Johannes Lieslehto

The number of people diagnosed with autism spectrum disorder (ASD) in childhood or adulthood has strongly increased over the past decades. While research demonstrates that people with ASD are at risk of adverse health outcomes including preterm mortality, scientific knowledge on the pathways leading to adverse health outcomes and an increased health care consumption, along with the effectiveness of different pharmacotherapies, is limited.The overall aim is to characterize pathways to increased health care consumption and adverse health outcomes in individuals with ASD diagnosed in childhood, as compared to those diagnosed in adulthood, and to examine the influence of various individual factors as well as treatment effectiveness in lowering the risk of adverse health outcomes and elevated health care needs.Data and method: The studies build on linked register data in Sweden and Finland. The study populations in Sweden include 84,012 individuals diagnosed with ASD during 2003-2018 as well as two comparison groups: 1) individuals from the general population

and 2) full-siblings. Cutting edge methodology such as network- and machine learning models as well as novel methods in pharmacoepidemiology will be applied. The five-year project involves interdisciplinary collaboration including clinicians and epidemiologists.This project provides crucial scientific knowledge necessary to design optimal health care and pharmacological treatment for patients with ASD.

Cannabis use is increasing worldwide and also certain European countries plan to legalize or decriminalize cannabis. This will further increase use rates and also result into higher number of people with cannabis use disorder. Cannabis use in persons with severe mental disorders, namely schizophrenia-spectrum disorders, bipolar disorders and major depressive disorder, has been reported to adversely impact on illness course and associate with non-adherence to treatments. However, impacts of cannabis use disorder on long-term treatment outcomes in severe mental disorders are not known.  The overall aim of this project is to investigate long-term treatment pathways and outcomes of patients with severe mental disorder and comorbid cannabis use disorder, to help in designing optimal health care for these patients. We aim to investigate healthcare service and medication use and work disability during first five years of illness, compared to patients with severe mental disorder without cannabis use disorder. We will also investigate risk of mortality and effectiveness of medications associated with decreased risk of illness relapse, and mortality. Finally, we will develop a prediction model for adverse clinical outcomes to help clinical practice to inform which patients are at the highest risk and in need of enhanced monitoring and effective interventions. Further, we will investigate whether treatment can be tailored based on the predicted risk level.