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We study the predictive power and associations of several psychological scales with respect to hospitalisations due to schizophrenic psychoses.
Temperament and Character Inventory, Physical Anhedonia Scale, Social Anhedonia Scale, Perceptual Aberration Scale, Hypomanic Personality Scale, Bipolar II Scale, and Schizoidia Scale were included in the 31-year follow-up survey of the prospective Northern Finland 1966 Birth Cohort (N=4,926). We compared subjects without any previous hospitalisations to those with previous hospital diagnoses (concurrent validity) and to those who in the eight year long follow-up were hospitalised due to schizophrenic psychosis (predictive validity). We also compared the subjects with schizophrenic psychoses and subjects with other psychiatric disorders (discriminant validity).
In most scales, subjects with schizophrenic psychoses differed from healthy subjects. The Perceptual Aberration Scale was the best scales for concurrent (Effect Size, d = 1.89) and discriminant validity (d = 0.64). Subjects having a high score in Hypomanic Personality Scale were in the highest risk for schizophrenic psychoses (OR 10.72; 95% CI 2.87-40.06).
Subjects with schizophrenic psychoses differed in most of the scales from healthy controls and from subjects with other psychiatric disorders. Many of the scales were useful predictors for future hospitalisations due to schizophrenic psychoses; however scales were not very diagnosis specific. The predictive power of the scales is limited, these scales are probably not useful as screening instruments but can be used in several ways when studying e.g. risk factors or genetics of schizophrenic psychoses.
To describe symptom expression and functional outcome in psychotic disorders in relation with temperament traits assessed with the Temperament and Character Inventory (TCI) in a population-based sample.
As part of the 31-year follow-up survey of the Northern Finland 1966 Birth Cohort, TCI temperament items were filled in by 4349 members of the cohort. In individuals with psychotic disorders, also positive and negative symptoms and outcome variables were assessed in a 35-year follow-up. Information of TCI and outcomes were available for altogether 41 individuals with psychosis.
Reward dependence (RD) (rho = −0.45) and Persistence (P) (rho = −0.52) were significantly correlated with Positive and Negative Syndrome Scale (PANSS) negative symptoms. Higher P scores predicted higher social and occupational functioning (as measured by Social and Occupational Functioning Assessment Scale [SOFAS]), and higher Harm avoidance (HA) predicted a higher likelihood of being on a disability pension.
Results indicate that understanding of personality dimensions support better understanding of outcome and symptom expressions in psychotic disorders.
The participation rates in epidemiologic studies have declined in recent decades. Missing data reduce sample size, statistical power, and scientific quality.
To study use of home interviews in recruiting individuals with a psychosis.
To evaluate effect of home-recruitment on non-response bias.
In the Northern Finland 1966 Birth Cohort, field surveys on psychosis were conducted in 1999-2001 and 2008-2010. In order to increase participation in the follow-up sample, cases were offered to be interviewed at home. We studied symptoms, illness severity, functioning, cognition, antipsychotics use, and grey matter (GM) volume between home-recruited and regular participants (RP), and non-participants (NP). Effect sizes (d) were calculated to compare the differences.
Altogether 18 (33%) out of the follow-up sample (n=54) were home-recruited, 27 did not participate. Home-recruited had more symptoms, lower functioning, cognition and GM volume, and they had used more antipsychotics compared to RP and NP in baseline. NP did not differ from RP. The same differences occurred when home-recruited were compared with RP in the follow-up study.
[Selected information from baseline study]
CVLT, total recall
Grey matter volume
Owing to the home-recruitment we were able to collect data that may be reasonably non-biased in terms of nonresponse bias, which will yield valid estimates in our future studies on change over time in brain and cognitive ability, prevalence and severity of psychotic illnesses, outcome, medication use, and other issues of interest.
Recently many studies have suggested more brain morphometric changes occurring in people with schizophrenia who use antipsychotic medication compared to those who do not.
We will study the brain morphology of subjects with schizophrenia spectrum disorder with and without antipsychotic medication.
Our aim was to compare the brain morphology of subjects with schizophrenia spectrum disorder with and without antipsychotic medication after in average ten years of illness, and analyse the association between cumulative dose of lifetime antipsychotic medication and brain morphology.
