The incidence of schizophrenia and schizophrenia spectrum disorders in Denmark in the period 2000-2012. A register-based study

The risk of diabetes and HbA1c deterioration during antipsychotic drug treatment: A Danish two-cohort study among patients with first-episode schizophrenia

BACKGROUND

Antipsychotics increase the risk of developing diabetes, but clinical trials are not generalizable with short follow-up, while observational studies often lack important information, particularly hemoglobin A1c (HbA1c).

METHODS

We followed two Danish cohorts with schizophrenia. First, using Danish nationwide registers, we identified all individuals diagnosed with first-episode schizophrenia (FES) between 1999 and 2019 (n = 31,856). Exposure was a redeemed prescription for an antipsychotic, and the outcome was diabetes, defined via hospital-based diagnosis and redeemed prescriptions for glucose-lowering drugs. Adjusted Cox regression calculated hazard rate ratios (HRR). Second, using data from the Central Denmark Region, we identified all individuals diagnosed with FES from October 2016 to September 2022 (n = 2671). Using a within-subject design, we analyzed the change in HbA1c during the 2 years after initiation of specific antipsychotics compared to the 2 years before.

RESULTS

In the nationwide cohort, 2543 (8.0%) individuals developed diabetes (incidence rate = 9.39 [95% CI = 9.03-9.76] per 1000 person-years). Antipsychotics, compared to periods without, were associated with an increased risk of developing diabetes (HRR = 2.04, 95% CI = 1.75-2.38). We found a dose-response association, particularly for second-generation antipsychotics, and different risk rates for specific antipsychotics. In the Central Denmark Region cohort, a total of 9.2% developed diabetes but mean HbA1c levels remained stable at 37 mmol/mol during the 2 years after initiation of antipsychotic medication.

CONCLUSION

This comprehensive real-world two-cohort study emphasizes that diabetes affects almost 10% of patients with FES. Antipsychotics increase this risk, while HbA1c deterioration requires longer treatment. These findings are important for clinicians and young patients with FES.

Impact of early risk factors on schizophrenia risk and age of diagnosis: A Danish population-based register study

BACKGROUND

While several risk factors for schizophrenia have been identified, their individual impacts are rather small. The relative independent and cumulative impacts of multiple risk factors on disease risk and age of onset warrant further investigation.

STUDY DESIGN

We conducted a register-based case-control study including all individuals receiving a schizophrenia spectrum disorder in Denmark from 1973 to 2018 (N = 29,142), and a healthy control sample matched 5:1 on age, sex, and parental socioeconomic status (N = 136,387). Register data included parental history of psychiatric illness, birth weight, gestational age, season of birth, population density of birthplace, immigration, paternal age, and Apgar scores. Data were analysed using logistic regression and machine learning.

RESULTS

Parental history of psychiatric illness (OR = 2.32 [95%CI 2.21-2.43]), high paternal age (OR = 1.30 [1.16-1.45]), and low birth weight (OR = 1.28 [1.16-1.41]) increased the odds of belonging to the patient group. In contrast, being a second-generation immigrant (OR = 0.65 [0.61-0.69]) and high population density of the birthplace (OR = 0.92 [0.89-0.96]) decreased the odds. The findings were supported by a decision tree analysis where parental history, paternal age, and birth weight contributed most to diagnostic classification (ACCtest = 0.69, AUCtest = 0.59, p < 0.001). Twenty percent of patients were child-onset cases. Here, female sex (OR = 1.82 [1.69-1.97]) and parental psychiatric illness (OR = 1.62 [1.49-1.77]) increased the odds of receiving the diagnosis <18 years.

CONCLUSION

Multiple early factors contribute independently to a higher psychosis risk, suggesting cumulative effects leading to symptom onset. Routine assessments of the most influential risk factors could be incorporated into clinical practise. Being female increased the risk of diagnosis during childhood, suggesting sex differences in the developmental trajectories of the disorder.

Cross-sectional associations between adaptive functioning and social cognitive and neurocognitive functions in adolescents with first-episode, early-onset schizophrenia spectrum disorders

BACKGROUND

Few studies have explored associations between adaptive functioning and cognition in adolescents with early-onset schizophrenia spectrum disorders (EOS).

METHODS

Adaptive functioning, cognition, positive, negative, and general symptoms were characterized in adolescents with EOS and healthy controls. A modified scale of negative, respectively, general symptoms was used. Bivariate analyses identified correlates of adaptive functioning to be included in multivariate analysis.

RESULTS

Adolescents with EOS showed significant impairments of social- and neurocognitive functions (-0.86 < Cohen´s ds < -0.58) and adaptive functioning (Cohen´s d = -2.23). Visual memory, verbal working memory, processing speed, reaction time, social cognition, and modified negative and general symptoms correlated significantly with adaptive functioning. The multiple regression analysis revealed only verbal working memory as uniquely associated with adaptive functioning (explaining 22.7 % of its variance). Verbal working memory also associated significantly with adaptive functioning in the context of the nonsignificant modified negative and the significant modified general symptoms dimension.

CONCLUSIONS

Adolescents with first-episode EOS had large impairments in adaptive functioning and moderate to large cognitive deficits. Verbal working memory was an important associate to concurrent adaptive functioning and may be a treatment target for trials to improve cognitive and adaptive functioning in adolescents with EOS.

Association between cannabis use disorder and schizophrenia stronger in young males than in females

BACKGROUND

Previous research suggests an increase in schizophrenia population attributable risk fraction (PARF) for cannabis use disorder (CUD). However, sex and age variations in CUD and schizophrenia suggest the importance of examining differences in PARFs in sex and age subgroups.

METHODS

We conducted a nationwide Danish register-based cohort study including all individuals aged 16-49 at some point during 1972-2021. CUD and schizophrenia status was obtained from the registers. Hazard ratios (HR), incidence risk ratios (IRR), and PARFs were estimated. Joinpoint analyses were applied to sex-specific PARFs.

RESULTS

We examined 6 907 859 individuals with 45 327 cases of incident schizophrenia during follow-up across 129 521 260 person-years. The overall adjusted HR (aHR) for CUD on schizophrenia was slightly higher among males (aHR = 2.42, 95% CI 2.33-2.52) than females (aHR = 2.02, 95% CI 1.89-2.17); however, among 16-20-year-olds, the adjusted IRR (aIRR) for males was more than twice that for females (males: aIRR = 3.84, 95% CI 3.43-4.29; females: aIRR = 1.81, 95% CI 1.53-2.15). During 1972-2021, the annual average percentage change in PARFs for CUD in schizophrenia incidence was 4.8 among males (95% CI 4.3-5.3; p < 0.0001) and 3.2 among females (95% CI 2.5-3.8; p < 0.0001). In 2021, among males, PARF was 15%; among females, it was around 4%.

CONCLUSIONS

Young males might be particularly susceptible to the effects of cannabis on schizophrenia. At a population level, assuming causality, one-fifth of cases of schizophrenia among young males might be prevented by averting CUD. Results highlight the importance of early detection and treatment of CUD and policy decisions regarding cannabis use and access, particularly for 16-25-year-olds.

A review of excluded groups and non-response in population-based mental health surveys from high-income countries

National mental health surveys play a critical role in determining the prevalence of mental disorders in a population and informing service planning. However, current surveys have important limitations, including the exclusion of key vulnerable groups and increasing rates of non-response. This review aims to synthesise information on excluded and undersampled groups in national mental health surveys. We conducted a targeted review of nationally representative adult mental health surveys performed between 2005 and 2019 in high-income OECD countries. Sixteen surveys met our inclusion criteria. The response rate for included surveys ranged between 36.3% and 80.0%. The most frequently excluded groups included people who were homeless, people in hospitals or health facilities and people in correctional facilities. Males and young people were the most commonly underrepresented groups among respondents. Attempts to collect data from non-responders and excluded populations were limited, but suggest that mental health status differs among some of these cohorts. The exclusion of key vulnerable groups and high rates of non-response have important implications for interpreting and using the results of national mental health surveys. Targeted supplementary surveys of excluded or hard-to-reach populations, more inclusive sampling methodologies, and strategies aimed at improving response rates should be considered to strengthen the accuracy and usefulness of survey findings.

