Increasingly, challenging behaviour is explained by way of psychiatric symptomatology. This poses possible pitfalls. First, the possibility exists that both psychiatric symptoms and challenging behaviour are concurrent expressions of common underlying factors. Second, psychiatric symptoms may be rated as present on the basis of challenging behaviour, which may render it more difficult to explain the latter by way of the former. The present study was conducted in order to investigate possible overlaps between psychiatric symptoms and challenging behaviour, when symptoms are rated by caregivers. The results indicate considerable overlaps. Implications for explaining challenging behaviour are discussed, as well as limitations of the study, first and foremost the use of untrained assessors and small sample size.