The world is facing multiple interconnected crises, from climate change and economic instability to social inequalities and geopolitical tensions. These crises do not occur in isolation; instead, they interact, reinforce each other, and create unexpected ripple effects – forming what is known as a polycrisis. Traditional ways of analysing problems often fail to grasp these interdependencies, making it difficult to find effective responses. We draw on system archetypes to describe and exemplify three polycrisis patterns. These provide a structured way to analyse how multiple crises unfold and interact, as well as insights into how to navigate such complexity.

The concept of a polycrisis describes the complex interconnections between global issues, which can lead to unexpected emergent behaviours and the possible convergence of undesirable impacts. Understanding these dynamics is crucial for anticipating compounded effects and for identifying leverage points for effective intervention. We propose that system archetypes – generic structures in system dynamics that capture recurring patterns of behaviour – can serve as a useful analytical tool to study polycrises. Specifically, we reinterpret three key system archetypes in this context: Converging Constraints (based on the Limits to Growth system archetype), Deepening Divides (based on Success to the Successful system archetype), and Crisis Deferral (drawing from the Policy Resistance system archetype). These patterns illustrate how resource limitations, structural inequalities, and short-term solutions can sustain or worsen crisis dynamics. Using real-world examples, we show how polycrisis patterns can be employed to map feedback structures between interacting crises and to guide effective interventions. Our work contributes to a more structured and systemic understanding of polycrises, by providing a tool to help researchers and policymakers better anticipate, navigate, and mitigate their effects.

‘Polycrisis patterns reveal how crises like climate change, economic instability, and inequality interact, amplifying their impacts’.

While early intervention in psychosis (EIP) programs have been increasingly implemented across the globe, many initiatives from Africa, Asia and Latin America are not widely known. The aims of the current review are (a) to describe population-based and small-scale, single-site EIP programs in Africa, Asia and Latin America, (b) to examine the variability between programs located in low-and-middle income (LMIC) and high-income countries in similar regions and (c) to outline some of the challenges and provide recommendations to overcome existing obstacles.

EIP programs in Africa, Asia and Latin America were identified through experts from the different target regions. We performed a systematic search in Medline, Embase, APA PsycInfo, Web of Science and Scopus up to February 6, 2024.

Most EIP programs in these continents are small-scale, single-site programs that serve a limited section of the population. Population-based programs with widespread coverage and programs integrated into primary health care are rare. In Africa, EIP programs are virtually absent. Mainland China is one of the only LMICs that has begun to take steps toward developing a population-based EIP program. High-income Asian countries (e.g. Hong Kong and Singapore) have well-developed, comprehensive programs for individuals with early psychosis, while others with similar economies (e.g. South Korea and Japan) do not. In Latin America, Chile is the only country in the process of providing population-based EIP care.

Financial resources and integration in mental health care, as well as the availability of epidemiological data on psychosis, impact the implementation of EIP programs. Given the major treatment gap of early psychosis in Africa, Latin America and large parts of Asia, publicly funded, locally-led and accessible community-based EIP care provision is urgently needed.

High cognitive activity possibly reduces the risk of cognitive decline and dementia.

To investigate associations between an individual's need to engage in cognitively stimulating activities (need for cognition, NFC) and structural brain damage and cognitive functioning in the Dutch general population with and without existing cognitive impairment.

Cross-sectional data were used from the population-based cohort of the Maastricht Study. NFC was measured using the Need For Cognition Scale. Cognitive functioning was tested in three domains: verbal memory, information processing speed, and executive functioning and attention. Values 1.5 s.d. below the mean were defined as cognitive impairment. Standardised volumes of white matter hyperintensities (WMH), cerebrospinal fluid (CSF) and presence of cerebral small vessel disease (CSVD) were derived from 3T magnetic resonance imaging. Multiple linear and binary logistic regression analyses were used adjusted for demographic, somatic and lifestyle factors.

Participants (n = 4209; mean age 59.06 years, s.d. = 8.58; 50.1% women) with higher NFC scores had higher overall cognition scores (B = 0.21, 95% CI 0.17–0.26, P < 0.001) and lower odds for CSVD (OR = 0.74, 95% CI 0.60–0.91, P = 0.005) and cognitive impairment (OR = 0.60, 95% CI 0.48–0.76, P < 0.001) after adjustment for demographic, somatic and lifestyle factors. The association between NFC score and cognitive functioning was similar for individuals with and without prevalent cognitive impairment. We found no significant association between NFC and WMH or CSF volumes.

A high need to engage in cognitively stimulating activities is associated with better cognitive functioning and less presence of CSVD and cognitive impairment. This suggests that, in middle-aged individuals, motivation to engage in cognitively stimulating activities may be an opportunity to improve brain health.