Cannabis Use Disorder and Subsequent Risk of Psychotic and Nonpsychotic Unipolar Depression and Bipolar Disorder

Importance

Cannabis use is increasing worldwide and is suspected to be associated with increased risk of psychiatric disorders; however, the association with affective disorders has been insufficiently studied.

Objective

To examine whether cannabis use disorder (CUD) is associated with an increased risk of psychotic and nonpsychotic unipolar depression and bipolar disorder and to compare associations of CUD with psychotic and nonpsychotic subtypes of these diagnoses.

Design, Setting, and Participants

This prospective, population-based cohort study using Danish nationwide registers included all individuals born in Denmark before December 31, 2005, who were alive, aged at least 16 years, and living in Denmark between January 1, 1995, and December 31, 2021.

Exposure

Register-based diagnosis of CUD.

Main Outcome and Measures

The main outcome was register-based diagnosis of psychotic or nonpsychotic unipolar depression or bipolar disorder. Associations between CUD and subsequent affective disorders were estimated as hazard ratios (HRs) using Cox proportional hazards regression with time-varying information on CUD, adjusting for sex; alcohol use disorder; substance use disorder; having been born in Denmark; calendar year; parental educational level (highest attained); parental cannabis, alcohol, or substance use disorders; and parental affective disorders.

Results

A total of 6 651 765 individuals (50.3% female) were followed up for 119 526 786 person-years. Cannabis use disorder was associated with an increased risk of unipolar depression (HR, 1.84; 95% CI, 1.78-1.90), psychotic unipolar depression (HR, 1.97; 95% CI, 1.73-2.25), and nonpsychotic unipolar depression (HR, 1.83; 95% CI, 1.77-1.89). Cannabis use was associated with an increased risk of bipolar disorder in men (HR, 2.96; 95% CI, 2.73-3.21) and women (HR, 2.54; 95% CI, 2.31-2.80), psychotic bipolar disorder (HR, 4.05; 95% CI, 3.52-4.65), and nonpsychotic bipolar disorder in men (HR, 2.96; 95% CI, 2.73-3.21) and women (HR, 2.60; 95% CI, 2.36-2.85). Cannabis use disorder was associated with higher risk for psychotic than nonpsychotic subtypes of bipolar disorder (relative HR, 1.48; 95% CI, 1.21-1.81) but not unipolar depression (relative HR, 1.08; 95% CI, 0.92-1.27).

Conclusions and Relevance

This population-based cohort study found that CUD was associated with an increased risk of psychotic and nonpsychotic bipolar disorder and unipolar depression. These findings may inform policies regarding the legal status and control of cannabis use.

Annual incidence of substance-induced psychoses in Scandinavia from 2000 to 2016

BACKGROUND

Substance-induced psychosis (SIP) is a serious condition and may predispose for schizophrenia. We know too little about SIP incidence over time and across countries, including substance-specific SIPs. We estimated annual incidence rate of SIP in Denmark, Norway, and Sweden according to substance, age, gender, and socioeconomic background.

METHODS

Data were drawn from registries covering the whole adult population in the countries. Annual incidence rate per 100 000 persons of SIPs was estimated for Denmark and Sweden from 2000 to 2016 and for Norway from 2010 to 2015.

RESULTS

The annual incidence rate of any SIP fluctuated between 9.3 and 14.1. The most commonly occurring SIPs were those induced by alcohol, cannabis, amphetamines, and multiple substances. There was a steady decrease in the incidence rate of alcohol-induced psychosis from the first to the last year of the observation period in Denmark (from 4.9 to 1.5) and Sweden (from 4.5 to 2.2). The incidence rate of cannabis-induced psychosis increased in all countries, from 2.6 to 5.6 in Denmark, from 0.8 to 2.7 in Sweden, and from 1.8 to 3.0 in Norway. Median age of any SIP decreased in Denmark (from 36 to 29 years) and Sweden (from 41 to 31 years). Incidence rates were higher in men and in individuals on disability pension, and increased more among those with high parental education.

CONCLUSIONS

We found similar and stable incidence rates of any SIP in all Scandinavian countries through the observation period. The incidence of alcohol-induced psychosis decreased. The incidence of cannabis-induced psychosis increased.

Transition From Substance-Induced Psychosis to Schizophrenia Spectrum Disorder or Bipolar Disorder

Objective: The authors investigated transitions to schizophrenia spectrum or bipolar disorder following different types of substance-induced psychosis and the impact of gender, age, number of emergency admissions related to substance-induced psychosis, and type of substance-induced psychosis on such transitions. Methods: All patients in the Norwegian Patient Registry with a diagnosis of substance-induced psychosis from 2010 to 2015 were included (N=3,187). The Kaplan-Meier method was used to estimate cumulative transition rates from substance-induced psychosis to either schizophrenia spectrum disorder or bipolar disorder. Cox proportional hazard regression was used to estimate hazard ratios for transitions to schizophrenia spectrum or bipolar disorders associated with gender, age, number of emergency admissions, and type of substance-induced psychosis. Results: The 6-year cumulative transition rate from substance-induced psychosis to schizophrenia spectrum disorder was 27.6% (95% CI=25.6–29.7). For men, the risk of transition was higher among younger individuals and those with either cannabis-induced psychosis or psychosis induced by multiple substances; for both genders, the risk of transition was higher among those with repeated emergency admissions related to substance-induced psychosis. The cumulative transition rate from substance-induced psychosis to bipolar disorder was 4.5% (95% CI=3.6–5.5), and the risk of this transition was higher for women than for men. Conclusions: Transition rates from substance-induced psychosis to schizophrenia spectrum disorder were six times higher than transition rates to bipolar disorder. Gender, age, number of emergency admissions, and type of substance-induced psychosis affected the risk of transition.

Sex differences across developmental domains among children with a familial risk of severe mental disorders

BACKGROUND

Sex differences in brain structure and neurodevelopment occur in non-clinical populations. We investigated whether sex had a similar effect on developmental domains amongst boys and girls with a familial risk of schizophrenia (FHR-SZ), bipolar disorder (FHR-BP), and controls.

METHODS

Through Danish registries, we identified 522 7-year-old children (242 girls) with FHR-SZ, FHR-BP, and controls. We assessed their performance within the domains of neurocognition, motor function, language, social cognition, social behavior, psychopathology, and home environment.

RESULTS

FHR-SZ boys compared with FHR-SZ girls had a higher proportion of disruptive behavior and attention-deficit hyperactivity disorder (ADHD) and exhibited lower performance in manual dexterity, balance, and emotion recognition. No sex differences were found between boys and girls within FHR-BP group. Compared with controls, both FHR-SZ boys and FHR-SZ girls showed impaired processing speed and working memory, had lower levels of global functioning, and were more likely to live in an inadequate home environment. Compared with control boys, FHR-SZ boys showed impaired manual dexterity, social behavior, and social responsiveness, and had a higher proportion of ADHD and disruptive behavior disorder diagnoses. Stress and adjustment disorders were more common in FHR-BP boys compared with control boys. We found no differences between FHR-BP girls and control girls.

CONCLUSIONS

Impairment within neurodevelopmental domains associated within FHR-SZ boys v. FHR-SZ girls was most evident among boys, whereas no sex differences were found within the FHR-BP group (FHR-BP boys v. FHR-BP girls). FHR-SZ boys exhibited the highest proportion of early developmental impairments.

Antipsychotic treatment and risk of discontinuation and hospitalization in first-episode schizophrenia: a nationwide population-based study

BACKGROUND

Current evidence on antipsychotic treatment and risk of psychiatric hospitalization in first-episode schizophrenia (FES) is largely based on the findings from randomized clinical trials (RCTs). However, the generalization of the findings to real-world patients is limited due to inherent caveats of the RCT. We aimed to investigate the treatment discontinuation and risk of psychiatric hospitalization using a nationwide population database.

METHODS

The Health Insurance Review Agency database in South Korea was obtained, and the observation period started from 1 January 2009 to 31 December 2016. We defined the maintenance period as the period from 6-month after the diagnosis of schizophrenia, which is utilized for the main results. For a total of 44 396 patients with FES, a within-individual Cox regression model was used to compare the risk of the treatment discontinuation and psychiatric hospitalization.

