Post History
That's tough, it sounds like a hundred page wall of dialogue to me. To eliminate most of it, I'd resort to flashback. Flashbacks are not that popular anymore; but they would be better than an endl...
Answer
#4: Attribution notice removed
Source: https://writers.stackexchange.com/a/46353 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/
#3: Attribution notice added
Source: https://writers.stackexchange.com/a/46353 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/
#2: Initial revision
That's tough, it sounds like a hundred page wall of dialogue to me. To eliminate most of it, I'd resort to flashback. Flashbacks are not that popular anymore; but they would be better than an endless wall of dialogue or thoughts. For flashback, write the recollection as a story, with a neutral narrator, [third person omniscient limited](https://www.thebalancecareers.com/third-person-point-of-view-1277092), focused on the character. For the psychiatrist, have them use a [Guided Imagery Therapy](http://www.minddisorders.com/Flu-Inv/Guided-imagery-therapy.html), i.e. the psychiatrist is asking questions of the patient to **tell** the memory in story form, to remember the details of what was seen, felt, who was there, etc, not in a demanding way, but as if curious. You can begin with this, and after a hundred words or so, drop into the patient's flashback of the experience, which you tell as if it is currently happening, and then at the end pop out of the flashback into the psychiatrist's office. Using this pattern the reader will see the conversation with the psychiatrist as prelude to a flashback. You can make a chapter out of each such flashback, the chapter begins and ends on the psychiatrist's couch. You could interleave these chapters with chapters about what is happening to the patient (or psychiatrist) in the present day, which may offer some parallelism with the flashbacks.