Completed Suicide Among Methamphetamine Users: A National Study

Methamphetamine Use and Suicide: A Case Report and Brief Review of Literature

Recreational use of methamphetamines has greatly increased in frequency across the world. Like other stimulants, methamphetamines can cause several health consequences, and their addictive nature can lead to psychiatric disorders. Suicidal ideation and attempts are common in methamphetamine users and have become a leading cause of death next to incidental overdoses. In the current report, we review a case of a methamphetamine user who attempted suicide by jumping off a bridge. Further, we contextualize this case by reviewing recent literature on the relationship between methamphetamine use and suicide.

Suicidal thoughts and behaviors among untreated illicit substance users: a population-based study

OBJECTIVES

Research regarding the contribution of specific psychoactive substances to suicidality has yielded equivocal results. The present study examined the prevalence and factors associated with suicidal thoughts and behaviors among a population-based sample of untreated illicit substance users.

METHODS

A total of 616 illicit substance users who were recruited from high-risk areas of Shiraz using snowball sampling participated in the study. Eligible participants were individuals aged 18 years and older who regularly used one illicit psychoactive substance (e.g., opioids, heroin, cannabinoids, stimulants, hallucinogens) for at least one year and who had received no treatment for their drug use during the past year. Data were collected regarding socio-demographic characteristics, mental history, and substance use habits. Data regarding suicidal thoughts and behaviors were assessed using the Beck Suicidal Ideation Scale (BSIS) and self-reports of previous suicide attempts. Multiple logistic regression analysis was used to identify independent variables associated with suicidality.

RESULTS

Among the participants, 23.6% reported having had suicidal thoughts during the past week and 6.7% reported having attempted suicide during the past year. Methamphetamine was reported as the primary substance of use among approximately half of the participants who attempted suicide during past year (49.2%). Multiple logistic regression analysis showed that current suicidal thoughts were independently associated with having no job, a history of mental health condition, previous suicidal attempts, concurrent use of more than one substance, and using methamphetamine and heroin as the primary substances. Suicidal thoughts were not associated with increased odds of regular opium and cannabis use.

CONCLUSION

Both methamphetamine and heroin use are significantly associated with current suicidal thoughts. Evaluation of the risk of suicidality by physicians and mental health care professionals in both community and outpatient settings would be especially appropriate among those individuals using these psychoactive substances.

Methamphetamine intoxication and suicidal ideation/behavior in the emergency department

BACKGROUND

This study investigates the association between Methamphetamine (MA) intoxication and suicidal ideation/behavior in patients presenting to emergency departments. Amidst rising MA use and co-use with opioids, this "twin epidemic" has manifested in increasing admissions for MA intoxication, often accompanied by psychiatric symptoms that can escalate to suicidal behaviors.

METHOD

This retrospective study utilized patient records and analyzed data from 629 patients admitted to a Texas emergency department in 2020, with MA intoxication confirmed via urine tests and patient interviews. The suicidal tendencies were assessed using the Columbia-Suicide Severity Scale. The 629 patients were divided into three groups for analysis: Group I (n = 188), MA positive with suicidal ideation (SI) (MA + SI+); Group II (n = 202), MA-positive without SI (MA + SI-); and Group III (n = 239), MA-negative with SI (MA- SI+). Multiple regression analysis was used to elicit clinical features predicting patients presenting to the emergency department with acute MA intoxication.

RESULTS

Results reveal that approximately half of patients with acute MA intoxication reported suicidal thoughts, indicating a significant association between MA use and suicidal tendencies. Females exhibited higher rates of suicidal thoughts, behavior, and subsequent medical attention compared to males. Sociodemographic characteristics and clinical features differed among MA-positive patients with and without SI. Multivariable regression analysis identified factors influencing MA use, including cannabis use, male gender, agitation, and an inverse association with alcohol use. Notably, the severity and potential lethality of suicidal behavior in MA-intoxicated patients paralleled those observed in psychiatric patients without MA use.

CONCLUSION

These results underscore the urgent need for targeted interventions to address the complex interplay between MA use and suicidal risks in the emergency department setting, as well as broader public health strategies to combat the increasing prevalence of MA use.

Modeling methamphetamine use disorder in mammals: Sex differences in behavioral, biochemical, and transcriptional consequences

Methamphetamine (METH) is the most commonly misused amphetamine-type stimulant throughout the globe. METH is very rewarding, and its misuse can lead to a diagnosis of METH use disorder (MUD). Although METH use is observed in both sexes, there are, however, reported differences in the clinical manifestations of METH use and its consequences. These observations indicate the need for more research on the long-term sex-dependent consequences of METH taking in both preclinical and clinical settings. In effect, sex is a biological variable that can impact conclusions drawn from various basic and clinical studies. Thus, the present chapter provides a succinct review of the current state of the research on METH and its sex-associated consequences. In addition to behavioral and cognitive aspects of METH use, we discuss METH-induced changes in neurotransmitter systems and structures in the brain. Thus, the book chapter serves to highlight the significance of sex as a critical element that needs to be considered during discussions of novel therapeutic approaches to MUD.

Causes and circumstances of death in stimulant and opioid use-A comparative study

AIMS

To investigate the individual characteristics, causes and circumstances around deaths in stimulant use, and to examine how individuals who died with stimulants in their body differ from individuals who died with opioids in their body.

METHODS

This study includes individuals who died during the years 2000-2018 and underwent a forensic autopsy at Forensic Medicine in Lund, Skåne County, Sweden. All individuals over 18 years of age with stimulants (n = 310), opioids (n = 2,039) or both stimulants and opioids (n = 385) in the body at the time of death, were included. The three groups were assessed regarding gender, age, place of death, BMI, other substances detected in forensic toxicological analysis, organ weights and underlying and contributing causes of death. The data were analysed by frequency and proportion calculations, cross-tabulations and comparisons of medians.

RESULTS

The median age at death of the study population (n = 2,734) was 45.5 years (interquartile range ☯IQR] 32-60 years) and 73.2% were men. The most common cause of death in the stimulant group was suicide (26.8%), higher proportion compared to the opioid group (20.8%) (p = 0.017) and in the polysubstance group accidental poisoning (38.2%), higher proportion compared to the opioid group (18.0%) (p<0.001). Death by transport accidents was significantly associated with the stimulant group (p<0.001) as well as death by other accidents (p = 0.016).

