What mental and emotional effects does the veldt have on the children, the parents, and the psychologist in Bradbury's "The Velt"?

Ray Bradbury's short story "The Veldt," published in 1951,
reflects the concerns of other science fiction writers such as Aldous Huxley
who published Brave New World in 1932:  The advancement of
technology ahead of the advancement of humanity.  Much as in his other short story
"There Will Come Soft Rains," in which the house continues to operate on its own after a
nuclear blast kills all the occupants, the playroom of the Hadley children virtually
controls the lives of the occupants.  The children "live for the nursery," says George
Hadley to his wife.

Thus, there is an uneasiness generated
in the parents as they sense the control that the Veldt room holds upon Wendy and Peter,
their children.  For, the children have alienated themselves from their parents,
expressing no desire to participate in any familial activities such as dinner.  Without
their children to care for, Lydia feels unneeded since the house responds to the
smallest need, such as ketchup.  For instance, when the diningroom table produces warm
dishes of food, George Hadley simply has to ask it for ketchup or anything else and the
item appears.

When the Hadley's friend David McClean, who
is a psychologist, arrives, they ask him to inspect the African veldtland.  Upon
entering this playroom of the children, McClean remarks that it does not "feel
good":

"This
is very bad.  My advice to you is to have the whole damn room torn down and your chidren
brought to me every day during the next year for treatment...In this case the room has
become a channel for destructive thoughts, instead of a release away from
them."

Further, the
psychologist tells George Hadley that he has allowed the room to take the place of him
and his wife in the children's affections.  But, when George tries to shut down the
room, Peter tells his father, "Oh, I hate you...I wish you were dead."  Peter's father
replies that he and his wife were dead, but now they are going to live as a family.  The
house has become what George Hadley has called "a nightmare."  And, the dramatic irony
of George's lines is that he does not realize how nightmarish it
is.