RESULTS

In group comparison, a long-acting injectable (LAI) antipsychotic group was associated with the lowest risk of the treatment discontinuation (0.64, 0.55-0.75) and psychiatric hospitalization (0.29, 0.22-0.38) in comparison with a typical antipsychotic group and no use, respectively. Among individual antipsychotics, the lowest risk of the treatment discontinuation was observed in LAI paliperidone (0.46, 0.37-0.66) compared to olanzapine. Clozapine was found to be the most effective antipsychotic in lowering the risk of psychiatric hospitalization as monotherapy compared to no use (0.23, 0.18-0.31).

CONCLUSIONS

In real-world patients with FES, LAI paliperidone and clozapine were associated with low treatment discontinuation and better effectiveness in lowering the risk of psychiatric hospitalization.

Identifying Diagnoses of Schizophrenia Spectrum Disorder in Large Data Sets

Objective

The authors used a large clinical data set to determine which index diagnoses of schizophrenia spectrum disorder were new diagnoses.

Methods

Using the Massachusetts All-Payer Claims Database (2012–2016), the authors identified patients with a schizophrenia spectrum disorder diagnosis in 2016 (index diagnosis) and then reviewed patients’ care histories for the previous 12, 24, 36, and 48 months to identify previous diagnoses. Logistic regression was used to examine patient characteristics associated with the index diagnosis being a new diagnosis.

Results

Overall, 7,217 individuals ages 15–35 years had a 2016 diagnosis of schizophrenia spectrum disorder; 67.7% had at least 48 months of historical data. Among those with at least 48 months of care history, 23% had no previous diagnoses. Diagnoses from inpatient psychiatric admissions or among female or younger patients were more likely to represent new diagnoses, compared with diagnoses from most other diagnosis locations or among males or older age groups, and outpatient diagnoses were less likely to represent new diagnoses than were most other diagnosis settings. Reviewing 48 instead of 12 months of data reduced estimated rates of new diagnoses from 112 to 66 per 100,000 persons; historical diagnoses were detected for 61% and 77% of patients with 12 or 48 months of care history, respectively.

Conclusions

Examining multiple years of patient history spanning all payers and providers is critical to identifying new schizophrenia spectrum disorder diagnoses in large data sets. Review of 48 months of care history resulted in lower rates of new schizophrenia spectrum disorder diagnoses than previously reported.

Psychopharmacological treatment patterns prior to a schizophrenia diagnosis: A Danish nationwide study

BACKGROUND

Many patients with schizophrenia experience psychiatric symptoms long before being diagnosed. We investigated patterns of pre-diagnostic psychopharmacological treatment in individuals diagnosed with first-episode schizophrenia during the last two decades.

DESIGN

Using Danish nationwide healthcare registers, we identified all individuals aged ≥10 years registered with their first ICD-10 schizophrenia diagnosis between January 1999 and March 2019. For each calendar year from 1999 to 2019, we calculated the proportion of patients - among those having received their first schizophrenia diagnosis in the respective calendar year - who redeemed prescriptions for various psychotropics in the two years preceding the schizophrenia diagnosis. We calculated proportions of all pre-diagnostic prescriptions since 1995 for a sub-population diagnosed 2011-2019 and for an age- and sex-matched reference group without schizophrenia.

RESULTS

Among 33,361 individuals with schizophrenia (58 % males), the schizophrenia incidence rate was stable during the study period but the mean age at diagnosis decreased by >10 years. In the two pre-diagnostic years, 69 % received psychopharmacological treatment (52 % antipsychotics, 40 % antidepressants). This was stable between 1999 and 2019. Among 14,425 individuals diagnosed 2011-2019, psychotropic drug use was observed among 14-20 % between 24 and 10 years before the diagnosis, being four times higher than the reference group. Particularly antipsychotic and antidepressant drug use increased steadily during the ten pre-diagnostic years.

CONCLUSIONS

Pre-diagnostic psychotropic drug use in schizophrenia was frequent but stable between 1999 and 2019 despite an earlier identification of schizophrenia patients. Our findings emphasize the continued importance of thorough diagnostic interviews, particularly among patients in need of antipsychotic treatment.

Free-of-charge dispensing of antipsychotics for schizophrenia in Denmark: Impact on the nationwide prescription registry and redemption of somatic medications

OBJECTIVE

Free-of-charge dispensing of antipsychotics for schizophrenia was introduced in Denmark around 2008. However, free-of-charge dispensing is not recorded in the Danish National Prescription Register (DNPR), potentially introducing bias and misclassification.

METHODS

We identified all 30,275 individuals with a first-episode schizophrenia diagnosis in Denmark between 1 January 1999 and 1 March 2017 including all redeemed prescriptions registered in the DNPR during the two years after the schizophrenia diagnosis. For each calendar year, we calculated the proportion of individuals who had filled ≥1 prescription for psychotropic and/or somatic medications within the first two years after the schizophrenia diagnosis.

RESULTS

From 2007 to 2017, the proportion of individuals with prescription-records for any psychotropic medication during the two years after the schizophrenia diagnosis decreased from 88% to 74%, particularly antipsychotics (from 83% to 61%) and antidepressants (from 49% to 35%). This was particularly observed among those aged 18-30 years at the schizophrenia diagnosis. A similar decrease was not observed for prescription-records of somatic medications.

CONCLUSION

The introduction of free-of-charge antipsychotics has affected the redemption of specific psychotropic drugs in the DNPR in first-episode schizophrenia. This limitation needs to be considered in register-based studies and emphasizes the need to identify solutions.

Risk for midlife psychosis in women: critical gaps and opportunities in exploring perimenopause and ovarian hormones as mechanisms of risk

Women show a heightened risk for psychosis in midlife that is not observed in men. The menopausal transition (i.e. perimenopause) and accompanying changes in ovarian hormones are theorized to account for this midlife increase in risk. This narrative review aims to empirically examine these theories by reviewing studies of midlife and perimenopausal psychosis risk in women and potential ovarian hormone mechanisms of effects. Clinical and pre-clinical studies examining the effects of midlife age, menopausal stage, and ovarian hormones across adulthood on psychosis risk were identified. Synthesis of this body of work revealed that the peak ages of midlife psychosis risk in women overlap with the age range of key menopausal stages (especially the perimenopausal transition), although studies directly assessing menopausal stage are lacking. Studies examining ovarian hormone effects have almost exclusively focused on earlier developmental stages and events (e.g. pregnancy, the menstrual cycle) and show increases in psychotic symptoms in women and female rats during periods of lower estradiol levels. Estrogen treatment also tends to enhance the effects of neuroleptics in females across species at various reproductive phases. Initial data are promising in suggesting a role for menopausal stage and ovarian hormones in psychosis risk. However, critical gaps in our knowledge base remain, as there is a tendency to rely on indirect and proxy measures of menopausal status and hormones. Opportunities for future research are discussed with the goal of increasing research in this critical area of women's health.

Diagnosed Incidence of Non-Affective Psychotic Disorders Amongst Adolescents in British Columbia and Sociodemographic Risk Factors: A Retrospective Cohort Study

OBJECTIVES

To estimate the diagnosed incidence of non-affective psychotic disorder between the ages of 13 and 19 years in South-Western British Columbia (BC) and to examine variation in risk by sex, family and neighbourhood income, family migration background, parent mental health contact and birth year.

METHODS

Linked individual-level administrative data were used to construct a cohort of individuals born in 1990-1998 and residing in South-Western BC (n = 193,400). Cases were identified by either one hospitalization or two outpatient physician visits within 2 years with a primary diagnosis of a non-affective psychotic disorder (ICD-10: F20-29, ICD-9: 295, 297, 298). We estimated cumulative incidence, annual cumulative incidence and incidence rate between the ages of 13 and 19 years, and conducted Cox proportional hazards regression to estimate associations between sociodemographic factors and risk over the study period.

RESULTS

We found that 0.64% of females and 0.88% of males were diagnosed with a non-affective psychotic disorder between the ages of 13 and 19 years, with increasing risk observed over the age range, especially amongst males. Incidence rate over the entire study period was 106 per 100,000 person-years for females and 145 per 100,000 person-years for males. Risk of diagnosis was elevated amongst those in low-income families and neighbourhoods, those with a parent who had a health service contact for a mental disorder, and more recent birth cohorts. Risk was reduced amongst children of immigrants compared to children of non-migrants.

CONCLUSIONS

Findings from this study provide important information for health service planning in South-Western BC. Future work should examine whether variations in diagnosed incidence is driven by differences in health service engagement or reflect genuine differences in risk.

