A Comparison of Methamphetamine-Induced Psychosis and Schizophrenia: A Review of Positive, Negative, and Cognitive Symptomatology

Developing a coordinated response to chemsex across health, justice and social care settings: expert consensus statement

SUMMARY

Chemsex occurs primarily among gay, bisexual and other men who have sex with men (GBMSM), and there is evidence of a subgroup of users who carry out chemsex-related criminal offences and experience harm. Challenges with chemsex can present to various settings; there are concerns that harm is increasing, including at interfaces between health, social care and criminal justice systems. The UK response to date has lacked a coordinated approach. An expert reference group was convened to share chemsex knowledge, articulate priorities for research and pathway development, and foster collaborative working between agencies. It made three key recommendations: develop and increase training and awareness across all services; implement a coordinated research programme with the development of a common data-set and assessment tool to fully characterise population-level needs; develop a professional network to share information, provide professional support and act as a knowledge hub. There was support for a unified multi-agency strategy incorporating the priorities identified as overarching principles.

Blocking Sigmar1 exacerbates methamphetamine-induced hypertension

AIM

Methamphetamine (METH) chronic exposure is an important risk factor for hypertension development. However, the mechanisms behind METH-induced hypertension remain unclear. Therefore, we aimed to reveal the potential mechanisms underlying METH-induced hypertension.

METHODS AND RESULTS

We structured the mouse hypertension model by METH, and observed that METH-treated mice have presented vascular remodeling (large-and small-size arteries) with collagen deposit around the vessel and increasing blood pressure (BP) and Sigma1 receptor (Sigmar1) in vascular tissue. We hypothesized that Sigmar1 is crucial in METH-induced hypertension and vascular remodeling. Sigmar1 knockout (KO) mice and antagonist (BD1047) pretreated mice exposed to METH for six-week showed higher BP and more collagen deposited around vessels than wild-type (WT) mice exposed to METH for six-week, in contrast, mice pretreated with Sigmar1 agonist (PRE-084) had unchanged BP and perivascular collagen despite the six-week METH exposure. Furthermore, we found that METH exposure induced vascular smooth muscle cells (VSMCs) and mesenchymal stem cells to differentiate into the myofibroblast-like cell and secrete collagen into surrounding vessels. Mechanically, Sigmar1 can suppress the COL1A1 expression by blocking the classical fibrotic TGF-β/Smad2/3 signaling pathway in METH-exposed VSMCs and mesenchymal stem cells.

CONCLUSION

Our results suggest that Sigmar1 is involved in METH-induced hypertension and vascular fibrosis by blocking the activation of the TGF-β/Smad2/3 signaling pathway. Accordingly, Sigmar1 may be a novel therapeutic target for METH-induced hypertension and vascular fibrosis.

A systematic review and meta-analysis of synthetic cathinone use and psychosis

RATIONALE

Synthetic cathinones (SC), commonly referred to as "bath salts", are stimulants resembling the natural alkaloid cathinone found in the khat plant. These substances have the potential to induce serious health risks such as hallucinations, delusions, paranoia and agitation which can lead to substance-induced psychotic disorders. Despite growing concerns, there is a limited understanding of the association between SC consumption and the devolvement of such psychopathologies.

METHODS

We conducted a systematic review to investigate the frequency of substance-induced psychotic disorder (SIPD) and associated conditions in humans following synthetic cathinone consumption. We qualitatively and quantitatively analyzed SC exposure cases.

RESULTS

A total of 32 studies were included, with a diverse range of demographics, synthetic cathinone types, and consumption patterns. The proportion of individuals developing psychotic symptoms was reported at 0.380 (Random-effects model, 95% CI 0.289 - 0.475). Additionally, the significant heterogeneity in diagnostic approaches limited our ability to provide a precise estimate of prevalence.

CONCLUSIONS

Synthetic cathinone consumption is associated with the risk of developing psychotic symptoms as indicated by the prevalence of hallucinations and/or delusions. Due to the lack of information on classifying factors, particularly duration of symptoms, we are unable to conclude synthetic cathinone-induced psychosis. Further research is warranted to elucidate the underlying mechanism linking synthetic cathinone consumption and psychosis. This review underscores the urgency of addressing the growing health risks posed by synthetic cathinone use. Additionally, it highlights the necessity of proper quantification of psychotic symptoms through scales and reporting of classification criteria to accurately diagnose SIPD.

Morphogenetic theory of mental and cognitive disorders: the role of neurotrophic and guidance molecules

Mental illness and cognitive disorders represent a serious problem for the modern society. Many studies indicate that mental disorders are polygenic and that impaired brain development may lay the ground for their manifestation. Neural tissue development is a complex and multistage process that involves a large number of distant and contact molecules. In this review, we have considered the key steps of brain morphogenesis, and the major molecule families involved in these process. The review provides many indications of the important contribution of the brain development process and correct functioning of certain genes to human mental health. To our knowledge, this comprehensive review is one of the first in this field. We suppose that this review may be useful to novice researchers and clinicians wishing to navigate the field.

Enhanced Beta2-band Oscillations Denote Auditory Hallucination in Schizophrenia Patients and a Monkey Model of Psychosis

An electroencephalographic (EEG) signature of auditory hallucinations (AHs) is important for facilitating the diagnosis and treatment of AHs in schizophrenia. We recorded EEG from 25 schizophrenia patients with recurrent AHs. During the period of AHs, EEG recordings exhibited significantly elevated beta2-band power in the temporal region, as compared to those recorded in the absence of AHs or during stimulation with verbal sounds. We further generated methamphetamine-treated rhesus monkeys exhibiting psychosis-like behaviors, including repetitive sudden searching actions in the absence of external intrusion, suggesting the occurrence of AHs. Epidural EEG beta2-band power in the temporal region of these monkeys was enhanced immediately after methamphetamine treatment and positively correlated with the frequency of sudden searching actions. Thus, the enhancement of temporal beta2-band oscillations represents a signature for AHs in both patients and a monkey model of psychosis, and this monkey model can be used for developing closed-loop neuromodulation approaches for the treatment of refractory AHs in schizophrenia.

Epigenome-wide association study on methamphetamine dependence

Repeated abuse of methamphetamine (METH) can cause dependence, repeated relapse of psychotic symptoms, compulsive drug-seeking behaviour, and various neurological symptoms. These long-term biological changes may be associated with epigenetic mechanisms; however, the association between METH use and epigenetic mechanisms has been poorly investigated. Thus, we performed an epigenome-wide association study of METH dependence using genomic DNA extracted from the blood samples of 24 patients with METH dependence and 24 normal controls. All participants were of Japanese descent. We tested the association between METH dependence and DNA methylation using linear regression analysis. We found epigenome-wide significant associations at four CpG sites, one of which occurred in the CNOT1 gene and another in the PUM1 gene. We especially noted the CNOT1 and PUM1 genes as well as several other genes that indicated some degree of association with METH dependence. Among the relatively enriched Gene Ontology terms, we were interested in terms of mRNA metabolism, respirasome, and excitatory extracellular ligand-gated ion channel activity. Among the relatively enriched Kyoto Encyclopedia of Genes and Genome pathways, we noted pathways of several neurological diseases. Our results indicate that genetic changes akin to those in other psychiatric or neurodegenerative disorders may also occur via epigenetic mechanisms in patients with METH dependence.

