Prediction of attempted suicide in men and women with crack-cocaine use disorder in Brazil

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.

Machine learning and the prediction of suicide in psychiatric populations: a systematic review

Machine learning (ML) has emerged as a promising tool to enhance suicidal prediction. However, as many large-sample studies mixed psychiatric and non-psychiatric populations, a formal psychiatric diagnosis emerged as a strong predictor of suicidal risk, overshadowing more subtle risk factors specific to distinct populations. To overcome this limitation, we conducted a systematic review of ML studies evaluating suicidal behaviors exclusively in psychiatric clinical populations. A systematic literature search was performed from inception through November 17, 2022 on PubMed, EMBASE, and Scopus following the PRISMA guidelines. Original research using ML techniques to assess the risk of suicide or predict suicide attempts in the psychiatric population were included. An assessment for bias risk was performed using the transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD) guidelines. About 1032 studies were retrieved, and 81 satisfied the inclusion criteria and were included for qualitative synthesis. Clinical and demographic features were the most frequently employed and random forest, support vector machine, and convolutional neural network performed better in terms of accuracy than other algorithms when directly compared. Despite heterogeneity in procedures, most studies reported an accuracy of 70% or greater based on features such as previous attempts, severity of the disorder, and pharmacological treatments. Although the evidence reported is promising, ML algorithms for suicidal prediction still present limitations, including the lack of neurobiological and imaging data and the lack of external validation samples. Overcoming these issues may lead to the development of models to adopt in clinical practice. Further research is warranted to boost a field that holds the potential to critically impact suicide mortality.

Gender Differences in Risks of Suicide and Suicidal Behaviors in the USA: A Narrative Review

PURPOSE OF REVIEW

We review recent research (2018-2023) on gender differences in suicidal behaviors (i.e., suicidal ideations and attempts, death by suicide). We examine research studies in the following areas: developmental period, substance use, and special populations (Veterans, sexual and gender minorities).

RECENT FINDINGS

Novel results were found in these different areas. For example, suicide rates for female youth are increasing at a faster rate relative to male youth. Further, some evidence suggests that heavy alcohol use/binge drinking is a significant and growing risk factor for suicidal behaviors in women. Military service may be a more significant risk factor for suicidal behaviors among male Veterans compared to female Veterans. Additionally, suicide rates are rising for gender minority youth/young adults. Recent research on gender differences in suicide outcomes demonstrates findings that align with previous research, as well as new insights on this important topic.

Cocaine-involved suspected suicide attempts in individuals age 50 and older reported to United States Poison Centers

CONTEXT

Despite a rapidly growing number of older cocaine users, the link between cocaine use and suicide attempt in older adults has not been examined. We examined associations between co-used other substances and (1) suspected suicide attempts versus other intentional misuse, and (2) major medical outcomes (major effect or death) of suspected suicide attempts and other intentional misuse.

METHODS

We used the 2015-2021 United States National Poison Data System (N = 5,191 cases age 50 and older). Descriptive statistics and generalized linear models for a Poisson distribution with a log link function were used to examine the study questions.

RESULTS

Cocaine exposures steadily increased from 2015 through 2021. Over the seven years, 52.3% and 47.7% were suicide attempts and other intentional misuse cases, respectively. Co-use of alcohol (incidence rate ratios = 1.24, 95% confidence interval = 1.14-1.35) and psychotropic (e.g., antidepressants: incidence rate ratios = 1.37, 95% confidence interval = 1.24-1.53) and cardiovascular medications were associated with a higher likelihood of suicide attempt, but co-use of prescription opioids, heroin, or other illicit drugs was associated with a lower likelihood of suicide attempt compared to other intentional misuse. Prescription opioids and amfetamine were associated with a higher likelihood of major effect or death in both suicide attempts and intentional misuse and heroin use and injection use were associated with a higher likelihood of major effect/death among intentional misuse cases.

CONCLUSIONS

These findings show that significant proportions of older cocaine users who attempted suicide also used psychotropic and cardiovascular medications. We suggest that healthcare providers screen for suicidal ideation among cocaine users, with special attention to an increased risk of suicide attempts among those who co-use cocaine with alcohol and psychotropic and other prescription medications.

