In Reply.—
In their very thoughtful letter, Drs Glue and Nutt suggest a number of possible reasons to account for the discrepant findings between our patients with affective disorder and their normal volunteers. We are in agreement with them that interpretation of our data is complicated by the greater pretreatment prolactin responses in the long-term lithium treatment group. We therefore conducted additional data analyses to examine the specific possibilities they raise.1. The difference in mean age between the two lithium groups does not appear to account for the discrepancy. Although the short-term group was older (42.5 ± 14.8 years) than the longterm group (35.2 ±12.5 years), this difference was not statistically significant (t= 1.4, P =.18). Moreover, in contrast to the significant negative correlation of age with peak prolactin response observed in our previous studies with normal volunteers, age was nonsignificantly positively correlated with peak prolactin response (p =.21, P