Lymphocyte-related ratios in methamphetamine-induced psychotic disorder in Taiwan, comparing with patients with schizophrenia

The lymphocyte-related ratios, neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR) and platelet-to-lymphocyte ratio (PLR) are new measures of inflammation within the body. Few studies have investigated the inflammatory response of patients with methamphetamine-induced psychotic disorder. Clinically, the psychotic symptoms and behavioural manifestation of methamphetamine-induced psychotic disorder are often indistinguishable from paranoid schizophrenia. We aimed to determine the differences in these inflammatory markers between patients with methamphetamine-induced psychotic disorder, patients with schizophrenia and healthy individuals. A total of 905 individuals were recruited. The NLR and MLR were found to be higher in both patients with methamphetamine-induced psychotic disorders and patients with schizophrenia compared with healthy controls. There was no significant difference between the three groups in PLR. When compared with the control group, the methamphetamine-induced psychotic disorder group was significantly higher in NLR 27% (95%CI = 11 to 46%, p = 0.001), MLR 16% (95%CI = 3% to 31%, p = 0.013) and PLR 16% (95%CI = 5% to 28%, p = 0.005). NLR of the group with methamphetamine-induced psychotic disorder was 17% (95%CI = 73% to 94%, p = 0.004) less than the group with schizophrenia, while MLR and PLR did not differ significantly between the two groups. This is the first study that investigated the lymphocyte-related ratios in methamphetamine-induced psychotic disorder when compared with patients with schizophrenia and healthy individuals. The results showed that both patients with methamphetamine-induced psychotic disorder and patients with schizophrenia had stronger inflammatory responses than the healthy control. Our finding also indicated that the inflammatory response of methamphetamine-induced psychotic disorder was between those of patients with schizophrenia and healthy individuals.

A Novel Form of Neuregulin 1 Type III Caused by N-Terminal Processing

Nrg1 (Neuregulin 1) type III, a susceptible gene of schizophrenia, exhibits a critical role in the central nervous system and is essential at each stage of Schwann's cell development. Nrg1 type III comprises double-pass transmembrane domains, with the N-terminal and C-terminal localizing inside the cells. The N-terminal transmembrane helix partially overlaps with the cysteine-rich domain (CRD). In this study, Nrg1 type III constructs with different tags were transformed into cultured cells to verify whether CRD destroyed the transmembrane helix formation. We took advantage of immunofluorescent and immunoprecipitation assays on whole cells and analyzed the N-terminal distribution. Astonishingly, we found that a novel form of Nrg1 type III, about 10% of Nrg1 type III, omitted the N-terminal transmembrane helix, with the N-terminal positioning outside the membrane. The results indicated that the novel single-pass transmembrane status was a minor form of Nrg1 type III caused by N-terminal processing, while the major form was a double-pass transmembrane status.

Enhanced methamphetamine sensitisation in a rat model of the brain-derived neurotrophic factor Val66Met variant: Sex differences and dopamine receptor gene expression

Brain-derived neurotrophic factor (BDNF) and the Val66Met polymorphism may play a role in the development of psychosis and schizophrenia. The aim of this study was to investigate long-term effects of methamphetamine (Meth) on psychosis-like behaviour and dopamine receptor and dopamine transporter gene expression in a novel rat model of the BDNF Val66Met polymorphism. At the end of a 7-day subchronic Meth treatment, female rats with the Met/Met genotype selectively showed locomotor hyperactivity sensitisation to the acute effect of Meth. Male rats showed tolerance to Meth irrespective of Val66Met genotype. Two weeks later, female Met/Met rats showed increased locomotor activity following both saline treatment or a low dose of Meth, a hyperactivity which was not observed in other genotypes or in males. Baseline PPI did not differ between the groups but the disruption of PPI by acute treatment with apomorphine was absent in Meth-pretreated Met/Met rats. Female Met/Met rats selectively showed down-regulation of dopamine D2 receptor gene expression in striatum. Behavioural effects of MK-801 or its locomotor sensitisation by prior Meth pretreatment were not influenced by genotype. These data suggest a selective vulnerability of female Met/Met rats to short-term and long-term effects of Meth, which could model increased vulnerability to psychosis development associated with the BDNF Val66Met polymorphism.

A Case Report of Treatment With Cariprazine in a Recurrent Psychosis Presumably Induced by Methamphetamine

This case report describes a 31-year-old male patient with psychosis presumably related to methamphetamine-associated psychosis (MAP). Our patient was experiencing persistent symptoms of visual, tactile, and auditory hallucinations after cessation of methamphetamine. He has a medical history of a substance use disorder, post-traumatic stress disorder, attention-deficit hyperactivity disorder, nicotine dependence and major depressive disorder. Previously, he received a wide range of antipsychotic drug treatment regimens at other psychiatric facilities, all with some degree of effect, but never with complete symptom relief. At the time of admission to our inpatient clinic, he was started on cariprazine and reported a significant decrease in visual, auditory, and tactile hallucinations with complete cessation for a period of two weeks. There appears to be a unique ability of cariprazine's mechanism of action to reverse symptoms of the presumable diagnosis of MAP that is unable to be achieved with other antipsychotic medications.

Knowing me, knowing you: a scoping review assessing the current field of social cognition in schizophrenia

BACKGROUND

Impaired social cognition (SC) occurs frequently in schizophrenia (SCZ), yet compared to autism spectrum disorder (ASD), the research on SC in SCZ is sparse and methodologically heterogeneous. To accurately assess between-group SC differences it is further necessary to establish the relationship between nonsocial cognition (NSC) and SC, particularly as this may not be identical across disorders.

PURPOSE

The present study aimed to map, index and assess the quality of research published between 2014-2021 investigating SC in SCZ, and to summarize existing limitations and recommendations for future research.

METHOD

Following the PRISMA guidelines for scoping reviews (PRISMA-ScR) fifteen (n = 15) case-control studies were identified and included across three electronic databases. Studies additionally utilizing ASD samples were included because of their clinical utility.

RESULTS

Most studies reported significant SC impairments in SCZ relative to healthy controls (HC) with varying effect sizes. Significant differences between SCZ and ASD were not found in most studies including both samples. Weak-to-moderate correlations between SC and NSC were often found, although often only within patient samples. Across studies, SC tests were inconsistently described as measurements of "social cognition", "mentalization" and, most frequently and varyingly, "theory of mind". Most studies lacked methodological transparency. Limitations related to sample sizes and test reliability were most frequently mentioned.

CONCLUSIONS

The current research on SC in SCZ is limited by conceptual and methodological uncertainties. Future research should focus on ensuring clear and valid definitions of key terms, evaluating and clarifying SC outcome measures and further untangling the relationship between SC and NSC.

