Where can I find articles written about art therapy that are
negetive-problem with the pratice?

I will add more momentarily.  However,
http://www.arttherapy.org/art_therapy_in_the_news.htm
says that:
"the biggest problem facing the field of art therapy is that there are
not enough art therapists and not enough institutions to train them,
especially in the Southwest - a problem she hopes some foundation can
address."
If you can call that negative...

Thank you for the comment but this is not what I need. I must have
creditable sources such as a mental health professionals, stating the
CONS in art therapy-for example-- “it encourages feelings to go
unverbalized”, or “there are unprofessional trained people doing the
work”, etc.  I need the cited research in order to argue all PROS. for
an argumentative research paper I am doing in English Compaction.  Our
professor requires at least three sources. Any help would be greatly
appreciated.

Certainly.  Thanks for the clarification.  I now have an idea of what
to look for, and will certainly do so.  I will try to find some mental
health organizations and see what they say, particularly the Boards
that decide credible treatment because, for a while, this form of
therapy was not accepted in the mental health community, and I am sure
there are plenty of their quotes still hanging around somewhere
online.

On a personal note, I have found the treatment to beneficial to some,
but not really for others.  Here is a personal experience I have seen,
although I must first note that I am not a mental health expert and
this experience describes my distanced observation of a woman and my
own opinions:

a woman who was undergoing counseling for post traumatic stress
syndrome tries this controversial form of treatment.  The person
treating her suggested she draw her feelings, her thoughts, and her
dreams in a sketchbook so that she would relieve the intense pain
buried in her, and to give him a better picture for what she could not
put into words.  Upon being faced with her thoughts in vivid color,
she becomes apprehensive about showing the work to family, who see the
book as the tangible manifestation of all of the things they could not
understand about her.  They want to understand and see the “art” the
woman has created, while she only wants to hide it and keep it a
personal thing between she and her therapist.  This creates a break
down in the family as the family is hurt by her hiding from them, and
to her with her mistrust and paranoia of them looking at her work. 
This could be seen as negative, because in treating one problem,
another has been produced.  She finds herself horrified at facing the
tangible manifestation of her thoughts.  She tends to lack
verbalization, using the private sketchbook as a crutch against
verbalizing her feelings to others.  She suppresses things.  My
thoughts are that the art therapy can be a good thing with some, but
particularly dangerous with certain patients.  You see, I feel that
therapy is most effective when a person can empty themselves of their
pain and guilt, and foster understanding with others.  By using the
sketchbook as a vessel for their pain, they are not sending it from
themselves and gaining support, but are simply moving the pain and
guilt to this new extension of themselves, where they must ultimately
face their pain alone…something some people are not mentally strong
enough to do.

This is hard for me to say considering that I worked as a studio
artist and find my work extremely therapeutic.  Then again, I can
handle facing the manifestation of my thoughts and feelings.  The
woman I described, could not.

Good luck in your search and I will try to track down those references
for you.

No luck as of yet on those references, although I must admit that I
took a short vacation in the midst of my searching.  I will, however,
resume looking and see if something won't pop up somewhere in the
nether regions of the 'net.

dexterpexter

Here is an article from cancer.org

http://www.cancer.org/docroot/ETO/content/ETO_5_3X_Art_Therapy.asp?sitearea=ETO

"Art therapy is considered safe and may be useful as a complementary
therapy to help people with cancer deal with their emotions. Although
uncomfortable feelings may be stirred up at times, this is considered
part of the healing process."


Another article:

http://www.findarticles.com/cf_0/g2603/0001/2603000173/p4/article.jhtml?term=

"Art materials and techniques should match the age and ability of the
client. People with impairments, such as traumatic brain injury or an
organic neurological condition, may have difficulties with the
self-discovery portion of the art therapy process depending on their
level of functioning. However, they may still benefit from art therapy
through the sensory stimulation it provides and the pleasure they get
from artistic creation.

While art is accessible to all (with or without a therapist to guide
the process), it may be difficult to tap the full potential of the
interpretive part of art therapy without a therapist to guide the
process. When art therapy is chosen as a therapeutic tool to cope with
a physical condition, it should be treated as a supplemental therapy
and not as a substitute for conventional medical treatments."

Hope these help...