CONCLUSIONS

Individuals who died with stimulants in their body died at a higher rate from suicide, transport accidents and other accidents, compared to individuals who died with opioids in their body. This study indicates the need to identify and prevent psychiatric conditions, elevated suicide risk, and risk-taking behaviors among people who use stimulants.

Methamphetamine use in homicide victims

Methamphetamine use is increasing in the Australian population. It has a known association with violent and erratic behaviour and with an increased risk of unnatural deaths. To determine whether victims of homicide have significant exposure to methamphetamine 100 randomly selected de-identified homicide cases from 2012 to 2021 were accessed from the Forensic Science SA (FSSA) Pathology Database to determine the type of homicide and whether methamphetamine was detected in the blood. A total of 76 males and 24 females were found (M:F = 3:1). Of these, 30 victims (30%) had methamphetamine detected in blood, consisting of 26 males and 4 females (M:F = 6:1; male age range 18-53 years, average 36.8 years; female age range 28-63 years average 44.8 years). Levels of methamphetamine ranged from 0.02 to 3.3 mg/L with an average of 0.64 mg/L, with the highest numbers of positive cases occurring in victims of gunshot wounds (45.5%), and the lowest in those with lethal blunt force trauma (23.5%). This study has demonstrated that victims of homicide in an Australian population are more likely to have used methamphetamine than members of the general population. The reasons for this remain unclear although involvement in a drug selling environment may be an important determinant.

Active learning impairments in substance use disorders when resolving the explore-exploit dilemma: A replication and extension of previous computational modeling results

BACKGROUND

Substance use disorders (SUDs) represent a major public health risk. Yet, our understanding of the mechanisms that maintain these disorders remains incomplete. In a recent computational modeling study, we found initial evidence that SUDs are associated with slower learning rates from negative outcomes and less value-sensitive choice (low "action precision"), which could help explain continued substance use despite harmful consequences.

METHODS

Here we aimed to replicate and extend these results in a pre-registered study with a new sample of 168 individuals with SUDs and 99 healthy comparisons (HCs). We performed the same computational modeling and group comparisons as in our prior report (doi: 10.1016/j.drugalcdep.2020.108208) to confirm previously observed effects. After completing all pre-registered replication analyses, we then combined the previous and current datasets (N = 468) to assess whether differences were transdiagnostic or driven by specific disorders.

RESULTS

Replicating prior results, SUDs showed slower learning rates for negative outcomes in both Bayesian and frequentist analyses (partial η2=.02). Previously observed differences in action precision were not confirmed. Learning rates for positive outcomes were also similar between groups. Logistic regressions including all computational parameters as predictors in the combined datasets could differentiate several specific disorders from HCs, but could not differentiate most disorders from each other.

CONCLUSIONS

These results provide robust evidence that individuals with SUDs adjust behavior more slowly in the face of negative outcomes than HCs. They also suggest this effect is common across several different SUDs. Future research should examine its neural basis and whether learning rates could represent a new treatment target or moderator of treatment outcome.

Factors associated with suicide in people who use drugs: a scoping review

BACKGROUND

Suicide is a significant contributor to global mortality. People who use drugs (PWUD) are at increased risk of death by suicide relative to the general population, but there is a lack of information on associated candidate factors for suicide in this group. The aim of this study was to provide a comprehensive overview of existing evidence on potential factors for death by suicide in PWUD.

METHODS

A scoping review was conducted according to the Arksey and O'Malley framework. Articles were identified using Medline, CINAHL, PsycINFO, SOCIndex, the Cochrane Database of Systematic Reviews and the Campbell Collaboration Database of Systematic Reviews; supplemented by grey literature, technical reports, and consultation with experts. No limitations were placed on study design. Publications in English from January 2000 to December 2021 were included. Two reviewers independently screened full-text publications for inclusion. Extracted data were collated using tables and accompanying narrative descriptive summaries. The review was reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines.

RESULTS

The initial search identified 12,389 individual publications, of which 53 met the inclusion criteria. The majority (87%) of included publications were primary research, with an uncontrolled, retrospective study design. The most common data sources were drug treatment databases or national death indexes. Eleven potential factors associated with death by suicide among PWUD were identified: sex; mental health conditions; periods of heightened vulnerability; age profile; use of stimulants, cannabis, or new psychoactive substances; specific medical conditions; lack of dual diagnosis service provision; homelessness; incarceration; intravenous drug use; and race or ethnicity. Opioids, followed by cannabis and stimulant drugs were the most prevalent drugs of use in PWUD who died by suicide. A large proportion of evidence was related to opioid use; therefore, more primary research on suicide and explicit risk factors is required.

CONCLUSIONS

The majority of studies exploring factors associated with death by suicide among PWUD involved descriptive epidemiological data, with limited in-depth analyses of explicit risk factors. To prevent suicide in PWUD, it is important to consider potential risk factors and type of drug use, and to tailor policies and practices accordingly.

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.

Active learning impairments in substance use disorders when resolving the explore-exploit dilemma: A replication and extension of previous computational modeling results

Background

Substance use disorders (SUDs) represent a major public health risk. Yet, our understanding of the mechanisms that maintain these disorders remains incomplete. In a recent computational modeling study, we found initial evidence that SUDs are associated with slower learning rates from negative outcomes and less value-sensitive choice (low "action precision"), which could help explain continued substance use despite harmful consequences.

Methods

Here we aimed to replicate and extend these results in a pre-registered study with a new sample of 168 individuals with SUDs and 99 healthy comparisons (HCs). We performed the same computational modeling and group comparisons as in our prior report (doi: 10.1016/j.drugalcdep.2020.108208) to confirm previously observed effects. After completing all pre-registered replication analyses, we then combined the previous and current datasets (N = 468) to assess whether differences were transdiagnostic or driven by specific disorders.

Results

Replicating prior results, SUDs showed slower learning rates for negative outcomes in both Bayesian and frequentist analyses (η 2 =.02). Previously observed differences in action precision were not confirmed. Logistic regressions including all computational parameters as predictors in the combined datasets could differentiate several specific disorders from HCs, but could not differentiate most disorders from each other.

