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Objective: The aim of this study was to explore changes in the incidences of childhood and early adulthood hospital‐treated psychiatric disorders in five large Finnish birth cohorts of individuals born between 1966 and 1997. Methods: The five birth cohorts were as follows: Northern Finland Birth Cohort 1966 (NFBC 1966) and 1986 (NFBC 1986), 1987 Finnish Birth Cohort (FBC 1987) and 1997 (FBC 1997), and Finnish 1981 Birth Cohort Study (FBCS 1981). Incidences of hospital‐treated psychiatric disorders in each cohort were calculated separately for males (N = 71,209) and females (N = 65,190). Poisson regression was used to test difference in proportions of psychiatric disorders in wide range of diagnosis classes separately in childhood and adolescence, and early adulthood. Results: The total incidences of psychiatric disorders in childhood and adolescence among males has increased in the birth cohorts over decades (Incidence Rate Ratio, IRR = 1.04 (1.04–1.05); p < 0.001). Similar result was seen among females (IRR = 1.04 (1.03–1.04); p < 0.001). In early adulthood, there was significant increase among females (IRR = 1.04 (1.03–1.05);p < 0.001), but among males, the change was not significant (IRR = 0.99 (0.99–1.00), p = 0.051). Conclusions: The main finding was that the cumulative incidence of hospital‐treated psychiatric disorders increased over the decades in Finland. The increasing trend in hospital‐treated psychiatric disorders in early adulthood was detected in females but not in males. In the youngest cohorts, the cumulative incidence of hospital‐treated psychiatric disorders was at the same level in males and females, whereas in oldest cohort, males had higher incidence than females.

Delayed motor developmental milestones have been reported to be associated with schizophrenia in previous studies, but no study has examined the relationship between early motor developmental milestones and schizotypy. We have examined this relationship in a prospective birth cohort. In the Northern Finland Birth Cohort 1966, data on 9 early motor developmental milestones were collected prospectively from visits to child welfare centers, and data on adult schizotypy were collected through a questionnaire (N = 4557–4674). Positive schizotypy was measured by the Perceptual Aberration Scale (PAS), negative schizotypy was measured by Physical Anhedonia Scale (PhAS) and Social Anhedonia Scale (SAS). Three related scales were included: Schizoidia Scale (SCHD), Hypomanic Personality Scale (HPS), and Bipolar II Scale (BIP2). We examined the milestone–schizotypy associations before and after excluding cases of schizophrenia from this population-based sample. Hierarchical regression analyses adjusted for covariates and separately for both genders were performed. In men, each extra month of delay in achievement of touching thumb with index finger, sitting unsupported, standing up, walking with support, or walking unsupported was associated with an increase in PAS, PhAS, or SCHD scores, or decrease in BIP2 score (P < 0.05). In women, each extra month of delay in achievement of turning from back to tummy was associated with an increase in PhAS and SAS scores (P < 0.05). Schizotypy is associated with delayed motor developmental milestones in early-life, but there is some heterogeneity with regards to types of milestones and gender. These findings suggest delayed motor development confers risk across the continuum of schizophrenia syndrome.

Background and aims: The notion that environment affects mental health has a long history; in this systematic review, we aimed to study whether the living environment is related to depressive mood. Methods: We searched databases of PubMed, Scopus and Web of Science for population-based original studies prior to October 2016. We included studies that measured depressive symptoms or depression and had measures of urbanization, population density, aesthetics of living environment, house/built environment, green areas, walkability, noise, air pollution or services. Results: Out of 1,578 articles found, 44 studies met our inclusion criteria. Manual searches of the references yielded 13 articles, resulting in 57 articles being included in the systematic review. Most of the studies showed statistically significant associations with at least one of the characteristics of living environment and depressive mood. House and built environment with, for example, poor housing quality and non-functioning, lack of green areas, noise and air pollution were more clearly related to depressive mood even after adjustment for different individual characteristics. On the contrary, the results in relation to population density, aesthetics and walkability of living environment, and availability of services and depressive mood were more inconsistent. Conclusion: Adverse house/built environment, including poor housing quality and non-functioning, lack of green spaces, noise and air pollution are related to depressive mood and should be taken into account during planning in order to prevent depressive mood.

The neurodevelopmental hypothesis of schizophrenia proposes that impaired brain development is a cause of the illness. Early motor developmental milestones, such as learning to walk, are predictors of later schizophrenia but studies have not been systematically reviewed. The aim of the present systematic review and meta-analysis was to explore the association between early motor developmental milestones and the risk of adult schizophrenia. In addition, we updated a systematic review on motor function and risk of schizophrenia. The PubMed, PsycINFO and Scopus databases were searched for original research articles published up to July 2015. Motor milestones were measured between ages 0 and 13 years. Random effect meta-analysis calculated effect estimates (Hedges’ g) for the association between individual motor milestones and schizophrenia risk. An electronic database and selected articles reference list search identified 5990 articles after removing duplicates. Sixty-nine full text articles were assessed for eligibility of which six were included in the review. Five studies provided sufficient data for meta-analyses. The following motor milestones were significantly associated with adult schizophrenia risk: walking unsupported (g = 0.46; 95% CI 0.27–0.64; p < 0.001), standing unsupported (g = 0.28; 0.16–0.40; p < 0.001) and sitting unsupported (g = 0.18; 0.05–0.31; p = 0.007). Results for the milestones ‘holding head up’ and ‘grabbing object’ were not statistically significant. Delayed walking, sitting and standing unsupported were associated with adult onset schizophrenia. The findings emphasise the importance of timely achievement of these motor milestones in childhood and can contribute to the identification of individuals at risk of psychosis.

