Prolactin response to neuroleptic challenge in late-life psychosis.

Psychosis in the elderly is superimposed on both age-related and disease-specific declines in dopaminergic function. Though the prolactin (PRL) response to neuroleptic challenge has been used as an in vivo measure of dopaminergic function in midlife adults, it remains uninvestigated in late-life psychoses. We examined the PRL response to intravenous perphenazine (PZ) in 11 elderly patients with psychotic symptoms complicating either a major depression (MD-P) or a dementia. The magnitude of increase in prolactin after PZ divided patients into three non-overlapping groups: dementia patients had a bimodal response and MD-P patients fell between the dementia groups. Our findings suggest that the PRL response to PZ may provide an in vivo measure of dopaminergic function in elderly patients. This finding must be confirmed through correlation with other measures of dopaminergic function in late-life psychoses and with measures of neuroleptic response and neuroleptic-induced extrapyramidal effects.