male gender, and being currently homelessness.

Conclusion: Policymakers should note the importance of substance use among psychotic patients. Developing active screening strategies and comprehensive preventive plans, especially in the high-risk population, is suggested.

Basolateral Amygdala Serotonin 2C Receptor Regulates Emotional Disorder-Related Symptoms Induced by Chronic Methamphetamine Administration

Globally, methamphetamine (MA) is the second most abused drug, with psychotic symptoms being one of the most common adverse effects. Emotional disorders induced by MA abuse have been widely reported both in human and animal models; however, the mechanisms underlying such disorders have not yet been fully elucidated. In this study, a chronic MA administration mouse model was utilized to elucidate the serotonergic pathway involved in MA-induced emotional disorders. After 4 weeks of MA administration, the animals exhibited significantly increased depressive and anxious symptoms. Molecular and morphological evidence showed that chronic MA administration reduced the expression of the 5-hydroxytryptamine (5-HT) rate-limiting enzyme, tryptophan hydroxylase 2, in the dorsal raphe and the concentrations of 5-HT and its metabolite 5-hydroxyindoleacetic acid in the basolateral amygdala (BLA) nuclei. Alterations in both 5-HT and 5-HT receptor levels occurred simultaneously in BLA; quantitative polymerase chain reaction, western blotting, and fluorescence analysis revealed that the expression of the 5-HT2C receptor (5-HT_2CR) increased. Neuropharmacology and virus-mediated silencing strategies confirmed that targeting 5-HT_2CR reversed the depressive and anxious behaviors induced by chronic MA administration. In the BLA, 5-HT_2CR-positive cells co-localized with GABAergic interneurons. The inactivation of 5-HT_2CR ameliorated impaired GABAergic inhibition and decreased BLA activation. Thus, herein, for the first time, we report that the abnormal regulation of 5-HT_2CR is involved in the manifestation of emotional disorder-like symptoms induced by chronic MA use. Our study suggests that 5-HT_2CR in the BLA is a promising clinical target for the treatment of MA-induced emotional disorders.

Derationalizing Delusions

Because of the traditional conceptualization of delusion as “irrational belief,” cognitive models of delusions largely focus on impairments to domain-general reasoning. Nevertheless, current rationality-impairment models do not account for the fact that (a) equivalently irrational beliefs can be induced through adaptive social cognitive processes, reflecting social integration rather than impairment; (b) delusions are overwhelmingly socially themed; and (c) delusions show a reduced sensitivity to social context both in terms of how they are shaped and how they are communicated. Consequently, we argue that models of delusions need to include alteration to coalitional cognition—processes involved in affiliation, group perception, and the strategic management of relationships. This approach has the advantage of better accounting for both content (social themes) and form (fixity) of delusion. It is also supported by the established role of mesolimbic dopamine in both delusions and social organization and the ongoing reconceptualization of belief as serving a social organizational function.

Reduction in social learning and increased policy uncertainty about harmful intent is associated with pre-existing paranoid beliefs: Evidence from modelling a modified serial dictator game

Current computational models suggest that paranoia may be explained by stronger higher-order beliefs about others and increased sensitivity to environments. However, it is unclear whether this applies to social contexts, and whether it is specific to harmful intent attributions, the live expression of paranoia. We sought to fill this gap by fitting a computational model to data (n = 1754) from a modified serial dictator game, to explore whether pre-existing paranoia could be accounted by specific alterations to cognitive parameters characterising harmful intent attributions. We constructed a ‘Bayesian brain’ model of others’ intent, which we fitted to harmful intent and self-interest attributions made over 18 trials, across three different partners. We found that pre-existing paranoia was associated with greater uncertainty about other’s actions. It moderated the relationship between learning rates and harmful intent attributions, making harmful intent attributions less reliant on prior interactions. Overall, the magnitude of harmful intent attributions was directly related to their uncertainty, and importantly, the opposite was true for self-interest attributions. Our results explain how pre-existing paranoia may be the result of an increased need to attend to immediate experiences in determining intentional threat, at the expense of what is already known, and more broadly, they suggest that environments that induce greater probabilities of harmful intent attributions may also induce states of uncertainty, potentially as an adaptive mechanism to better detect threatening others. Importantly, we suggest that if paranoia were able to be explained exclusively by core domain-general alterations we would not observe differential parameter estimates underlying harmful-intent and self-interest attributions.

