During the past 75 years, the proportion of elderly individuals in the USA has grown twice as fast as the general population. Depression in this age-group occurs four times more frequently than in the general population (Butler, 1975), and the suicide rate for people over 65 years of age is 15 times greater than that of the general population (Lehman, 1980).
The elderly may be more susceptible to depression due to biological and/or psychosocial variables. Elderly people experience significant losses associated with increasing age, including death of spouse and friends, loss of work, social status, and physical and mental abilities (Lehman, 1980). The biogenic amine hypothesis suggests that the aging brain may experience a decrease in the functional availability of neurotransmitters (Lehman, 1980); this decrease may also play a role in the aetiology of depression.
Due to age-related changes in the body, the elderly can be more sensitive to drug therapy. Older patients may require careful dosage adjustments and may also be more prone to experiencing drug-related adverse events. The elderly often receive medication for various indications, and drug interactions are a concern (Thompson et al, 1983). Therefore, efficacy and safety studies of new antidepressants in elderly patients are particularly important. We pooled data from both double-blind and open-label studies to evaluate the efficacy and safety of fluoxetine in geriatric outpatients with DSM-III major depression. Positive results of fluoxetine in the treatment of geriatric depression were reported in one of these studies (Feighner & Cohn, 1985). The favourable safety and side-effect profile of fluoxetine in the general population has been discussed elsewhere (Wernicke, 1985). Plasma concentrations of fluoxetine in elderly subjects are similar to those in younger individuals (I.emberger et al, 1985). These findings, combined with a lack of cardiovascular effects (Fisch, 1985), and low lethality with overdose, indicated promise for fluoxetine as a geriatric antidepressant.