Leave a comment only once

Hi,
I’m using Jot 1.1.2 on Modx 96. It works fine.
I created a page and register users leave a comment on it.
But I don’t want that a user leave more than one comment, so is it possible that a register user leaves a comment only once?
Thanks.
Matteo

This is a good solution:
http://modxcms.com/forums/index.php/topic,15402.0.html
if time is long enough..
Thanks to gadiandi.

Matteo