All generated 5-HT1A receptor knock-out (5-HT1A-/-) mice in several strains displayed enhanced anxiety (Heisler et al., 1998; Parks et al., 1998; Ramboz et al., 1998), although the anxious phenotype was dependent on the paradigm used (Pattij et al., 2001). The gene discussed is HTR1A; the disease is Anxiety.