We did not find indications for a triangular relationship of challenging behaviour, the application of restrictive measures and PD prescriptions. Future longitudinal research is needed to better understand this complex relationship and should investigate the indication and the effect of treatment. WHAT THIS PAPER ADDS?: This study is a first exploration of the potential triangular relationship between symptoms of challenging behaviour, psychotropic drug (PD) prescription, and the application of restrictive measures. Prescribing PDs and applying restrictive measures are two interventions which are commonly used to manage challenging behaviour in people with intellectual disabilities. Both have been subject of research separately in recent years. However, it is conceivable that the PD prescription in treatments for challenging behaviour could be a substitute for another form of a restrictive measure, for example a physical or mechanical restraint. For this purpose, we defined and compared four mutually exclusive groups of participants. We found no indication for this triangular relationship. On the other hand, we found the highest severity of challenging behaviour in the group who used PDs as restrictive measure next to other restrictive measures. Our results may suggest that both prescribing PDs and applying non-pharmacological restrictive measures are used simultaneously in managing challenging behaviour, are not sufficiently implemented or effective.