Analysis of Acute and Chronic Methamphetamine Treatment in Mice on Gdnf System Expression Reveals a Potential Mechanism of Schizophrenia Susceptibility

The increase in presynaptic striatal dopamine is the main dopaminergic abnormality in schizophrenia (SCZ). SCZ is primarily treated by modulating the activity of monoamine systems, with a focus on dopamine and serotonin receptors. Glial cell line-derived neurotrophic factor (GDNF) is a strong dopaminergic factor, that recently was shown to correlate with SCZ in human CSF and in striatal tissue. A 2-3-fold increase in GDNF in the brain was sufficient to induce SCZ-like dopaminergic and behavioural changes in mice. Here, we analysed the effect of acute, chronic, and embryonic methamphetamine, a drug known to enhance the risk of psychosis, on Gdnf and its receptors, Gfra1 and Ret, as well as on monoamine metabolism-related gene expression in the mouse brain. We found that acute methamphetamine application increases Gdnf expression in the striatum and chronic methamphetamine decreases the striatal expression of GDNF receptors Gfra1 and Ret. Both chronic and acute methamphetamine treatment upregulated the expression of genes related to dopamine and serotonin metabolism in the striatum, prefrontal cortex, and substantia nigra. Our results suggest a potential mechanism as to how methamphetamine elicits individual psychosis risk in young adults-variation in initial striatal GDNF induction and subsequent GFRα1 and RET downregulation may determine individual susceptibility to psychosis. Our results may guide future experiments and precision medicine development for methamphetamine-induced psychosis using GDNF/GFRa1/RET antagonists.

Rho kinase inhibitors ameliorate cognitive impairment in a male mouse model of methamphetamine-induced schizophrenia

Schizophrenia (SCZ) is a severe psychiatric disorder characterized by positive symptoms, negative symptoms, and cognitive deficits. Current antipsychotic treatment in SCZ improves positive symptoms but has major side effects and little impact on negative symptoms and cognitive impairment. The pathoetiology of SCZ remains unclear, but is known to involve small GTPase signaling. Rho kinase, an effector of small GTPase Rho, is highly expressed in the brain and plays a major role in neurite elongation and neuronal architecture. This study used a touchscreen-based visual discrimination (VD) task to investigate the effects of Rho kinase inhibitors on cognitive impairment in a methamphetamine (METH)-treated male mouse model of SCZ. Systemic injection of the Rho kinase inhibitor fasudil dose-dependently ameliorated METH-induced VD impairment. Fasudil also significantly suppressed the increase in the number of c-Fos-positive cells in the infralimbic medial prefrontal cortex (infralimbic mPFC) and dorsomedial striatum (DMS) following METH treatment. Bilateral microinjections of Y-27632, another Rho kinase inhibitor, into the infralimbic mPFC or DMS significantly ameliorated METH-induced VD impairment. Two proteins downstream of Rho kinase, myosin phosphatase-targeting subunit 1 (MYPT1; Thr696) and myosin light chain kinase 2 (MLC2; Thr18/Ser19), exhibited increased phosphorylation in the infralimbic mPFC and DMS, respectively, after METH treatment, and fasudil inhibited these increases. Oral administration of haloperidol and fasudil ameliorated METH-induced VD impairment, while clozapine had little effect. Oral administration of haloperidol and clozapine suppressed METH-induced hyperactivity, but fasudil had no effect. These results suggest that METH activates Rho kinase in the infralimbic mPFC and DMS, which leads to cognitive impairment in male mice. Rho kinase inhibitors ameliorate METH-induced cognitive impairment, perhaps via the cortico-striatal circuit.

Ameliorative effects of Fingolimod (FTY720) on microglial activation and psychosis-related behavior in short term cuprizone exposed mice

Schizophrenia is a psychiatric disorder that affects around 1% of the population in widespread populations, with severe cases leading to long-term hospitalization and necessitation of lifelong treatment. Recent studies on schizophrenia have highlighted the involvement of inflammatory and immunoregulatory mechanisms with the onset of symptoms, and the usage of anti-inflammatory treatments are being tested against periods of rapid psychosis. In the central nervous system, microglia are the innate immune population which are activated in response to a wide range of physical and psychological stress factors and produce proinflammatory mediators such as cytokines. Microglial activation and neuroinflammation has been associated to numerous psychiatric disorders including schizophrenia, especially during psychotic episodes. Thus, novel treatments which dampen microglial activation may be of great relevance in the treatment of psychiatric disorders. Fingolimod (FTY720) is a drug used as an immunosuppressive treatment to multiple sclerosis. Recent clinical trials have focused on FTY720 as a treatment for the behavioral symptoms in schizophrenia. However, the mechanisms of Fingolimod in treating the symptoms of schizophrenia are not clear. In this study we use a recently developed neuroinflammatory psychosis model in mice: cuprizone short-term exposure, to investigate the effects of FTY720 administration. FTY720 administration was able to completely alleviate methamphetamine hypersensitivity caused by cuprizone exposure. Moreover, administration of FTY720 improved multiple measures of neuroinflammation (microglial activation, cytokine production, and leucocyte infiltration). In conclusion, our results highlight the future use of FTY720 as a direct anti-inflammatory treatment against microglial activation and psychosis.

Identification of PROK2 gene polymorphisms as predictors of methamphetamine use disorder risk and indicators of craving scale in the Chinese Han population

Background: Methamphetamine use disorder (MUD) has become a global problem due to the highly addictive nature of methamphetamine. Earlier research have demonstrated that PROK2 functions as a compensatory and protective response against neurotoxic stress by stimulating astrocyte reactivity. The aim of our study was to evaluate the correlation between the PROK2 gene and both MUD risk susceptibility and craving scale in the Chinese Han population. Methods: A total of 5,282 participants (1,796 MUD patients and 3,486 controls) were recruited. Seven tag SNPs of the PROK2 gene were chosen and genotyped in the samples. Genetic association analyses were performed to capture the significant SNPs. To investigate the relationship between PROK2 levels and craving scores with the associated-SNP genotypes, we conducted a linear model. Results: SNP rs75433452 was significantly linked with MUD risk (p-value = 1.54 × 10^-8), with the A allele being positively correlated with an increased risk of MUD. Moreover, the average serum level of PROK2 decreased when more copies of the A allele were presented in both MUD patients (p-value = 4.57 × 10^-6) and controls (p-value = 1.13 × 10^-5). Furthermore, the genotypes of SNP rs75433452 were strongly correlated with the craving scores in MUD patients (p-value = 4.05 × 10^-4). Conclusion: Our study identified a significant association signal of the PROK2 gene with MUD risk susceptibility and methamphetamine craving scores in the Chinese Han population, providing potential valuable insights into the underlying mechanisms of METH dependence.

