Maybe the most "suggestive" aspect of any of these drugs is the reduction of inhibitions and worry. But it's all relative to a person's sense of self and force of will -- they don't change you into another person, just remove some of the emotional blocks which prevent you from being, doing, or saying what you want to.
This transforms you into an Anime character. Then your jaw spontaneously shatters and your eyes start hemorrhaging rainbows.
Jokes aside, I've wondered about this as well. Especially if you treated the interrogatee in a mellow manner while he or she was captive, then slipped in some doses without them knowing, and then set the music right, or had them shacked up in some Swiss chalet with a wine cellar and a breath taking view. People spilling their guts on MDMA is a function the environment with the drug is a catalyst. And it's not like you're completely out of your mind; you are well aware of your surroundings and you would almost certainly know you've been detained, which would taint the whole experience.
This is merely anecdotal evidence, but having ingested MDMA and experienced these effects, I would say no. There is still very much a feeling that certain things are off-limits. I couldn't imagine that someone would, for example, confess to a murder whilst being interrogated under the influence of MDMA (unless they felt extreme guilt, perhaps).
However, I could easily see myself admitting that I'm not actually a heart surgeon.
On the other side, I'd never thought of using an intoxicant to invalidate lie detecting devices.