Data of 66 subjects with schizophrenia spectrum disorder (mean duration of illness 10.4 years) from the Northern Finland 1966 Birth Cohort were gathered by interview and from hospital records. Structural MRI data at age 34 years were acquired from all participants on a GE Signa system operating at 1.5T.
Of the subjects 16 (24%) had taken no antipsychotics during the previous year. We found no significant differences on total grey matter volumes (TGM) between subjects with and without antipsychotic medication. In the voxel-based analyses subjects with medication had lower volume in left parahippocampal gurys (p = 0.003), when adjusted for sex, onset age, TGM and remission status. There were no associations between lifetime antipsychotic dose and brain morphology.
We were able to study effects of antipsychotic medication in population-based sample. Brain morphology in medicated and non-medicated persons were similar and the cumulative lifetime medication had no effect on brain morphology, which suggests that possible medication effect in cross-sectional measures of brain morphology is small.
Recent studies have shown that cannabis use acts as a specific risk factor provoking the onset of psychosis in vulnerable individuals. Association of adolescent cannabis use and psychosis risk was studied after adjustment with prodromal symptoms.
To assess possible causality between cannabis use and the risk of psychosis.
To examine associations between cannabis use and the risk of psychosis in 10 years follow-up while taking into account the prodromal symptoms of psychosis in a prospective general population sample.
The sample (N=6258) composed of a prospective Northern Finland Birth Cohort 1986. Questionnaire on prodromal symptoms for psychosis (PROD-screen) and on drug use was conducted when the cohort members were 15-16 years old. The participants were asked if they had tried cannabis: never, once, 2-4 times, 5 times or more. Information on psychoses was gathered from registers until age 27 years.
In total 102 new psychoses emerged. The proportion of psychoses in the groups 'never”, 'once”, '2-4 times”, '5 times or more” were 1.5%, 2.8%, 3.6%, and 8.5%, respectively. The hazard ratio (HR) for risk of psychosis in subjects who had tried cannabis 5 times or more was 5.9 (95% CI 2.4-14.4) when compared to non-users. The association remained statistically significant when adjusted for prodromal symptoms and parental psychosis (HR 2.6, 1.0-6.6). When gender and smoking was taken into account association was no longer significant (HR 2.3, 0.9-6.0).
Adolescent cannabis use associates with increased risk of first-episode psychosis even after controlling for baseline prodromal symptoms.
Relatively little is known on longitudinal effects of antipsychotic medication on brain morphometry in schizophrenia after the illness onset. There are inconsistent findings on medication effects on brain structures.
We will study the effect of antipsychotic medication on brain volumes in schizophrenia.
The aim of the current study was to systematically review previous literature on longitudinal MRI studies of antipsychotic effects on brain morphometric changes in schizophrenia and related psychoses.
Studies were systematically collected using four different databases. A study was included if subjects were scanned twice, the average scanning interval was at least two years and antipsychotic medication data was used to predict morphometric changes. The studies focused on several different brain areas; we categorized these into eleven larger areas.
In total 22 studies fulfilled our inclusion criteria. The main finding of our study was that most of the reported correlations were statistically non-significant. The significant associations between antipsychotic use and brain changes were reported from various areas. In the studies with significant findings, use of antipsychotics more often associated with decrease than increase of brain volumes, even in the very few studies taking into account illness severity.
Antipsychotic medication should be adjusted to lowest possible dose for reducing psychotic symptoms and prescribed with caution especially to people not suffering from psychosis. More studies in different kind of patient populations are needed to clarify the possible adverse effect antipsychotic medication may have on brain structure.
Whether long-term psychodynamic therapy (LPP) and psychoanalysis (PA) differ from each other and require different therapist qualities has been debated extensively, but rarely investigated empirically.
In a quasi-experimental design, LPP was provided for 128 and PA for 41 outpatients, aged 20–46 years and suffering from mood or anxiety disorder, with a 5-year follow-up from start of treatment. Therapies were provided by 58 experienced therapists. Therapist characteristics, measured pre-treatment, were assessed with the Development of Psychotherapists Common Core Questionnaire (DPCCQ). General psychiatric symptoms were assessed as the main outcome measure at baseline and yearly after start of treatment with the Symptom Check List, Global Severity Index (SCL-90-GSI).