Suicide risk classification with machine learning techniques in a large Brazilian community sample

Even though suicide is a relatively preventable poor outcome, its prediction remains an elusive task. The main goal of this study was to develop machine learning classifiers to identify increased suicide risk in Brazilians with common mental disorders. With the use of clinical and sociodemographic baseline data (n = 4039 adult participants) from a large Brazilian community sample, we developed several models (Elastic Net, Random Forests, Naïve Bayes, and ensemble) for the classification of increased suicide risk among individuals with common mental disorders. 1120 participants (27.7%) presented increased suicide risk. The Random Forests model achieved the best AUC ROC (0.814), followed by Naive Bayes (0.798) and Elastic Net (0.773). Sensitivity varied from 0.922 (Naive Bayes) to 0.630 (Random Forests), while specificity varied from 0.792 (Random Forests) to 0.473 (Naive Bayes). The ensemble model presented an AUC ROC of 0.811, sensitivity of 0.899, and specificity of 0.510. Features representing depression symptoms were the most relevant for the classification of increased suicide risk. Some of our models presented good performance metrics in the classification of increased suicide risk in the investigated sample, which can provide the means to early preventive interventions.

From Bumps to Binges: Overview of Deaths Associated with Cocaine in England, Wales and Northern Ireland (2000-2019)

The UK, as the "cocaine capital of Europe," currently accounts for ∼75% of all cocaine-related hospital admissions in Europe. This study aims to analyze the trends in cocaine-related deaths in England, Wales and Northern Ireland over 20 years (2000-2019). Cases reported to the National Programme on Substance Abuse Deaths (NPSAD) occurring between 2000 and 2019 where cocaine was detected at post-mortem (PM) were extracted for analysis. A total of 5,339 cases were retrieved, with an increase in the rate of reporting over time. Cocaine was deemed a cause of death and quantified in PM blood samples along with its major metabolite benzoylecgonine in 685 cases. Of these 685 cases, 25% (n = 170/685) occurred following acute use, 22% (n = 154/685) following chronic/binge use, 40% (n = 271/685) in combination with morphine, 4% (n = 29/685) in drug packer/swallower circumstances and 9% (n = 61/685) in a suicide context. Cardiac complications were evident in 22% of cases (n = 154/685). The average concentration of cocaine detected in cardiac cases (900 ng/mL) was considerably lower than that detected in cases where acute (19,100 ng/mL) or chronic/binge (6,200 ng/mL) dosing was evident. This is the first cocaine-related mortality study in these geographical areas. Deaths following cocaine use continue to rise despite its Class A drug listing in the UK. While underlying and external risk factors including polydrug use, cardiac complications and mental health can all contribute to the incidence of fatal drug toxicity following cocaine use, this study demonstrates that the risk of a cocaine overdose cannot be attributed to a specific blood concentration range.

Factors Associated with Cocaine Consumption among Suicide Victim

Cocaine use is an increasingly frequent event, especially in young people, and can cause irreversible consequences, such as suicide. To evaluate the factors associated with cocaine use in the moments preceding to suicide. This is a population-based, cross-sectional, and analytical study conducted in the Brazilian Federal District by researchers from the Department of Health and the Civil Police Institute of Criminalistics. All people who died due to suicide in 2018 were included in the survey. Cocaine use was considered the dependent variable, and robust Poisson regression was performed to estimate the crude and adjusted prevalence ratios and their respective population confidence intervals. In 2018, 12,157 deaths were recorded, of which suicide accounted for 1.56% of all deaths. It was observed that being between 25 and 44 years old, male, and under the influence of alcohol or cannabis, had a strong positive association with cocaine consumption among suicide victims. Males, people with black skin, with lower level of education, with employment, and who were under the effect of the use of cannabis and/or alcohol in the previous hours of death had a higher propensity to consume cocaine immediately before suicide, with a moderate to strong magnitude of prevalence ratio. The findings of this research indicated the need for monitoring, by health services, of people most vulnerable to suicide through the consumption of psychoactive substances.

Factors associated with suicidal ideation during the COVID-19 pandemic in a population in the Brazilian Legal Amazon

This article aims to analyze the factors associated with suicidal ideation in the COVID-19 pandemic. A cross-sectional home-based survey, with three-stage cluster sampling, was conducted with 4,203 adults from ten municipalities in the Mato Grosso, Brazil. The data collection was carried households to assessment of sociodemographic characteristics, substance use and behavior in the pandemic. The Level 1 Symptom Cross Scale was used to identify suicidal ideation and aspects of mental health (somatic symptoms, sleep disturbances, dissociation, depression, anger, mania, anxiety, thoughts, substance use and memory). Chemiluminescence was used to detect IgG anti-SARS-CoV-2 antibodies. The prevalence of suicidal ideation was 19.2%, and the associated with increased consumption of alcohol (RP=1.16), smoking (RP=1.30), COVID-19 symptoms (RP=1.03), having one's life affected (RP=1.04), mental illness (RP=1.09) somatic symptoms (RP=1.15), sleep disturbance (RP=1.30), dissociation (RP=1.24), depression (RP=1.24), anger (RP=1.11), anxiety (RP=1.26), substance use (RP=1.19), drug prescription use (RP=1.18) and memory (RP=1.87). Highlights the high prevalence of suicidal ideation related to COVID-19 symptoms, changes in behavior post-pandemic and mental health factors.