Effect of methamphetamine on ultraweak photon emission and level of reactive oxygen species in male rat brain

All living cells, including neurons, generate ultra-weak photon emission (UPE) during biological activity, and in particular, in the brain, it has been shown that UPE is correlated with neuronal activity and associated metabolic processes. Various intracellular factors, as well as external factors, can reduce or increase the intensity of UPE. In this study, we have used Methamphetamine (METH) as one potentially effective external factor, which is a substance that has the property of stimulating the central nervous system. METH can impair mitochondrial function by causing toxicity via various pathways, including an increase in the number of mitochondria, hyperthermia, the increased metabolic activity of the brain, and the production of glutamate and excess calcium. In addition to mitochondrial dysfunction, METH alters cellular homeostasis, leading to cell damage and the production of excess ROS. The aim of this study is to measure and compare the UPE intensity and reactive oxygen species (ROS) levels of the prefrontal, motor, and visual cortex before and after METH administration. Twenty male rats were randomly assigned to two groups, the control, and METH groups. In the control group, 2 h after injection of normal saline and without any intervention, and in the experimental group 2 h after IP injection of 20 mg/kg METH, sections were prepared from three areas: prefrontal, motor, and V1-V2 cortex, which were used to evaluate the emission of UPE using a photomultiplier tube (PMT) device and to evaluate the amount of ROS. The results showed that the amount of ROS and UPE in the experimental group in all three areas significantly increased compared to the control group. So, METH increases UPE and ROS in the prefrontal, motor, and visual regions, and there is a direct relationship between UPE intensity and ROS production. Therefore, UPE may be used as a dynamic reading tool to monitor oxidative metabolism in physiological processes related to ROS and METH research. Also, the results of this experiment may create a new avenue to test the hypothesis that the excess in UPE generation may lead to the phenomenon of phosphene and visual hallucinations.

Methamphetamine-induced locomotor sensitization in mice is not associated with deficits in a range of cognitive, affective and social behaviours: interaction with brain-derived neurotrophic factor Val66Met genotype

Chronic methamphetamine (Meth) abuse may induce psychosis similar to that observed in schizophrenia. Brain-derived neurotrophic factor (BDNF) has been implicated in the development of psychosis. We have previously shown long-term protein expression changes in mice treated chronically with Meth depending on BDNF Val66Met genotype. The aim of this study was to investigate if these protein expression changes were associated with differential changes in a range of behavioural paradigms for cognition, anxiety, social and other behaviours. Male and female Val/Val, Val/Met and Met/Met mice were treated with an escalating Meth dose protocol from 6 to 9 weeks of age, with controls receiving saline injections. Several overlapping cohorts were tested in the Y-maze for short-term spatial memory, novel-object recognition test, context and cued fear conditioning, sociability and social preference, elevated plus maze for anxiety-like behaviour and prepulse inhibition (PPI) of acoustic startle. Finally, the animals were assessed for spontaneous exploratory locomotor activity and acute Meth-induced locomotor hyperactivity. Acute Meth caused significantly greater locomotor hyperactivity in mice previously treated with the drug than in saline-pretreated controls. Meth-pretreated female mice showed a mild increase in spontaneous locomotor activity. There were no Meth-induced deficits in any of the other behavioural tests. Val/Met mice showed higher overall social investigation time and lower PPI compared with the Val/Val genotype independent of pretreatment. These results show limited long-term effects of chronic Meth on a range of cognitive, affective and social behaviours despite marked drug-induced locomotor sensitization in mice. There was no interaction with BDNF Val66Met genotype.

Methamphetamine-associated cardiomyopathy: an addiction medicine perspective

Methamphetamine-associated cardiomyopathy (MaCM) is an increasingly recognised serious complication from methamphetamine (MA) use. It is characterised as the development of otherwise unexplained heart failure in the context of MA use. MaCM predominantly affects a young and vulnerable population with high morbidity and mortality. It is the second leading cause of mortality in patients with MA use disorder (MUD). Our understanding of MaCM pathogenesis is based on observational cohorts and autopsy studies. Currently, the treatment of MaCM is predicated on abstinence. Medical therapies offer some benefit to a minority of patients; however, without abstinence, medical therapies are often ineffective. Abstinence is difficult for most patients to achieve; all clinicians require an understanding of MaCM and how to educate patients on the risks of ongoing use. Where available, referral to addiction medicine specialists to assist with treatment of MUD is recommended. This review aims to: (i) explain the proposed pathologic mechanisms of MaCM; (ii) summarise recent recommendations of the screening and treatment of MaCM; and (iii) highlight the role of addiction medicine in the management of patient with MaCM.

Increased Lipid Peroxidation and Lowered Antioxidant Defenses Predict Methamphetamine Induced Psychosis

BACKGROUND

a significant percentage of methamphetamine (MA) dependent patients develop psychosis. The associations between oxidative pathways and MA-induced psychosis (MIP) are not well delineated.

OBJECTIVE

the aim of this study is to delineate whether acute MA intoxication in MA dependent patients is accompanied by increased nitro-oxidative stress and whether the latter is associated with MIP.

METHOD

we recruited 30 healthy younger males and 60 acutely intoxicated males with MA dependence and assessed severity of MA use and dependence and psychotic symptoms during intoxication, and serum oxidative toxicity (OSTOX) biomarkers including oxidized high (oxHDL) and low (oxLDL)-density lipoprotein, myeloperoxidase (MPO), malondialdehyde (MDA), and nitric oxide (NO), and antioxidant defenses (ANTIOX) including HDL-cholesterol, zinc, glutathione peroxidase (GPx), total antioxidant capacity (TAC), and catalase-1.

RESULTS

a large part (50%, n = 30) of patients with MA dependence could be allocated to a cluster characterized by high psychosis ratings including delusions, suspiciousness, conceptual disorganization and difficulties abstract thinking and an increased OSTOX/ANTIOX ratio. Partial Least Squares analysis showed that 29.9% of the variance in MIP severity (a first factor extracted from psychosis, hostility, excitation, mannerism, and formal thought disorder scores) was explained by HDL, TAC and zinc (all inversely) and oxLDL (positively). MA dependence and dosing explained together 44.7% of the variance in the OSTOX/ANTIOX ratio.

CONCLUSIONS

MA dependence and intoxication are associated with increased oxidative stress and lowered antioxidant defenses, both of which increase risk of MIP during acute intoxication. MA dependence is accompanied by increased atherogenicity due to lowered HDL and increased oxLDL and oxHDL.

Differential Effects of Chronic Methamphetamine Treatment on High-Frequency Oscillations and Responses to Acute Methamphetamine and NMDA Receptor Blockade in Conscious Mice

Dysregulation of high-frequency neuronal oscillations has been implicated in the pathophysiology of schizophrenia. Chronic methamphetamine (METH) use can induce psychosis similar to paranoid schizophrenia. The current study in mice aimed to determine the effect of chronic METH treatment on ongoing and evoked neuronal oscillations. C57BL/6 mice were treated with METH or vehicle control for three weeks and implanted with extradural recording electrodes. Two weeks after the last METH injection, mice underwent three EEG recording sessions to measure ongoing and auditory-evoked gamma and beta oscillatory power in response to an acute challenge with METH (2 mg/kg), the NMDA receptor antagonist MK-801 (0.3 mg/kg), or saline control. A separate group of mice pretreated with METH showed significantly greater locomotor hyperactivity to an acute METH challenge, confirming long-term sensitisation. Chronic METH did not affect ongoing or evoked gamma or beta power. Acute MK-801 challenge reduced ongoing beta power whereas acute METH challenge significantly increased ongoing gamma power. Both MK-801 and METH challenge suppressed evoked gamma power. Chronic METH treatment did not modulate these acute drug effects. There were minor effects of chronic METH and acute METH and MK-801 on selected components of event-related potential (ERP) waves. In conclusion, chronic METH treatment did not exert neuroplastic effects on the regulation of cortical gamma oscillations in a manner consistent with schizophrenia, despite causing behavioural sensitisation.