Professionally less affirming and personally more forceful and less aloof therapists predicted less symptoms in PA than in LPP at the end of the follow-up. A faster symptom reduction in LPP was predicted by a more moderate relational style and work experiences of both skillfulness and difficulties, indicating differences between PA and LPP in the therapy process.
Results challenge the benefit of a classically “neutral” psychoanalyst in PA. They also indicate closer examinations of therapy processes within and between the two treatments, which may benefit training and supervision of therapists.
Social withdrawal is among the first signs of the prodromal state of psychosis seen in clinical samples. The aim of this prospective study was to find out whether difficulty in making contact with others and social withdrawal precede first episode psychosis in the young general population.
The members of the Northern Finland Birth Cohort 1986 (n = 6274) completed the PROD-screen questionnaire in 2001–2002. The Finnish Hospital Discharge Register was used to detect both new psychotic and non-psychotic disorders requiring hospitalisation during 2003–2008.
Twenty-three subjects developed psychosis and 89 developed a non-psychotic mental disorder requiring hospitalisation during the follow-up. Of those who developed psychosis, 35% had reported difficulty or uncertainty in making contact with others and 30% social withdrawal in adolescence. In hospitalised non-psychotic disorder, the corresponding precentages were 10 and 13% and in the control group without hospital-treated mental disorder 9 and 11%. The differences between psychotic and non-psychotic hospitalised subjects (P < 0.01) as well as controls (P < 0.001) were statistically significant regarding difficulty or uncertainty in making contact with others.
In this general population-based sample self-reported difficulty or uncertainty in making contact with others in adolescence preceded psychosis specifically compared to hospitalised non-psychotic mental disorders and controls.
Substance abuse and mental health problems have been increasing among young population.
To find out the prevalence of alcohol and tobacco usage and their association with depressive symptoms among university students.
Web-based questionnaire was sent to all 13397 university students of Oulu University, Finland in November 2011. 2167 (16,2%) replied, 31,5% were males and 68,5% females. The questionnaire included Alcohol Use Disorders Identification Test (AUDIT-C), questions concerning tobacco, and Symptom Check List-90 (SCL-90). We analyzed the prevalence of alcohol and tobacco usage and their association with depressive symptoms by gender.
Among males 46,0% had hazardous drinking habits (AUDIT-C score 4-7) and 21,3% had very hazardous drinking habits (AUDIT-C score 8-12). Among females 63,2% had hazardous drinking habits (AUDIT-C score 3-7) and 4,8% had very hazardous drinking habits (AUDIT-C score 8-12). 14,8% of males and 12,1% of females were smoking tobacco irregularly and 4,8% of males and 4,4% of females smoked regularly. There was no statistically significant association between usage of alcohol and symptoms of depression among males or females. Among males, but not among females, there was statistically significant positive association between tobacco smoking and depressive symptoms (p=0,001).
The prevalence of hazardous drinking habits in our sample was very high compared to earlier studies conducted among university students. Contrary to earlier studies there was no association between hazardous drinking habits and depressive symptoms. In the future factors associating to hazardous drinking and the prevention of this phenomenon should be studied in more detail.
To analyse associations between brain morphology and longitudinal and cross-sectional measures of outcomes in schizophrenia in a general population sample.
The sample was the Northern Finland 1966 Birth Cohort. In 1999–2001, structural brain MRI and measures of clinical and functional outcomes were analysed for 54 individuals with schizophrenia around the age of 34. Sex, total grey matter, duration of illness and the use of antipsychotic medication were used as covariates.
After controlling for multiple covariates, increased density of the left limbic area was associated with less hospitalisations and increased total white matter volume with being in remission. Higher density of left frontal grey matter was associated with not being on a disability pension and higher density of the left frontal lobe and left limbic area were related to better functioning. Higher density of the left limbic area was associated with better longitudinal course of illness.
This study, based on unselected general population data, long follow-up and an extensive database, confirms findings of previous studies, that morphological abnormalities in several brain structures are associated with outcome. The difference in brain morphology in patients with good and poor outcomes may reflect separable aetiologies and developmental trajectories in schizophrenia.
In schizophrenia, brain morphometric changes may be associated with antipsychotic medication. Only limited data is available concerning individuals with schizophrenia without antipsychotic medication. We aimed to study the associations of: use versus no use of antipsychotic medication; length of continuous time without antipsychotic medication; cumulative dose of lifetime antipsychotic medication; and type of antipsychotic medication; with brain morphometry in schizophrenia after an average of 10 years of illness.
