Opioid dependency is a medical diagnosis characterized by an individual's inability to stop using opioids even when objectively in his or her best interest to do so. In 1964 the WHO Expert Committee on Drug Dependence introduced "dependence" as “A cluster of physiological, behavioural and cognitive phenomena of variable intensity, in which the use of a psychoactive drug (or drugs) takes on a high priority. The necessary descriptive characteristics are preoccupation with a desire to obtain and take the drug and persistent drug-seeking behaviour. Determinants and problematic consequences of drug dependence may be biological, psychological or social, and usually interact”. The core concept of the WHO definition of “drug dependence” requires the presence of a strong desire or a sense of compulsion to take the drug; and the WHO and DSM-IV-TR clinical guidelines for a definite diagnosis of “dependence” require that three or more of the above six characteristic features be experienced or exhibited:
1. A strong desire or sense of compulsion to take the drug;
2. Difficulties in controlling drug-taking behaviour in terms of its onset, termination, or levels of use;
3. A physiological withdrawal state when drug use is stopped or reduced, as evidenced by: the characteristic withdrawal syndrome for the substance; or use of the same (or a closely related) substance with the intention of relieving or avoiding withdrawal symptoms;
4. Evidence of tolerance, such that increased doses of the drug are required in order to achieve effects originally produced by lower doses;
5. Progressive neglect of alternative pleasures or interests because of drug use, increased amount of time necessary to obtain or take the drug or to recover from its effects;
6. Persisting with drug use despite clear evidence of overtly harmful consequences, such as harm to the liver, depressive mood states or impairment of cognitive functioning.
Some feel that this is a physical and psychological condition that develops from the long term use, or more often abuse, of naturally occurring opiates such as morphine or codeine or synthetically derived opiates (opioids) such as Demerol or oxycodone. Others feel that the disease state is a failure to relate to other individuals and that the opioid use itself, while critical for the diagnosis, is only the first target of treatment. Treatment approaches include abstinence-based and harm-reduction methodologies. Both include participation in detoxification through the use of methadone or other long-acting opioids. Alternative detox protocols call for total abstention from all opiates, with the use of various benzodiazepines and other medications to reduce the uncomfortable withdrawal symptoms associated with abstinence. In an abstinence-based approach, a gradual taper of the medications follows detox, while in the harm-reduction approach, the patient remains on an ongoing dose of methadone or buprenorphine.
Symptoms of withdrawal
Symptoms of withdrawal from opiates include, but are not limited to, depression,Aggression and irritability, leg cramps, abdominal cramps, vomiting, diarrhea, insomnia, and cravings for the drug itself. Detoxification is best conducted in an in patient facility that provides a controlled environment. Patients who are isolated and exposed solely to care givers and other patients in this environment have a better rate of staying clean then those who detox out-patient.
Additional withdrawal symptoms include, but are not limited to, rhinitis (irritation and inflammation of the nose), lacrimation (tearing), severe fatigue, lack of motivation, moderate to severe and crushing depression, feelings of panic, sensations in the legs (and occasionally arms) causing kicking movements which disrupt sleep, increased heartrate and blood pressure, chills, gooseflesh, headaches, anorexia (lack of appetite), mild or moderate tremors, and other adrenergic symptoms, severe aches and pains in muscles and perceivably bones, and weight loss in severe withdrawal.
Depending on the quantity, type, frequency, and duration of opioid use, the physical withdrawal symptoms last for as little as 5 days and as much as 14 days. The user, upon returning to the environment where they usually used opiates, can experience environmentally implied physical withdrawal symptoms well-after regaining physical homeostasis - or the termination of the physical withdrawal phase by synthesis of endogenous opioids (endorphins) and upregulation of opioid receptors to the effects of normal levels of endogenous opioids. These implied symptoms are often just as distressing and painful as the initial withdrawal phase.
It can take up to two months for the brain's opioid receptors to return to their normal efficacy to endogenous opioids, meaning depression and anxiety can linger for this time period. Opioid use usually leaves no permanent damage to the brain or the opioid receptors.
War on Drugs—War on Pain Management By Dr. Stephen F. Grinstead, LMFT, ACRPS, CADC-II 2006. 
Volkow N. What do we know and what don't we know about opiate analgesic abuse? Keynote address, Wednesday, March 30, 2005. Program and abstracts of the 24th Annual Scientific Meeting of the American Pain Society; March 30-April 2, 2005; Boston, Massachusetts.
Fishbain DA, Rosomoff HL, Rosomoff RS (1992), Drug abuse, dependence, and addiction in chronic pain patients. Clin J Pain 8(2):77-85.
Hoffmann NG, Olofsson O, Salen B, Wickstrom L (1995), Prevalence of abuse and dependency in chronic pain patients. Int J Addict 30(8):919-927.
Chabal C, Erjavec MK, Jacobson L et al. (1997), Prescription opiate abuse in chronic pain patients: clinical criteria, incidence, and predictors. Clin J Pain 13(2):150-155.
Kouyanou K, Pither CE, Wessely S (1997), Medication misuse, abuse and dependence in chronic pain patients. J Psychosom Res 43(5):497-504.
Reid MC, Engles-Horton LL, Weber MB et al. (2002), Use of opioid medications for chronic noncancer pain syndromes in primary care. J Gen Intern Med 17(3):173-179.
Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision 2002. 
WHO Expert Committee on Addiction-Producing Drugs, Thirteenth Report, World Health Organization Technical Report Series No. 273. Geneva: World Health Organization, 1964.
WHO. 5th Review of Psychoactive Substances for International Control. Geneva: World Health Organization, November 16-20, 1981.
NIDA. Trends in Prescription Drug Abuse 2006. 
American Pain Society (APS) Bulletin • Volume 9, Number 5, September/October 1999.
Mahowald ML, Singh JA, Majeski P. - Opioid use by patients in an orthopedics spine clinic // Arthritis Rheum. 2005 Jan;52(1):6-10.
Use of Essential Narcotic Drugs to Treat Pain is Inadequate, Especially in Developing Countries. International Narcotics Control Board (INCB), Annual Report, 3 March 2004.
Walid MS, Hyer LA, Ajjan M, Barth ACM, Robinson JS. Prevalence of opioid-dependence in spine surgery patients and correlation with length of stay. J Opioid Management 2007, Volume 3, Number 3. 
Walid MS, Hyer LA, Ajjan M, Robinson JS: Predicting Opioid-Dependence Using Pain Intensity and Length of Pain Suffering in Pre-Spine-Surgery Patients. The Internet J Pain, Symptom Control and Palliative Care. 2007; Volume 5, Number 2.