Conclusions

These results provide robust evidence that individuals with SUDs have more difficulty adjusting behavior in the face of negative outcomes than HCs. They also suggest this effect is common across several different SUDs. Future research should examine its neural basis and whether learning rates could represent a new treatment target or moderator of treatment outcome.

Characteristics and circumstances of cocaine-related completed suicide in Australia, 2000-2021

BACKGROUND

There has been a substantial global increase in cocaine use and associated harms. The current study aimed to: 1. Determine the case characteristics and circumstances of death of cocaine-related suicide in Australia 2000-2021; and 2. Determine the toxicological profiles of cases.

METHODS

Retrospective study of cocaine-related death in Australia, 2000-2021, retrieved from the National Coronial Information System (NCIS). Suicide intent was based upon the NCIS code for "Intentional Self-harm", derived from case circumstances and coroners' conclusions. Sex comparisons were made for all major variables.

RESULTS

A total of 157 cases were identified, 82.2% male, 79.5% employed, with a mean age of 32.3 years. Concerns for mental health were documented in 65.6%, a previous suicide attempt in 21.0%, a history of substance use treatment and/or negative consequences of substance use in 45.9% and injecting drug use in 14.6%. Manner of death amongst both sexes was predominantly by physical means (82.8%). Written intent was documented in 29.3%. Intense agitation prior to the incident was noted in 28.0% and conflict in 24.8%. The median blood cocaine concentration was 0.060 mg/L (range 0.007-5.500). Other drugs were present in 95.5%, most commonly alcohol (63.1%) with a median concentration of 0.140 g/100 ml. Psychostimulants other than cocaine were present in 31.2%.

CONCLUSIONS

The 'typical' cocaine-related suicide case was a male, aged in their early thirties, who was highly likely to be employed. The majority of cases used physical means, and a substantial minority were highly agitated and engaged in conflict prior to the fatal incident.

Changing trends and characteristics of one punch deaths in Australia (2012-2018)

One-punch assaults also known as 'coward punches', are characterised by a single severe blow to the head causing the victim to lose consciousness, resulting in a secondary impact between the head and surrounding environment. Such impacts may result in brain injury leading to fatality or permanent neurological impairment. In a previous publication, there were 90 one punch deaths around Australia between 2000 and 2012, mostly involving young men drinking alcohol at a licensed venue at the weekend. This prompted a surge of public education and awareness campaigns around Australia, in addition to regulatory and legislative changes aimed at curbing social violence. This retrospective descriptive study aimed to examine one punch deaths since 2012 in Australia to determine if there has been a decrease in deaths, and whether the demographics and circumstances of these deaths have changed. A search of the National Coronial Information System was undertaken for all closed coronial cases between 1 January 2012 and 31 December 2018. Additional information was collected from medicolegal reports including toxicology, pathology and coronial findings. There were 80 one punch fatalities in Australia, almost exclusively involving males. The median age was 43.5 (range 18-71) years and there was a decreasing trend in the number of deaths annually. Most fatal assaults occurred in the state of New South Wales (28.8%) followed by Queensland (23.8%), and in metropolitan locations (64.6%) rather than regional areas (35.4%). Alcohol was the most commonly detected drug, found in 47 cases of the 71 cases where toxicology results were available (66%), with a median concentration of 0.14 and 0.19 g/100 mL in antemortem and postmortem samples, respectively (range 0.005-0.32 g/100 mL). Five deaths reported methylamphetamine, with THC detected in 21.1% of cases. Assaults more commonly occurred on a footpath or roadside (41.3%), followed by a home or dwelling (32.5%). 8.8% of assaults occurred inside hotels, bars or other licenced venues. Most transpired on a weekday, which differed from the pre-2012 period when these assaults occurred mainly on the weekend. While some trends are positive, there has been a shift in the victim demographic as well as the typical environment for fatal one punch assaults, highlighting the importance of public health surveillance in providing a current evidence base to inform policy and practice.

Risk factors for relapse among methamphetamine users receiving a joint legal-medical treatment program as a diversion intervention: A one-year follow-up study

BACKGROUND

Methamphetamine (METH) is a Schedule II illicit drug in Taiwan. A 12-month legal-medical joint intervention program has been developed for first-time METH offenders during deferred prosecution. Risk factors associated with METH relapse use among these individuals were unknown.

METHODS

We enrolled a total of 449 METH offenders referred by the Taipei District Prosecutor's Office to Taipei City Psychiatric Center. The study defines relapse as having any positive urine toxicology result or self-report of METH use during 12-month treatment. We compared demographic and clinical variables between a relapse group and nonrelapse group and used a Cox proportional hazards model to determine variables associated with time to relapse.

RESULTS

Of all participants, 37.8 % relapsed to use METH and 23.2 % were noncompleters in the one-year follow-up. Compared to the nonrelapse group, the relapse group had lower educational attainment, more severe psychological symptoms, longer duration of METH use, higher odds of polysubstance use, higher craving severity, and higher odds of positive baseline urine. The Cox analysis revealed individuals with positive urine results and higher craving severity at baseline were at higher risks of METH relapse (hazard ratio [95 % CI]: 3.85 [2.61-5.68] and 1.71 [1.19-2.46], respectively, p < 0.001). Baseline positive urine results and high craving could also predict a shorter length of time to relapse than their respective counterparts.

CONCLUSIONS

Positive urine screening for METH at baseline and high craving severity are two indicators of an increased risk of drug relapse. Tailored treatment plans incorporating these findings to prevent relapse are warranted in our joint intervention program.

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.