A great deal of work has tried to explain paranoia through general cognitive principles, although relatively little has tried to understand whether paranoia may be explained by specific changes to social learning processes. This question is crucial, as paranoia is inherently a social phenomenon, and requires mechanistic explanations to match with its dynamic phenomenology. In this paper we wanted to test whether pre-existing and live paranoid beliefs about others specifically altered how an individual attributed harmful intent–the live expression of paranoia–to partners over a series of live interactions. To do this we applied a novel computational model and network analysis to behavioural data from a large sample of participants in the general population that had played a modified Dictator game online, and required them to attribute whether the behaviour of their partner was due to their intent to harm, or their self-interest, on two mutually exclusive scales. Pre-existing paranoid beliefs about others reduced the value of new partner behaviours on evolving attributions of harmful intent. We suggest that both pre-existing paranoid beliefs and momentary paranoia may incur an adaptive cognitive state to better track potentially threatening others, and demonstrate phenomenological specificity associated with mechanisms of live paranoia.

What Constitutes Sufficient Evidence for Case Formulation-Driven CBT for Psychosis? Cumulative Meta-analysis of the Effect on Hallucinations and Delusions

OBJECTIVE

Following 2 decades of research on cognitive behavioral therapy for psychosis (CBTp), it is relevant to consider at which point the evidence base is considered sufficient. We completed a cumulative meta-analysis to assess the sufficiency and stability of the evidence base for hallucinations and delusions.

METHOD

We updated the systematic search from our previous meta-analytic review from August 2013 until December 2019. We identified 20 new randomized controlled trials (RCTs) resulting in inclusion of 35 RCTs comparing CBTp with treatment-as-usual (TAU) or active controls (AC). We analyzed data from participants with psychosis (N = 2407) over 75 conventional meta-analytic comparisons. We completed cumulative meta-analyses (including fail-safe ratios) for key comparisons. Publication bias, heterogeneity, and risk of bias were examined.

RESULTS

Cumulative meta-analyses demonstrated sufficiency and stability of evidence for hallucinations and delusions. The fail-safe ratio demonstrated that the evidence base was sufficient in 2016 for hallucinations and 2015 for delusions. In conventional meta-analyses, CBTp was superior for hallucinations (g = 0.34, P < .01) and delusions (g = 0.37, P < .01) when compared with any control. Compared with TAU, CBTp demonstrated superiority for hallucinations (g = 0.34, P < .01) and delusions (g = 0.37, P < .01). Compared with AC, CBT was superior for hallucinations (g = 0.34, P < .01), but not for delusions although this comparison was underpowered. Sensitivity analyses for case formulation, primary outcome focus, and risk of bias demonstrated increases in effect magnitude for hallucinations.

CONCLUSIONS

The evidence base for the effect of CBTp on hallucinations and delusions demonstrates sufficiency and stability across comparisons, suggesting limited value of new trials evaluating generic CBTp.

Dopamine manipulations modulate paranoid social inferences in healthy people

Altered dopamine transmission is thought to influence the formation of persecutory delusions. However, despite extensive evidence from clinical studies there is little experimental evidence on how modulating the dopamine system changes social attributions related to paranoia, and the salience of beliefs more generally. Twenty seven healthy male participants received 150mg L-DOPA, 3 mg haloperidol, or placebo in a double-blind, randomised, placebo-controlled study, over three within-subject sessions. Participants completed a multi-round Dictator Game modified to measure social attributions, and a measure of belief salience spanning themes of politics, religion, science, morality, and the paranormal. We preregistered predictions that altering dopamine function would affect (i) attributions of harmful intent and (ii) salience of paranormal beliefs. As predicted, haloperidol reduced attributions of harmful intent across all conditions compared to placebo. L-DOPA reduced attributions of harmful intent in fair conditions compared to placebo. Unexpectedly, haloperidol increased attributions of self-interest about opponents' decisions. There was no change in belief salience within any theme. These results could not be explained by scepticism or subjective mood. Our findings demonstrate the selective involvement of dopamine in social inferences related to paranoia in healthy individuals.

