Yes, some topless dancers do drugs or drink alcohol to get high and use it as a crutch to make her more comfortable in taking her clothes off.  The topless club scene lends itself to the drug scene.  There are guys trying to score with topless dancers by offering them drugs, dancers sharing drugs with other dancers, undercover agents trying to sell drugs, etc.

 Some clubs monitor the dancers for drugs and they will fire you if you're caught.  Other clubs just don’t care what the dancers do.  Should you reject a dancer that appears to be drunk or high on drugs?  No, because she may be feeling rather loose and perhaps even horny and this can be to your advantage by making your prey easier to catch.  Plus, you may be able to talk her into a free table dance.
 

That's why it's better to go to topless clubs just before closing time.  Later in the night the dancers may be drunk or high and under these influences they may shed their inhibitions.  Also, if they appear to be drunk or high while giving you a table dance, be sure and ask her to show you her bush.  Legally she's not supposed to do that in a topless club, but being that she's under the influence she just may do it.

One final word of advice.  If it's obvious that she's drunk or high don't come on real strong and be sexually aggressive with her.  She may think you're trying to take advantage of her because she's loaded.  Just be friendly with her and treat her with respect.