In psychiatry we don’t tend to wear scrubs – though it would make it easier deciding what to wear!
In other hospitals the colour/pattern can tell you what role someone has, e.g. physios will wear one type of uniform, OTs another. Nurses will often have slight differences which will show seniority, such as the matron will have one colour, e.g. dark blue, the staff nurses another e.g. light blue, the students another etc. The differences vary depending on which hospital you’re in.
There isnt really a difference between doctors that wear scrubs, it’s just what they have clean in the changing rooms! A&E scrubs will often have “doctor” or “consultant” stitched on to them