Associations of substance use, psychosis, and mortality among people living in precarious housing or homelessness: A longitudinal, community-based study in Vancouver, Canada

BACKGROUND

The "trimorbidity" of substance use disorder and mental and physical illness is associated with living in precarious housing or homelessness. The extent to which substance use increases risk of psychosis and both contribute to mortality needs investigation in longitudinal studies.

METHODS AND FINDINGS

A community-based sample of 437 adults (330 men, mean [SD] age 40.6 [11.2] years) living in Vancouver, Canada, completed baseline assessments between November 2008 and October 2015. Follow-up was monthly for a median 6.3 years (interquartile range 3.1-8.6). Use of tobacco, alcohol, cannabis, cocaine, methamphetamine, and opioids was assessed by interview and urine drug screen; severity of psychosis was also assessed. Mortality (up to November 15, 2018) was assessed from coroner's reports and hospital records. Using data from monthly visits (mean 9.8, SD 3.6) over the first year after study entry, mixed-effects logistic regression analysis examined relationships between risk factors and psychotic features. A past history of psychotic disorder was common (60.9%). Nonprescribed substance use included tobacco (89.0%), alcohol (77.5%), cocaine (73.2%), cannabis (72.8%), opioids (51.0%), and methamphetamine (46.5%). During the same year, 79.3% of participants reported psychotic features at least once. Greater risk was associated with number of days using methamphetamine (adjusted odds ratio [aOR] 1.14, 95% confidence interval [CI] 1.05-1.24, p = 0.001), alcohol (aOR 1.09, 95% CI 1.01-1.18, p = 0.04), and cannabis (aOR 1.08, 95% CI 1.02-1.14, p = 0.008), adjusted for demographic factors and history of past psychotic disorder. Greater exposure to concurrent month trauma was associated with increased odds of psychosis (adjusted model aOR 1.54, 95% CI 1.19-2.00, p = 0.001). There was no evidence for interactions or reverse associations between psychotic features and time-varying risk factors. During 2,481 total person years of observation, 79 participants died (18.1%). Causes of death were physical illness (40.5%), accidental overdose (35.4%), trauma (5.1%), suicide (1.3%), and unknown (17.7%). A multivariable Cox proportional hazard model indicated baseline alcohol dependence (adjusted hazard ratio [aHR] 1.83, 95% CI 1.09-3.07, p = 0.02), and evidence of hepatic fibrosis (aHR 1.81, 95% CI 1.08-3.03, p = 0.02) were risk factors for mortality. Among those under age 55 years, a history of a psychotic disorder was a risk factor for mortality (aHR 2.38, 95% CI 1.03-5.51, p = 0.04, adjusted for alcohol dependence at baseline, human immunodeficiency virus [HIV], and hepatic fibrosis). The primary study limitation concerns generalizability: conclusions from a community-based, diagnostically heterogeneous sample may not apply to specific diagnostic groups in a clinical setting. Because one-third of participants grew up in foster care or were adopted, useful family history information was not obtainable.

CONCLUSIONS

In this study, we found methamphetamine, alcohol, and cannabis use were associated with higher risk for psychotic features, as were a past history of psychotic disorder, and experiencing traumatic events. We found that alcohol dependence, hepatic fibrosis, and, only among participants <55 years of age, history of a psychotic disorder were associated with greater risk for mortality. Modifiable risk factors in people living in precarious housing or homelessness can be a focus for interventions.

Exposure to HIV risks among young people who use drugs (YPUD) in three cities in Vietnam: time to develop targeted interventions

Introduction

The aim of this study is to identify the profiles of young people who use drugs (YPUD) and their exposure to HIV risks in the 3 main cities of Vietnam, Haiphong, Hanoi, and Ho Chi Minh City (HCMC), in order to design a community-based intervention to prevent HIV.

