The issue is rather the weight put on the medical evidence. Medical evidence only goes so far - for example that the symptoms are compatible with torture as the 1994 proposals for Guidelines illustrate. A person can be rejected as not credible provided the medical evidence has been considered. There are pros and cons about informality in the hearing. The quality and content of a medical report and time spent with the patient is what matters and, unfortunately, this translates into dollars.
Cultural barriers can block people going to a psychiatrist.
Unfortunately, the IRB can take the view that a victim of torture case is complex and so requires a full hearing. Things can also be done to reduce stress in a hearing as the 1994 proposal for guidelines shows. A hearing can be suspended now - but the lawyer must ask and make the case for this. There can be short breaks in the proceedings. The regular rules can be adapted for example to take bedside testimony or to use character witnesses.