Hi Creativerachna,
  
Thanks for submitting your question about art therapy and child development. My experience with art therapy is that it provides a great way for children to overcome and express sensitive and traumatic issues and emotions without the use of verbal expression.  As a former teacher, I once had an elementary student who lost her father and part of her grieving process involved drawing pictures of memories with her father, which evolved to expressing her fear and anger of losing him to gunfire, by drawing images of the 911 violent tragedy (2 years after the occurrence) as a metaphoric representation.
 
Many times children are at a lack of words or too shocked to be able to access the verbal language to express how they're really feeling about a tragic or horrific experience. Drawing or creating art that is representative of their experience can often be a safer way for them to slowly peel back the layers of the armor protecting them from their deep emotions and allow them safety from retraumatization.
  
I have also had experience with a student who was very troubled due to a variety of reasons, from his home life to his cognitive abilities and the impact of these issues came to a head through his dark drawings, which were evidence enough for me to refer him for priority counseling within the school where I worked.
  
I have attached a link from a Dr. Laura Just Ask answer describing art therapy for supporting a young victim of abuse.  Included at the end of the article are a host of links for further reading on the subject.
  
http://www.education.com/question/activities-7-year-abuse-background/
  
This last link is for a great article outlining the importance of art therapy for cognitive, speech and language, motor and socio-emotional development.
  
http://www.education.com/reference/article/art-enhance-major-areas-development/
  
We can learn a lot about a child and their development from their art creations. I'm glad you brought this issue to light.
  
Best regards,
Lori