Methods

A survey using respondent-driven sampling (RDS) was conducted among YPUD aged 16–24. Participants were eligible if they reported drug use, confirmed by a urine test. After obtaining informed consent, they were screened for HIV/HCV and assessed using face-to-face questionnaires and self-report. A cluster analysis was conducted, taking into account risk behaviors and confirmed HIV-positive status.

Results

Seven hundred and three YPUD aged 16–24 were recruited between October 2016 and February 2017, 584 of whom were included in the final analysis. Median age was 21 (17.7, 23.0); 79% were male, 18% female, and 2% transgender. Methamphetamines use was reported by 77%, followed by cannabis (51%) and heroin (17%); polydrug use was common; 15% had “ever” injected drugs. HIV prevalence was 7%. Among all participants, 48% reported non-consistent condom use and 1% reported needle/syringe sharing during the previous month. Four distinct profiles of HIV risk behaviors were identified: The high multiple-risk group mixed unsafe drug use with unsafe sexual practices and had higher prevalence of HIV; the second group practiced high-risk sex with non-consistent condom combined with methamphetamine use; the third group was a moderate-risk group with limited unsafe sexual practices; and the fourth was considered at “low-risk” as reportedly, most never had sex and never injected. The highest risk group included more female YPUD, living in HCMC, who used heroin and had unsafe sex with their regular partners. The second high-risk group included most of the MSM and all transgender people and frequently reported mental health disorders.

Conclusions

The profiles of YPUD who are at risk of HIV vary according to age, location, and population group. Injecting YPUD are the most exposed to risk and need immediate attention. Sexual exposure to HIV is very common. Mental health is a major concern. Interventions need to be integrated in a differentiated but holistic approach.

Resurgent Methamphetamine Use at Treatment Admission in the United States, 2008-2017

Objectives. To evaluate trends and correlates of methamphetamine use in the United States.Methods. Data are from 15 747 334 drug-related treatment admissions among persons aged 12 years or older in the 2008-2017 Treatment Episode Data Set. We analyzed trends and used multivariable logistic regression.Results. Methamphetamine-related admissions increased from 15.1% of drug-related treatment admissions in 2008 to 23.6% in 2017. Increases occurred among nearly all demographic groups. Methamphetamine injection increased from 17.5% of admissions in 2008 to 28.4% in 2017. Among methamphetamine-related admissions, heroin use increased from 5.3% of admissions in 2008 to 23.6% in 2017. Characteristics associated with increased odds of reporting methamphetamine use at admission included female sex; admissions aged 35 to 44 years; admissions in the Midwest, South, and West; unemployment; not in labor force; living dependent; living homeless; and having a referral from criminal justice, a health care provider, or other community treatment source.Conclusions. Treatment admissions involving methamphetamine use increased significantly over the past decade and appear to be linked to the ongoing opioid crisis in the United States. Efforts to mobilize public health prevention, treatment, and response strategies to address rising methamphetamine use and overdose are needed.

Dopamine and glutamate in schizophrenia: biology, symptoms and treatment

Glutamate and dopamine systems play distinct roles in terms of neuronal signalling, yet both have been proposed to contribute significantly to the pathophysiology of schizophrenia. In this paper we assess research that has implicated both systems in the aetiology of this disorder. We examine evidence from post-mortem, preclinical, pharmacological and in vivo neuroimaging studies. Pharmacological and preclinical studies implicate both systems, and in vivo imaging of the dopamine system has consistently identified elevated striatal dopamine synthesis and release capacity in schizophrenia. Imaging of the glutamate system and other aspects of research on the dopamine system have produced less consistent findings, potentially due to methodological limitations and the heterogeneity of the disorder. Converging evidence indicates that genetic and environmental risk factors for schizophrenia underlie disruption of glutamatergic and dopaminergic function. However, while genetic influences may directly underlie glutamatergic dysfunction, few genetic risk variants directly implicate the dopamine system, indicating that aberrant dopamine signalling is likely to be predominantly due to other factors. We discuss the neural circuits through which the two systems interact, and how their disruption may cause psychotic symptoms. We also discuss mechanisms through which existing treatments operate, and how recent research has highlighted opportunities for the development of novel pharmacological therapies. Finally, we consider outstanding questions for the field, including what remains unknown regarding the nature of glutamate and dopamine function in schizophrenia, and what needs to be achieved to make progress in developing new treatments.

