[rossdavidh]

"Spazzy" or "spastic" is not especially offensive in the US, although I suppose given our ever-escalating sensitivity it soon will be. It mostly just implies "given to spasms", which I suppose is the origin. More generally, it implies not terribly well-organized in behavior. A person might say it of their own behavior without meaning anything exceptionally bad.

[morelisp]

It has been offensive in the US since the 90s. It just gets used anyway anytime there's some "anti-PC" movement, along with "gay" to mean "bad", the r word, sudden spikes in the use of "niggardly", and so on. Like those, its offensiveness does not come from offense taken by the person/thing it is proximately describing.