The associations of cannabis and methamphetamine use with cognitive performance over the first 2 years of treatment in schizophrenia spectrum disorders

AIM

Cognitive deficits are a core feature of schizophrenia, and comorbid substance use may be a contributory factor. Methamphetamine use has been associated with cognitive impairment in schizophrenia, while associations with cannabis use are less clear-cut. This study aimed to investigate the associations of cannabis and methamphetamine use with cognitive performance in first-episode schizophrenia spectrum disorders over the first 2 years of treatment.

METHODS

This was a longitudinal cohort study in 81 patients treated with flupenthixol decanoate according to a standardized protocol over 24 months. Cognitive performance was assessed with the Measurement and Treatment Research to Improve Cognition in Schizophrenia Cognitive Consensus Battery at four time points, and urine testing for cannabis and methamphetamine was conducted at six time points. We used linear mixed-effect models for repeated measures to assess visit-wise changes in composite cognitive scores in patients (n = 91) compared to matched controls without psychiatric or medical disorders (n = 100). Linear regression models were constructed to examine pre-treatment and end-point effects in patients.

RESULTS

Compared to controls, patients exhibited greater cognitive impairments at baseline, which improved with treatment, but remained significantly lower throughout. The number of positive methamphetamine, but not cannabis, tests predicted less cognitive improvement in patients.

CONCLUSIONS

Our findings suggest a negative association between methamphetamine and cognition, but not cannabis.

Neural signaling of methamphetamine craving and seeking intensified by bupropion in the ventral tegmental area-cortico-accumbens circuitry in mice

Previously, bupropion (BUP), a norepinephrine (NE)/dopamine (DA) transporter blocker and nicotinic acetylcholine receptors (nAChRs) antagonist, was found to intensify methamphetamine (METH) craving behaviours in mice. Intense craving causes relapse in drug dependence. This study characterized local field potential (LFP) patterns in the brain regions associated with METH-conditioned place preference (CPP) enhanced by BUP. Male Swiss albino ICR mice were implanted with LFP electrodes to the ventral tegmental area (VTA), medial prefrontal cortex (mPFC) and the nucleus accumbens core (NAcc). Animals received sessions to learn the association between injection effects (1 mg/kg METH and normal saline) with contextual environments (METH- and saline-paired compartments) during the conditioning phase. A total of 20 mg/kg BUP was given to animals before LFP, and behaviour recording in the CPP apparatus during the post-conditioning phase. The results showed that increased CPP scores and % number of entries to the METH-paired zone, as well as changes in VTA, mPFC and NAcc spectral powers and coherence among these areas, were associated with METH-CPP. Treatment with BUP increased VTA delta and gamma I, decreased mPFC alpha, increased NAcc gamma I and decreased gamma II powers. Coherence analyses revealed that BUP decreased gamma II VTA-mPFC and increased beta and gamma I VTA-NAcc connectivity. Altogether, BUP produced additional effects to that of METH-CPP alone. These findings demonstrated changes in neural circuit activities associated with METH-CPP intensified by BUP. Moreover, modulation of NE/DA systems and/or nAChRs actions in the VTA-cortico-accumbens loop might underlie METH craving and dependence.

Comparing Cognitive Functions in Patients with Schizophrenia and Methamphetamine-Induced Psychosis with Healthy Controls

BACKGROUND

There are similar findings about the similarities and differences of cognitive dysfunctions in patients with schizophrenia and methamphetamine-induced psychosis (MIP). This study aimed to compare cognitive functioning in schizophrenia and MIP patients, using a performance-based cognitive assessment battery and an interview-based assessment of cognition.

METHODS

Three groups participated in this study including, (a) 30 patients with MIP, (b) 30 patients with schizophrenia, and (c) 30 healthy individuals. All participants received the Brief Assessment of Cognition in Schizophrenia (BACS), a standardized performance-based cognitive battery, the Schizophrenia Cognition Rating Scale (SCoRS), and the interview-based assessment of cognition.

FINDINGS

Both groups of patients with schizophrenia and MIP performed poorly on all the BACS cognitive domains compared with the healthy controls. The two patient groups were significantly different on the three BACS subscales including verbal fluency, verbal memory, and speed of information processing. Schizophrenia patients performed worse than the MIP group concerning these three subscales. However, the two patient groups were similar in executive function, working memory, and motor speed. Moreover, the SCoRS-informant, SCoRS-global, and PANSS-negative significantly differed between schizophrenia and MIP patients.

CONCLUSION

Although cognitive dysfunctions are mostly similar in patients with MIP and schizophrenia, there are some differences especially in the functions related to prefrontal and temporal lobes.

Neurocognitive Functions Related to Parietal Lobe in Patients with Schizophrenia and Methamphetamine Induced Psychotic Disorder and Healthy Individuals: A Comparative Study

BACKGROUND

There are some inconsistent findings about neurocognitive functions in schizophrenia and methamphetamine induced psychosis (MIP). This study aimed to compare these two disorders in terms of neurocognitive functions related to parietal lobe.

METHODS

This was a cross-sectional study in which 30 patients with schizophrenia, 30 patients with MIP, and 32 healthy individuals were compared. The two groups of patients were selected through convenience sampling from among patients hospitalized in Shahid Beheshti hospital in Kerman, Iran and healthy individuals were selected via convenience sampling from among the employees of Kerman University of Medical Sciences. The three groups were administered clock-drawing test (CDT), Rey-Osterrieth complex figure (ROCF) copying test, and interlocking finger test (IFT) and their demographic and clinical data were collected. The one-way analysis of variance (ANOVA) was used to investigate the differences between the groups. Multivariate analysis of covariance was also used to examine the effects of confounding factors. Besides, follow-up pairwise comparisons were performed after adjustment for multiple testing.

FINDINGS

The group with schizophrenia had significantly more impairment than the group with MIP with reference to the results of IFT and the ROCF test. However, the scores of patients with MIP on these two tests were not different from those of the normal controls. With regard to the CDT, the only significant difference was observed between the group with schizophrenia and controls.

CONCLUSION

On the condition that the results are replicated in other studies, some parietal lobe neurocognitive tests might be used when it is difficult to differentially diagnose schizophrenia and MIP.

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.

Psychopathology and Poor Clinical Insight in Psychotic Patients: Does the Diagnosis Matter?

