RARE CASE: A federal lawsuit claims popular antidepressant Zoloft has no more benefit than a dummy pill, so patients who took it should be reimbursed for their costs.

OPPOSING VIEWS: Lawyer Brent Wisner says Zoloft shouldn't have been approved because there wasn't enough evidence it works. Zoloft maker Pfizer and several psychiatry experts say studies and two decades of use by patients show the pill is effective.

COMPLEX SCIENCE: It's hard to exactly measure an antidepressant's value. Most patients need to try a few to find one that works for them, and they help patients with severe depression the most.