Data of 63 individuals with schizophrenia (mean duration of illness 10.4 years) from the Northern Finland Birth Cohort 1966 were gathered by interview and from hospital and outpatient records. Structural MRI data at age 34 years were acquired and grey matter volume maps with voxel-based morphometry were analyzed using FSL tools.
Of the individuals studied, 15 (24%) had taken no antipsychotic medication during the previous year. Individuals with antipsychotic medication had lower total grey matter (TGM) volume compared with non-medicated subjects, although this association was not statistically significant (Cohen's d = –0.51, P = 0.078). Time without antipsychotic medication associated with increased TGM (P = 0.028). Longer time without antipsychotic medication associated with increased regional volume in right precentral gyrus and right middle frontal gyrus. There were no associations between cumulative dose of lifetime antipsychotic medication or type of antipsychotic medication and brain morphometry.
Unlike some previous investigators, we found no association between cumulative dose of lifetime antipsychotic medication and brain morphological changes in this population-based sample. However, longer continuous time without antipsychotic medication preceding the MRI scan associated with increased gray matter volume.
Long duration of untreated psychosis (DUP) predicts poor short- and long-term outcome in schizophrenia. It may also be a marker of resilience and associate with lower doses or shorter periods of using antipsychotic medication which may or may not be correlated with the association between DUP and outcome.
To study the association between DUP and the use of antipsychotic medication in long-term follow-up.
To find out whether the delayed treatment in first-episode psychosis associates with using less antipsychotic medication during the course of illness
In the prospective Northern Finland 1966 Birth Cohort length of DUP and information on lifetime use of antipsychotic medication for 60 individuals with schizophrenia was assessed from medical records from the first episode until age 34 years. Association between length of DUP and cumulative dose-years of antipsychotics was analysed using linear regression analysis. Logarithmic transformations of DUP and dose years were used.
Mean DUP was 227 days (SD 359) and mean of cumulative dose years was 2.41 (SD 1.29). Symptoms measured using PANSS ranged from 30 to 122, mean 53 (SD 21). Duration of untreated psychosis did not associate with the use of antipsychotic medication (beta = −0.124, p = 0.343).
There was no evidence of an association between DUP and the use of antipsychotic medication. Although long DUP has long-term association with poor outcome, it does not have an association with the use of antipsychotic medication based on the population-based long-term follow-up.
Individuals with epilepsy have commonly comorbid psychiatric disorders but only a few studies have focused on psychotic disorders.
To study the possible comorbidity between epilepsy and psychotic disorders.
To investigate how epilepsy and non-organic psychotic disorders associate in a large population based birth cohort.
The study sample comprised 10,933 individuals from the prospective Northern Finland Birth Cohort 1966. Cox regression analysis (Hazard Ratios, HR) was used to study risk of psychotic disorders among those with and without epilepsy. Gender, mental retardation and family history of psychosis were used as covariates. Epilepsy diagnoses were based on various nationwide registers and questionnaires. Information on psychoses (ICD-10) was based on nationwide registers.
A total of 373 (3.4%) cohort members suffered from non-organic psychotic disorders and 386 (3.5%) of epilepsy by the age of 46 years. Members with epilepsy had 2.0-fold risk for psychosis when compared to those without (adjusted HR 2.0; 95% Confidence Interval 1.4-2.9). The risk was high for non-schizophrenic psychoses (adjHR 4.0; 2.4-6.6), whereas epilepsy did not associate with schizophrenia spectrum diagnoses (adjHR 1.1; 0.6-2.0). Especially individuals with focal epilepsies developed commonly (12 of 87, 13.8%) psychotic disorders.
Epilepsy increases risk for subsequent non-schizophrenic psychoses even when adjusted with other factors. Those with focal epilepsies were especially in risk. There are several possible etiologies and pathomechanisms, including genetic, structural, functional and metabolic factors. Common comorbidity between epilepsy and psychoses demands active and extensive clinical care by the multidisciplinary team.
Alcohol and other substance use problems are common among individuals with schizophrenia. Many of the previous studies have focused on clinical comorbidity, not on longitudinal studies aiming to look for possible causal associations. We aimed to investigate if premorbid or early substance use predicts long-term clinical and social course in schizophrenia.
