5-HT1A modulator 1 (Compound 24) shows clear antagonist action at 5HT2A receptor subtype in mice. The antagonism is nearly complete at the dose of 1 mg/kg ip for 5-HT1A modulator 1 (94% of antagonism, p<0.01). 5-HT1A modulator 1 completely blocks the stereotypies and the climbing at the dose of 1 mg/kg ip (100% of antagonism). 5-HT1A modulator 1 is also tested in rats, using the same paradigm. After oral administration, 5-HT1A modulator 1 significantly (p<0.05) reduces the hyperactivity by 50% at the doses of 2 and 4 mg/kg po, respectively 63% and 58% of antagonism for 5-HT1A modulator 1; the antagonism is complete (103% and 108%) at the respective doses of 8 and 16 mg/kg po for 5-HT1A modulator 1 (p<0.01).