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Substance use disorders and addictions are mental disorders deeply interconnected with other psychiatric conditions – and this connection is of fundamental importance. Although addictions are formally recognized as mental health disorders, they are often not addressed as such in research or clinical practice. Psychiatric research, clinical care, and treatment development remain largely organized along traditional diagnostic boundaries. While diagnostic classifications provide structure and clinical utility, it is increasingly evident that psychiatric diagnoses are neither fully separable nor independent entities. Despite extensive discussion on comorbidity, addictions are frequently excluded from broader conceptualizations of the intertwined nature of mental disorders. Yet, they share substantial commonalities with other psychiatric conditions across clinical presentation, psychopathology, genetic vulnerability, neurobiological mechanisms, socioenvironmental risk factors, and treatment strategies. Maintaining a conceptual divide between addictions and other psychiatric disorders reinforces diagnostic “tunnel vision,” constraining our understanding of neuropsychopathology and contributing to persistent gaps in care and treatment accessibility. This narrative review examines the overlapping risk factors, clinical features, and therapeutic approaches that link addictions with other mental disorders. We argue that advancing psychiatric research and nosology requires a deliberate acknowledgement of these transdiagnostic overlaps and shared mechanisms. The challenge is particularly evident in the understanding and treatment of dual disorders. Progress will depend on integrative, collaborative frameworks that bridge scientific and clinical perspectives and foster dynamic feedback between empirical research and clinical practice. Recognizing mental disorders as interdependent systems may offer a more coherent and effective foundation for understanding and treatment.
To characterise hospital-treated multimorbidity patterns in people who subsequently died a drug-related death in Scotland, and to identify clinically meaningful associations among conditions and decedent to inform prevention and care.
Methods:
A register-based retrospective cohort study using nationally linked hospital admission (1996–2019) and mortality (2008–2019) records for 5,749 decedents. We identified hospital admissions for Elixhauser comorbidities using ICD-10 codes. Correlation analysis, network analysis, and Bayesian clustering were used to describe co-occurring conditions and identify patient clusters with distinct comorbidity profiles.
Results:
Over half (50.9%) of decedents had at least one admission for an Elixhauser comorbidity. The most frequent were related to alcohol use (38.2%), drug use (29.1%), other neurological disorders (18.0%, mainly epilepsy/seizures/anoxic brain injury), depression (15.2%), and psychoses (12.5%). Network analysis highlighted drug use, alcohol use, psychoses, depression, and neurological disorders as central conditions. Bayesian clustering identified seven distinct patient clusters, including groups characterised by: high psychiatric and drug-use admissions; extensive physical comorbidities; alcohol and liver disease; dominant neurological issues and depression.
Conclusions:
Individuals experiencing drug-related deaths exhibit substantial multimorbidity with distinct patterns often dominated by substance use and mental ill-health but also including significant physical health clusters. These distinct profiles underscore the need for integrated, tailored care strategies addressing substance use, psychiatric, and physical health needs to mitigate mortality risk.
Howard CH Khoe, National Psychiatry Residency Programme, Singapore,Cheryl WL Chang, National University Hospital, Singapore,Cyrus SH Ho, National University Hospital, Singapore
Chapter 28 covers the topic of opioid use disorder. Through a case vignette with topical MCQs for consolidation of learning, readers go through the management of a patient with opioid use disorder from from first presentation to subsequent complications of the condition and its treatment. Topics covered include symptoms and diagnosis of acute intoxication and withdrawal symptoms of opioids and management including that of use in pregnant women.
Howard CH Khoe, National Psychiatry Residency Programme, Singapore,Cheryl WL Chang, National University Hospital, Singapore,Cyrus SH Ho, National University Hospital, Singapore
Chapter 29 covers the topic of hallucinogen use disorder. Through a case vignette with topical MCQs for consolidation of learning, readers go through the management of a patient with hallucinogen use disorder from from first presentation to subsequent complications of the condition and its treatment. Topics covered include symptoms and diagnosis of acute intoxication and withdrawal symptoms of phencylidine and hallucinogen-persisting perception disorder.
