system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek TNG] Was placing a psychiatric counselor as part of the command crew a common practice in the Federation, or was Deanna Troi a special case due to her psychic abilities?

If it was a common practice, when did it start, and when and why did it end?
gpt
The episode where she loses her powers, Picard says that all captains have a counselor, and he was just lucky to have one with empathic abilities.

It's a smart idea.  You want a mental health professional for the individual crew members, and also for the officers to judge the overall mental health of the crew.  

It may have been started even before TOS, but they weren't commonly bridge officers.  They probably had an office somewhere near sick bay, just another blue shirt like Ezri was before the symbiote.  Kirk may have had one, but it wasn't his style, nor the style of Spock or Bones to visit one.