According to this site, nothing can be done re: your Tourette's Sybdrome neighbor, as he has rights like everyone else re: fair housing.
(A pretty extensive info site)
http://realmentalhealth.com/tourettes/living_housing.aspThoughts:
You could move into different apt. same complex without beaking your lease.
You may have rights regarding this situation in that the apt. owner may be responsible for adding soundproofing to yours or the neighbor's apt. (read in the article site above)
You may want to ask FHA if you should have been informed of possible noise disturbance prior to leasing your apt.