Incidence rates and employment trends in schizophrenia spectrum disorders, bipolar affective disorders and recurrent depression in the years 2000-2013: a Danish nationwide register-based study

AIMS

The study aimed to investigate time trends in incidence rates in schizophrenic spectrum disorders (ICD-10: F20-F29), bipolar affective disorder (ICD-10: F30, F31), and recurrent depression (ICD-10: F33) and to investigate the rates of employment for all incident cases.

METHOD

We used nationwide longitudinal data from 2000 to 2013 on all psychiatric inpatients and outpatients contacts in Denmark. Age-adjusted incidence rate ratios were calculated for the three diagnostic groups, and rates of employment, education, and disability pension were measured 1 year before and 2 years after the diagnosis for all the incident cases.

RESULTS

The incidence rates increased significantly in all diagnostic groups and both sexes. Comparing the incidence rates in 2013 with 2000 yielded an incidence rate ratio of 1.67 (95% CI 1.51-1.84) for schizophrenic spectrum disorders, 3.82 (95% CI 3.23-4.52) for bipolar affective disorder, and 2.80 (95% CI 2.58-3.04) for recurrent depression. During the same observation period, the employment rates decreased, both 1 year before and 2 years after diagnosis in all three subgroups. In the year 2002, employment rates, 2 years after diagnosis, were 24.6% for schizophrenia spectrum disorder, 35.0% for bipolar affective disorder and 47.1% for recurrent depression. These rates had declined to 15.8%, 26.8%, and 34.7%, respectively, in 2013.

CONCLUSION

This study of three severe mental illness subgroups shows significant increasing incidence rates and decreasing employment rates both before and after the diagnosis between 2000 and 2013, highlighting the importance of timely and correct volume of the psychiatric treatment and vocational rehabilitation programs.

Identification of potential blood biomarkers for early diagnosis of schizophrenia through RNA sequencing analysis

Schizophrenia (SCZ) is a highly heritable, polygenic complex mental disorder with imprecise diagnostic boundaries. Finding sensitive and specific novel biomarkers to improve the biological homogeneity of SCZ diagnosis is still one of the research hotspots. To identify the blood specific diagnostic biomarkers of SCZ, we performed RNA sequencing (RNA-seq) on 30 peripheral blood samples from 15 first-episode drug-naïve SCZ patients and 15 healthy controls (CTL). By performing multiple bioinformatics analysis algorithms based on RNA-seq data and microarray datasets, including differential expression genes (DEGs) analysis, WGCNA and CIBERSORT, we first identified 6 specific key genes (TOMM7, SNRPG, KRT1, AQP10, TMEM14B and CLEC12A) in SCZ. Moreover, we found that the proportions of lymphocyte, monocyte and neutrophils were significantly distinct in SCZ patients with CTL samples. Therefore, combining various features including age, sex and the novel blood biomarkers, we constructed the risk prediction model with three classifiers (RF: Random Forest; SVM: support vector machine; DT: decision tree) through repeated k-fold cross validation ensuring better generalizability. Finest result of Area under Receiver Operating Characteristic (AUROC) score of 0.91 was achieved by RF classifier and with a comparable good performance of AUROC 0.77 in external validation dataset. A lower AUROC of 0.63 was demonstrated when it was further applied to a Bipolar disorder (BPD) cohort. In conclusion, the study identified three peripheral core immunocytes and six key genes associated with the occurrence of SCZ, and further studies are required to test and validate these novel biomarkers for early diagnosis and treatment of SCZ.

Psychiatric hospitalization in Korea, 2011-2020: the impact of the Mental Health Act revision of 2017 in consideration of the COVID-19 pandemic

OBJECTIVE

This study was performed to examine the changes in psychiatric hospitalization in Korea after the mental health law revision of 2017 with consideration of the COVID-19 pandemic.

METHODS

The data were obtained from National Health Insurance and Medical Aid statistical yearbooks of 2011-2020. The changes in the inpatient and outpatient utilization for schizophrenia from 2011 to 2020 were compared with those for other psychiatric disorders and the general population. With difference-in-differences analysis, the changes in utilization of inpatient and outpatient care for schizophrenia after the law revision of 2017 were analyzed with two comparison groups.

RESULTS

While the number of inpatients and inpatient days for schizophrenia decreased between 2017 and 2019, the number of outpatients and outpatient visits for schizophrenia increased during the period. Inpatient care utilization in two comparison groups increased during the same period. Whereas the COVID-19 pandemic of 2020 led to a general decrease in health care use among the population including inpatient care for schizophrenia, the number of outpatients for schizophrenia increased slightly after the pandemic. Difference-in-differences analysis showed that the law revision was associated with the decrease in the use of inpatient care for schizophrenia after adjustment for the effect of the COVID-19 pandemic.

CONCLUSIONS

The mental health law revision in Korea led to a significant decrease in hospitalization for schizophrenia. However, the limited effect of revision on the Medical Aid beneficiaries suggests that the revision was not followed by the provision of the proper alternatives which can replace hospitalization of the most vulnerable population.

Development Over Time of the Population-Attributable Risk Fraction for Cannabis Use Disorder in Schizophrenia in Denmark

IMPORTANCE

Cannabis use and potency of cannabis have increased during the past 2 decades. If the association between cannabis use and schizophrenia is causal, this should be reflected in an increase in the proportion of cases of schizophrenia being attributable to cannabis, the population-attributable risk fraction (PARF).

OBJECTIVE

To determine whether the PARF for cannabis use disorder in schizophrenia has increased over time.

DESIGN, SETTING, AND PARTICIPANTS

This nationwide, register-based historical prospective cohort study included all people in Denmark born before December 31, 2000, who were alive and 16 years or older at some point from January 1, 1972, to December 31, 2016. Data analysis was performed from August 2020 to April 2021.

EXPOSURE

Diagnosis of cannabis use disorder.

MAIN OUTCOMES AND MEASURES

Diagnosis of schizophrenia, with estimated PARF of cannabis use disorder in schizophrenia from 1972 to 2016.

RESULTS

A total of 7 186 834 individuals were included in the analysis, including 3 595 910 women (50.0%) and 3 590 924 men (50.0%). The adjusted hazard ratio for schizophrenia fluctuated at approximately 4 (with 95% CIs ranging from approximately 3 to 6) throughout most of the study period when people diagnosed with cannabis use disorder were compared with those without cannabis use disorder. The PARF of cannabis use disorder in schizophrenia also fluctuated, but with clear evidence of an increase from 1995 (when the PARF was relatively stable around 2.0%, with a 95% CI of approximately 0.3% to either side) until reaching some stability around 6.0% to 8.0% (with a 95% CI of approximately 0.5% to either side) since 2010.

CONCLUSIONS AND RELEVANCE

The results from these longitudinal analyses show the proportion of cases of schizophrenia associated with cannabis use disorder has increased 3- to 4-fold during the past 2 decades, which is expected given previously described increases in the use and potency of cannabis. This finding has important ramifications regarding legalization and control of use of cannabis.

Gender differences in the use of atypical antipsychotics in early-onset schizophrenia: a nationwide population-based study in Brazil

BACKGROUND

The use of atypical antipsychotics for the treatment of schizophrenia and other mental disorders in populations under 18 years of age is increasing worldwide. Little is known about treatment patterns and the influence of gender differences, which may be a predictor of clinical outcomes. The aim of this study was to investigate gender differences in the use of atypical antipsychotics in patients with early-onset schizophrenia (EOS) assisted by the public health system in Brazil.

METHODS

We conducted a cross-sectional study of outpatients with EOS aged 10 to 17 years who received at least one provision of atypical antipsychotics (clozapine, olanzapine, risperidone, quetiapine or ziprasidone) from a large Brazilian pharmaceutical assistance programme. Data were retrieved from a nationwide administrative database from 2008 to 2017.

RESULTS

Of the 49,943 patients with EOS, 63.5% were males, and the mean age was 13.6 years old. The patients were using risperidone (62.5%), olanzapine (19.6%), quetiapine (12.4%), ziprasidone (3.3%) and clozapine (2.2%). We found gender differences, especially in the 13-17 year age group (65.1% for males vs. 34.9% for females, p < 0.001), in the use of risperidone (72.1% for males vs. 27.9% for females, p < 0.001) and olanzapine (66.5% for males vs. 33.5% for females, p < 0.001). Only in the 13 to 17 years age group were the prescribed doses of olanzapine (p = 0.012) and quetiapine (p = 0.041) slightly higher for males than for females.