Methamphetamine Induces Systemic Inflammation and Anxiety: The Role of the Gut–Immune–Brain Axis

Methamphetamine (METH) is a highly addictive drug abused by millions of users worldwide, thus becoming a global health concern with limited management options. The inefficiency of existing treatment methods has driven research into understanding the mechanisms underlying METH-induced disorders and finding effective treatments. This study aims to understand the complex interactions of the gastrointestinal–immune–nervous systems following an acute METH dose administration as one of the potential underlying molecular mechanisms concentrating on the impact of METH abuse on gut permeability. Findings showed a decreased expression of tight junction proteins ZO-1 and EpCAm in intestinal tissue and the presence of FABP-1 in sera of METH treated mice suggests intestinal wall disruption. The increased presence of CD45+ immune cells in the intestinal wall further confirms gut wall inflammation/disruption. In the brain, the expression of inflammatory markers Ccl2, Cxcl1, IL-1β, TMEM119, and the presence of albumin were higher in METH mice compared to shams, suggesting METH-induced blood–brain barrier disruption. In the spleen, cellular and gene changes are also noted. In addition, mice treated with an acute dose of METH showed anxious behavior in dark and light, open field, and elevated maze tests compared to sham controls. The findings on METH-induced inflammation and anxiety may provide opportunities to develop effective treatments for METH addiction in the future.

Stimulant use in suicides: A systematic review

Suicide remains a global public health concern and the increased supply and use of synthetic stimulants globally may have implications for the burden of suicides attributable to substance use. This systematic review investigated any potential associations of stimulant use detected in post-mortem biological specimens and suicides. We conducted a systematic review and narrative synthesis (CRD42021237966). Medline, EMBASE, TOXLINE, and Scopus databases were searched for terms related to forensic toxicology, post-mortem toxicology, suicide and stimulants. The primary outcome was to estimate the prevalence of stimulant use in suicides. There were 26 studies whichcontributed to prevalence measures; in studies reporting at the individual compound level, suicides involved cocaine (0.1-23%), caffeine (3.2-22%), 3,4-methylenedioxymethamphetamine (0.1-17%), amphetamine (0.2-9.3%), methamphetamine (3.1-7%), and phentermine (0.9-1%). Overall, stimulant use in suicides was over-represented compared to estimates of stimulant use in the general population and has increased over time. Thirteen case reports used to contextualise suicides involving stimulants found no examples of cocaine or methamphetamine mono-intoxication of suicidal intent. This suggests mechanisms other than acute toxicity involved in stimulant-associated suicide. Future research by in-depth psychological autopsies of suicides involving stimulants, in combination with segmental hair analysis to determine the chronicity of stimulant exposure, may contribute to a better understanding of the burden of suicide attributable to stimulant use.

Sex-Dependent Alterations in the mRNA Expression of Enzymes Involved in Dopamine Synthesis and Breakdown After Methamphetamine Self-Administration

Sex differences have been reported in methamphetamine (METH) use disorder in humans and in animal models of METH exposure. Specifically, animals that self-administer METH show sex-related dissimilarities in dopamine (DA) metabolism. To better understand the molecular bases for the differences in DA metabolism, we measured the levels of mRNAs of enzymes that catalyze DA synthesis and breakdown in the prefrontal cortex (PFC), nucleus accumbens (NAc), dorsal striatum (dSTR), and hippocampus (HIP) of rats that had self-administered METH. There were significant sex differences in control rats, with males having higher basal levels of Th in the PFC and dSTR, Ddc in the NAc, and MaoB in the HIP. In contrast, female controls showed higher basal levels of Comt in the HIP. Male and female METH SA rats also showed some distinct responses to the drug. Specifically, female METH rats exhibited increased expression of Ddc and MaoB, whereas male METH animals showed higher levels of Comt mRNA in the PFC compared to their respective controls. In the NAc, male METH rats displayed decreased Th and Ddc mRNA levels. Together, our results identified sex-dependent and region-specific changes in the mRNA expression of several enzymes involved in DA synthesis and breakdown in response to METH SA, with the majority of differences being observed in the mesocorticolimbic dopaminergic system. These findings are of significant translational importance providing further support for the inclusion of sex as an important variable when planning and evaluating therapeutic interventions against METH use disorder in human clinical studies.

Sex differences in methamphetamine use disorder perused from pre-clinical and clinical studies: Potential therapeutic impacts

Methamphetamine (METH) use, and misuse are associated with severe socioeconomic consequences. METH users develop tolerance, lose control over drug taking behaviors, and suffer frequent relapses even during treatment. The clinical course of METH use disorder is influenced by multifactorial METH-induced effects on the central and peripheral nervous systems. Although these METH-induced consequences are observed in humans of all ages, races, and sexes, sexual dimorphism in these outcomes have been observed in both pre-clinical and clinical settings. In this review, we have provided a detailed presentation of the sex differences reported in human and animal studies. We have therefore presented data that identified the influences of sex on METH pharmacokinetics, METH-induced changes in behaviors, cognitive processes, structural changes in the brain, and the effects of the drug on neurotransmitter systems and molecular mechanisms. Finally, we highlighted the potential significance of sex as a critical variable that should be considered when planning the development of new pharmacotherapeutic approaches against MEH use disorder in humans.

Sex-Specific Alterations in Dopamine Metabolism in the Brain after Methamphetamine Self-Administration

Methamphetamine (METH) use disorder affects both sexes, with sex differences occurring in behavioral, structural, and biochemical consequences. The molecular mechanisms underlying these differences are unclear. Herein, we used a rat model to identify potential sex differences in the effects of METH on brain dopaminergic systems. Rats were trained to self-administer METH for 20 days, and a cue-induced drug-seeking test was performed on withdrawal days 3 and 30. Dopamine and its metabolites were measured in the prefrontal cortex (PFC), nucleus accumbens (NAc), dorsal striatum (dSTR), and hippocampus (HIP). Irrespective of conditions, in comparison to females, male rats showed increased 3,4-dihydroxyphenylalanine (DOPA) in the PFC, dSTR, and HIP; increased cys-dopamine in NAc; and increased 3,4-dihydroxyphenylethanol (DOPET) and 3,4-dihydroxyphenylacetic acid (DOPAC) in dSTR. Males also showed METH-associated decreases in DA levels in the HIP but increases in the NAc. Female rats showed METH-associated decreases in DA, DOPAL, and DOPAC levels in the PFC but increases in DOPET and DOPAC levels in the HIP. Both sexes showed METH-associated decreases in NAc DA metabolites. Together, these data document sex differences in METH SA-induced changes in DA metabolism. These observations provide further support for using sex as an essential variable when discussing therapeutic approaches against METH use disorder in humans.

