Abstract
Recent research on lone-actor terrorism has found a high prevalence of mental health disorders among these offenders. This research note addresses two shortcomings in these existing studies. First, it investigates whether selection effects are present in the selection process of terrorist recruits. Second, it builds on the argument that mental health problems and terrorist behavior should not be treated as a yes/no dichotomy. Descriptive results of mental health disorders are outlined utilizing a number of unique datasets.