Depression affects hundreds of millions of people worldwide, yet more than half of patients do not respond to standard psychotherapy. The SYNTHESIS project, led by Prof. Dr. Eirini Karyotaki at the University of Amsterdam, addresses this challenge directly. By integrating Individual Patient Data (IPD) from over 573 randomised controlled trials, including more than 73,000 patients and combining advanced network meta-analyses with machine learning, SYNTHESIS aims to identify which psychotherapy works best for whom. As the project biostatistician, you will be the methodological engine behind the most innovative part of SYNTHESIS: the integration of machine learning into Individual Patient Data (Component) Network Meta-Analyses. Working closely with the postdoctoral researchers, PhD candidates, and Prof. Dr. Karyotaki, you will develop and implement the ensemble learning pipelines, predictive models, and interpretability frameworks that will ultimately inform personalised clinical decision-making tools for psychotherapy.