CONCLUSIONS

Our findings showed gender differences among patients diagnosed with EOS and who received atypical antipsychotics. More attention should be devoted to gender differences in research and clinical practice.

Incidence of schizophrenia and influence of prenatal and infant exposure to viral infectious diseases

OBJECTIVE

There is conflicting evidence in recent literature about whether the incidence of schizophrenia is increasing or decreasing. A role for prenatal and early childhood viral infections in the aetiology of schizophrenia has also been debated. We examined the incidence of schizophrenia and the catatonic subtype of schizophrenia over a 30-year period in Finland. We also investigated whether the incidence rate of the catatonic subtype of schizophrenia was linked to changes in exposure to viral infection (polio and measles) during the prenatal or infant period.

METHODS

Persons with schizophrenia were identified from the Hospital Discharge Register. Cumulative incidence of schizophrenia from 1956 to 1989 in 4 age groups was calculated with follow-up from 1972 to 2014. Annual rates of polio and measles were derived from nationwide registers. The association between log-transformed polio and measles incidence and incidence of schizophrenia, and specifically catatonic schizophrenia, were analysed using linear models.

RESULTS

Cumulative incidence of schizophrenia among individuals born 1956-1989 decreased by 23% (from 13 to 10 cases per 1000 live births). The decline was the most prominent in those with onset of schizophrenia diagnosed 16-25 years of age (-41%). The incidence of catatonic schizophrenia declined by 90% over three decades, and there was a significant association between annual polio incidence during the birth year and incidence of catatonic schizophrenia.

CONCLUSIONS

The results indicate that the incidence of schizophrenia in Finland has declined for individuals born between 1956 and 1989, and that the decline of catatonic schizophrenia may be partially attributable to eradication of polio.

The impact of study design on schizophrenia incidence estimates: A systematic review of Northern European studies 2008-2019

The best estimates of the incidence of schizophrenia range more than 25-fold from 3 to 80 per 100,000 person-years. To what extent do differences in study design explain this wide variation? We selected all studies published between 2008-2019 reporting the incidence of schizophrenia in general populations of Northern Europe. We identified 17 estimates covering 85 million person-years and more than 15,000 individual cases. The estimates ranged from 4-72 per 100,000 person-years (median 30; interquartile range 13-41). We classified the estimates in terms of three study design factors (coverage of services, time frame, and diagnostic quality) and two population factors (urbanicity and age). A meta-regression model of the three design factors, using the two population factors as covariates, explained 91% of between-study variation. Studies performed in general psychiatric services reported similar estimates [incidence rate ratio 1.12 (95% confidence interval 0.88 to 1.43)] to those performed in specialized services. But studies applying a cumulative time frame to diagnosis reported fourfold higher estimates [4.04 (3.14 to 5.2)] than those applying a first-contact time frame. And studies based on clinical diagnoses reported lower estimates [0.55 (0.43 to 0.72)] than those based on standardized research diagnoses. The three study design factors by themselves explained 67% of between-study variation. When comparing incidence rates from different populations, distorsions arising from differences in study design can eclipse differences caused by schizophrenia risk factors, such as gender, age or migrant status.

Schizophrenia Related Hospitalizations - a Big Data Analysis of a National Hospitalization Database

Schizophrenia is a mental disorder characterized by long hospitalizations and frequent need for chronic/acute psychiatric care. Hospitalizations represent a valuable quality of care indicator in schizophrenia patients. The aim of this study was to describe a nationwide perspective of schizophrenia related hospitalizations. We performed a retrospective observational study using a nationwide hospitalization database containing all hospitalizations registered in Portuguese public hospitals from 2008 to 2015. Hospitalizations with a primary diagnosis of schizophrenia were selected based on the definition by CCS - Clinical Classification Software diagnostic single-level 659. Schizophrenia subtypes were identified based on International Classification of Diseases version 9, Clinical Modification (ICD-9-CM) codes of diagnosis 295.xx. A total of 25,385 hospitalizations were registered belonging to 14,279 patients. 68.0% of the hospitalizations occurred in male patients and the median length of stay was 18.0 days. In male patients' hospitalizations, the most frequent age group was 31-50 years followed by the age group of 18-30 years (55.9 and 24.0% respectively). For female patients, the most frequent age group was 31-50 years followed by 51-70 years (54.1 and 22.6%, respectively). There were 73 hospitalization with a deadly outcome (0.29%). Paranoid type was the most frequent subtype of schizophrenia (50.5%). The mean hospitalization charges were 3509.7€ per episode, with a total charge of 89.1 M€ in the 8-year period. This is a nationwide study using Big Data analysis giving a broad perspective of schizophrenia hospitalization panorama at a nationwide level. We found differences in hospitalization characteristics according to patients' gender, age and primary diagnosis.

No evidence of associations between genetic liability for schizophrenia and development of cannabis use disorder

BACKGROUND

Cannabis use and cannabis use disorder (CUD) is increased in patients with schizophrenia. It is important to establish if this is explained by non-causal factors, such as shared genetic vulnerability. We aimed to investigate whether the polygenic risk scores (PRS) for schizophrenia and other psychiatric disorders would predict CUD in controls, patients with schizophrenia, and patients with other psychiatric disorders.

METHODS

We linked nationwide Danish registers and genetic information obtained from dried neonatal bloodspots in an observational analysis. We included people with schizophrenia, other psychiatric disorders, and controls. The exposures of interest were the PRS for schizophrenia, attention-deficit hyperactivity disorder (ADHD) autism spectrum disorder, and anorexia nervosa. The main outcome of interest was the diagnosis of CUD.

RESULTS

The study included 88 637 individuals. PRS for schizophrenia did not predict CUD in controls [hazard ratio (HR) = 1.16, 95% CI 0.95-1.43 per standard-deviation increase in PRS, or HR = 1.47, 95% CI 0.72-3.00 comparing highest v. remaining decile], but PRS for ADHD did (HR = 1.27, 95% CI 1.08-1.50 per standard-deviation increase, or HR = 2.02, 95% CI 1.27-3.22 for the highest decile of PRS). Among cases with schizophrenia, the PRS for schizophrenia was associated with CUD. While CUD was a strong predictor of schizophrenia (HR = 4.91, 95% CI 4.36-5.53), the inclusion of various PRS did not appreciably alter this association.

CONCLUSION

The PRS for schizophrenia was not associated with CUD in controls or patients with other psychiatric disorders than schizophrenia. This speaks against the hypothesis that shared genetic vulnerability would explain the association between cannabis and schizophrenia.

Case Report: Pharmacogenetics Applied to Precision Psychiatry Could Explain the Outcome of a Patient With a New CYP2D6 Genotype

Precision medicine applied to psychiatry provides new insight into the promising field of precision psychiatry. Psychotic disorders are heterogeneous, complex, chronic, and severe mental disorders. Not only does the prognosis and the course of the disease vary among patients suffering from psychotic disorders, but the treatment response varies as well. Although antipsychotic drugs are the cornerstone of the treatment of schizophrenia, many patients only partially respond to these drugs. Furthermore, patients often experience adverse events which can lead to poor treatment adherence. Interindividual variability in drug response could be related to age, gender, ethnicity, lifestyle factors, pharmacological interactions, obesity, and genetics, all of which influence the process of drug metabolism. Commonly prescribed antipsychotics are metabolized by cytochrome P450 (CYP450) enzymes, and CYP450 genes are highly polymorphic. Pharmacogenetic testing is increasingly being used to predict a patient's drug response and could help to find the most appropriate therapy for an individual patient. In this report, we describe a psychotic patient who did not receive adequate clinical follow-up and subsequently presented adverse events, which could be explained by his pharmacogenetic profile and the drug interactions resulting from the polypharmacy prescribed.

A modelling approach to estimate the prevalence of treatment-resistant schizophrenia in the United States

INTRODUCTION

Schizophrenia is a condition that places a significant burden on individuals with the condition, their family, and society. A large proportion of those treated for schizophrenia do not experience treatment response and are referred to as having "treatment-resistant schizophrenia" (TRS). Expert opinion has long held that the prevalence of TRS among individuals with schizophrenia is 30%, but the basis of this estimate is unclear. This article presents a model developed for estimating the prevalence of TRS in the United States 2014.