Howard CH Khoe, National Psychiatry Residency Programme, Singapore,Cheryl WL Chang, National University Hospital, Singapore,Cyrus SH Ho, National University Hospital, Singapore
Chapter 25 covers the topic of alcohol use disorder. Through a case vignette with topical MCQs for consolidation of learning, readers are brought through the diagnosis to management of a patient with alcohol use disorder. Topics covered include symptoms and diagnosis of acute intoxication and withdrawal symptoms of alcohol use, investigations, Wernicke’s enceophaloptahy, common co-morbidity, symptoms and treatment of alcohol withdrawal, delirium tremens, pharmacological and non-pharmacological management of alcohol use disorder.
Howard CH Khoe, National Psychiatry Residency Programme, Singapore,Cheryl WL Chang, National University Hospital, Singapore,Cyrus SH Ho, National University Hospital, Singapore
Chapter 30 covers the topic of gambling disorder. Through a case vignette with topical MCQs for consolidation of learning, readers go through the management of a patient with gambling disorder from from first presentation to subsequent complications of the condition and its treatment. Topics covered include symptoms and diagnosis of gambling disorder, risk factors, co-morbidities, non-pharmacological management psychotherapies and pharmacolgical management.
Howard CH Khoe, National Psychiatry Residency Programme, Singapore,Cheryl WL Chang, National University Hospital, Singapore,Cyrus SH Ho, National University Hospital, Singapore
Chapter 27 covers the topic of stimulants use disorder. Through a case vignette with topical MCQs for consolidation of learning, readers are brought through the diagnosis of a patient with stimulants use disorder on first presentation. Topics covered include symptoms and diagnosis of acute intoxication and withdrawal symptoms of stimulants use.
Howard CH Khoe, National Psychiatry Residency Programme, Singapore,Cheryl WL Chang, National University Hospital, Singapore,Cyrus SH Ho, National University Hospital, Singapore
Chapter 26 covers the topic of cannabis use disorder. Through a case vignette with topical MCQs for consolidation of learning, readers are brought through the diagnosis of a patient with cannabis use disorder on first presentation. Topics covered include symptoms and diagnosis of acute intoxication and withdrawal symptoms of cannabis use and amotivational syndrome.
This paper reviews the development of Aotearoa-New Zealand’s (New Zealand’s) specialist Mental Health and Addiction Services (MH&A Services) and Mental Health and Addiction plans (MH&A Plans) to improve the mental well-being of all New Zealanders. It does so in the context of New Zealand’s 2022 health reforms, and the government’s response to its 2018 Inquiry into MH&A (He Ara Oranga). First, the context for reform is described, including New Zealand’s sociodemography, existing data monitoring systems, mental health epidemiology and a current overview of its specialist MH&A Services. The findings of the He Ara Oranga Inquiry and the goals of the MH&A plans are then outlined, along with progress in establishing new initiatives related to them. Finally, challenges to the new direction for New Zealand’s MH&A system are reviewed, with possible strategies to address them and other key implementation challenges involving the separation and operationalisation of the main strategies of MH&A plans. A high-level view of MH&A Services is taken, rather than one detailing speciality services such as age-related, cultural or addiction services.
Although suicide bereavement is associated with suicide and self-harm, evidence regarding mechanisms is lacking. We investigated whether depression and substance use (alcohol and/or other drugs) explain the association between partner suicide bereavement and suicide.
Methods
Linkage of nationwide, longitudinal data from Denmark for the period 1980–2016 facilitated a comparison of 22 668 individuals exposed to bereavement by a partner's suicide with 913 402 individuals bereaved by a partner's death due to other causes. Using causal mediation models, we estimated the degree to which depression and substance use (considered separately) mediated the association between suicide bereavement and suicide.
Results
Suicide-bereaved partners were found to have a higher risk of suicide (HRadj = 1.59, 95% CI 1.36–1.86) and of depression (ORadj 1.16, 95% CI 1.09–1.25) when compared to other-bereaved partners, but a lower risk of substance use (ORadj 0.83; 95% CI 0.78–0.88). An increased risk of suicide was found among any bereaved individuals with a depression diagnosis recorded post-bereavement (ORadj 3.92, 95% CI 3.55–4.34). Mediation analysis revealed that depression mediated 2% (1.68%; 95% CI 0.23%–3.14%; p = 0.024) of the association between suicide bereavement and suicide in partners when using bereaved controls.
