It’s also far easier to reach a definitive conclusion with respect to smoking — a recreational activity that doesn’t in itself offer medical benefits. Suggesting that people may be better off quitting is not likely to harm them, and may in fact help them. Taking antidepressants, on the other hand, is an established treatment for very real psychiatric conditions, and suggesting that the medications are dangerous to fetuses — before all the observational evidence is in — could have disastrous results.