Prevalence of suicide in cocaine users accessing health services: a systematic review and meta-analysis

OBJECTIVE

This study reviewed and analyzed the prevalence of suicidal behaviors among cocaine users who sought health services.

METHODS

This is a systematic review and meta-analysis of studies published until January 2021. PubMed/MEDLINE, Scopus, Embase, PsycINFO, and LILACS were searched. The inclusion criteria were observational (retrospective or prospective), case-control, and/or cross-sectional reports that contained samples of cocaine users aged over 14 years who were assessed in health facilities or were in treatment. The random-effects model was used to calculate the overall prevalence of suicidal behavior with a 95% confidence interval. Subgroup analysis was conducted to investigate sources of heterogeneity.

RESULTS

Twenty articles were included, yielding a total of 2,252 cocaine users. The estimated prevalence was 43.59% (95%CI 31.10-57.38) for suicidal ideation and 27.71% (95%CI 21.63-34.73)for suicide attempts. High heterogeneity was found between studies for both outcomes (I² ≥ 93%), although subgroup analysis considering the quality of the studies showed a significant difference in suicide attempts (p = 0.03).

CONCLUSION

: Cocaine use can be considered a risk factor for suicidal behavior, and prevention and early screening measures should be implemented to facilitate adequate treatment.

Occurrence and severity of cocaine-induced hallucinations: Two distinct phenotypes with shared clinical factors but specific genetic risk factors

Cocaine-induced transient hallucinations (CIH) are a frequent complication following cocaine intake that is associated with addiction severity.

METHODS

Two hundred and forty-two non-psychotic and Caucasian lifetime cocaine users were included in a French multicentric study. Clinical variables and dopamine pathway genotype data were extracted and tested with CIH scores using a zero-inflated binomial model, which allows for the exploration of factors associated with occurrence and severity separately.

RESULTS

Cocaine dependence (p_occurrence= 6.18 × 10^-5, p_severity= 9.25 × 10^-8), number of cocaine dependence DSM IV-Tr criteria (p_occurrence= 1.22 × 10^-7, p_severity= 5.09 × 10^-6), and frequency of intake during the worst period of misuse (p_occurrence= 8.51 × 10^-04, p_severity= 0.04) were associated with greater occurrence and higher severity of CIH. The genetic associations did not yield significant results after correction for multiple tests. However, some nominal associations of SNPs mapped to the VMAT2, DBH, DRD1, and DRD2 genes were significant. In the multivariate model, the significant variables were the number of cocaine dependence criteria, lifetime alcohol dependence, and the nominally associated SNPs.

CONCLUSION

Our study shows that CIH occurrence and severity are two distinct phenotypes, with shared clinical risk factors; however, they likely do not share the same genetic background.

Childhood trauma and the severity of past suicide attempts in outpatients with cocaine use disorders

INTRODUCTION

Suicide attempts have been associated with both cocaine use disorder (CocUD) and childhood trauma. We investigated how childhood trauma is an independent risk factor for serious and recurrent suicide attempts in CocUD. Method: 298 outpatients (23% women) with CocUD underwent standardized assessments of substance dependence (Diagnostic and Statistical Manual-mental disorders, fourth edition, text revised), impulsiveness, resilience, and childhood trauma, using validated tools. Suicide attempts history was categorized as single vs. recurrent or non-serious vs. serious depending on the lifetime number of suicide attempts and the potential or actual lethality of the worst attempt reported, respectively. Bivariate and multinomial regression analyses were used to characterize which childhood trauma patterns were associated with the suicide attempts groups. Results: 58% of CocUD patients reported childhood trauma. Recurrent and serious suicide attempts clustered together and were thus combined into "severe SA." Severe suicide attempt risk increased proportionally to the number of childhood traumas (test for trend, p = 9 × 10^-7). Non-severe suicide attempt risk increased with impulsiveness and decreased with resilience. In multinomial regression models, a higher number of traumas and emotional abuse were independently and only associated with severe vs. non-severe suicide attempts (effect size = 0.82, AUC = 0.7). The study was limited by its cross-sectional design. Conclusion: These preferential associations between childhood trauma and severe suicide attempts warrant specific monitoring of suicide attempts risk in CocUD, regardless of the severity of addiction profiles.