Psychiatry mistakes

Neuroleptic drugs don't work as truth serum. Hypnotizing doesn't help much, either. People will always only confess what they want to confess. Hypnotized people can be good liars. The character of a human being cannot be changed by hypnotic suggestion.
Benzodiazepines (e.g. Valium) or simply wine (in vino veritas) are more useful if you want people to talk. But the writers didn't bother, obviously.

And a baby (<6 month) doesn't have traumatic memories. Early childhood psychological trauma may start with 2 years of age.