Pre-morbid personality and aggressive behaviour in psychogeriatic inpatients In the present study, the correlation was examined between pre-morbid personality traits and the occurrence of aggressive behaviour in residents of a psychogeriatric nursing home. The participants in the study were the close relatives of 39 residents of a psychogeriatric nursing home. These residents were selected on the basis of two subscales of the BOP assessment scale for elderly patients: Aggressive and annoying behaviour, and Mental disability. Residents were divided into two groups: one group did not display aggressive behaviour, the other group displayed a great deal of such behaviour. The groups were comparable with regard to the degree of mental disability. To ascertain pre-morbid personality traits, use was made of the hetero-anamnestic personality questionnaire (HAP) and the Quick Big Five (QBF). We found no significant differences in any of the pre-morbid personality traits between the two groups. We could not confirm the conclusion of other authors that emotional lability (neuroticism) is a personality trait which makes people susceptible to developing aggressive behaviour. In conclusion, our study did not confirm the hypothesis that pre-morbid personality traits are useful to explain the occurrence of aggressive behaviour in residents of a psychogeriatric nursing home.