Conclusions
Depression is a partial mediator of the association between suicide bereavement and suicide. Efforts to prevent and optimize the treatment of depression in suicide-bereaved people could reduce their suicide risk. Our findings might be conservative because we did not include cases of depression diagnosed in primary care. Further work is needed to understand this and other mediators.
People who inject drugs are at risk of acute bacterial and fungal injecting-related infections. There is evidence that incidence of hospitalizations for injecting-related infections are increasing in several countries, but little is known at an individual level. We aimed to examine injecting-related infections in a linked longitudinal cohort of people who inject drugs in Melbourne, Australia. A retrospective descriptive analysis was conducted to estimate the prevalence and incidence of injecting-related infections using administrative emergency department and hospital separation datasets linked to the SuperMIX cohort, from 2008 to 2018. Over the study period, 33% (95%CI: 31–36%) of participants presented to emergency department with any injecting-related infections and 27% (95%CI: 25–30%) were admitted to hospital. Of 1,044 emergency department presentations and 740 hospital separations, skin and soft tissue infections were most common, 88% and 76%, respectively. From 2008 to 2018, there was a substantial increase in emergency department presentations and hospital separations with any injecting-related infections, 48 to 135 per 1,000 person-years, and 18 to 102 per 1,000 person-years, respectively. The results emphasize that injecting-related infections are increasing, and that new models of care are needed to help prevent and facilitate early detection of superficial infection to avoid potentially life-threatening severe infections.
Psychiatric disorders and homelessness are related, but temporal associations are unclear. We aimed to explore the overlap between hospital-based psychiatric disorders and sheltered homelessness.
Methods
This population-based cohort study was conducted using the Danish registers e.g., the Danish Homeless Register and the Danish National Patient Register. The study cohort included all individuals aged 15 years or older, living in Denmark at least one day during 2002–2021 (born 1984–2006). First psychiatric diagnosis was used to define psychiatric disorder and first homeless shelter contact to define homelessness. Adjusted incidence rate ratios (IRRs) and cumulative incidences were estimated.
Results
Among 1 530 325 individuals accounting for 16 787 562 person-years at risk aged 15–38 years, 11 433 (0.8%) had at least one homeless shelter contact. Among 1 406 410 individuals accounting for 14 131 060 person-years at risk, 210 730 had at least one psychiatric disorder. People with any psychiatric disorder had increased risk of sheltered homelessness relative to individuals with no psychiatric disorder [IRR 9.2, 95% confidence interval (CI) 8.8–9.6]. Ten years after first psychiatric disorder, 3.0% (95% CI 2.9–3.1) had at least one homeless shelter contact. Individuals experiencing homelessness had increased risk of any psychiatric disorder compared to individuals with no homeless shelter contact (IRR 7.0, 95% CI 6.7–7.4). Ten years after first homeless shelter contact, 47.1% (45.3–48.0) had received a hospital-based psychiatric diagnosis.
Conclusion
Strong bidirectional associations between psychiatric disorders and homelessness were identified. Health and social care professionals should be aware of and address these high risks of accumulated psychiatric and social problems.
Despite a high prevalence of problematic substance use among people living with HIV in South Africa, there remains limited access to substance use services within the HIV care system. To address this gap, our team previously developed and adapted a six-session, peer-delivered problem-solving and behavioral activation-based intervention (Khanya) to improve HIV medication adherence and reduce substance use in Cape Town. This study evaluated patient and provider perspectives on the intervention to inform implementation and future adaptation.
Methods
Following intervention completion, we conducted semi-structured individual interviews with patients (n = 23) and providers (n = 9) to understand perspectives on the feasibility, acceptability, and appropriateness of Khanya and its implementation by a peer. Patients also quantitatively ranked the usefulness of individual intervention components (problem solving for medication adherence ‘Life-Steps’, behavioral activation, mindfulness training, and relapse prevention) at post-treatment and six months follow-up, which we triangulated with qualitative feedback to examine convergence and divergence across methods.
Results
Patients and providers reported high overall acceptability, feasibility, and appropriateness of Khanya, although there were several feasibility challenges. Mindfulness and Life-Steps were identified as particularly acceptable, feasible, and appropriate components by patients across methods, whereas relapse prevention strategies were less salient. Behavioral activation results were less consistent across methods.