Healthcare utilization and psychiatric and physical comorbidities before suicide mortality in patients with methamphetamine use disorder: A nationwide case-control study

BACKGROUND

Since the late 1990s, methamphetamine use has become a considerable public health concern. Despite high suicide rates among methamphetamine users, studies exploring medical utilization and psychiatric and physical comorbidities before suicide are scant. We aim to examine the pattern of medical utilization and distribution of comorbidities shortly before suicide in methamphetamine users who died of suicide and compared these data with those of living methamphetamine users.

METHODS

From Taiwan's National Health Insurance Research Database, we identified the cohort with methamphetamine use disorder (n = 23,248) between January 1, 2001, and December 31, 2005. We identified 5972 deceased patients (of whom 745 died of suicide) by linking each patient with the national mortality database during the study period. By conducting a nested case-control study with risk-set sampling, from the methamphetamine cohort, we selected four age- and sex-matched controls for each patient who died of suicide (cases). We applied conditional logistic regression to investigate differences in medical utilization and physical and psychiatric comorbidities between cases and controls.

RESULTS

Cases had higher medical utilization within 3 months before suicide, particularly in the departments of psychiatry, internal medicine, emergency, and family practice. Cases had higher risks of physical comorbidities, including pneumonia and renal disease, and psychiatric comorbidities, including depressive disorder, sleep disorder, drug-induced mental disorder, schizophrenia, and bipolar disorder.

CONCLUSIONS

The findings of increased medical utilization and the higher risks of physical and psychiatric comorbidities in cases are crucial for developing specific interventions to prevent suicide in this patient population.

A Systematic Review of Risk Factors for Suicide Among Persons Living with HIV (1996-2020)

Persons living with HIV (PWH) are at elevated risk for suicide. We conducted a systematic literature review following PRISMA-P guidelines to examine risk factors associated with suicide as a cause of morbidity among PWH. We searched six electronic databases using search terms (suicide, suicide attempt, self-harm, self-injurious behavior, HIV, AIDS, PWH). We focused on factors that were specific to HIV infection (CD4 count, HIV-1 RNA, and antiretroviral therapy [ART]). The initial search yielded N = 2657 studies. Eligible studies included suicide as an outcome, quantitative study design, and publication in peer-reviewed journals from 1996 through 2020. Fourteen studies met inclusion criteria. PWH share risk factors for suicide found in the general population: psychiatric illness, previous suicide attempt, drug and alcohol misuse. PWH also have HIV-specific risk factors for suicide. HIV diagnosis in the past two years and transmission related to injection drug use were associated with increased risk; HIV-1 RNA, ART, and AIDS-defining illness were not.

Hypocretin/Orexin Interactions with Norepinephrine Contribute to the Opiate Withdrawal Syndrome

We previously found that human heroin addicts and mice chronically exposed to morphine exhibit a significant increase in the number of detected hypocretin/orexin (Hcrt)-producing neurons. However, it remains unknown how this increase affects target areas of the hypocretin system involved in opioid withdrawal, including norepinephrine containing structures locus coeruleus (LC) and A1/A2 medullary regions. Using a combination of immunohistochemical, biochemical, imaging, and behavioral techniques, we now show that the increase in detected hypocretin cell number translates into a significant increase in hypocretin innervation and tyrosine hydroxylase (TH) levels in the LC without affecting norepinephrine-containing neuronal cell number. We show that the increase in TH is completely dependent on Hcrt innervation. The A1/A2 regions were unaffected by morphine treatment. Manipulation of the Hcrt system may affect opioid addiction and withdrawal.SIGNIFICANCE STATEMENT Previously, we have shown that the hypothalamic hypocretin system undergoes profound anatomic changes in human heroin addicts and in mice exposed to morphine, suggesting a role of this system in the development of addictive behaviors. The locus coeruleus plays a key role in opioid addiction. Here we report that the hypothalamic hypocretin innervation of the locus coeruleus increases dramatically with morphine administration to mice. This increase is correlated with a massive increase in tyrosine hydroxylase expression in locus coeruleus. Elimination of hypocretin neurons prevents the tyrosine hydroxylase increase in locus coeruleus and dampens the somatic and affective components of opioid withdrawal.

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.

All-cause and suicide mortality among people with methamphetamine use disorder: a nation-wide cohort study in Taiwan

BACKGROUND AND AIMS

Although methamphetamine use is a serious public health problem, large-scale cohort studies assessing methamphetamine-related mortality are scant. This study investigated all-cause mortality and suicide methods in people with methamphetamine use disorder.

DESIGN

A cohort record-linkage study using data from Taiwan's National Health Research Institute Database (NHIRD) linked to Taiwan's National Death Certification System.

SETTING

Taiwan.

PARTICIPANTS

A total of 23 248 individuals with methamphetamine use disorder between 1 January 2001 and 31 December 2005.

MEASUREMENTS

The outcome variables included mortality rates and standardized mortality ratios (SMRs) for all causes of death and for each suicide method.

FINDINGS

Compared with the general population, the current cohort had an increased all-cause mortality (SMR = 5.4), with the SMR for unnatural causes (14.8) higher than that for natural causes (7.5). Among all causes of death, suicide had the highest SMR (16.3), followed by neurological diseases (9.7). Among the methods of choice for suicide, drug overdose had the highest SMR (24.9). The incidence of charcoal burning and hanging was significantly higher in men and that of jumping from a high place was significantly higher in women.

CONCLUSION

People in Taiwan with methamphetamine use disorder appear to have a significantly increased all-cause mortality rate compared with the general population, with suicide having the highest contribution, particularly suicide via drug overdose. The methods of choice for suicide revealed distinct patterns between men and women.