Childhood trauma may impact the course of schizophrenia spectrum disorders (SSD), specifically in relation to the increased severity of depressive or negative symptoms. The type and impact of trauma may differ between sexes. In a large sample of recent-onset patients, we investigated the associations of depressive and negative symptoms with childhood trauma and whether these are sex-specific.

A total of 187 first-episode psychosis patients in remission (Handling Antipsychotic Medication: Long-term Evaluation of Targeted Treatment study) and 115 recent-onset SSD patients (Simvastatin study) were included in this cross-sectional study (men: n = 218; women: n = 84). Total trauma score and trauma subtypes were assessed using the Childhood Trauma Questionnaire Short Form; depressive and negative symptoms were rated using the Positive And Negative Symptoms Scale. Sex-specific regression analyses were performed.

Women reported higher rates of sexual abuse than men (23.5% v. 7.8%). Depressive symptoms were associated with total trauma scores and emotional abuse ratings in men (β: 0.219–0.295; p ≤ 0.001). In women, depressive symptoms were associated with sexual abuse ratings (β: 0.271; p = 0.011). Negative symptoms were associated with total trauma score and emotional neglect ratings in men (β: 0.166–0.232; p ≤ 0.001). Negative symptoms in women were not linked to childhood trauma, potentially due to lack of statistical power.

Depressive symptom severity was associated with different types of trauma in men and women with recent-onset SSD. Specifically, in women, depressive symptom severity was associated with childhood sexual abuse, which was reported three times as often as in men. Our results emphasize the importance of sex-specific analyses in SSD research.

Epidemiological studies indicate that individuals with one type of mental disorder have an increased risk of subsequently developing other types of mental disorders. This study aimed to undertake a comprehensive analysis of pair-wise lifetime comorbidity across a range of common mental disorders based on a diverse range of population-based surveys.

The WHO World Mental Health (WMH) surveys assessed 145 990 adult respondents from 27 countries. Based on retrospectively-reported age-of-onset for 24 DSM-IV mental disorders, associations were examined between all 548 logically possible temporally-ordered disorder pairs. Overall and time-dependent hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards models. Absolute risks were estimated using the product-limit method. Estimates were generated separately for men and women.

Each prior lifetime mental disorder was associated with an increased risk of subsequent first onset of each other disorder. The median HR was 12.1 (mean = 14.4; range 5.2–110.8, interquartile range = 6.0–19.4). The HRs were most prominent between closely-related mental disorder types and in the first 1–2 years after the onset of the prior disorder. Although HRs declined with time since prior disorder, significantly elevated risk of subsequent comorbidity persisted for at least 15 years. Appreciable absolute risks of secondary disorders were found over time for many pairs.

Survey data from a range of sites confirms that comorbidity between mental disorders is common. Understanding the risks of temporally secondary disorders may help design practical programs for primary prevention of secondary disorders.

Intermittent explosive disorder (IED) is characterised by impulsive anger attacks that vary greatly across individuals in severity and consequence. Understanding IED subtypes has been limited by lack of large, general population datasets including assessment of IED. Using the 17-country World Mental Health surveys dataset, this study examined whether behavioural subtypes of IED are associated with differing patterns of comorbidity, suicidality and functional impairment.

IED was assessed using the Composite International Diagnostic Interview in the World Mental Health surveys (n = 45 266). Five behavioural subtypes were created based on type of anger attack. Logistic regression assessed association of these subtypes with lifetime comorbidity, lifetime suicidality and 12-month functional impairment.

The lifetime prevalence of IED in all countries was 0.8% (s.e.: 0.0). The two subtypes involving anger attacks that harmed people (‘hurt people only’ and ‘destroy property and hurt people’), collectively comprising 73% of those with IED, were characterised by high rates of externalising comorbid disorders. The remaining three subtypes involving anger attacks that destroyed property only, destroyed property and threatened people, and threatened people only, were characterised by higher rates of internalising than externalising comorbid disorders. Suicidal behaviour did not vary across the five behavioural subtypes but was higher among those with (v. those without) comorbid disorders, and among those who perpetrated more violent assaults.

The most common IED behavioural subtypes in these general population samples are associated with high rates of externalising disorders. This contrasts with the findings from clinical studies of IED, which observe a preponderance of internalising disorder comorbidity. This disparity in findings across population and clinical studies, together with the marked heterogeneity that characterises the diagnostic entity of IED, suggests that it is a disorder that requires much greater research.

Mental disorders are associated with lower subjective social status (SSS), but a more nuanced understanding of this relationship is needed. We examined the influence of disorder age of onset and recency on SSS and studied whether mental disorders are also associated with the discrepancy between actual and desired SSS.

Data are from the baseline and second wave of the Netherlands Mental Health Survey and Incidence Study-2 (NEMESIS-2). Mental disorders were assessed with the Composite International Diagnostic Interview (CIDI 3.0), while both actual and desired SSS were assessed with a ten-rung ladder. Linear regression was used to examine the association between mental disorders and SSS.