Increases in methamphetamine use among heroin treatment admissions in the United States, 2008-17

BACKGROUND AND AIMS

Due to their small sample sizes, geographic specificity and limited examination of socio-demographic characteristics, recent studies of methamphetamine use among people using heroin in the United States are limited in their ability to identify national and regional trends and to characterize populations at risk for using heroin and methamphetamine. This study aimed to examine trends and correlates of methamphetamine use among heroin treatment admissions in the United States.

DESIGN

Longitudinal analysis of data from the 2008 to 2017 Treatment Episode Data Set. Descriptive statistics, trend analyses and multivariable logistic regression were used to examine characteristics associated with methamphetamine use among heroin treatment admissions.

SETTING

United States.

PARTICIPANTS

Treatment admissions of people aged ≥ 12 years whose primary substance of use is heroin.

MEASUREMENTS

Primary measurement was heroin treatment admissions involving methamphetamine. Secondary measurements were demographics of sex, age, race/ethnicity, US census region, living arrangement and employment status.

FINDINGS

The percentage of primary heroin treatment admissions reporting methamphetamine use increased each year from 2.1% in 2008 to 12.4% in 2017, a relative percentage increase of 490% and an annual percentage change (APC) of 23.4% (P < 0.001). During the study period, increases were seen among males and females and among all demographic and geographic groups examined. Among primary heroin treatment admissions reporting methamphetamine use in 2017, 47.1% reported injecting, 46.0% reported smoking, 5.1% reporting snorting and 1.8% reported oral/other as their usual route of methamphetamine use.

CONCLUSIONS

Methamphetamine use among heroin treatment admissions in the United States increased from one in 50 primary heroin treatment admissions in 2008 to one in 8 admissions in 2017.

An association study between methamphetamine use disorder with psychosis and polymorphisms in MiRNA

BACKGROUND

Methamphetamine (MA) is an addictive psychostimulant substance that mainly leads to schizophrenia-like psychotic symptoms. The expression of miRNAs in brain plays an important role in neurological disorders and may affect by genetic variant(s) in the target site (MiRSNPs). In this study, we investigated whether polymorphisms in miRNAs are associated with MA disorder with psychosis.

METHODS

We carried out a case-control association study in 400 MA users with psychotic characters and 448 controls. Six MiRSNPs with predicted functional relevance miRNAs (miR-181b, miR-181a, miR-15b, miR-let-7e and miRlet-7d) were selected for genotyping. Allele and genotype frequencies were compared between MA users and healthy individuals. The expression of five miRNAs were measured by quantitative real-time RT-PCR in 55 cases and 57 controls. We also explored an expression Quantitative Trait Loci (eQTL) analysis based on the miRNAs expression and SNP genotype.

RESULTS

The SNP rs10760371 within miR-181a was nominally associated with MA disorder (P = 0.046). For rs1099308, rs10760371 and rs10993081 in strong linkage disequilibrium (LD), no significant association had been detected from haplotype analysis. Discrepancy had been found between MA users and healthy individuals (P < 0.01) in terms of the expression of miR-181a, miR-15b, miR-let-7e and miR-let-7d. and no noticeable difference had been found from the eQTL analysis.

CONCLUSION

Our findings suggest that rs10760371 within miR-181a may relate to the development of MA dependence with psychosis. The miRNAs expression is unlikely to be regulated by the SNPs within it.

Is there a discrete negative symptom syndrome in people who use methamphetamine?