ABSTRACT

Poor clinical insight is one of the most common features of schizophrenia spectrum disorders and plays a critical role in prognosis and treatment. Considering the biological and phenomenological overlap between schizophrenia and bipolar I disorder with psychotic features (BID) and increasing incidents of methamphetamine-induced psychotic disorder (MIPD) patients in Iran, it is necessary to have a clear picture of insight among these three groups. The aim of the present study was to compare clinical insight and other aspects of illness among three different disorders: schizophrenia, BID, and MIPD. In addition, we sought to examine the relationship of the severity of psychotic symptoms with clinical insight in each group. A total of 115 male inpatients, including 48 persons diagnosed with schizophrenia, 35 persons diagnosed with BID, and 32 persons diagnosed with MIPD, were selected. All participants completed the Scale to Assess Unawareness of Mental Disorder and the Positive and Negative Syndrome Scale. The results of analysis of variance indicated that schizophrenia patients reported higher rates of illness duration and number of hospital admissions in comparison to the MIPD and BID groups. In addition, persons diagnosed with BID reported more of these outcomes than MIPD groups. However, the three groups showed similar patterns in terms of age of onset and educational, marital, and occupational statuses. The results also revealed that awareness of the disorder was more impaired in schizophrenia patients compared with BID and MIPD patients and in MIPD compared with BID groups. However, the level of awareness of the effect of medication, the awareness of social consequences, and the total score of clinical insight were similar across the three diagnostic groups. As expected, poor clinical insight was correlated with high levels of positive, negative, and cognitive symptoms in the schizophrenia group; with high levels of positive, cognitive, and depressive symptoms in the BID group; and with high levels of positive and excitement symptoms in MIPD. In addition, hierarchical linear regression analyses revealed that only cognitive symptoms in the schizophrenia group and excitement symptoms in the MIPD group significantly predicted the overall score of clinical insight. In the BID group, both cognitive and depressive symptoms significantly predicted clinical insight. These findings suggest that there are differing levels of poor clinical insight in schizophrenia, MIPD, and BID and that poor clinical insight found within each group may have different antecedents.

Psychiatric and substance use disorders in a predominately low-income, black sample in early midlife

Decades of research have documented elevated rates of psychopathology among individuals affected by poverty. However, many studies have relied on predominately White samples, and on brief symptom screening measures which may not fully capture the experiences of individuals of color (who are disproportionately affected by poverty in the United States.) The present study examines prevalence rates of probable major depressive disorder, generalized anxiety disorder, post-traumatic stress disorder, substance use disorder, and alcohol use disorder in a predominately Black sample that grew up in urban poverty, utilizing structured neuropsychiatric interview methods. Data are drawn from a subsample of the Chicago Longitudinal Study (CLS), which has followed a large cohort for over four decades. Outcomes were assessed using the Mini International Neuropsychiatric Interview (M.I.N.I.) 7.0.2. Results indicate high probable rates of all measured outcomes, with notably high rates of substance use and alcohol use disorder compared to rates reported in previous national studies. Differences by sex and childhood neighborhood poverty, as well as significant comorbidity among psychiatric, substance and alcohol use disorders were also detected. Findings underscore an urgent need for community-based, culturally tailored prevention and intervention initiatives to support the mental health of individuals living in poverty. The high prevalence of psychiatric, substance and alcohol use disorders in this study likely reflect systematic inequities faced by low-income people of color in the United States. Future directions for research and practice are discussed.

Quercetin Mitigates Methamphetamine-Induced Anxiety-Like Behavior Through Ameliorating Mitochondrial Dysfunction and Neuroinflammation

Methamphetamine (MA) abuse results in neurotoxic outcomes, including increased anxiety and depression. Studies have reported an association between MA exposure and anxiety, nonetheless, the underlying mechanism remains elusive. In the present study, we developed a mouse model of anxiety-like behavior induced by MA administration. RNA-seq was then performed to profile the gene expression patterns of hippocampus (HIPP), and the differentially expressed genes (DEGs) were significantly enriched in signaling pathways related to psychiatric disorders and mitochondrial function. Based on these, mitochondria was hypothesized to be involved in MA-induced anxiety. Quercetin, as a mitochondrial protector, was used to investigate whether to be a potential treatment for MA-induced anxiety; accordingly, it alleviated anxiety-like behavior and improved mitochondrial impairment in vivo. Further experiments in vitro suggested that quercetin alleviated the dysfunction and morphological abnormalities of mitochondria induced by MA, via decreasing the levels of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and increasing the oxygen consumption rate (OCR) and ATP production. Moreover, the study examined the effect of quercetin on astrocytes activation and neuroinflammation, and the results indicated that it significantly attenuated the activation of astrocytes and reduced the levels of IL-1β, TNFα but not IL-6. In light of these findings, quantitative evidence is presented in the study supporting the view that MA can evoke anxiety-like behavior via the induction of mitochondrial dysfunction. Quercetin exerted antipsychotic activity through modulation of mitochondrial function and neuroinflammation, suggesting its potential for further therapeutic development in MA-induced anxiety.

Ameliorative effects of alkaloid extract from Mitragyna speciosa (Korth.) Havil. Leaves on methamphetamine conditioned place preference in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Mitragyna speciosa (Korth.) Havil., popularly known as Kratom (KT), is a medicinal plant used for pain suppression in Southeast Asia. It has been claimed to assist drug users withdraw from methamphetamine (METH) dependence. However, its use was controversial and not approved yet.

AIM OF THE STUDY

This study was conducted to characterize local field potential (LFP) patterns in the nucleus accumbens (NAc) and the hippocampus (HP) in mice with METH conditioned place preference (CPP) that were treated with KT alkaloid extract.

MATERIALS AND METHODS

Male Swiss albino ICR mice were implanted with intracraneal electrodes into the NAc and HP. To induce METH CPP, animals were injected intraperitoneally once a day with METH (1 mg/kg) and saline (0.9% w/v) alternately and put into METH/saline compartments to experience the associations between drug/saline injection and the unique environmental contexts for 10 sessions. Control group received saline injection paired with both saline/saline compartments. On post-conditioning day, effects of 40 (KT40), 80 (KT80) mg/kg KT alkaloid extract and 20 mg/kg bupropion (BP) on CPP scores and LFP powers and NAc-HP coherence were tested.

RESULTS

Two-way ANOVA revealed significant induction of CPP by METH sessions (P < 0.01). Multiple comparisons indicated that METH CPP was completely abolished by KT80 (P < 0.001). NAc gamma I (30.0-44.9 Hz) and HP delta (1.0-3.9 Hz) powers were significantly increased in mice with METH CPP (P < 0.01). The elevated NAc gamma I was significantly suppressed by KT80 (P < 0.05) and the increased HP delta was significantly reversed by KT40 (P < 0.01) and KT80 (P < 0.001). In addition, NAc-HP coherence was also significantly increased in gamma I (30.0-44.9 Hz) frequency range (P < 0.05) but it was reversed by KT80 (P < 0.05). Treatment with BP did not produce significant effect on these parameters.

CONCLUSIONS

These findings demonstrated that KT alkaloid extract significantly reversed CPP scores and LFP patterns induced by METH administration. The ameliorative effects of the extract might be beneficial for treatment of METH craving and addiction.

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.

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.

Elevated endogenous GDNF induces altered dopamine signalling in mice and correlates with clinical severity in schizophrenia

Presynaptic increase in striatal dopamine is the primary dopaminergic abnormality in schizophrenia, but the underlying mechanisms are not understood. Here, we hypothesized that increased expression of endogenous GDNF could induce dopaminergic abnormalities that resemble those seen in schizophrenia. To test the impact of GDNF elevation, without inducing adverse effects caused by ectopic overexpression, we developed a novel in vivo approach to conditionally increase endogenous GDNF expression. We found that a 2-3-fold increase in endogenous GDNF in the brain was sufficient to induce molecular, cellular, and functional changes in dopamine signalling in the striatum and prefrontal cortex, including increased striatal presynaptic dopamine levels and reduction of dopamine in prefrontal cortex. Mechanistically, we identified adenosine A2a receptor (A_2AR), a G-protein coupled receptor that modulates dopaminergic signalling, as a possible mediator of GDNF-driven dopaminergic abnormalities. We further showed that pharmacological inhibition of A_2AR with istradefylline partially normalised striatal GDNF and striatal and cortical dopamine levels in mice. Lastly, we found that GDNF levels are increased in the cerebrospinal fluid of first episode psychosis patients, and in post-mortem striatum of schizophrenia patients. Our results reveal a possible contributor for increased striatal dopamine signalling in a subgroup of schizophrenia patients and suggest that GDNF-A_2AR crosstalk may regulate dopamine function in a therapeutically targetable manner.