Conclusions
Findings underscore the importance of examining patients’ perspectives on specific intervention components within intervention packages. While mindfulness training and peer delivery models were positively perceived by consumers, they are rarely used within task-shared behavioral interventions in low- and middle-income countries.
Cognitive impairment is common in individuals with substance use disorders (SUDs), yet no evidence-based guidelines exist regarding the most appropriate screening measure for use in this population. This systematic review aimed to (1) describe different cognitive screening measures used in adults with SUDs, (2) identify substance use populations and contexts these tools are utilised in, (3) review diagnostic accuracy of these screening measures versus an accepted objective reference standard, and (4) evaluate methodology of included studies for risk of bias.
Methods:
Online databases (PsycINFO, MEDLINE, Embase, and CINAHL) were searched for relevant studies according to pre-determined criteria, and risk of bias and applicability was assessed using the Quality Assessment of Diagnostic Accuracy Studies–2 (QUADAS–2). At each review phase, dual screening, extraction, and quality ratings were performed.
Results:
Fourteen studies met inclusion, identifying 10 unique cognitive screening tools. The Montreal Cognitive Assessment (MoCA) was the most common, and two novel screening tools (Brief Evaluation of Alcohol-Related Neuropsychological Impairments [BEARNI] and Brief Executive Function Assessment Tool [BEAT]) were specifically developed for use within SUD populations. Twelve studies reported on classification accuracy and relevant psychometric parameters (e.g., sensitivity and specificity). While several tools yielded acceptable to outstanding classification accuracy, there was poor adherence to the Standards for Reporting Diagnostic Accuracy Studies (STARD) across all studies, with high or unclear risk of methodological bias.
Conclusions:
While some screening tools exhibit promise for use within SUD populations, further evaluation with stronger methodological design and reporting is required. Clinical recommendations and future directions for research are discussed.
The COVID-19 pandemic has drastically changed society and introduced many new factors to consider in adolescent suicide risk assessment and prevention. One complexity that warrants consideration is the male-specific impacts of the pandemic within adolescence.
Methods:
A review of the relevant literature.
Results:
Matters of social distancing, virtual education, and substance use may impact adolescent men in fashions that raise their suicide risk more significantly relative to adolescent women. Social distancing may impact adolescents’ friendships and generate a regression back to the nuclear family; qualities of male adolescents’ friendships and of masculinity suggest that these impacts may be more severe in adolescent men and may directly raise suicide risk. Virtual schooling yields educational and social setbacks; losses of team sports, male mentors, and the implications of diminished educational advancement may more adversely affect adolescent men and raise risk. Substance use has increased in the pandemic, particularly amongst adolescent men. There are direct associations with suicide risk as well as indirectly through increased parental conflict and punishment.
Conclusion:
As adolescent men die by suicide at significantly elevated rates relative to adolescent women, a male-specific consideration of these impacts is indicated to address adolescent suicide in our current era. Recommendations are made for integrating these considerations into updated adolescent suicide risk assessment and prevention efforts.
The study examines how age, sex and substance use disorder are associated with the risk of committing a criminal offence. The study explicitly examines the risk after the first contact to the psychiatric hospital system and after the diagnosis of schizophrenia for those with no previous criminal record; the association between previous non-violent criminality and later violent criminality is also analysed. The study sample comprised 4619 individuals ever diagnosed with schizophrenia. All solved offences were accessible. Data were analysed using Cox's regression. Schizophrenic men had twice the risk of schizophrenic women of committing both violent and non-violent offences. A registered substance use disorder increased the risk 1.9- to 3.7-fold, depending on the starting point for the analyses, while increasing age on first contact or when diagnosed with schizophrenia diminished the risk. Previous non-violent criminality increased the risk for later violent criminality 2.5- to 2.7-fold, depending on the starting point for the analyses. The results suggest that the psychiatric treatment system can play an active role in preventing criminality among individuals with schizophrenia. The preventive measures should be based on a thorough assessment including criminal history at intake and alertness toward young psychotic men with substance use disorders and especially if they also have a criminal history.
