The Methamphetamine-Associated Psychosis Spectrum: a Clinically Focused Review

Psychotomimetic compensation versus sensitization

It is a paradox that psychotomimetic drugs can relieve symptoms that increase risk of and cooccur with psychosis, such as attention and motivational deficits (e.g., amphetamines), pain (e.g., cannabis) and symptoms of depression (e.g., psychedelics, dissociatives). We introduce the ideas of psychotomimetic compensation and psychotomimetic sensitization to explain this paradox. Psychotomimetic compensation refers to a short-term stressor or drug-induced compensation against stress that is facilitated by engagement of neurotransmitter/modulator systems (endocannabinoid, serotonergic, glutamatergic and dopaminergic) that mediate the effects of common psychotomimetic drugs. Psychotomimetic sensitization occurs after repeated exposure to stress and/or drugs and is evidenced by the gradual intensification and increase of psychotic-like experiences over time. Theoretical and practical implications of this model are discussed.

The effects of paranoia and dopamine on perception of cohesion and conspiracy: a pre-registered, double-blind, placebo-controlled experiment

Paranoia is a common symptom of psychotic disorders but is also present on a spectrum of severity in the general population. Although paranoia is associated with an increased tendency to perceive cohesion and conspiracy within groups, the mechanistic basis of this variation remains unclear. One potential avenue involves the brain's dopaminergic system, which is known to be altered in psychosis. In this study, we used large-N online samples to establish the association between trait paranoia and perceptions of cohesion and conspiracy. We further evaluated the role of dopamine on perceptions of cohesion and conspiracy using a double-blind, placebo-controlled laboratory experiment where participants received levodopa or a placebo control. Our results were mixed: group perceptions and perceptions of cohesion were higher among more paranoid individuals but were not altered under dopamine administration. We outline the potential reasons for these discrepancies and the broader implications for understanding paranoia in terms of dopamine dysregulation.

Association between rumination and drug craving in Chinese male methamphetamine use disorder patients with childhood trauma

BACKGROUND

In China, males make up the majority of methamphetamine (MA) dependent individuals and the majority of treatment seekers. Childhood trauma (CT) and rumination are associated with an increased risk of MA use. However, the association between CT, rumination, and drug craving remains largely unknown.

OBJECTIVE

The present study aims to explore the association between rumination and drug craving in methamphetamine use disorder (MAUD) patients with CT.

PARTICIPANTS AND SETTING

This study recruited 404 male participants with MAUD from a male drug rehabilitation center in Southwest China.

METHODS

Patients with CT were identified by the short form of Childhood Trauma Questionnaire (CTQ-SF). Rumination and drug craving were assessed by the Ruminative Responses Scale (RRS) and the Obsessive Compulsive Drug Use Scale (OCDUS), respectively.

RESULTS

188 patients (46.5 %) experienced CT. Patients who had experienced CT showed significantly higher RRS symptom rumination score and OCDUS total score than those who had not. In patients with CT, RRS total and all subscale scores were positively associated with OCDUS interference of drug. Furthermore, the RRS brooding (β = 0.34, p < 0.001) and total scores (β = 0.38, p < 0.001) were determined to be separate contributors to the OCDUS total score in patients with CT.

CONCLUSIONS

Our study suggests that CT is common in male MAUD patients, and those who have suffered CT may exhibit higher levels of rumination and drug craving. Moreover, CT may play an influential role in the association between rumination and drug craving in patients with MAUD.

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.

Impact of adolescent methamphetamine use on social cognition: A human-mice reverse translation study

BACKGROUND

Methamphetamine dependence is associated with social cognition deficits that may underpin negative social outcomes. However, there are considerable inter-individual differences in social cognition within people with methamphetamine dependence, with age of onset of methamphetamine use being a potential contributing factor.

MATERIALS AND METHODS

We conducted two sequential studies examining the link between age of onset of methamphetamine use (adolescence versus young adulthood) and performance in social cognition tests: (1) a human cross-sectional study in 95 participants with methamphetamine dependence varying in age of onset (38 with adolescent onset and 57 with adult onset) and 49 drug-naïve controls; (2) a mice study in which we tested the effects of methamphetamine exposure during adolescence versus young adulthood on social interaction and aggression, and their potential neurochemical substrates in the striatal dopaminergic system.

RESULTS

We initially showed that people with methamphetamine dependence who started use in adolescence had higher antisocial beliefs (p = 0.046, Cohen's d=0.42) and worse emotion recognition (p = 0.031, Cohen's d=0.44) than those who started use during adulthood. We reasoned that this could be due to either social cognition deficits leading to earlier onset of methamphetamine use, or methamphetamine-induced neuroadaptive effects specific to adolescence. Mice experiments showed that methamphetamine exposure during adolescence specifically decreased social investigation during social interaction and upregulated striatal tyrosine hydroxylase (p < 0.05, Bonferroni corrected). There was no evidence of adolescent-specific methamphetamine effects on aggression or other measures of dopaminergic function.