BACKGROUND

Positive psychotic symptoms have consistently been associated with methamphetamine use but the presence of a negative symptom cluster remains unclear. We used exploratory factor analysis to examine whether a discrete negative syndrome could be delineated among methamphetamine users, and to examine the clinical correlates of this syndrome.

METHOD

Participants (N = 154) were people who used methamphetamine at least monthly and did not meet DSM-IV diagnostic criteria for lifetime schizophrenia. Scores on the Brief Psychiatric Rating Scale for the past month were subject to exploratory factor analysis. Latent class analysis was applied to resultant factor scores to determine whether negative and positive factors were experienced by the same participants. Past-month substance use measures were days of use for each drug type and methamphetamine dependence assessed using the Severity of Dependence Scale.

RESULTS

We articulated a three-factor model including 'positive/activation symptoms' (e.g. suspiciousness, hallucinations, conceptual disorganisation, tension), 'affective symptoms' (e.g. depression, anxiety) and 'negative symptoms' (e.g. blunted affect, motor retardation). Positive-activation and affective symptoms (but not negative symptoms) were positively correlated with past month days of methamphetamine use (r = 0.16; r = 0.25) and severity of dependence (r = 0.24; r = 0.41). Negative symptoms were correlated with heroin (r = 0.24) and benzodiazepine use (r = 0.21). Latent class analysis revealed a three-class model comprising a positive-symptom class (44%, high positive-activation, low negative symptoms), a negative-symptom class (31%, low positive-activation, high negative symptoms), and a low-symptom class (38%, low on all factors).

CONCLUSIONS

A negative symptom syndrome exists among people who use methamphetamine, but this appears related to polysubstance use rather than forming a part of the psychotic syndrome associated with methamphetamine use. Overlooking the role of polysubstance use on negative symptoms may conflate the profiles of methamphetamine-associated psychosis and schizophrenia.

A study protocol for the N-ICE trial: A randomised double-blind placebo-controlled study of the safety and efficacy of N-acetyl-cysteine (NAC) as a pharmacotherapy for methamphetamine ("ice") dependence

BACKGROUND

There are currently no approved pharmacotherapies for managing methamphetamine dependence. N-acetylcysteine (NAC) has been found to reduce the craving for methamphetamine and other drugs, but its effect on methamphetamine use and other clinically related endpoints are uncertain. The N-ICE trial is evaluating the safety and efficacy of NAC as a take-home pharmacotherapy for methamphetamine dependence.

METHODS/DESIGN

This is a two-arm parallel double-blind placebo-controlled three-site randomised trial (ratio 1:1) using permuted block randomisation, with variable block sizes. It is stratified by site, sex and whether the methamphetamine is injected or not. Participants (N = 180; 60 per site) need to be dependent on methamphetamine, interested in reducing their methamphetamine use and not currently receiving treatment for substance use disorders. The trial is being conducted in outpatient settings in Melbourne, Geelong and Wollongong, Australia. Participants will receive either 2400 mg oral NAC or a matched placebo, delivered as a take-home medication for 12 weeks. Two 600 mg capsules are self-administered in the morning and two more in the evening. Adherence is being monitored using eCAP™ medication bottle lids, which record the date and time of each occasion the bottle is opened. The primary outcome is methamphetamine use during the 12-week trial medication period, measured as (a) days of use, assessed using the timeline followback, and (b) methamphetamine-positive saliva tests, taken weekly. Secondary measures include weekly assessment of methamphetamine craving, severity of methamphetamine dependence, methamphetamine withdrawal symptoms and psychiatric symptoms (depression, suicidality, psychotic symptoms and hostility). Adverse events are monitored at each weekly assessment. Tolerability is assessed using the Treatment Satisfaction Questionnaire for Medication.

DISCUSSION

The N-ICE trial is the first clinical trial to assess whether NAC can reduce methamphetamine use. This trial will improve our understanding of the potential utility of NAC in managing methamphetamine dependence and clinically related outcomes. If found to be effective, take-home NAC could be a potentially scalable and affordable pharmacotherapy option for treating methamphetamine dependence.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry, ACTRN12618000366257 . Registered on 29 May 2018.