Whilst that may be true still for the U.S. in the rest of the western world, despite an attempt to introduce it in the 1970's to capture the youth who were beginning to drift away, the happy-clappy evangalistic style of religious fervour never took off. These days (which again Marx could not have foreseen) television is the "opium of the people"

I find myself in agreement with @RobLes. Religion is the ultimate placebo, which the image you've provide clearly ignores. Karl Marx's 'opiate of the masses' quote comes from a period in history when the throne propped up the altar, and vice versa--the two were in league with one another, and the public were incredibly ignorant and undervalued. Education replaces the need for opiates, and religion begins to fade in significance.

Just found this on Reddit. Proof positive?

This is also the reason so many rehab groups an organizations are religiously oriented. Addicts can become the most dedicated believers if they can channel their addiction into a religious belief, and the crazier their faith, the more of those chemicals get released, the more they believe. My guess is, if the Westboro Church members were tested when they are out spewing their hate messages, their dopamine and other euphoric numbers would be off the charts!

I think religion played a key and likely nearly essential role in helping human civilizations evolve into what they are today.

I also think this mental health axiom applies to religion well-what you once did for survival is now your biggest limitation.

As for religion being a drug, I experienced numerous delusional highs as a religious person. The problem is you keep wanting those fixes but there's only so many times you can trick your brain into pumping all those chemicals.

That's extremely interesting. I never thought of religion that way. It makes sense why theists cling so vigorously to their faith.