Antidepressant medications are an effective treatment for depression. There are dozens of antidepressants, and they are all about equally effective. Psychotherapy is about as effective as antidepressant medications. Exercise is about as effective as psychotherapy and antidepressants. All of these treatments are on average only slightly more effective than a sugar pill. Most of the clinical benefit from any of these treatments is attributable to the placebo effect.
It turns out a sugar pill–i.e., a placebo–is a pretty good treatment for depression. Or, framed differently, a placebo prods the human mind to do a pretty good job of healing itself. The power of the placebo effect is the reason we need double-blind randomized controlled trials to establish the effectiveness of various medications. Without them, virtually every substance would appear to be therapeutic, and not just for depression.
The placebo effect works via the power of suggestion. We believe we are going to benefit from the pill, and that belief becomes a self-fulfilling prophecy. If we didn’t believe, it wouldn’t work.
In a previous OP, I played with the question of why is there such an emphasis on belief in Christianity. I hypothesized that belief in Jesus’ divinity “evolved after the crucifixion as the thing that defined Christians in relation to other contemporary groups, and thus became associated with conversion and radical transformation, a.k.a., ‘salvation.’”
But maybe it’s a lot simpler than that. Maybe Christianity works on the placebo effect. If you believe you are saved, you feel saved. Your burdens are lifted. If you don’t, you don’t, and they aren’t.
Could it be that simple?