Substance use and deaths by suicide: A latent class analysis of the National Violent Death Reporting System

Substance use is strongly associated with suicide completions. However, little is known about the patterns of substances used in suicide deaths. The purpose of this analysis is to determine latent classes of toxicology-reported substances among individuals who completed suicide. The sample consists of suicide victims in the National Violent Death Reporting System (NVDRS) during years 2003-2017 (n = 202,838). Toxicology reports were used to construct latent class analyses of substance use among suicide victims. Correlates for latent class membership included sex, race/ethnicity, previous experiences of child abuse, homelessness, and intimate partner violence (IPV) victimization. The majority of suicide victims were male (77.7%), straight/heterosexual (99.5%) and white (88.3%). The final unconditional model yielded a four-class model, including a "No substance/single substance use" class, an "Alcohol and other substance" class, a "Marijuana and other substance" class, and an "Opiate use" class. Compared to the reference class of "No substance/single substance," females were more likely than males to be classified in the "Alcohol and other substance" class, the "Multi-substance use" class, and the "Opiate use" class. Homelessness was associated with classification in the "Marijuana and other substance" class and the "Opiate use" class compared to the "No substance/single substance" class. IPV was associated with both polysubstance use classes ("Alcohol plus other substance" and "Marijuana plus other substance") along with the "Opiate use" class compared to the "No substance/single substance" class. These classes highlight profiles of suicide descendants and emphasize the importance of polysubstance use prevention among females, homeless individuals, and those who experience IPV.

Prevalence, sociodemographic variables, mental health condition, and type of drug use associated with suicide behaviors among people with substance use disorders: a systematic review and meta-analysis

We assessed the prevalence, sociodemographic variables, mental health condition, and type of drug use associated with suicide behaviors among patients with substance use disorders (SUD). Studies in English published from January 1, 1995 to December 31, 2020 were searched on PubMed, Scopus, Cochrane and Web of Science to identify studies on variables associated with suicidal behaviors (ideations and attempts) among patients with SUD. After reviewing for study duplicates, the full-text of selected articles were assessed for eligibility using Population, Intervention, Comparator, Outcomes (PICO) criteria: (i) population: patients with SUD; (ii) intervention: suicide behaviors in the past year; (iii) comparator: SUD who had not suicide behaviors; (iv) outcome: suicide ideations or attempts in the last year; and (v) study type: cross-sectional, cohort, and case-control studies. Out of 10,810 articles, 48 studies met eligibility criteria. Our findings showed a pooled prevalence rate of suicide ideations of 35% (95% CI, 22% 48%) and suicide attempts of 20% (95% CI, 17% 23%) in the last year among patients with SUD. Smoking, previous history of sexual abuse, depression, and alcohol and cannabis use disorders were significantly associated with suicide ideations. Study findings also showed that being female, smoking, history of physical and sexual abuse, depression and alcohol, cannabis, cocaine, amphetamine use disorders, and polysubstance abuse were significantly associated with suicide attempts among patients with SUD. These findings have implications for developing prevention programs. Appropriate initiatives for reducing the risk of suicide behaviors like systematic assessments of changes in drug use pattern at the emergency departments or at other key health providers may be more broadly implemented. Motivational therapy to improve help-seeking, increased information on adverse consequences of heavy substance use, and crisis plan resolutions to face suicide behaviors could also be consolidated.

Methamphetamine deaths: Changing trends and diagnostic issues

The term 'amphetamine' refers to a class of synthetic drugs which includes methamphetamine. The latter is a globally popular drug of abuse which induces euphoria, affecting cognitive/psychomotor performance and sleep. It also provokes risk taking and violent behaviour. The central effects of methamphetamine are due to the overproduction of neurotransmitters, resulting in high levels of dopamine. In recent years, there have been significant increases in cases of methamphetamine abuse in North and South America, Australia and Asia due to its ready availability and low cost. The following review examines changing trends in methamphetamine use and problems that arise diagnostically in medico-legal cases in determining the significance of post-mortem blood levels, the relationship of these to ante-mortem levels, the possible effects on physical and psychological behaviours and the possible contribution of the drug to a lethal episode.

Surveillance of suicide deaths involving gases in Australia using the National Coronial Information System, 2006 to 2017

BACKGROUND

There have been concerns about the increased use of helium and nitrogen gas as a suicide mechanism in Australia.

METHODS

National Coronial Information System data were used to investigate gas-specific suicides in Australia over the period 2006-2017. Characteristics were compared between helium or nitrogen, carbon monoxide and seven other gases.

RESULTS

Gas inhalation accounted for 10% (3,103/31,002) of all suicide deaths in Australia between 2006 and 2017. The mean age of individuals who died by suicide was 47.6 years (SD 16.9, R 14-97) and 83.3% were male. The number of gas suicides declined over the study period (IRR=0.96). The fall was associated with a 47% decline in carbon monoxide suicides (IRR=0.93). There was an increase in deaths due to argon (IRR=1.60) and nitrogen (IRR=1.27). Compared to individuals using other non-carbon monoxide gases, individuals who died by suicide from helium or nitrogen were significantly more likely to be older, have a physical illness and/or disability, have contacted a euthanasia group and have accessed instructional material and purchased gas online.

CONCLUSIONS

Suicides by carbon monoxide decreased between 2006 and 2017 alongside an increase in argon and nitrogen gas use - particularly among older adults. The ease of access to these gases points to new targets for means restriction. Implications for public health: Identifying the types of gases used in suicide deaths and emerging trends may enable targeted interventions that could potentially reduce access.

Methamphetamine-related postmortem cases in Jeddah, Saudi Arabia

A more than 500% increase in the number of deaths involving methamphetamine occurred between 2016 and 2018 in Jeddah, Saudi Arabia. As such, this report employed a validated liquid chromatography tandem mass spectrometry method to quantify methamphetamine and its metabolites in bodily fluids from 47 postmortem cases in which methamphetamine was involved. The mean age of the deceased was 33 years old (median: 30, range: 16-63), and 94% were male. Methamphetamine was co-ingested with another drug in 32 of the cases (68%); however, the deaths were only due to the combined toxicity of methamphetamine and another drug in 15 of the cases (32%). Of note, 13 of these deaths (28% of all deaths) involved heroin. When methamphetamine was the sole cause of death (32% of the studied cases), the median concentrations of methamphetamine and amphetamine were 527 and 128 ng/mL. When methamphetamine was combined toxicity with another drug, the median concentrations of methamphetamine and amphetamine decreased to 161 and 53 ng/mL. When deaths were unrelated to methamphetamine, the median concentrations of methamphetamine and amphetamine were 130 and 44 ng/mL, respectively. The highest median methamphetamine concentration was found in urine (5281 ng/mL), followed by stomach contents (878 ng/mL), bile (762 ng/mL), vitreous humor (3 ng/mL), and blood (208 ng/mL). Almost 40% of the studied cases involved violence, 61% were accidental, 21% were suicides, 17% were homicides, and 2% were natural deaths. Methamphetamine is highly addictive. Increases in deaths have been seen in various countries. More awareness, education and treatment programs are required to reduce the likelihood of addiction, crimes, suicide, and other fatalities resulting from methamphetamine abuse.

