Hmmm... well, first off... everyone has something they need to "deal with"... whether its bad breath, being messy, being too stingy, hogging the bed or having PTSD... so, Id say NOT the first date for sure!
My fav hobby (and relaxation) is watching dating shows. I think people really make a mistake when they completely unload on a date and give them a list of all their flaws... ESPECIALLY when they blow it way out of proportion... "I have tourettes and it could be passed on to our children and it makes me uncomfortable in certain situations and when I get stressed my face ticks etc". Yet, I think its also fraud to conceal these things and not be yourself. That is... dont be fake-ass barbie but, you dont need to read from your psych-jacket either! Aim for average-cautious-conciencious on this one.
I'd say how soon you announce it probably depends on your symptoms a little too right? Like do you scream out loud in the night, do you have an anger issue, are you unable to be sexual and intimate in a way that might make you or the other person feel bad, rejected, awkward etc... And also how far you are in your treatment... that is.. how much will this affect the other person... a little or a lot?! I think these all are factors.
My 3-cents is... first date is fun and flirty, second date too. If there is anything that anyone dating you (like GwenDR said) is absolutely necessary to know... like you cannot go on a motorcycle and you know they have a motorcycle as their only transportation or they should never try and grab you from behind... best to tell that info out right from the get-go.
After that... Don't share anything with anyone you arent connecting with as you will regret this later as you will feel like you gave a piece of yourself to someone who didnt care... and dont share anything with anyone you can't trust with that info; that is, someone who isn't connecting with you on simple empathy level to begin with; I personally would not share "details" (nor another date)... if they are irritated that you had to pee three times during the movie, not a good candidate; if they talk badly about other people, are insensitive etc... not a good candidate.
... dole a little out at a time.
If the other person is emotionally intimate with you and shares stuff like they "have fears about being cheated on" you might say you "have anxiety about moving too quickly due to past relationships" and comment that you "both have reasons to get to know eachother slowly". At some point you can even say you have a "stress condition" from a bad past experience and would like to share more sometime in the future. See how they are reacting with the little crumbs before hitting them over the head with the whole loaf. Certainly don't blurt out the whole thing and don't go on and on about it in the beginning. And how/what/when this stuff happened to you.
This is YOUR story! Make them earn the right to hear it but, don't keep it a secret you take to the grave either! Give info as needed and as they do and as you feel comfortable!
Good luck and be sure to let me know how it goes! I live to hear aboyt dates!
Xoxo!