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.

Altered Fecal Microbiota Correlated With Systemic Inflammation in Male Subjects With Methamphetamine Use Disorder

Methamphetamine use disorder (MUD) is a major public health problem worldwide with limited effective treatment options. Previous studies have reported methamphetamine-associated alterations in gut microbiota. A potential role of gut microbiota in regulating methamphetamine-induced brain dysfunction through interactions with the host immune system has been proposed, but evidence for this hypothesis is limited. The present study aimed to investigate the alterations in the fecal microbiota and explore its relationship with systemic inflammation in MUD. Fecal samples were obtained from 26 male subjects with MUD and 17 sex- and age- matched healthy controls. Fecal microbial profiles were analyzed by 16S rRNA sequencing. Plasma inflammatory markers were measured using enzyme-linked immunosorbent assay. Associations between fecal microbiota, systemic inflammatory markers and clinical characteristics were examined by Spearman partial correlation analysis while controlling for possible confounders. Compared with healthy controls, individuals with MUD showed no difference in fecal microbial diversity, but exhibited differences in the relative abundance of several microbial taxa. At the genus level, a higher abundance of Collinsella, Odoribacter and Megasphaera and lower levels of Faecalibacterium, Blautia, Dorea and Streptococcus were detected in subjects with MUD. More importantly, altered fecal microbiota was found to be correlated with plasma levels of CRP, IL-2, IL-6 and IL-10. The order Lactobacillales, exhibiting lower abundance in participants with MUD, was positively related to the duration of methamphetamine abstinence and the plasma level of anti-inflammatory cytokine IL-10. This study is the first to provide evidence for a link between altered fecal microbiota and systemic inflammation in MUD. Further elucidation of interactions between gut microbiota and the host immune system may be beneficial for the development of novel therapeutic approaches for MUD.

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.

Sex difference in the interrelationship between TNF-α and oxidative stress status in first-episode drug-naïve schizophrenia

Background

Increasing evidence indicates that dysregulated TNF-α and oxidative stress (OxS) contribute to the pathophysiology of schizophrenia. Additionally, previous evidence has demonstrated sex differences in many aspects of schizophrenia including clinical characteristics, cytokines, and OxS markers. However, to the best of our knowledge, there is no study investigating sex differences in the association between TNF-α, the OxS system, and their interaction with clinical symptoms in schizophrenia patients, especially in first-episode drug-naïve (FEDN) patients.

Methods

A total of 119 FEDN schizophrenia patients and 135 healthy controls were recruited for this study. Serum TNF-α, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and malondialdehyde (MDA) were measured. The Positive and Negative Syndrome Scale (PANSS) was applied to evaluate psychotic symptoms. Two-way ANOVA, partial correlation analysis, and multivariate regression analysis were performed.

Results

A sex difference in MDA levels was demonstrated only in healthy controls (F = 7.06, p_Bonferroni = 0.045) and not seen in patients. Furthermore, only male patients had higher MDA levels than male controls (F = 8.19, p_Bonferroni = 0.03). Additionally, sex differences were observed in the association of TNF-α and MDA levels with psychotic symptoms (all p_Bonferroni < 0.05). The interaction of TNF-α and MDA was only associated with general psychopathology symptom in male patients (B = − 0.07, p = 0.02).

Conclusion

Our results demonstrate the sex difference in the relationship between TNF-α, MDA, and their interaction with psychopathological symptoms of patients with schizophrenia.

Altered fecal microbiota composition in individuals who abuse methamphetamine

As a severe public health problem, methamphetamine (METH) abuse places a heavy burden on families and society. A growing amount of evidence has indicated communication between gut microbiota and the CNS in drug addiction, with associations to neural, endocrine and immune pathways. Thus, we searched for alterations in the gut microbiota and their potential effects in METH users through 16S rRNA gene sequencing. A decreased Shannon index indicated lower bacterial diversity in the METH users than in the age-matched control group. The gut microbial community composition in the METH users was also altered, including reductions in Deltaproteobacteria and Bacteroidaceae abundances and increases in Sphingomonadales, Xanthomonadales, Romboutsia and Lachnospiraceae abundances. Moreover, the Fusobacteria abundance was correlated with the duration of METH use. Enterobacteriaceae, Ruminococcaceae, Bacteroides, and Faecalibacterium had statistically significant correlations with items related to the positive and negative symptoms of schizophrenia and to general psychopathology in the METH users, and all have previously been reported to be altered in individuals with psychotic syndromes, especially depression. Abstraction, one of the items of the cognitive assessment, was positively related to Blautia. These findings revealed alterations in the gut microbiota of METH users, and these alterations may play a role in psychotic syndrome and cognitive impairment. Although the mechanisms behind the links between these disorders and METH abuse are unknown, the relationships may indicate similarities in the pathogenesis of psychosis induced by METH abuse and other causes, providing a new paradigm for addiction and METH use disorder treatment.

Recent advances in developing optical and electrochemical sensors for analysis of methamphetamine: A review

Recognition of misused stimulant drugs has always been a hot topic from a medical and judicial perspective. Methamphetamine (MAMP) is an addictive and illegal drug that profoundly affects the central nervous system. Like other illicit drugs, the detection of MAMP in biological and street samples is vital for several organizations such as forensic medicine, anti-drug headquarters and diagnostic clinics. By emerging nanotechnology and exploiting nanomaterials in sensing applications, a great deal of attention has been given to the design of analytical sensors in MAMP tracing. For the first time, this study has briefly reviewed all the optical and electrochemical sensors in MAMP detection from earlier so far. How various receptors with engineering nanomaterials allow developing novel approaches to measure MAMP have been studied. Fundamental concepts related to optical and electrochemical recognition assays in which nanomaterials have been used and relevant MAMP sensing applications have been comprehensively covered. Challenges, opportunities and future outlooks of this field have also been discussed at the end.

Improving Criminal Responsibility Determinations Using Structured Professional Judgment

Forensic psychologists commonly utilize unstructured clinical judgment in aggregating clinical and forensic information in forming opinions. Unstructured clinical judgment is prone to evaluator bias and suboptimal levels of inter-rater reliability. This article proposes Structured Professional Judgment (SPJ) methods as a potential remedy. Following a review of canonical forensic assessment models, the prevalence of bias in forensic judgments, and inter-rater agreement in criminal responsibility (CR) determinations, this article presents a SPJ model for CR evaluations translated from violence risk assessment methodology. A systematic user-friendly methodology is described, applying procedural checklists, application of a mental state at time of the offense (MSO) model using structured data collection methods, aggregation of empirical evidence guidelines, and post-hoc hypothesis testing using the Analysis of Competing Hypotheses (ACH). A case study describes application of the procedural and CR decision model in a complex homicide case. The model demonstrates the power and efficacy of the application of SPJ to forensic decision-making and is relevant to other types of forensic assessment (e.g., competency to stand trial, post-acquittal release decision-making).