Of 5303 participants, 2237 had a lifetime mental disorder at baseline. These participants reported significantly lower actual SSS (6.28) at follow-up than healthy participants (6.66, B = −0.38 [95% CI −0.48 to −0.27], p < 0.001) and a significantly greater actual-desired SSS discrepancy (1.14 v. 1.05 after controlling for actual SSS, B = 0.09 [0.01–0.17], p = 0.024). Lower age of onset of the first mental disorder was marginally significantly associated with lower actual SSS (B = 0.006 [0.000–0.012], p = 0.046). More recent disorders were also associated with lower actual SSS (B = 0.015 [0.005–0.026], p = 0.005), such that participants whose disorder remitted ⩾6 years before baseline were statistically indistinguishable from healthy participants.

Lifetime mental disorders are associated with lower actual SSS and a slightly greater discrepancy between actual and desired SSS. However, people with mental disorders in (long-term) remission have a similar social status as healthy participants.

Studies investigating the underlying mechanisms of hallucinations in patients with schizophrenia suggest that an imbalance in top-down expectations v. bottom-up processing underlies these errors in perception. This study evaluates this hypothesis by testing if individuals drawn from the general population who have had auditory hallucinations (AH) have more misperceptions in auditory language perception than those who have never hallucinated.

We used an online survey to determine the presence of hallucinations. Participants filled out the Questionnaire for Psychotic Experiences and participated in an auditory verbal recognition task to assess both correct perceptions (hits) and misperceptions (false alarms). A hearing test was performed to screen for hearing problems.

A total of 5115 individuals from the general Dutch population participated in this study. Participants who reported AH in the week preceding the test had a higher false alarm rate in their auditory perception compared with those without such (recent) experiences. The more recent the AH were experienced, the more mistakes participants made. While the presence of verbal AH (AVH) was predictive for false alarm rate in auditory language perception, the presence of non-verbal or visual hallucinations were not.

The presence of AVH predicted false alarm rate in auditory language perception, whereas the presence of non-verbal auditory or visual hallucinations was not, suggesting that enhanced top-down processing does not transfer across modalities. More false alarms were observed in participants who reported more recent AVHs. This is in line with models of enhanced influence of top-down expectations in persons who hallucinate.

To determine the number and proportion of healthcare worker (HCW) tuberculosis (TB) cases infected while working in healthcare institutions in the Netherlands and to learn from circumstances that led to these infections.

Cohort analysis.

We included all HCW TB patients reported to the Netherlands TB Register from 2000 to 2015. Using data from this register, including DNA fingerprints of the bacteria profile and additional information from public health clinics, HCW TB cases were classified into 4 categories: (1) infected during work in the Netherlands, (2) infected in the community, (3) infected outside the Netherlands, or (4) outside these 3 categories. An in-depth analysis of category 1 cases was performed to identify factors contributing to patient-to-HCW transmission.

In total, 131 HCW TB cases were identified: 32 cases (24%) in category 1; 13 cases (10%) in category 2; 42 cases (32%) in category 3; and 44 cases (34%) in category 4. The annual number of HCW TB cases (P<.05), the proportion among reported cases (P<.01), and the number of category 1 HCW TB cases (P=.12) all declined over the study period. Delayed diagnosis in a TB patient was the predominant underlying factor of nosocomial transmission in 47% of category 1 HCW TB patients, most of whom were subsequently identified in a contact investigation. Performing high-risk procedures was the main contributing factor in the other 53% of cases.

In low-incidence countries, every HCW TB case should warrant timely and thorough investigation to help further define and fine-tune the HCW screening policy and to monitor its proper implementation.

Infect Control Hosp Epidemiol 2017;38:976–982

The aim of this study was to identify inter-centre differences in persistent ductus arteriosus treatment and their related outcomes.

We carried out a retrospective, multicentre study including infants between 24+0 and 27+6 weeks of gestation in the period between 2010 and 2011. In all centres, echocardiography was used as the standard procedure to diagnose a patent ductus arteriosus and to document ductal closure.

In total, 367 preterm infants were included. All four participating neonatal ICU had a comparable number of preterm infants; however, differences were observed in the incidence of treatment (33–63%), choice and dosing of medication (ibuprofen or indomethacin), number of pharmacological courses (1–4), and the need for surgical ligation after failure of pharmacological treatment (8–52%). Despite the differences in treatment, we found no difference in short-term morbidity between the centres. Adjusted mortality showed independent risk contribution of gestational age, birth weight, ductal ligation, and perinatal centre.

Using benchmarking as a tool identified inter-centre differences. In these four perinatal centres, the factors that explained the differences in patent ductus arteriosus treatment are quite complex. Timing, choice of medication, and dosing are probably important determinants for successful patent ductus arteriosus closure.