METHODS

An incidence-prevalence-mortality model was developed to estimate the prevalence of TRS in the United States. The model was populated with data from public health agencies and published literature. Prevalence in 2014 was modelled using a Markov cohort simulation for each birth cohort between 1930 to 2014.

RESULTS

Using different scenarios for baseline incidence, relative risks of mortality, it was estimated that approximately 22% of individuals with schizophrenia would be considered treatment-resistant in 2014.

DISCUSSION

The results suggests that prevalence of TRS may be somewhat lower than the 30% often reported, however this is highly dependent on the definition of treatment resistance. Methods such as this may help answer epidemiological and health policy questions as well as test the influence of key underlying assumptions.

Epidemiology of schizophrenia and its management over 8-years period using real-world data in Spain

BACKGROUND

Real-World Data (RWD) studies provide important insights in disease epidemiology, in real clinical populations, with long follow-up periods. The aim of the present study was to describe the epidemiology of schizophrenia spectrum disorders (SD) during an 8-year period in Spain.

METHODS

A retrospective cohort of subjects aged 15 to 64 years was followed-up using electronic healthcare databases of the Valencia region (2008-2015). SD cases included outpatient and inpatient settings (ICD 9 codes 295.XX). Prevalence of SD was assessed. Incidence rate (IR) in the subpopulation aged between 15 and 34 years was also provided. Healthcare utilization (HCU) rates, including outpatient, specialists, hospitalizations and antipsychotic dispensations were estimated.

RESULTS

The cohort included 3,976,071 subjects; 24,749 of them had a prevalent diagnosis of SD. The overall prevalence for SD was 6.2 per 1000 persons. SD were 76% more prevalent in men than women. IR in the subpopulation aged between 15 and 34 years was 50.25 per 100,000 persons years and was more than 2 times higher for men than for women. 83.4% of the overall outpatient visits from the cohort of patients were related to SD. The 21,095 overall hospitalizations with the SD code resulted in 286,139 days of hospitalization, with a median of 4 days (IQR: 1.6-9.2) per person-year. 93.2% of subjects diagnosed with SD were ever treated with some antipsychotic drug during the study period, and 70% of the patients were ever treated with antipsychotic polypharmacy.

CONCLUSIONS

This large population-based study using RWD provides novel and recent information SD in a southern European country. The prevalence and IR of SD showed is greater than previously published and higher in men than in women. The fact of having used a large arsenal of electronic data (including outpatient and inpatient) for 8 years may have influenced. SD represents high burden and healthcare utilization. Contrary to guidelines recommendations the majority of patients were ever treated with antipsychotic polypharmacy.

Cannabis use in early adulthood is prospectively associated with prescriptions of antipsychotics, mood stabilizers, and antidepressants

OBJECTIVE

Cannabis is an acknowledged risk factor for some mental disorders, but for others the evidence is inconclusive. Prescribed medicinal drugs can be used as proxies for mental disorders. In this study, we investigate how use of cannabis is prospectively related to prescription of antipsychotics, mood stabilizers, antidepressants, and anxiolytics.

METHODS

Data on cannabis exposure and relevant confounders were obtained from 2,602 individuals in the longitudinal Young in Norway Study, providing survey data from four data collection waves between 1992 and 2006. Data were coupled with information about prescriptions for psychotropic drugs from the Norwegian Prescription Database between 2007 and 2015.

RESULTS

Past year cannabis use increased the risk of prescription of antipsychotics (OR = 5.56, 95 % CI 1.64 - 18.87), mood stabilizers (OR = 5.36, 95 % CI 1.99 - 14.44) and antidepressants (OR = 2.10, 95 % CI 1.36 - 3.25), after accounting for sociodemographic variables, conduct problems, additional drug use, mental distress, and prescriptions the year before cannabis use was measured.

CONCLUSIONS

In this study of young adults from the general population, past year cannabis use was associated with later prescriptions of antipsychotics, mood stabilizers, and antidepressants.

Incidence Rates and Cumulative Incidences of the Full Spectrum of Diagnosed Mental Disorders in Childhood and Adolescence

IMPORTANCE

Knowledge about the epidemiology of mental disorders in children and adolescents is essential for research and planning of health services. Surveys can provide prevalence rates, whereas population-based registers are instrumental to obtain precise estimates of incidence rates and risks.

OBJECTIVE

To estimate age- and sex-specific incidence rates and risks of being diagnosed with any mental disorder during childhood and adolescence.

DESIGN

This cohort study included all individuals born in Denmark from January 1, 1995, through December 31, 2016 (1.3 million), and followed up from birth until December 31, 2016, or the date of death, emigration, disappearance, or diagnosis of 1 of the mental disorders examined (14.4 million person-years of follow-up). Data were analyzed from September 14, 2018, through June 11, 2019.

EXPOSURES

Age and sex.

MAIN OUTCOMES AND MEASURES

Incidence rates and cumulative incidences of all mental disorders according to the ICD-10 Classification of Mental and Behavioral Disorders: Diagnostic Criteria for Research, diagnosed before 18 years of age during the study period.

RESULTS

A total of 99 926 individuals (15.01%; 95% CI, 14.98%-15.17%), including 41 350 girls (14.63%; 95% CI, 14.48%-14.77%) and 58 576 boys (15.51%; 95% CI, 15.18%-15.84%), were diagnosed with a mental disorder before 18 years of age. Anxiety disorder was the most common diagnosis in girls (7.85%; 95% CI, 7.74%-7.97%); attention-deficit/hyperactivity disorder (ADHD) was the most common in boys (5.90%; 95% CI, 5.76%-6.03%). Girls had a higher risk than boys of schizophrenia (0.76% [95% CI, 0.72%-0.80%] vs 0.48% [95% CI, 0.39%-0.59%]), obsessive-compulsive disorder (0.96% [95% CI, 0.92%-1.00%] vs 0.63% [95% CI, 0.56%-0.72%]), and mood disorders (2.54% [95% CI, 2.47%-2.61%] vs 1.10% [95% CI, 0.84%-1.21%]). Incidence peaked earlier in boys than girls in ADHD (8 vs 17 years of age), intellectual disability (5 vs 14 years of age), and other developmental disorders (5 vs 16 years of age). The overall risk of being diagnosed with a mental disorder before 6 years of age was 2.13% (95% CI, 2.11%-2.16%) and was higher in boys (2.78% [95% CI, 2.44%-3.15%]) than in girls (1.45% [95% CI, 1.42%-1.49%]).

CONCLUSIONS AND RELEVANCE

This nationwide population-based cohort study provides a first comprehensive assessment of the incidence and risks of mental disorders in childhood and adolescence. By 18 years of age, 15.01% of children and adolescents in this study were diagnosed with a mental disorder. The incidence of several neurodevelopmental disorders peaked in late adolescence in girls, suggesting possible delayed detection. The distinct signatures of the different mental disorders with respect to sex and age may have important implications for service planning and etiological research.

Societal Costs of Schizophrenia in Denmark: A Nationwide Matched Controlled Study of Patients and Spouses Before and After Initial Diagnosis

BACKGROUND

Information on welfare cost of patients with schizophrenia and spouses is limited.

AIM

The main aim of this study to investigate factual societal mean annual costs per individual during 5 years before and after the initial diagnosis of schizophrenia.

METHOD

A register-based cohort study of 12 227 patients with incident schizophrenia (International Classification of Diseases, Tenth Revision F20-F20.99) with spouses and 48 907 matched controls in Denmark during 2002-2016.

RESULTS

The total annual costs of health care and lost productivity were Euro 43 561 higher for patients with schizophrenia and health care costs and costs of lost productivity were increased during 5 years before the initial diagnosis. The total annual direct health care and indirect costs of lost productivity were Euro 21 888 higher for spouses to patients with schizophrenia than spouses of individuals with no diagnosis of schizophrenia. Also before initial diagnosis, health care costs and lost productivity were increased among spouses of patients with schizophrenia.