Neurotoxicity of methamphetamine: Main effects and mechanisms

Methamphetamine (METH) is an illicit psychostimulant that is abused throughout the world. METH addiction is also a major public health concern and the abuse of large doses of the drug is often associated with serious neuropsychiatric consequences that may include agitation, anxiety, hallucinations, paranoia, and psychosis. Some human methamphetamine users can also suffer from attention, memory, and executive deficits. METH-associated neurological and psychiatric complications might be related, in part, to METH-induced neurotoxic effects. Those include altered dopaminergic and serotonergic functions, neuronal apoptosis, astrocytosis, and microgliosis. Here we have endeavored to discuss some of the main effects of the drug and have presented the evidence supporting certain of the molecular and cellular bases of METH neurotoxicity. The accumulated evidence suggests the involvement of transcription factors, activation of dealth pathways that emanate from mitochondria and endoplasmic reticulum (ER), and a role for neuroinflammatory mechanisms. Understanding the molecular processes involved in METH induced neurotoxicity should help in developing better therapeutic approaches that might also serve to attenuate or block the biological consequences of use of large doses of the drug by some humans who meet criteria for METH use disorder.

Changes of BDNF exon IV DNA methylation are associated with methamphetamine dependence

Aim: We investigated DNA methylation of BDNF in methamphetamine (METH) dependence in humans and an animal model. Materials & methods: BDNF methylation at exon IV was determined by pyrosequencing of blood DNA from METH-dependent and control subjects, and from rat brain following an escalating dose of METH or vehicle. Bdnf expression was determined in rat brain. Results: BDNF methylation was increased in human METH dependence, greatest in subjects with psychosis and in prefrontal cortex of METH-administered rats; rat hippocampus showed reduced Bdnf methylation and increased gene expression. Conclusion: BDNF methylation is abnormal in human METH dependence, especially METH-dependent psychosis, and in METH-administered rats. This may influence BDNF expression and contribute to the neurotoxic effects of METH exposure.

Substance-related exogenous psychosis: a postmodern syndrome

There is growing recognition that substance use is associated with the emergence of psychosis.Elements of post-modernity dominate contemporary social contexts and operate as existential background factors that contribute to the emergence of substance-related psychotic phenomena, particularly use of potent and highly rewarding novel psychoactive substances (NPS). About 25% of first-episode psychoses are substance-induced (SIP). DSM-5 SIP diagnosis is based on the assumption that symptoms are transient and disappear after sustained abstinence. This narrowed definition does not consider the issue of persistent SIP. There is a clear need for a new diagnostic framework that provides reliable, unambiguous clinical criteria to differentiate between comorbid conditions (i.e., schizophrenia patients with a substance use disorder) and substance-related psychoses. In the present contribution, we aim to outline a novel and separate clinical entity: substancerelated exogenous psychosis (SREP). Within this diagnostic category, we refer to both transientand persistent psychoses associated with substance use. SREP is conceived as a distinct psychoticdisorder with psychopathological specificities that clearly differentiate it from schizophrenia. We address differences in terms of clinical presentation, epidemiology, etiological models and treatment response. SREP is characterized by altered states of consciousness, persecutory delusions, visual and cenesthetic hallucinations, impulsivity and psychomotor agitation, affectiveand negative symptoms, a pervasive feeling of unreality and intact insight. Delusions are typically secondary to abnormal perception resulting from a characteristic "sensorialization" of the world. Longitudinal studies are warranted to substantiate our hypothesis of a novel diagnostic categoryand support the clinical validity of SREP. This may have important implications in terms of early differential diagnosis and staging (i.e., between comorbid conditions, persistent and transientsubstance-related psychotic states) as well as choice of treatment interventions.

The transcranial direct current stimulation over prefrontal cortex combined with the cognitive training reduced the cue-induced craving in female individuals with methamphetamine use disorder: A randomized controlled trial

BACKGROUND

Craving and cognitive deficits are potential treatment targets for methamphetamine use disorder (MUD). Previous studies implied that transcranial direct current stimulation (tDCS) and cognitive training respectively improve these symptoms, but the combined effect is unknown. In this study, we investigated the combined effects of tDCS over dorsolateral prefrontal cortex (DLPFC) and computerized cognitive addiction therapy (CCAT) on cue-induced craving and cognitive functions among female individuals with MUD.

METHODS

Seventy-five patients with MUD were randomly assigned to three groups: CCAT + tDCS group, CCAT + sham tDCS group and the control group. The former two groups received 20 sessions of cognitive training combined 1.5 mA active/sham tDCS over DLPFC (20min/session, 5times/week), while the control group received usual care which includes routine medical care, health education, physical exercises and psychological support related to relapse prevention. The cue-induced craving and cognitive functions were tested at the baseline, the end of 2nd week and 4th week.

RESULTS

The CCAT + tDCS group showed a significant reduction in cue-induced craving after 4-week intervention. Moreover, the craving score of the real CCAT + tDCS group was significantly lower than that of the CCAT + sham tDCS group and that of the control group at the end of 4th week. A significant improvement in accuracy of TWOB task was only observed in the CCAT + tDCS group at the end of 4th week when compared to baseline. Unexpectedly, participants who received CCAT plus active or sham tDCS did not change their discounting, whereas those in the control group performed more impulsively over time.

CONCLUSIONS

The study found that the intervention of tDCS over DLPFC combined with CCAT may have potential benefit in improving treatment outcome in patients with MUD. More research is needed to explore the underlying mechanism.

Psychostimulant use disorder emphasizing methamphetamine and the opioid -dopamine connection: Digging out of a hypodopaminergic ditch

BACKGROUND

Approved food and drug administration (FDA) medications to treat Psychostimulant Use Disorder (PUD) are needed. Both acute and chronic neurological deficits related to the neurophysiological effects of these powerfully addictive drugs can cause stroke and alterations in mood and cognition.

OBJECTIVE

This article presents a brief review of the psychiatric and neurobiological sequelae of methamphetamine use disorder, some known neurogenetic associations impacted by psychostimulants, and explores treatment modalities and outcomes.

HYPOTHESIS

The authors propose that gentle D2 receptor stimulation accomplished via some treatment modalities can induce dopamine release, causing alteration of D2-directed mRNA and thus enhanced function of D2 receptors in the human. This proliferation of D2 receptors, in turn, will induce the attenuation of craving behavior, especially in genetically compromised high-risk populations.

DISCUSSION

A better understanding of the involvement of molecular neurogenetic opioid, mesolimbic dopamine, and psychostimulant connections in "wanting" supports this hypothesis. While both scientific and, clinical professionals search for an FDA approved treatment for PUD the induction of dopamine homeostasis, via activation of the brain reward circuitry, offers treatment for underlying neurotransmitter functional deficits, potential prophylaxis, and support for recovery efforts.

CONCLUSION

Dopamine regulation may help people dig out of their hypodopaminergia ditch.