Advancing urban mental health research: from complexity science to actionable targets for intervention

Urbanisation and common mental disorders (CMDs; ie, depressive, anxiety, and substance use disorders) are increasing worldwide. In this Review, we discuss how urbanicity and risk of CMDs relate to each other and call for a complexity science approach to advance understanding of this interrelationship. We did an ecological analysis using data on urbanicity and CMD burden in 191 countries. We found a positive, non-linear relationship with a higher CMD prevalence in more urbanised countries, particularly for anxiety disorders. We also did a review of meta-analytic studies on the association between urban factors and CMD risk. We identified factors relating to the ambient, physical, and social urban environment and showed differences per diagnosis of CMDs. We argue that factors in the urban environment are likely to operate as a complex system and interact with each other and with individual city inhabitants (including their psychological and neurobiological characteristics) to shape mental health in an urban context. These interactions operate on various timescales and show feedback loop mechanisms, rendering system behaviour characterised by non-linearity that is hard to predict over time. We present a conceptual framework for future urban mental health research that uses a complexity science approach. We conclude by discussing how complexity science methodology (eg, network analyses, system-dynamic modelling, and agent-based modelling) could enable identification of actionable targets for treatment and policy, aimed at decreasing CMD burdens in an urban context.

Long-term deep brain stimulation of the ventral anterior limb of the internal capsule for treatment-resistant depression

OBJECTIVE

Deep brain stimulation (DBS) reduces depressive symptoms in approximately 40%-60% of patients with treatment-resistant depression (TRD), but data on long-term efficacy and safety are scarce. Our objective was to assess the efficacy and safety of DBS targeted at the ventral anterior limb of the internal capsule (vALIC) in 25 patients with TRD during a 1-year, open-label, maintenance period, which followed a 1-year optimisation period.

METHODS

Depression severity was measured using the 17-item Hamilton Depression Rating Scale (HAM-D-17), Montgomery-Asberg Depression Rating Scale (MADRS) and self-reported Inventory of Depressive Symptomatology (IDS-SR). Primary outcomes were response rate (≥50% HAM-D-17 score reduction) after the maintenance phase, approximately 2 years after DBS surgery, and changes in depression scores and occurrence of adverse events during the maintenance phase.

RESULTS

Of 25 operated patients, 21 entered and 18 completed the maintenance phase. After the maintenance phase, eight patients were classified as responder (observed response rate: 44.4%; intention-to-treat: 32.0%). During the maintenance phase, HAM-D-17 and MADRS scores did not change, but the mean IDS-SR score decreased from 38.8 (95% CI 31.2 to 46.5) to 35.0 (95% CI 26.1 to 43.8) (p=0.008). Non-responders after optimisation did not improve during the maintenance phase. Four non-DBS-related serious adverse events occurred, including one suicide attempt.

CONCLUSIONS

vALIC DBS for TRD showed continued efficacy 2 years after surgery, with symptoms remaining stable after optimisation as rated by clinicians and with patient ratings improving. This supports DBS as a viable treatment option for patients with TRD.

TRIAL REGISTRATION NUMBER

NTR2118.

A population-based retrospective study comparing cancer mortality between Moluccan migrants and the general Dutch population: equal risk 65 years after immigration?

OBJECTIVE

To test the hypothesis that cancer mortality rates among the Moluccan-Dutch, the oldest non-Western migrant group to arrive in the Netherlands after the Second World War, are similar to those in the general Dutch population.

DESIGN

Population-based retrospective study.

SETTING

Data from the national cause of death registry in the Netherlands and municipal registries.

PARTICIPANTS

Using historic records containing family names of all Moluccan-Dutch who arrived in the Netherlands in 1951, we identified 81 591 Moluccan-Dutch persons in the national cause of death registry of the Netherlands. The reference group consisted of 15 866 538 persons of the general Dutch population.

OUTCOME MEASURES

Mortality data were linked to demographic data from municipal registries. We calculated all-cancer and cancer-specific mortality and measured differences between the two groups using Poisson regression, adjusting for sex, age and area socioeconomic status. We conducted a sub-analysis for the first-generation and second-generation Moluccan-Dutch.

RESULTS

There was no difference in all-cancer mortality between Moluccan-Dutch and the general Dutch population. Mortality was higher among Moluccan-Dutch for liver, cervix and corpus uteri cancers, but lower for stomach, oesophagus, kidney and nervous system cancers. For most cancers, mortality risk as compared with the general Dutch population varied between different generations of Moluccan-Dutch.

CONCLUSIONS

Several decades after migration, the Moluccan-Dutch show similar all-cancer mortality, but different cancer-specific mortality rates, when compared with the general Dutch population.

Higher self-reported prevalence of hypertension among Moluccan-Dutch than among the general population of The Netherlands: results from a cross-sectional survey

Background

Several studies in the Netherlands revealed ethnic disparities in hypertension prevalence, but none have focused on the Moluccan-Dutch, a migrant group from Indonesia that settled in the Netherlands in 1951. The Moluccan-Dutch are considered to be fairly well integrated in Dutch society. The aim of this study was to compare hypertension prevalence among the Moluccan-Dutch to the native Dutch and to explore the contribution of known risk factors.

Methods

A health interview survey was conducted from August 2012 till March 2013 among nineteen Moluccan neighborhoods, resulting in the inclusion of 708 participants. The primary outcome variable was self-reported prevalence of hypertension. Explanatory variables were BMI, exercise, smoking, alcohol intake and mental health status. Data on the control group was extracted from the Dutch National Health Survey 2011, using a similar questionnaire. Differences in risk factor exposure were explored using Chi-square tests and the contribution of risk factors, separately and combined, was explored using multivariate logistic regression analysis.

Results

Moluccan-Dutch showed higher odds for reporting hypertension when compared to native Dutch, after adjusting for age and level of education (OR = 1.38; 95% CI = 1.13-1.69) and additional risk factors (OR = 1.49; 95% CI = 1.19-1.88). A higher prevalence of hypertension was found in both Moluccan-Dutch men (26.4% vs. 16.7%; p < 0.001) and women (26.7% vs. 17.9%; p < 0.001), when compared to the control group. Not only middle-aged, but also young Moluccan-Dutch men showed higher prevalence of hypertension.

Conclusion

The Moluccan-Dutch may be at increased risk for reporting hypertension. These results suggest that long-term stay over several generations does not necessarily result in similar levels of hypertension prevalence as the host population.