CONCLUSION

Patients with schizophrenia differed from the general population with respect to all included costs. The study documented a significant burden on spouses. The excess health care costs of schizophrenia are further increased by psychiatric and somatic comorbidity, and the societal costs are 4-10 times higher than chronic neurological disorders such as epilepsy and multiple sclerosis. Early onset of schizophrenia implies that patients are affected before finishing school and before entrance to labor market. Cost savings could be achieved by investments in preventive interventions reaching young people's needs; in initiatives to reduce hospital admissions caused by medication side effects, substance misuse, and lifestyle factors; and in occupational training.

Annual Prevalence and Incidence of Schizophrenia and Similar Psychotic Disorders in the Republic of Korea: A National Health Insurance Data-Based Study

OBJECTIVE

We conducted this study to address the incidence and prevalence of schizophrenia and similar psychosis in South Korea with Health Insurance Review and Assessment (HIRA) database.

METHODS

We used HIRA database, which includes diagnostic information of nearly all Korean nationals to collect number of cases with diagnosis of schizophrenia and schizophrenia-similar disorders (SSP), including schizophreniform, acute/transient psychotic disorders, schizoaffective disorders, and other/unspecific nonorganic psychosis (ICD-10 codes F20/23/25/28/29) between 2010 and 2015. The annual prevalence and incidence were calculated using the population data from the Korean Statistical Office.

RESULTS

The 12-month prevalence of SSP of Korea between 2010 and 2015 were 0.48-0.66%. The 12-month prevalence of schizophrenia were 0.40-0.52%; The annual incidence rates (IR) of SSP between 2010 and 2015 were 118.8-148.7 per 100,000 person-year (PY). For schizophrenia, IR per 100,000 PY were 77.6-88.5 between 2010 and 2015.

CONCLUSION

The 12-month prevalence found in the present study was higher than that reported in community-based epidemiologic studies in South Korea but similar to those from other countries. The annual incidence of SSP and schizophrenia was found to steadily increase and was higher than that of other countries. The high incidence rate observed in the current study needs to be studied further.

Estimating the incidence of first-episode psychosis using population-based health administrative data to inform early psychosis intervention services

BACKGROUND

Discrepancies between population-based estimates of the incidence of psychotic disorder and the treated incidence reported by early psychosis intervention (EPI) programs suggest additional cases may be receiving services elsewhere in the health system. Our objective was to estimate the incidence of non-affective psychotic disorder in the catchment area of an EPI program, and compare this to EPI-treated incidence estimates.

METHODS

We constructed a retrospective cohort (1997-2015) of incident cases of non-affective psychosis aged 16-50 years in an EPI program catchment using population-based linked health administrative data. Cases were identified by either one hospitalization or two outpatient physician billings within a 12-month period with a diagnosis of non-affective psychosis. We estimated the cumulative incidence and EPI-treated incidence of non-affective psychosis using denominator data from the census. We also estimated the incidence of first-episode psychosis (people who would meet the case definition for an EPI program) using a novel approach.

RESULTS

Our case definition identified 3245 cases of incident non-affective psychosis over the 17-year period. We estimate that the incidence of first-episode non-affective psychosis in the program catchment area is 33.3 per 100 000 per year (95% CI 31.4-35.1), which is more than twice as high as the EPI-treated incidence of 18.8 per 100 000 per year (95% CI 17.4-20.3).

CONCLUSIONS

Case ascertainment strategies limited to specialized psychiatric services may substantially underestimate the incidence of non-affective psychotic disorders, relative to population-based estimates. Accurate information on the epidemiology of first-episode psychosis will enable us to more effectively resource EPI services and evaluate their coverage.

Medication, hospitalizations and mortality in 5 years after first-episode psychosis in a Swedish nation-wide cohort

AIM

To investigate medication, rehospitalizations and mortality after first-episode hospital-treated psychosis.

METHODS

A population-based nation-wide cohort (n = 2488) with a first hospitalization for psychosis at ages between 16 and 25 was identified. Cases were followed for up to 5 years after the first psychosis hospitalization with regard to mortality, hospitalizations and dispensations of antipsychotics and benzodiazepines.

RESULTS

The proportion of patients dispensing antipsychotics decreased from 80% year 1 after first discharge to 55% year 5. The proportion of patients having episodes of inpatient care also decreased year by year from 46% year 1 to 27% year 5. Of 863 cases with 5 years of observation time 41% had dispensations of antipsychotics every year; 21% had no dispensation of antipsychotics or hospitalization after the first year. The cumulative 5-year mortality was 3.9%. Cumulative suicide mortality was 2.4%. Incidence of suicide was highest in the first year. Male gender, benzodiazepines, recent hospital-discharge and self-harm were identified as risk factors for suicide.

CONCLUSIONS

The proportion of cases dispensing antipsychotics decreases year by year after first discharge. Mortality and rates of rehospitalization also decrease year by year from high levels the first year.

Gender differences in the prevalence, comorbidities and antipsychotic prescription of early-onset schizophrenia: a nationwide population-based study in Taiwan

Early-onset schizophrenia (EOS) is defined as patients diagnosed with schizophrenia before the age of 18. Whether the EOS population has gender differences is currently a matter of considerable debate. This study used a representative nationwide sample to examine potential gender differences in the prevalence, comorbidities, and prescription of antipsychotics among the EOS population. We identified a total of 401 patients with EOS (200 males and 201 females) from Taiwan's National Health Insurance Database between 2000 and 2012. The annual prevalence rate of overall patients with EOS increased significantly from 17.1 to 41.8 per 100,000 persons among the youth population (≤ 18 years). Sulpiride, Risperidone, and Aripiprazole were the most common antipsychotics of first choice for treating EOS. Compared to female patients, male patients were more likely to experience the following comorbidities: attention deficit hyperactivity disorder (15.5% vs. 5.5%), autism spectrum disorder (10.0% vs. 3.0%), intellectual disability (19.0% vs. 10.4%), developmental disorder (8.0% vs. 3.0%), and history of physical injury (65.5% vs. 48.8%), prior to being diagnosed with schizophrenia. We observed no significant gender differences with regard to incidence, prevalence, age of onset, and categories and doses of patients' first antipsychotic prescription. Our findings did not support the empirical opinion that males with EOS experience the onset earlier or are more prevalent than EOS female patients. However, male patients were more likely to have neurodevelopmental comorbidities and a history of physical injury. These results can function as an important reference for planning services that target real-world patient treatment.

Sex and gender differences in schizophrenic psychoses-a critical review

Many sex and gender differences in schizophrenic psychoses have been reported, but few have been soundly replicated. A stable finding is the later age of onset in women compared to men. Gender differences in symptomatology, comorbidity, and neurocognition seem to reflect findings in the general population. There is increasing evidence for estrogens being psychoprotective in women and for hypothalamic-pituitary-gonadal dysfunction in both sexes.More methodologically sound, longitudinal, multi-domain, interdisciplinary research investigating both sex (biological) and gender (psychosocial) factors is required to better understand the different pathogenesis and etiologies of schizophrenic psychoses in women and men, thereby leading to better tailored treatments and improved outcomes.

The effect of implementation of an early detection team: A nationwide register-based study of characteristics and help-seeking behavior in first-episode schizophrenia in Denmark

BACKGROUND

In an effort to make people with signs of psychosis seek help as early as possible, Region Zealand launched in 2012 an early detection team project as the first and only in Denmark. The project consisted of a combination of easy access and an information campaign targeting the public. This nation-wide study examined characteristics and help-seeking behavior of patients with first-episode schizophrenia (FES) in the early detection region in comparison with other Danish regions.

METHOD

Data from the Danish National Schizophrenia register on all Danish patients diagnosed with first-episode schizophrenia during 2012 to 2015 were linked to demographic and health care data drawn from official national registers. Binary logistic regression analyses examined the difference between the early detection region and other regions controlling for demographic characteristics and utilization of mental health care services and contacts to general practitioner (GP).

RESULTS

Patients in the early detection region were younger (OR = 0.51; CI: 0.42-0.62; p < 0.000) than in regions without early detection teams. Furthermore, they were more likely to be of Danish origin, and less likely to have contact with mental health services and GPs prior to FES.

CONCLUSION

The study suggests that implementing an early detection team in combination with an information campaign contributed to detecting patients with first-episode schizophrenia earlier than in regions without the early detection team. The study gives an indication of different pathways among patients in the early detection region.

