Cecilie K. Lemvigh, Copenhagen University Hospital

My interest in schizophrenia began already as a young university student and was motivated by a growing curiosity of how the human mind works. I am particularly interested in the developmental perspective on cognitive and brain maturation to examine trajectories leading to psychopathology. Currently, a precise understanding of the abnormal processes resulting in psychosis is lacking. I strongly believe that a better understanding of complex developmental trajectories may help progress the field in terms of more effective prevention programs, improved diagnosis, and individualised treatment strategies.

My presentation at the 2022 SIRS Annual Congress focused on this issue by examining how the combination of multiple early risk factors such as parental history of psychosis, low birth weight, premature birth, winter/spring birth, urbanicity, immigration status, paternal age, maternal smoking during pregnancy, and Apgar scores influence the age of illness onset in children, adolescents, and adults with psychosis. We conducted a nationwide register study of all individuals in Denmark receiving a schizophrenia spectrum diagnosis from 1973-2018 (N≈30.000) and a healthy control sample (N≈140.000). Here we found that parental history of psychosis, advanced paternal age, maternal smoking and low birth weight independently increased the risk of a schizophrenia spectrum disorder. Subgroup analyses based on sex revealed that advanced paternal age only increased the risk in females. Approximately 20% of the patients could be characterized as child-onset cases (<18 years) with female sex and parental history of psychosis as significant predictors of having an early onset. We also observed a cumulative effect of the early risk factors on age of illness onset with more risk exposures resulting in an earlier age of onset. These findings provide a basis for future treatment strategies in terms of individual risk stratification and early intervention, which from a health policy perspective is necessary in order to prevent, delay or attenuate the impact of schizophrenia spectrum disorders.

In ongoing studies, we relate the register data to our clinical cohorts and explore how these early risk factors influence cognitive performance at the time of illness onset. A better understanding of how multiple early risk factors acting in combination influence neurodevelopment may shed light on the mechanism underlying cognitive deficits in schizophrenia.

The inclusion of register data limits the effect of recall bias when examining exposures occurring many years prior to illness onset. The combination of clinical and register data is highly unique worldwide and will hopefully contribute with valuable knowledge to the field of psychosis.

Participating in SIRS 2022 and receiving the honour of an early career award was highly beneficial to further broaden my current knowledge and expertise, expand my international network, exchanging ideas and establishing new collaborations.

Finally, although we already know a lot about the development of the brain, we still have a lot to learn regarding the abnormal processes leading to cognitive impairments and emerging psychopathology. Much more research is needed to develop more effective treatments and improve the life of our patients. In this regard, I would like to express my deepest gratitude and appreciation towards all the patients in our studies for putting research before their own suffering, sharing a piece of their story and enduring long hours of psychiatric evaluation and neuropsychological testing.