Salivation and depression: a role for appetitive factors.

A decrease in salivary flow rate (SFR) is associated with depressive illness although the mechanisms underlying this association are unknown. Appetitive factors are known to influence SFR, but are not adequately considered in the studies of salivation and depression. Diminished SFR in depressive illness may be more closely related to the appetite disturbances commonly associated with depressive illness than to mood disorder or depressive illness per se. The implications for considering SFR as a physiological correlate of depressive illness are discussed in light of this possibility.