Schizophrenia is a complex mental health disorder and its etiology can be investigated based on different theoretical prerequisites. The present thesis examines schizophrenia from the neurodevelopmental and psychosis continuum perspectives. Neurodevelopmental theories of schizophrenia see abnormalities in the developing nervous system as early predictors of vulnerability to the disease. Schizophrenia can be seen also as a progressive disorder and a continuum of symptomatology from personality traits (schizotypy) to full-blown schizophrenia. The aim of the present thesis is to study incidence of schizophrenia; prevalence of schizotypy; and associations between schizophrenia and schizotypy with early motor developmental milestones. The research design includes prospective cohort studies and systematic review, and meta-analysis. In two successive Northern Finland Birth Cohorts (NFBC) studies, 20 years apart (1966 and 1986), the incidence of schizophrenia remained the same, but the incidence of other psychoses and therefore all psychoses was higher in NFBC 1986. In NFBC 1966, mean schizotypy scores were among the lowest and the highest scores among 24 general population studies. When early motor developmental milestones were investigated in the meta-analyses (3 to 5 studies), a significant small effect size for walking, sitting, and standing unsupported was found with respect to adult schizophrenia. When schizotypy outcome was studied in the NFBC 1966, later achievement of turning from back to tummy, touching thumb with index finger, standing up, sitting unsupported, and walking with support were found to be associated with an increase in schizotypy scales and varied somewhat by gender. To conclude, there have been changes in the incidence of all psychoses but not in schizophrenia between the two NFBCs. This is in line with other studies on the trends of incidence of psychoses, which highlights the role of changes in diagnostic systems and practices that can in, Tiivistelmä Skitsofrenia on monimuotoinen mielenterveyden häiriö, jonka etiologiaa voidaan tutkia erilaisissa teoreettisissa viitekehyksissä. Tämä väitöskirja tutkii skitsofreniaa neurologisen kehityksen ja psykoosin jatkumon näkökulmista. Skitsofrenian neurokehitykselliset teoriat pitävät kehittyvän keskushermoston poikkeavuuksia varhaisina skitsofrenian alttiuden ennustajina. Skitsofreniaa voidaan pitää myös progressiivisena sairautena ja oireiden jatkumona persoonallisuuden piirteistä (skitsotypaalisuudesta) täysimittaiseen skitsofreniaan. Tämän väitöskirjatutkimuksen tavoitteena on tutkia skitsofrenian ilmaantuvuutta, skitsotypaalisten piirteiden yleisyyttä ja skitsofrenian ja skitsotypaalisten piirteiden yhteyttä varhaiseen motoriseen kehitykseen. Tutkimusasetelmina ovat prospektiiviset syntymäkohortit, systemaattinen katsaus ja meta-analyysi. Kahdessa peräkkäisessä 20 vuoden välein kerätyssä Pohjois-Suomen syntymäkohortissa (1966 ja 1986) skitsofrenian ilmaantuvuus pysyi samana, mutta muiden psykoosien ja siten kaikkien psykoosien ilmaantuvuudet olivat korkeampia vuoden 1986 syntymäkohortissa. Vuoden 1966 syntymäkohortissa negatiivisen skitsotypaalisuuden piirteet olivat korkeita ja positiivisen skitsotypaalisuuden piirteet alhaisia verrattuna 24 muuhun väestöaineistoon. Varhaisen motorisen kehityksen ja aikuisiän skitsofrenian välistä yhteyttä tutkittiin meta-analyysin (3–5 tutkimusta) avulla. Tilastollisesti merkitsevä pieni negatiivinen yhteys löytyi aikuisiän skitsofrenian ja kävelemään, istumaan ja seisomaan oppimisen välillä. Pohjois-Suomen vuoden 1966 syntymäkohortissa skitsotypaaliset piirteet liittyivät hitaampaan vatsalleen kääntymisen, peukalo-etusormi otteen, seisomisen, tuetta istumisen ja tuen kanssa kävelemisen oppimiseen. Näissä yhteyksissä oli vaihtelua tutkittavan sukupuolen mukaan. Yhteenvetona voidaan todeta, että psykoosien ilmaantuvuus on kasvanut Pohjois-Suomen syntymäkohorteissa, mutta skitsofrenian ei. Tämä on linjassa aikaisempien tut