Age differences in depression and anxiety symptoms: a structural equation modelling analysis of data from a general population sample

Background. There is debate as to whether the elderly are really at lower r isk for depressive disorders, or whether endorsement of symptoms is artefac tually low. The present paper assesses the effects of age on anxiety and de pression, and examines whether age has direct effects on self-report of ind ividual symptoms independent of its effect on the underlying dimensions of anxiety and depression. Methods. Structural equation modelling was used to assess the structure of the items and their associations with age and a number of demographic varia bles. The sample of 2622 participants aged between 18 and 79 years from Can berra (Australia) was drawn from the Electoral Roll. Two instruments were u sed: the anxiety and depression scales of Goldberg et al. (1988) and the Pe rsonal Disturbance Scale from the DSSI of Bedford et al. (1976). Results. Both scales were found to fit satisfactorily to a two factor model . Age correlated negatively with depression. After controlling for the effe cts of gender, marital status, education and financial difficulty, direct e ffects of age were found on items from both instruments, indicating that ce rtain depression items were associated with a differential probability of e ndorsement in older people, even when the level of depression was equal to that of younger people. Items with direct age effects reflected physical (f eeling slowed down; waking early) and psychological (hopeless about the fut ure) components of depression. Direct effects of age on items from both anx iety scales were also found. Conclusions. The nature of the depression and anxiety experienced by younge r and older people may differ qualitatively. Depression may be associated w ith an increase in somatic symptoms linked to physical changes and to an in crease in endorsement of items which reflect the narrowing of opportunities in the long-term.