Causal Discovery from Medical Data: Dealing with Missing Values and a Mixture of Discrete and Continuous Data

Causal discovery is an increasingly popular method for data analysis in the field of medical research. In this paper we consider two challenges in causal discovery that occur very often when working with medical data: a mixture of discrete and continuous variables and a substantial amount of missing values. To the best of our knowledge there are no methods that can handle both challenges at the same time. In this paper we develop a new method that can handle these challenges based on the assumption that data is missing completely at random and that variables obey a non-paranormal distribution. We demonstrate the validity of our approach for causal discovery for empiric data from a monetary incentive delay task. Our results may help to better understand the etiology of attention deficit-hyperactivity disorder (ADHD).