A systematic review to identify potentially relevant studies was conducted. Only studies with a follow-up period of at least two years were included. We studied following outcomes: negative, positive and total symptoms, clinical remission, hospitalizations, social functioning, employment, and global outcome.
The search identified 9343 unique potentially relevant articles of which 20 studies presenting results from 24 samples met our inclusion criteria. The meta-analysis included 5 to 13 studies in each outcome category. The studied in outcome groups were mainly moderate to high heterogeneous. In meta-analysis, substance use associated modestly with outcome, all the associations (Spearman's r) were non-significant and between −0.05 and 0.10. Non-significant findings are explained by the fact that the original studies found often opposite results, indicating both worse and better long-term outcome for early substance users.
Although comorbid substance use associates with poorer outcome in schizophrenia, the early substance use has only a modest effect as a predictor of long-term outcome. This difference between these two designs may be explained for instance with poorer treatment adherence of dual diagnosed patients.
We analyzed longitudinal course of illness in schizophrenia until age 43 years, and its correlates to antipsychotic medication and cognition.
Northern Finland 1966 Birth Cohort Study has been followed serially since mid-pregnancy. Structural and functional MRI, cognitive, and clinical examinations were performed at ages 34 (73 schizophrenic psychoses, 104 controls) and 43 (63 schizophrenic psychoses, 192 controls); 40 cases and 75 controls participated in both surveys. Psychiatric outcomes have been ascertained through data linkage to a national case registers, hospital charts and clinical evaluations.
Prognosis of schizophrenia is heterogeneous: minority of individuals experience recovery, some achieve remission, but many are on disability pension, and excess mortality (especially suicides) is common. Long duration of untreated psychosis, early age of illness onset and presence of suicidal ideation associated with poorer long-term outcome. Both cases and non-psychotic controls show a small decline in verbal learning and memory, but the difference in decline is not significantly more pronounced in cases. Higher doses of antipsychotics at age 43-years associated to lower education and poorer clinical and functional outcomes, and high cumulative life-time use of antipsychotics associated to decrease of verbal learning and memory in 9-year follow-up.
Based on this naturalistic sample, midlife progression of schizophrenia may follow a variety of different trajectories. Poor clinical course is common but not necessary outcome. Compared to controls, more pronounced cognitive decline was not seen in schizophrenia cases. However, high doses of antipsychotics may relate to a decrease of verbal learning and memory.
We have previously investigated the association between family history of psychosis and long-term outcome in schizophrenia in a systematic review and found no studies that focused on social outcome.
To study effect of family history on long-term occupational, social, clinical and global outcome in schizophrenia.
Aims: In this study we aimed to investigate how family history affects long-term occupational, social, clinical and global outcome in schizophrenia in a population-based cohort study.
Sixty nine persons with schizophrenia spectrum diagnosis from the Northern Finland Birth Cohort 1966 were examined at around 43 years of age, in average 17 years since onset of psychosis. A Strauss-Carpenter Outcome Scale –interview was conducted to gather information regarding occupational, social, clinical and global outcome. The family history of psychosis was examined based on register data and interviews.
Seventeen (24.6%) of the schizophrenia cases had family history of psychosis. The presence of family history of psychosis did not associate statistically significantly to occupational (FH+ vs FH-: mean 24.9 vs. 28.4; p = 0.470), social (34.5 vs. 33.2; p = 0.811), clinical (29.9 vs. 33.4; p = 0.510) or global outcome (22.2 vs. 22.7; p = 0.827).
This was the first original study on effects of family history of psychosis on long-term social outcome in schizophrenia. We did not find statistically significant association between family history of psychosis and long-term outcome in schizophrenia. Since the number of subjects with family history of psychosis was quite low, a study with larger sample size is desirable.
Since the outcome in schizophrenia is heterogeneous and often poor, identification of specific predictors of outcome would be useful in clinical practice.
Subjects with schizophrenic psychoses (n = 103) included in the Northern Finland 1966 Birth Cohort (n = 12,058), representing the general population, were followed-up for an average of 16.4 years. Predictor and outcome data were collected from the nationwide Finnish Hospital Discharge Register, hospital records and interviews.
Insidious onset of illness predicted a rehospitalization due to psychosis in the 2 years after the initial discharge. Being single, having an early onset, insidious onset, suicidal ideations upon the first admission, a rehospitalization and a high number of treatment days due to psychosis in the early stages of the illness all predicted a poorer clinical outcome in the longer term, after a minimum follow-up of 10 years.
