This article is from the Psychology FAQ, by Rolf Marvin Bøe Lindgren roffe@tag.uio.no with numerous contributions by others.
There are two dangers in choosing a friend for support rather than a
psychologist. I call them the container effect and the birds of a
feather effect.
The container
The container patiently listens to your problems and identifies or has
empathy with you. They're good to have because they provide basic
support, and are often an individual in distress' sole need: when the
immediate problem is solved, the problem ceases to be.
However, in order to actually solve a difficult problem, the container
can help to maintain a problem because the container is a friend and
does not confront, or, confronts but inappropriately. This can
jeopardize a friendship which is of course valuable in its own right,
without solving anything.
A trained psychologist does not contain, and confronts appropriately.
Birds of a feather flock together
Poeple who suffer from the same problems tend to seek together, either
unconsciously or for support. Once to many, I've seen people who have
the same problem refuse to confront it, and as a result actually
accelerate each other's psychopathology.
This occurs relatively fast and is one of the reasons why group
therapy may be very effective. In group therapy, the interaction
between people and their symptoms are supervised by the therapist, who
(hopefully) will confront the clients when appropriate.
 
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