You have nothing to back that up. In fact, all the evidence I've seen points towards the opposite: the places with the least opiate abuse are (1) not happy countries (2) with very strict laws. See Qatar, Saudi Arabia, Singapore, etc.

If money and greed on the supply side, and lack of happiness on the demand side is the true cause of this, surely those countries would be ravaged with an opiate epidemic. But they are not. The problem is much more nuanced than you make it out to be.