A study at Uppsala university in Sweden on the side effects of long time usage of opiates (morphine, methadone, subutex, etc.). Users of opiates to treat long time pain reported the following side effects from long time use of opiates:

• 60 % reported a kind of mental tiredness and blunting. They are more prone to lack of strong feelings, lack of motivation, just sitting and doing nothing, tiredness, lack of energy, memory problems, cognitive capacity problems.
• 56 % reported weight gain.
• 54 % reported sleeping problems.
• Many also reported sweating, sexual dysfunction, shortness of breath, swelling, constipation (hard shit, difficulty pooping).
• Some reported paradoxically that opiates caused an increase in sensitivity to pain, causing new kinds of pain. This new kind of pain could not be treated with more opiates, rather the reverse, more opiates caused more of this new kind of pain..