The invention provides an indene compound represented by the following general formula (I): ##STR1## wherein R.sub.1 means a lower alkyl group, R.sub.2 and R.sub.3 denote a lower alkyl group individually or an alkylenedioxy group in combination, and R.sub.4 and R.sub.5 mean individually a substituted or unsubstituted lower alkyl or aryl group or in combination a substituted or unsubstituted piperidino, piperazinyl or homopiperazinyl group together with the adjacent nitrogen atom, with a proviso that not both R.sub.4 and R.sub.5 are a methyl group at the same time.
