Re: Medicine & Psychology.
Just as a point to think about, Psychiatrists have to be fully qualified medical doctors before specialising in psychiatry - just as a cardiologist has to be a doctor before specialising in cardiology.
Psychologists don't - they're about equivelant to registered nurses or physiotherapists.
In practice, the difference is whether or not the practitioner can prescribe drugs: a psychiatrist can, a psychologist can't.
That said, I've always envisaged Troi (for example) as more of a psychologist than psychiatrist - to my knowledge, we never saw her prescribe any drugs, and she even referred Riker to Crusher when he needed 'something to help him sleep'.
So perhaps a more accurate breakdown would be that the Psychology could be a specialisation of either Medicine or Persuade/Influence, depending on the practitioner.
Hmmm...have to think about that one...
When you are dead, you don't know that you are dead. It is difficult only for others.
It's the same when you are stupid...