This population-based study indicates that clinical and sociodemographic factors around the onset of illness have significance for the long-term outcome in schizophrenia. These prognostic factors should be taken into account in clinical practice.
Midlife progression of schizophrenia shows evidence of longitudinal brain volume decrease and heterogeneous outcomes.
We analyzed the relation between brain volume changes, lifetime antipsychotic medication and clinical outcomes.
Psychotic members (n= 41) and non-psychotic controls (n=75) of the Northern Finland 1966 Birth Cohort were invited for a MRI brain scan and clinical and cognitive assessment at the age of 34 years (mean 10 years after onset of illness). A follow-up was 9 years later at age 43.
Clinical outcomes were heterogeneous and generally poor: 10% were recovered. The mean annual whole brain volume reduction was 0.69% in schizophrenia and 0.49 % in controls, especially in temporal lobe and periventricular area. Symptom severity, functioning level, and decline in cognition were generally not associated with volume reduction. However, decline in social and occupational function was associated with supramarginal gyrus reduction and was independent from antipsychotics exposure. Larger amount of antipsychotics over the follow-up associated significantly with larger brain volume loss. Higher doses of lifetime antipsychotic medication were associated to larger decrease of verbal learning change in a 9-year follow-up.
Brain volume and verbal learning reduction occurs in schizophrenia long after the onset of illness. Antipsychotics may contribute to these reductions. We do not know the real effectiveness and benefits/risks of antipsychotic drugs in schizophrenia from longitudinal and lifespan view. New data does not change current care guidelines but may expand clinical decision making into lower doses, even medication discontinuation in selected groups, and biopsychosocial care.
Alcohol and other substance use problems are common among individuals with schizophrenia.
Many of the previous studies have focused on clinical comorbidity, not on longitudinal design.
The aim of this study was to investigate if premorbid or early substance use predicts long-term clinical and social course in schizophrenia.
A systematic review to identify potentially relevant studies was conducted. Studies with a follow-up period of at least two years were included. Following outcomes were studied: negative, positive and total symptoms, clinical remission, hospitalizations, social functioning, employment, and global outcome. Spearman's correlations were used to summarize results, negative correlations indicating poorer outcome with substance use.
The search identified 10776 unique potentially relevant articles of which 25 studies met our inclusion criteria. The meta-analysis included 5 to 13 studies in each outcome category. Moderate to high heterogeneity was found between studies in each outcome group. In meta-analysis, substance use associated modestly with outcome. All the associations were non-significant and correlations between −0.06 and 0.09. Non-significant findings are explained by the fact that the original studies found often opposite results, indicating both worse and better long-term outcome for early substance users.
Although comorbid substance use associates with poorer outcome in schizophrenia, the early substance use has only a modest effect on long-term outcome. This difference to studies on current comorbidity may indicate that those who continue substance abuse have poor outcome, e.g. due to poor treatment adherence, whereas those who stop the abuse may have relatively good outcome.
There are limited amount of studies comparing time trends of incidence and risk factors of psychosis.
To compare time trends of incidence of psychosis in two population samples.
To study 1) onset age and cumulative incidence of psychoses in two Northern Finland Birth Cohorts (NFBC), 2) changes in type of diagnosis and risk factors.
The NFBC 1966 (N=12,058) and NFBC 1986 (N=9,432) are prospective cohorts of the two provinces of Finland with the live born children followed since pregnancy. The data for psychosis and risk factors were collected from variety of nationwide registers and earlier collected data of the NFBCs. The follow-up time was in both cohorts in average 26.5 years.
Proportion of all psychoses was higher in NFBC 1986 than in the NFBC 1966 (1.81% vs 1.0%). There were more affective psychoses in NFBC 1986 (0.5% vs 0.1%), but incidence of schizophrenia was the same (0.4%) in both cohorts. The age of onset was lower in NFBC 1986 than in NFBC 1966 and majority of this cases were females. Only parental psychosis was a significant risk factor predicting psychosis (Hazard Ratios >3.0) in both cohorts.
In conclusion, two birth cohorts within 20 years covering altogether about 40 years showed changes in terms of incidence, age of onset, and type of psychosis.