Methamphetamine (MA) dependence contributes to neurotoxicity and neurocognitive deficits. Although combined alcohol and MA misuse is common, how alcohol consumption relates to neurocognitive performance among MA users remains unclear. We hypothesized that alcohol and MA use would synergistically diminish neurocognitive functioning, such that greater reported alcohol consumption would exert larger negative effects on neurocognition among MA-dependent individuals compared to MA-nonusing persons.
Methods:
Eighty-seven MA-dependent (MA+) and 114 MA-nonusing (MA−) adults underwent neuropsychological and substance use assessments. Linear and logistic regressions examined the interaction between MA status and lifetime average drinks per drinking day on demographically corrected global neurocognitive T scores and impairment rates, controlling for recent alcohol use, lifetime cannabis use, WRAT reading performance, and lifetime depression.
Results:
MA+ displayed moderately higher rates of impairment and lower T scores compared to MA−. Lifetime alcohol use significantly interacted with MA status to predict global impairment (ORR = 0.70, p = .003) such that greater lifetime alcohol use increased likelihood of impairment in MA−, but decreased likelihood of impairment in MA+. Greater lifetime alcohol use predicted poorer global T scores among MA− (b = −0.44, p = .030) but not MA+ (b = 0.08, p = .586).
Conclusions:
Contrary to expectations, greater lifetime alcohol use related to reduced risk of neurocognitive impairment among MA users. Findings are supported by prior research identifying neurobiological mechanisms by which alcohol may attenuate stimulant-driven vasoconstriction and brain thermotoxicity. Replication and examination of neurophysiologic mechanisms underlying alcohol use in the context of MA dependence are warranted to elucidate whether alcohol confers a degree of neuroprotection.
In the current opioid epidemic, identifying high-risk patients among those with substance and opioid use may prevent deaths. The objective of this study was to determine whether frequent emergency department (ED) use and degree of frequent use are associated with mortality among ED patients with substance and opioid use.
Methods
This cohort study used linked population-based ED (National Ambulatory Care Reporting System) and mortality data from Alberta. All adults ≥ 18 years with substance or opioid use-related visits based on diagnostic codes from April 1, 2012, to March 31, 2013, were included (n = 16,389). Frequent use was defined by ≥ 5 visits in the previous year. Outcomes were unadjusted and adjusted (for age, sex, income) mortality within 90 days (primary), and 30 days, 365 days, and 2 years (secondary). To examine degree, frequent use was subcategorized into 5–10, 11–15, 16–20, and > 20 visits.
Results
Frequent users were older, lower income, and made lower acuity visits than non-frequent users. Frequent users with substance use had higher mortality at 365 days (hazard ratio [HR] 1.36 [1.04, 1.77]) and 2 years (HR 1.32 [1.04, 1.67]), but not at 90 or 30 days. Mortality did not differ for frequent users with opioid use overall. By degree, patients with substance use and > 20 visits/year and with opioid use and 16–20 visits/year demonstrated a higher 365-day and 2-year mortality.
Conclusions
Among patients with substance use, frequent ED use and extremely frequent use (> 20 visits/year) were associated with long-term but not short-term mortality. These findings suggest a role for targeted screening and preventive intervention.
There is renewed interest in the inverse association between psychiatric hospital and prison places, with reciprocal time trends shown in more than one country. We hypothesised that the numbers of admissions to psychiatric hospitals and committals to prisons in Ireland would also correlate inversely over time (i.e. dynamic measures of admission and committal rather than static, cross-sectional numbers of places).
Method
Publicly available activity statistics for psychiatric hospitals and prisons in Ireland were collated from 1986 to 2010.
Results
There was a reciprocal association between psychiatric admissions and prison committals (Pearson r=−0.788, p<0.001), an increase of 91 prison committals for every 100 psychiatric hospital admissions foregone.
Conclusion
Penrose’s hypothesis applies to admissions to psychiatric hospitals and prisons in Ireland over time (dynamic measures), just as it does to the numbers of places in psychiatric hospitals and prisons in Ireland and elsewhere (static, cross-sectional measures). Although no causal connection can be definitively established yet, mentally disordered prisoners are usually known to community mental health services. Psychiatric services for prisons and the community should be linked to ensure that the needs of those currently accessing care through prisons can also be met in the community.