Pleasure, addiction, and hypocretin (orexin)

The hypocretins/orexins were discovered in 1998. Within 2 years, this led to the discovery of the cause of human narcolepsy, a 90% loss of hypothalamic neurons containing these peptides. Further work demonstrated that these neurons were not simply linked to waking. Rather these neurons were active during pleasurable behaviors in waking and were silenced by aversive stimulation. This was seen in wild-type mice, rats, cats, and dogs. It was also evident in humans, with increased Hcrt release during pleasurable activities and decreased release, to the levels seen in sleep, during pain. We found that human heroin addicts have, on average, an increase of 54% in the number of detectable Hcrt neurons compared to "control" human brains and that these Hcrt neurons are substantially smaller than those in control brains. We found that in mice, chronic morphine administration induced the same changes in Hcrt neuron number and size. Our studies in the mouse allowed us to determine the specificity, dose response relations, time course of the change in the number of Hcrt neurons, and that the increased number of Hcrt neurons after opiates was not due to neurogenesis. Furthermore, we found that it took a month or longer for these anatomical changes in the mouse brain to return to baseline. Human narcoleptics, despite their prescribed use of several commonly addictive drugs, do not show significant evidence of dose escalation or substance use disorder. Similarly, mice in which the peptide has been eliminated are resistant to addiction. These findings are consistent with the concept that an increased number of Hcrt neurons may underlie and maintain opioid or cocaine use disorders.

Methamphetamine, Amphetamine, and MDMA Use and Emergency Department Recidivism

BACKGROUND

Emergency department (ED) recidivism and the use of amphetamine and associated derivatives such as methamphetamine and MDMA (MAE), are intersecting public health concerns.

OBJECTIVE

This study aims to determine the frequency of ED recidivism of patients who use MAE and associated factors.

METHODS

The study was a retrospective 6-year electronic medical record review of patients with MAE-positive toxicology screens and single and multiple ED visits in the span of 12 months.

RESULTS

There were 7844 ED visits by 5568 MAE-positive patients. Average age was 42 ± 13 years. The majority were male (65%), white (46%), tobacco smokers (55%), and in the psychiatric discharge diagnostic-related group (41%), followed by blunt trauma (20%). Admission rate was 35%, with another 17% transferred to inpatient psychiatric treatment facilities. Occasional (2-5 visits/year), heavy (6-11 visits/year), and super users (≥12 visits/year) altogether accounted for 20% of patients and 43% of visits. Heavy and super users combined represented 2% of patients and 10% of visits, with significant differences for race/ethnicity, health insurance, tobacco smoking, and psychiatric/cardiovascular/trauma discharge diagnostic-related groups. Heavy and super users were less likely to be admitted and more likely to be discharged to an inpatient psychiatric treatment facility. Regression analysis revealed racial/ethnic differences, female gender, and tobacco smoking to be associated with super and heavy use. Heavy users were more likely to have cardiovascular-related discharge diagnoses.

CONCLUSIONS

The prevalence of ED recidivism in patients who use MAE is similar to published ranges for general ED users. Significant differences in demographics, discharge diagnoses, insurance, smoking, and disposition exist between nonfrequent and frequent ED users.

Dark Times: The Role of Negative Reinforcement in Methamphetamine Addiction

Methamphetamine use is associated with substantial adverse outcomes including poor mental and physical health, financial difficulties, and societal costs. Despite deleterious long-term consequences associated with methamphetamine, many people use drugs for short-term reduction of unpleasant physical or emotional sensations. By removing these aversive states, drug use behaviors are negatively reinforced. Abstinence from methamphetamine can then result in a return to previous aversive emotional states linked to withdrawal and craving, often contributing to an increased likelihood for relapse. This negative reinforcement cycle is hypothesized to be a motivating and maintaining factor for addiction. Thus, this review highlights the current evidence for negative reinforcement mechanisms in methamphetamine use disorder by integrating studies of subjective experience, behavior, functional magnetic resonance imaging, positron emission tomography, and event-related potentials and examining the efficacy of treatments targeting aspects of negative reinforcement. Overall, the literature demonstrates that individuals who use methamphetamine have diminished cognitive control and process emotions, loss of reward, and interoceptive information differently than non-using individuals. These differences are reflected in behavioral and subjective experiments as well as brain-based experiments which report significant differences in various frontal regions, insula, anterior cingulate cortex, and striatum. Together, the results suggest methamphetamine users have an altered experience of negative outcomes, difficulties employing effective emotion regulation, and difficulty engaging in adaptive or goal-directed decision-making. Suggestions for future research to improve our understanding of how negative reinforcement contributes to methamphetamine addiction and to develop effective interventions are provided.

Methamphetamine-associated psychosis: links to drug use characteristics and similarity to primary psychosis

Objectives: Despite the prevalence of methamphetamine-associated psychosis, how characteristics of drug use affect the severity and clinical course, and its optimal treatments have not been established. We addressed these questions, assessing clinical features of methamphetamine-associated psychosis, and compared it with primary psychosis.Methods: Hospitalised patients with methamphetamine-associated (n = 70) or primary schizophrenic psychosis (n = 70) were matched on sex, age and duration of psychosis. Association of drug use variables (age at initiation, duration of methamphetamine use) with the Brief Psychiatric Rating Scale (BPRS) scores and psychosis duration were examined for patients with methamphetamine-associated psychosis, and the groups were compared on the BPRS scores.Results: Methamphetamine use initiation age correlated negatively with the BPRS total score and the Activation subscale score; methamphetamine use duration correlated positively with psychosis duration. Methamphetamine-associated psychosis group scored lower on the Hostility-Suspiciousness and Anergia subscales of the BPRS (adjusted p values < .05).Conclusions: Association of early initiation of methamphetamine with psychosis severity may suggest a lasting effect on brain development. Correlation of drug use and psychosis durations may suggest a cumulative effect of methamphetamine exposure. Less severe paranoia and negative symptoms in the methamphetamine-using group could implicate better social functioning of these patients. Further mechanistic studies are warranted.Key pointsEarly initiation of methamphetamine use is associated with psychosis severity.Methamphetamine use duration associates with psychosis duration.Methamphetamine-associated and primary schizophrenic psychoses were similar in symptoms.Methamphetamine psychosis patients were less severe in paranoia and negative symptoms.

