Relationship between incidence and prevalence in psychotic disorders: An incidence-prevalence-mortality model

Urbanicity and psychotic disorders: Facts and hypotheses

In the present qualitative literature review, we summarise data on psychotic disorders and urbanicity, focusing particularly on recent findings. Longitudinal studies of the impact of urbanicity on the risk for psychotic disorders have consistently shown a significant association, with a relative risk between 2 and 2.5. However, most of the original studies were conducted in Western Europe, and no incidence studies were conducted in low- and middle-income countries. European studies suggest that neighbourhood-level social fragmentation and social capital may partly explain this association. Exposure to air pollution (positive association) and green space (negative association) may also be part of the explanation, but to date, available data do not make it possible to conclude if they act independently from urbanicity, or as part of the effect of urbanicity on psychotic disorders. Finally, several studies have consistently shown significant associations between the polygenic risk score for schizophrenia and urbanicity, with several possible explanations (pleiotropic effects, results of prodromic symptoms, or selection/intergenerational hypothesis). Thus, more studies are needed to understand the factors that explain the association between urbanicity and the risk of psychotic disorders. Further studies should account for the interdependence and/or interactions of different psychosocial and physical exposures (as well as gene-environment interactions), and explore this association in low- and middle-income countries.

Temporal variation in the incidence of treated psychotic disorders in young people

INTRODUCTION

The incidence of psychotic disorders varies between geographical areas, however less is known about whether it varies over time in the same region. Analyzing this temporal variation of incidence could improve the allocation of healthcare resources and our understanding of the aetiology of psychotic disorders. This study aimed to determine whether there was a change in the incidence of psychotic disorders over a six-year period.

METHODS

Young people aged 15 to 24 presenting with a first episode of psychosis (FEP) attending an early intervention service in Melbourne between 2011 and 2016 were included. The population at-risk was determined from the two corresponding census periods and analyses were adjusted for age, sex and migrant status.

RESULTS

A total of 1217 young people presented with a FEP over the six-year period and the crude incidence rate in 2011 was 102.4 per 100,000 population at-risk, compared to 125.4 in 2016. There was an increase in the incidence by 33% in 2015 (aIRR = 1.33, 95% CI 1.09-1.63) and 28% in 2016 (aIRR = 1.28, 95% CI 1.05-1.56). When examined according to diagnostic groups, there was an increase in the incidence of substance-induced psychotic disorders among females in 2015 (aIRR = 4.62, 95% CI 1.02-20.8).

DISCUSSION

This study shows significant temporal variations in the incidence of treated psychotic disorders. These findings demonstrate that early intervention services should continually monitor incidence case numbers and funding should be provided accordingly, to ensure the required intensive and comprehensive treatments can be sustained.

Therapeutic strategies for social anxiety disorder: where are we now?

Introduction: Classical well-established treatments of social anxiety disorder (SAD) are now complemented by more recent therapeutic strategies. This review aims to summarize available therapies for SAD and discuss recent evidence-based findings on the management of this disorder.Areas covered: Recent guidelines recommend psychotherapy, particularly cognitive-behavioral therapy (CBT), and pharmacotherapy, as first-line treatments of patients with SAD, without a clear superiority of one option over the other. CBT includes classical approaches such as in vivo exposure to social situations and cognitive therapy, but new modalities and techniques have been recently developed: third-wave approaches, internet-delivered therapy, virtual reality exposure, and cognitive bias modification. Selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors have been also extensively studied and shown to be effective in SAD. Two alternative strategies have been developed to treat SAD with disappointing results: cognitive bias modification, and pharmacological augmentation of psychotherapy using D-cycloserine during exposure sessions.Expert opinion: Personalized treatments for SAD patients are now available. Innovative strategies such as online psychotherapy and virtual reality exposure are useful alternatives to CBT and SSRIs. Future developments and optimization of attention bias modification and of pharmacological augmentation of psychotherapy can be promising.

Relationship between incidence and prevalence in psychotic disorders: An incidence-prevalence-mortality model

OBJECTIVES

Incidence-prevalence-mortality (IPM) models have been developped to estimate incidence or prevalence when one of these two measures is unavailable. We aimed to test the consistency of an IPM model of psychotic disorders on a recent incidence-prevalence couple dataset and to identify potential causes of inconsistency by applying the model to (a) the whole population, (b) female and male subgroups, (c) migrant subgroups, and (d) psychotic disorders with age at onset (AAO) between 18 and 24 (18-24 AAO).

METHODS

We modelled prevalence (MP) using incidence data and the expected mortality and remission values. We then compared the MP to the observed prevalence (OP).

RESULTS

In the whole population, the model significantly underestimated the prevalence (MP = 3.30, 95% CI [2.97, 3.66]; OP = 4.98, 95% CI [4.58, 5.41]). The results were similar for the two genders. In the migrants group, results were in the opposite direction, the model significantly overestimating the prevalence. Finally, in the 18-24 AAO subgroup, the model performed well, with OP and MP not significantly different.

CONCLUSION

These results suggest that standard IPM models do not perform well for psychotic disorders and more complex models taking into account the heterogeneity of the sample (in terms of remission, mortality, population movements, etc.) need to be developed.