CONCLUSION

Together, translational findings demonstrate heightened sensitivity to methamphetamine effects on social cognition during adolescence.

Daily heroin injection and psychiatric disorders: A cross-sectional survey among People Who Inject Drugs (PWID) in Haiphong, Vietnam

BACKGROUND

Psychiatric comorbidities are frequent among people who inject drugs, they are associated with a poorer prognosis and need to be addressed. Their interaction with daily heroin injection requires clarification.

METHODS

A cross-sectional survey was conducted among PWID recruited in the city of Haiphong, Vietnam, by respondent-driven sampling. The inclusion criteria were age 18 or older and current injection drug use, verified by skin marks and positive urine tests for heroin or methamphetamine. Data on socio-demographic characteristics, drug use, sexual behaviour and access to treatment were collected using face-to-face questionnaires by trained interviewers. PWID were screened by trained psychiatrists for depression, psychotic disorder and suicidality, using the MINI questionnaire.

RESULTS

418 participants were included in the analyses. All were injected heroin users, 21 % were diagnosed with a current major depressive disorder, 15 % with a current psychotic disorder and 12 % presented a suicide risk. In the bivariate analyses, regular meth use, cannabis use and ketamine use were positively associated with presenting at least one psychiatric condition while daily heroin injection and being currently treated with methadone were negatively associated. In the multivariate model, poly-substance use was positively associated with depression (methamphetamine and drinking in addition to heroin) and psychotic disorder (methamphetamine and/or hazardous drinking in addition to heroin) while daily heroin injection and current methadone treatment were negatively and independently associated with depression and psychotic syndrome.

CONCLUSIONS

Our survey confirms the burden of methamphetamine use and the protective effect of methadone but also a possible protective effect of daily heroin injection.

Methamphetamine use in an early psychosis service: a cross-sectional retrospective cohort study

OBJECTIVE

Methamphetamine-associated psychotic symptoms are common among regular users, and can overlap with the emergence of a primary psychotic disorder. In contrast to previous research, this retrospective observational study aims to describe the characteristics of young people experiencing early psychosis who use methamphetamine regularly. We also aimed to investigate associations between regular methamphetamine use and markers of psychosocial functioning, psychosis outcomes and substance use.

METHOD

This study involved 116 young people (19 using methamphetamine regularly) referred to the Camperdown Early Intervention in Psychosis Service from January 2015 to January 2016. Variables including demographic information, psychosocial functioning and psychosis outcomes were collected on referral to the service, updated throughout treatment and at discharge.

RESULTS

There were significant associations found between regular methamphetamine use and a criminal history (p<0.001), regular cannabis use (p=0.002) and regular nicotine use (p<0.001).

CONCLUSION

This study suggests that in early psychosis, regular methamphetamine use could signify a subgroup of young people who use multiple substances and may engage in criminal activity. Addressing substance use in early psychosis may be an important treatment target for this vulnerable group of young people.

Emotion Recognition and Impulsive Choice in Relation to Methamphetamine Use and Psychosis Symptoms

Introduction: The cognitive profiles of people with methamphetamine use disorder are characterized by impulsivity and impairment in social cognition. However, previous studies have not fully accounted for the presence and impact of co-occurring mental health problems on these domains. For instance, psychotic symptoms are commonly experienced by people who use methamphetamine and may influence cognitive performance. We aimed to examine decision making and emotion recognition in individuals with methamphetamine use, compared to healthy controls, to map the nature and degree of impairments in relation to the presence of psychotic symptoms. Method: In this naturalistic study, we assessed reward-based decision-making and facial emotion recognition across three groups, methamphetamine-using individuals with (MAP, n = 29) and without psychotic symptoms (MNP, n = 70), and healthy controls (HC, n = 32). Results: In comparison to healthy controls, methamphetamine-using individuals presented with poorer performance on tasks of decision-making and emotion recognition. Emotion recognition was impaired across all methamphetamine-using individuals, with significantly poorer recognition of anger and sadness in those with psychotic symptoms. Conclusion: We found specific impairments in emotion recognition in relation to psychotic symptoms in people who use methamphetamine regularly. This builds on previous evidence on cognitive profiles in methamphetamine use disorder, highlighting the need to assess co-morbid mental health and psychotic symptoms. Our finding that methamphetamine-using individuals with psychotic symptoms present with particular difficulties recognizing anger has implications for frontline clinicians.