Scoring systems have been derived to assess the likelihood of opiate addiction in chronic pain patients. Prescription opioids are the source of nearly half of misused opioids and the majority of these are initiated for trauma or surgery pain management. Further to this, healthcare practitioners have long been aware that despite the effective use of opioids for managing pain, the empirical evidence that supports the use of opioids long term is minimal. In addition to this, many studies that involved patients with chronic pain have failed to show any sustained improvement in their pain or ability to function with long term opioid use.According to position papers on the treatment of opioid dependence published by the United Nations Office on Drugs and Crime and the World Health Organization, care providers should not treat opioid use disorder as the result of a weak moral character or will but as a medical condition. Some evidence suggests the possibility that opioid use disorders occur due to genetic or other chemical mechanisms which may be difficult to identify or change, such as dysregulation of brain circuitry involving reward and volition. However, the exact mechanisms involved are unclear, leading to debate regarding the influence of biology and free will. Mechanism
Addiction
Addiction is a brain disorder characterized by compulsive drug use despite adverse consequences.
Foodborne disease can also be caused by a large variety of toxins that affect the environment.Furthermore, foodborne illness can be caused by a number of chemicals, such as pesticides, medicines, and natural toxic substances such as vomitoxin, poisonous mushrooms or reef fish. Bacteria
Bacteria are a common cause of foodborne illness. The United Kingdom, in 2000, reported the individual bacteria involved as the following: Campylobacter jejuni 77.3%, Salmonella 20.9%, Escherichia coli O157:H7 1.4%, and all others less than 0.56%. In the past, bacterial infections were thought to be more prevalent because few places had the capability to test for norovirus and no active surveillance was being done for this particular agent. Toxins from bacterial infections are delayed because the bacteria need time to multiply. As a result, symptoms associated with intoxication are usually not seen until 12–72 hours or more after eating contaminated food. However, in some cases, such as Staphylococcal food poisoning, the onset of illness can be as soon as 30 minutes after ingesting contaminated food. Most common bacterial foodborne pathogens are:

Campylobacter jejuni which can lead to secondary Guillain–Barré syndrome and periodontitis
Clostridium perfringens, the "cafeteria germ"
Salmonella spp. – its S. typhimurium infection is caused by consumption of eggs or poultry that are not adequately cooked or by other interactive human-animal pathogens
Escherichia coli O157:H7 enterohemorrhagic (EHEC) which can cause hemolytic-uremic syndromeOther common bacterial foodborne pathogens are:
Bacillus cereus
Escherichia coli, other virulence properties, such as enteroinvasive (EIEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroaggregative (EAEC or EAgEC)
Listeria monocytogenes
Shigella spp.