If it is just your eye that is twitching, I dont see any cause for worry. Eye twitching can be cause by many things, like lack of sleep or stress. I have eye twitches as well sometimes. They will either last a couple of minutes or go on and off for a day or so. It isnt often it happens. I woukd say, if the twitching gets worse, doesnt stop, or other parts of your face twitch, then you would need to seek some medical help, especially if you are on antipsycotics. Like maddie has stated, some medications can cause uncontrolled muscle movements, and uncontrolled mouth movement, called "tardive dyskenesia." It can become permanent if not treated right away. If the twitching goes beyond your eye, and frequents all over your face, then seek some medical help. Are you on seroquel, because that is what I am on and its one of the medications that can cause this as one of the sever side effects.
I have bi-polar and used to smoke marijuana habitually. I find quitting greatly improved my symptoms, but I am not here to lecture you. Marijuana causes eye irritation, so this could be a factor. Also, if you are on meds they could be causing this effect.
Are you on any meds? Some of the psychiatric meds can cause muscle spasms like that over long-term use. I'd research whichever meds you're on to see if anything correlates.