The role of childhood maltreatment in cortisol in the hypothalamic-pituitary-adrenal (HPA) axis in methamphetamine-dependent individuals with and without depression comorbidity and suicide attempts

BACKGROUND

The hypothalamic-pituitary-adrenal (HPA) axis dysregulation which was found to have an important role in the pathophysiology of depression, suicide, and substance dependence, may be influenced by childhood maltreatment (CM). The present study aimed to investigate the relationship between CM and cortisol changes in methamphetamine-dependent individuals.

METHODS

In a cross-sectional study, methamphetamine-dependent individuals (n = =195) with or without both comorbid major depressive disorder (MDD) and a history of suicide attempts were selected and completed the Childhood Trauma Questionnaire-Short Form (CTQ-SF), the Beck Scale for Suicide Ideation (BSSI), and the Beck Depression Inventory-II (BDI-II). To assess cortisol levels, saliva samples were collected at six time intervals for two consecutive days.

RESULTS

A history of CM significantly predicted wake-up cortisol level, cortisol awakening response (CAR), and diurnal cortisol slope. Methamphetamine-dependent individuals with both MDD and lifetime suicide attempts had higher CM and higher cortisol levels with a blunted diurnal cortisol slope than individuals who were merely methamphetamine-dependent. Individuals with high CM showed higher cortisol levels with a blunted diurnal slope than those with low or without CM.

LIMITATIONS

Cross-sectional data and use of self-report scales, especially retrospective measurements (e.g., the CTQ-SF), were important limitations of this study.

CONCLUSION

Findings suggest that methamphetamine-dependent individuals with adverse psychological factors such as CM, MDD, and suicide attempts may show dysregulation in biological factors including cortisol level. In addition, CM and its effects on cortisol in the HPA axis may emerge as important factors regarding psychopathological use of methamphetamine.

Psychological treatment for methamphetamine use and associated psychiatric symptom outcomes: A systematic review

BACKGROUND

Regular methamphetamine use is associated with increased rates of psychiatric symptoms. Although there has been a substantial body of research reporting on the effectiveness of psychological treatments for reducing methamphetamine use, there is a paucity of research examining the effects of these treatments on co-occurring psychiatric symptoms. We addressed this gap by undertaking a systematic review of the evidence of the effectiveness of psychological treatments for methamphetamine use on psychiatric symptom outcomes in randomized controlled trials.

METHODS

A narrative synthesis of studies was conducted following the Cochrane Handbook for Systematic Reviews of Interventions and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement to inform methodology. Eight electronic peer-reviewed databases were searched. Ten eligible studies were assessed.

RESULTS

Most studies found an overall reduction in levels of methamphetamine use and psychiatric symptoms among samples as a whole. Although brief interventions were effective, there is evidence that more intensive interventions have greater impact on methamphetamine use and/or psychiatric symptomatology. Intervention attendance was variable.

CONCLUSIONS

The evidence suggests that a variety of psychological treatments are effective in reducing levels of methamphetamine use and improving psychiatric symptoms. Future research should consider how psychological treatments could maximize outcomes in the co-occurring domains of methamphetamine use and psychiatric symptoms, with increasing treatment attendance as a focus. PROSPERO registration number: CRD42016043657.

Mortality among people with regular or problematic use of amphetamines: a systematic review and meta-analysis

BACKGROUND AND AIMS

Amphetamines are the second most commonly used class of illicit drugs. We aimed to produce pooled estimates of mortality risks among people with regular or dependent use of amphetamines, with a focus upon all-cause mortality as well as specific causes of death.

DESIGN

Systematic review and meta-analysis of cohorts of people with problematic use or dependence on amphetamines with data on all-cause or cause-specific mortality.

SETTING AND PARTICIPANTS

Of 4240 papers, 30 were eligible, reporting on 25 cohorts that measured all-cause mortality, drug poisoning, suicide, accidental injuries, homicide and cardiovascular mortality. Cohorts (n = 35-74 139) were in North America, several Nordic countries and Asia Pacific.

MEASUREMENT

Titles/abstracts were independently screened by one reviewer and excluded those reviewed by a second reviewer. Full-text screening was by two reviewers with discrepancies resolved via a third reviewer. We extracted data on crude mortality rates (CMR) per 100 person-years (py), standardized mortality ratios (SMRs). We imputed SMRs where possible if not reported by study authors. We also calculated mortality relative risks. Data were pooled using random-effects models; potential reasons for heterogeneity were explored using subgroup analyses and meta-regressions.

FINDINGS

Twenty-three cohorts contributed data for the pooled all-cause CMR: 1.14 per 100 py [95% confidence interval (CI) = 0.92-1.42]. Pooled cause-specific mortality rates were: drug poisoning, 0.14 per 100 py (95% CI = 0.06-0.34); cardiovascular disease, 0.13 per 100 py (95% CI = 0.06-0.29); suicide, 0.20 per 100 py (95% CI = 0.07-0.55); accidental injury, 0.20 per 100 py (95% CI = 0.08-0.47) and homicide, 0.03 per 100 py (95% CI = 0.02-0.06). There was substantial heterogeneity for all pooled CMR estimates except homicide. The pooled all-cause SMR was 6.83 (95% CI = 5.27-8.84). Pooled cause-specific SMRS were: poisoning, 24.70 (95% CI = 16.67, 36.58); homicide, 11.90 (95% CI = 7.82-18.12); suicide, 12.20 (95% CI = 4.89-30.47); cardiovascular disease, 5.12 (95% CI = 3.74-7.00) and accidental injury, 5.12 (95% CI = 2.88-9.08).

CONCLUSIONS

People with regular or dependent amphetamine use are at elevated risk of a range of causes of mortality compared with people without regular or dependent amphetamine use.