As a child psychiatrist I see a lot of children who have been adopted, and with good reason. It is a major event in a person's life, how can it not be an enormously emotionally loaded event. Research notes that adopted kids have 9 times greater likelihood to have psychiatric issues. Reasons for this may be numerous. The developmental struggle when the adoptee is trying to develop their sense of identity, the genetics that are very strong (after all, the bio parents may have gotten in their predicament because they were impulsive, risk taking, unable to take care of their child, etc.), attachment issues if the child was old enough to expierence the separation and loss of the primary care-giver, etc.
It is important for people planning on adopting to realized that some of these factors are so strong that love isn't enough to change the emotional and behavioral ups and downs that may follow! It is important to realize that the decision to adopt will be life changing both for the better but also for the more challenging. Now, there are wonderful adoptive parents that have been challenged in tremendously painful fashion that have persevered and stuck with their child, working hard to overcome the challenges and getting to the point where there was a turn for the better years later as the child matured. I have been impressed and inspired by parents like these. Not everyone can do this, in fact I 'm not sure I would be strong enough. When parents have told me that their child has never told them they loved them and they are 8 years old, they have invariably told me this with tears in their eyes. Yet, two families that come to mind have been wonderfully blessed by their children who became awesome teen-agers and who were finally able to reciprocate and express their love to them. They are special young people who were blessed with parents who wanted them so badly and were willing to sacrifice for them. If you are thinking of adoption, go into it with open eyes but be willing to persevere no matter what life brings you, sometimes there are greater rewards in one's sacrifice.