Comparative Effectiveness of Antipsychotic Drugs for Rehospitalization in Schizophrenia-A Nationwide Study With 20-Year Follow-up

Very little is known about the comparative long-term effectiveness of novel antipsychotics in relapse prevention, especially in first-episode schizophrenia. Nationwide data from Finnish health care registers were gathered prospectively for all persons with periods of inpatient care due to schizophrenia in Finland during 1972-2014. Altogether 62250 persons were included in the prevalent cohort, and 8719 in the incident (first-episode schizophrenia) cohort. The follow-up for antipsychotic use started at 1996 for the prevalent cohort, and at the first discharge from inpatient care for the incident cases. Within-individual Cox regression models for risk of psychiatric and all-cause hospitalization were constructed to compare risk during antipsychotic use and no use using individual as his/her own control to eliminate selection bias. With follow-up time up to 20 years (median = 14.1, interquartile range = 6.9-20.0), 59% of the prevalent cohort were readmitted to psychiatric inpatient care. Olanzapine long-acting injection (LAI; adjusted hazard ratio = 0.46, 95% confidence interval = 0.36-0.61), clozapine (0.51, 0.49-0.53), and paliperidone LAI (0.51, 0.40-0.66) were associated with the lowest risk of psychiatric rehospitalization in the prevalent cohort. Among first-episode patients, the lowest risks were observed for flupentixol LAI (0.24, 0.12-0.49), olanzapine LAI (0.26, 0.16-0.44), and perphenazine LAI (0.39, 0.31-0.50). Clozapine and LAIs were associated with the lowest risk of all-cause hospitalization in both cohorts. Clozapine and LAIs are the most effective treatments in preventing psychiatric and all-cause hospitalization among chronic and first-episode patients with schizophrenia.

Investigation of the synergistic effects of haloperidol combined with Calculus Bovis Sativus in treating MK-801-induced schizophrenia in rats

Clinical studies that focused on treating schizophrenia showed that Calculus Bovis Sativus (CBS), a substitute of Calculus Bovis, when used in combination with haloperidol could significantly lower the dosage of haloperidol compared with treatment with haloperidol alone, whereas efficacy was maintained. The aim of this study was to investigate the synergetic anti-schizophrenia effects in rats using CBS in combination with haloperidol. An open field test was conducted to verify the pharmacodynamic effects of a combination treatment of CBS and haloperidol on MK-801-induced schizophrenic rats. Rat plasma concentrations of intragastric haloperidol and intravenous haloperidol were determined after oral administration of a single dose or 1-week of pretreatment with CBS (50 mg/kg). The pharmacodynamic data showed a significant decrease in locomotor activity and an increase in the percentage of the central distance when haloperidol was concomitantly administered with CBS compared with haloperidol administration alone. The AUC0-∞ and Cmax of haloperidol in the orally coadministered groups were significantly higher compared with the oral treatment with haloperidol alone. In conclusion, oral coadministration of CBS with haloperidol resulted in a synergistic effect in rats. The enhanced oral bioavailability of haloperidol when combined with CBS might be attributed to the interaction between them.

The interaction of gender and cannabis in early phase psychosis

Cannabis is the third most common recreational drug used world-wide after tobacco and alcohol. Globally, cannabis legalization is becoming more common. In light of its known link to psychosis development, it is imperative that we are well-informed regarding the impact of cannabis on the course of psychosis, in both males and females. However, the majority of the work to date on the role of cannabis in psychosis outcomes has not had a gender focus, important when considering patient specific treatments. This review examines what is currently known, from gender focused studies, about the interaction of gender, cannabis use and psychotic disorders.

The incidence, psychiatric co-morbidity and pharmacological treatment of severe mental disorders in children and adolescents

BACKGROUND

Antipsychotic drug use among children and adolescents is increasing, and there is growing concern about off-label use and adverse effects. The present study aims to investigate the incidence, psychiatric co-morbidity and pharmacological treatment of severe mental disorder in Norwegian children and adolescents.

METHODS

We obtained data on mental disorders from the Norwegian Patient Registry on 0-18 year olds who during 2009-2011 were diagnosed for the first time with schizophrenia-like disorder (International Classification of Diseases, 10th revision codes F20-F29), bipolar disorder (F30-F31), or severe depressive episode with psychotic symptoms (F32.3 or F33.3). Data on filled prescriptions for psychotropic drugs were obtained from the Norwegian Prescription Database.

RESULTS

A total of 884 children and adolescents (25.1 per 100 000 person years) were first time diagnosed with schizophrenia-like disorder (12.6 per 100 000 person years), bipolar disorder (9.2 per 100 000 person years), or severe depressive episode with psychotic symptoms (3.3 per 100 000 person years) during 2009-2011. The most common co-morbid mental disorders were depressive (38.1%) and anxiety disorders (31.2%). Antipsychotic drugs were prescribed to 62.4% of the patients, 72.0% of the schizophrenia-like disorder patients, 51.7% of the bipolar disorder patients, and 55.4% of the patients with psychotic depression. The most commonly prescribed drugs were quetiapine (29.5%), aripiprazole (19.6%), olanzapine (17.3%), and risperidone (16.6%).

CONCLUSIONS

When a severe mental disorder was diagnosed in children and adolescents, the patient was usually also prescribed antipsychotic medication. Clinicians must be aware of the high prevalence of depressive and anxiety disorders among early psychosis patients.

Determinants of duration of untreated psychosis among first-episode psychosis patients in Denmark: A nationwide register-based study

BACKGROUND

Information on determinants of duration of untreated psychosis (DUP) is still needed to inform campaigns targeting people with first episode psychosis (FEP). This nation-wide study analysed the association between demographic factors (age, sex, ethnicity, marital status, and geographic area), premorbid and illness-related factors (global functional level, substance misuse, and contact to police), healthcare factors (referral source and first FEP contact) and DUP.

METHOD

The study population of 1266 patients aged 15-25years diagnosed with FEP (ICD10 F20.0-F20.99) was drawn from the Danish National Indicator Project during 2009-2011. The study population was combined with data from national administrative registers. A multinomial regression model was estimated to analyse the impact of demographic, premorbid and illness-related, and healthcare factors on DUP.

RESULTS

One third of the population had a DUP below 6months. DUP longer than 12months was associated with older age at onset, being female, having cannabis misuse, and living in peripheral municipalities. Being charged by the criminal authorities during one year before FEP was associated with a DUP over 6months.

CONCLUSION

DUP is related to a number of demographic, premorbid and healthcare factors. These findings suggest that future information campaigns should focus on increasing the awareness of early signs of psychosis not only among mental health professionals but also other professionals in contact with adolescents such as the police. It may also be useful to consider how to target information campaigns towards persons living in peripheral areas.

Waiting time variation in Early Intervention Psychosis services: longitudinal evidence from the SEPEA naturalistic cohort study

PURPOSE

Early Intervention Psychosis [EIP] services have gained traction internationally, but are currently undergoing various forms of reconfiguration. In England, such services are now mandated to ensure 50% of accepted referrals commence care within 14 days, but no empirical evidence exists. We sought to estimate waiting times to EIP services in a large, representative epidemiological cohort in England, and investigate possible reasons for any variation.

METHODS

We estimated median waiting time from referral to acceptance by EIP services and investigated whether this varied by clinical, demographic or neighbourhood-level factors, amongst 798 participants, 16-35 years old, presenting to six EIP services over 3.5 years in a defined catchment area serving 2.5 million people. We used parametric survival analysis to inspect variation in waiting times (in days).

RESULTS

Median waiting time was 15 days (interquartile range 7-30), although this varied across services (p < 0.01). Waiting times increased over the case ascertainment period by an average of 4.3 days (95% CI 1.3, 6.2; p < 0.01). Longer waiting times were associated with greater diagnostic uncertainty, indexed by an organic presentation (+ 9.1 days; 95% CI 1.9, 16.6; p < 0.01), polysubstance abuse (+ 2.6; 0.6, 3.9; p < 0.01), absence of psychotic disorder (+1.8; -0.1, 3.0; p = 0.05) and insidious onset (+1.8; -0.1, 3.0; p = 0.06). Waiting times did not vary by most demographic or neighbourhood-level characteristics.

CONCLUSIONS

EIP services operate close to new waiting time standards in England, with little systematic variation by sociodemographic position. However, waiting times increased over the study period, coinciding with substantial service reorganisation. Longer waiting times associated with greater diagnostic uncertainty highlight opportunities to reduce delays in certain clinical groups at initial referral.