Pharma has trouble recruiting patients for trials --could excessive exclusion criteria be the reason?

This month's R&D Directions has an article about the difficulty pharmaceutical companies have in recruiting patients for their trials. The article suggests that the problem may lie with trial sponsors that have not thought through their recruiting strategies, and with patients who are scared about side effects and product withdrawals.I can think of a few more reasons:

• Trial protocols often have long lists of exclusion criteria. These criteria make recruiting difficult and if anything they harm the results. For example, an article by Posternak et al. in the American Journal of Psychiatry 159:2, said, "Many of the standard exclusion criteria currently used in antidepressant trials may not be achieving their goals of maximizing drug-placebo differences. The practice of excluding subjects with particular clinical profiles, which greatly reduces the generalizability of antidepressant efficacy studies, appears to lack empirical support."
• Some sponsors are disorganized and difficult for sites to work with. Leading sites have more trials than they can handle and will favor enrolling patients in the trials that are easier to run
• Some of the trials are mainly for marketing purposes. It's not necessarily in a patient's best interest to enroll. Contrary to popular belief, well-informed patients are not necessarily the most interested in enrolling in trials