BACKGROUND Clinicians see many more nonagenarian patients now and there is a need for epidemiological data relating to this group. The aim of the present study was to investigate the prevalence of depressive symptoms and syndromes in this age group.

METHOD The DSM-IV and the ICD-10 criteria for depression were used and correlated with physical health, disability in daily life, gender, use of drugs, social circumstances and cognitive dysfunction. Data were derived from 329 persons aged 90 and over, registered in a parish of Stockholm, who had been extensively examined by physicians and nurses.

RESULTS/CONCLUSIONS The prevalence of Major Depressive Episode as defined in DSM-IV was 7.9%; and of mild, moderate and severe Depressive Episode (combined); as defined in ICD-10 9.1%. No gender difference was found. Disability in daily life and the use of psychotropic drugs were found to correlate with depressive symptoms and syndromes.