The term "men in white suits" refers to people working for a mental institution. The employees usually wore white uniforms. The implication is that if somebody is giving an invitation to the "men in white suits", they are crazy or acting crazy. The term "happy pills" refers to the fact that many mental hospitals did (and some still do) give the patients powerful drugs to keep them calm. Another term for this is the "men with butterfly nets", because they would sometimes use nets and restraints to hold violent patients. It is a very insensitive term. Don't use it!

happy pills - good stuff, i want some :P

Yes. So it means. "I am going crazy!"

Happy Pill – I think we can use it referring to drugs narkomans have

Yes, someone here really need that "Happy Pill" or else he will keep on going crazy.