Is it possible to give yourself synesthesia?

Yes, You Can Teach Yourself Synesthesia (And Here's Why You Should) A synesthete-turned-scientist on why it's helpful to "hear" colors and "see" sounds. Berit Brogaard has had synesthesia, a neurological condition in which different senses combine in unusual ways, for as long as she can remember.

Can you suddenly develop synesthesia?

However, in some cases synaesthesia has a sudden onset, for example, caused by posthypnotic suggestions, drug exposure, or brain injury. Moreover, associative learning during a critical developmental period also seems to play an important role. Synaesthesia may even be acquired by training in adulthood.