HTR1A and mood disorder: Alterations in 5-HT1A receptor function have been related to mood disorders, as imaging analysis shows that depressive patients have reduced 5-HT1A receptor binding (Drevets et al., 1999; Sargent et al., 2000) as well as blunted responses to 5-HT1A receptor agonists (Lesch et al., 1990a,b).