Based on the documented cases of psychotic break and the number of people who meditate, the odds are approximately a million to one in your favor of getting some benefit out of mediation vs. a psychotic break.

From what I've read, psychotic episodes were preceded by exceedingly long meditation sessions. Essentially, don't meditate for more than an hour a day and you should be okay, the psychotic breaks have a higher tendency to happen at meditation 'retreats' where they do like 8 hours a day of meditation.