Can you get hallucinations of smell and touch?

We put this question to Professor Paul Fletcher...

Paul - You certainly can - you can get hallucinations in any sensory modality. You can get hallucinations of taste, smell, touch, as well as visual and auditory. In fact, in certain cases of mental illness, hallucinations of smell can be exceedingly unpleasant and people can have the belief that they're actually rotting from the inside.

Chris - That's not very pleasant.

Paul - It sounds horrible.