I actually agree with .Lucid. somewhat but I think that the psychological component has more to do with it than he realizes. Although I have never had a strong physical addiction to an opiate I have been dropping pharmaceutical opioids in recreational doses for several years now, and a while ago I took a 10 month break from all opiates, which by all physiological indications should have brought my tolerance down to "baseline". However at the end of the break I attempted to start back with 25mg hydrocodone, a dose that once would have had me nodding, but was rewarded with only a moderate, non-inebriating buzz. The effect was reproducible with several different opiates. I think that while the opioid receptors may downregulate to similar levels as before one started using, the brain's response to drug induced pleasure never quite returns back to what it was like the first few times.
There is basically no physcological factors involved with level of 'high' from heroin, maybe if you're doing 20 on the odd weekend, but not when she's got you man...there is a HUGE difference between pharms and smack. Popping pills yes there is a lot of placebo effects involved with different mindsets, but with smack, doesn't matter what your head space you feel it, especially when you're talking 4 years.
I CAN get high from oxy's not swallowing anymore really, just the feel good, and bit of an itch at very high doses, I haven't done that in a loong time such a waste! I used too get high even after I'd cleaned up, but as soon as I injected it, nothing else will get me high like it used to, except, either iv'ing the pills or heroin..
For people who haven't been there it can be hard to grasp, I understand that, logic and science indicate that you can get high from swallowing them, you just have to take more, people start throwing all the BA bollocks at you. While this is true, you can still feel the opiate effects at high doses, it certainly isn't high, it's like drinking a hot chocolate when it's snowing outside, you just feel nice...That's why people that do first time iv, never turn back, why people get soo addicted, and why you should never ever try it!