Opium is a highly addictive non-synthetic narcotic extracted from the poppy plant (Papaver somniferum). The opium poppy is the key source for many narcotics, including morphine, codeine, and Heroin. 

Basically, opium is just a mixture (or "cocktail") of several different drugs known as opiate alkaloids. They are all found in the opium poppy's natural latex or "resin." This resin is eaten, smoked, made into tea, or chemically processed to separate each alkaloid for drug production (whether legally for pharmaceutical purposes or illegally for illicit drug manufacture). 

Street names

Aunti Emma
Big O
Black
Black hash
Black pill
Black Russian
Black stuff
Buddha
Chillum
Chinese molasses
Chinese tobacco
Dopium
Dover’s deck
Dover’s powder
Dream gun
Dream stick
Dreams
Easing powder
Fi-do-nie
Gee
God’s medicine
Great tobacco
Hard stuff
Indonesian bud
Joy plant
Midnight oil
Ope
Pen yan
Pin gon
Pin yen
Pox 
Skee
Toxy
Toys
When-shee
Yen Shee 
Suey
Zero 
[5]

History

The poppy plant, Papaver somniferum, is the source of opium. It was grown in the Mediterranean region as early as 5,000 B.C., and has since been cultivated in a number of countries throughout the world. The milky fluid that seeps from its incisions in the unripe seed pod of this poppy has been scraped by hand and air-dried to produce what is known as opium.
A more modern method of harvesting for pharmaceutical use is by the industrial poppy straw process of extracting alkaloids from the mature dried plant (concentrate of poppy straw). All opium and poppy straw used for pharmaceutical products are imported into the United States from legitimate sources in regulated countries.
[2]

Pharmacology

Opium itself is not a single drug or chemical, and does not have its own distinct chemical structure. Instead, opium is a "cocktail" of different drugs (opiate alkaloids) which all occur in the plant's resin naturally. There are many different active substances (alkaloids) found in the resin (opium latex). The main psychoactives are morphine, codeine, and thebaine, however, there are many others. Each one of these opiate alkaloids has its own unique chemical structure and properties. Each one also acts independently on the central nervous system (CNS) when opium is ingested, but they all produce (somewhat) similar effects which compliment each other.

So basically, opium is just a mixture (or "cocktail") of several different drugs known as opiate alkaloids. They are all found in the opium poppy's natural "latex" or "resin". This resin is eaten, smoked, made into tea, or chemically processed to separate each alkaloid for drug production (whether legally for pharmaceutical purposes, or illegally for illicit drug manufacture).
[2]

Uses

Opium can be smoked, intravenously injected, or taken in pill form. Opium is also abused in combination with other drugs. For example, “Black” is a combination of marijuana, opium, and methamphetamine, and
“Buddha” is potent marijuana spiked with opium.
[2]

Scheduling

Opium is a Schedule II drug under the Controlled Substances Act. Most opioids are Schedule II, III, IV, or V drugs. Some drugs that are derived from opium, such as heroin, are Schedule I drugs.

[1]

Psychological and physical addiction liability

The intensity of opium’s euphoric effects on the brain depends on the dose and route of administration. It works quickly when smoked because the opiate chemicals pass into the lungs, where they are quickly absorbed and then sent to the brain. An opium “high” is very similar to a heroin “high”; users experience a euphoric rush, followed by relaxation and the relief of physical pain.
[3] 

Long term effects

The long term effects of taking opium, is wanting more of the drug in order to get the equal pleasurable effect as taken on the first time of usage , or scientific terms the effects of euphoria. People who inject opium can have damaged veins, and higher the chances of contaminating the parts of the heart, by a large amount. People who smoke, or take in the drug, will have their important body organs quickly get destroyed, also it is impossible for the liver, and kidneys to not get damaged no matter how it is eaten, or smoked. Victims can also expect to get massive damage to the lungs, and brain when it comes to long term effects. Opium on the body in a long term effect could bring the body into needing the drug, and relying on the drug. The body would want more of the enjoyable effects of opium that come in short term effects (euphoric, also known as happiness) therefore finding drugs to get the same euphoric effects. The body would want more of the drug, otherwise known as addiction.
[4]

Physical effects

Opium inhibits muscle movement in the bowels leading to constipation. It also can dry out the mouth and mucous membranes in the nose. Opium use leads to physical and psychological dependence, and can lead to overdose.
Overdose effects include: Slow breathing, seizures, dizziness, weakness, loss of consciousness, coma, and possible death.
[4]

Withdrawal Effects

Early symptoms of withdrawal include:

Agitation
Anxiety
Muscle aches
Increased tearing
Insomnia
Runny nose
Sweating
Yawning

Late symptoms of withdrawal include:

Abdominal cramping
Diarrhea
Dilated pupils
Goose bumps
Nausea
Vomiting

Opium withdrawal reactions are very uncomfortable but are not life threatening. Symptoms usually start within 12 hours and may last until 30 hours.
[3]

Medical Treatment options

Medical treatment involves supportive care and medications. The most commonly used medication, clonidine, primarily reduces anxiety, agitation, muscle aches, sweating, runny nose, and cramping.

Buprenorphine (Suptex) has been shown to work better than other medications for treating withdrawal from opiates, and it can shorten the length of detox. It may also be used for long-term maintenance like methadone.

People withdrawing from methadone may be placed on long-term maintenance. This involves slowly decreasing the dosage of methadone over time. This helps reduce the intensity of withdrawal symptoms.

Some drug treatment programs have widely advertised treatments for opiate withdrawal called detox under anesthesia or rapid opiate detox. Such programs involve placing you under anesthesia and injecting large doses of opiate-blocking drugs, with hopes that this will speed up the return the body to normal opioid system function.

There is no evidence that these programs actually reduce the time spent in withdrawal. In some cases, they may reduce the intensity of symptoms. However, there have been several deaths associated with the procedures, particularly when it is done outside a hospital.
[5]

Psychological treatment options

Among the treatment options, the following are the ones, commonly suggested:

Natural Detoxification:

During natural detoxification, medications dispensed to opium or opiate addicted patients remain conservative. Anti-anxiety drugs, antidepressants and anti-psychotics may be prescribed to alleviate any withdrawal-induced or preexisting mental health issues that may impede recovery. Over-the-counter medications may be given to help the patient remain comfortable during his or her stay and mitigate withdrawal symptoms. Medical supervision is provided during natural detoxification as well, to guard against complications and to ensure monitoring of vital signs and overall health.

Clinical Therapy as Opium Addiction Treatment:

Sessions with a qualified mental health counselor have been shown to make rehabilitation more effective than simply detoxification or group meetings alone. Clinical therapy methods used in opium or opiate addiction treatment can range widely, from Cognitive Behavioral Therapy (CBT) approaches that focus on behavior and belief modification to reward-based contingency management therapy (CMT). Depending on the opium treatment facility, patients may also undergo other therapies alongside traditional cognitive therapy, such as EMDR or art therapy.

12-Step Opium Treatment Modalities:

Related opioid drugs

The other drugs related to Opium are: Morphine, codeine, heroin, methadone, hydroquinone, fentanyl, and oxycodone 

Related opioid derived synthetics

The following are the synthetic derivatives of Opium that are currently available:

Acetyldihydrocodeine
Benzylmorphine
Buprenorphine
Desomorphine
Dihydrocodeine
Dihydromorphine
Ethylmorphine
Diamorphine
Hydrocodone
Hydromorphinol
Hydromorphone
Nicocodeine
Nicodicodeine
Nicomorphine
Oxycodone
Oxymorphone
[4]

References

[1] http://www.nlm.nih.gov/medlineplus/ency/article/000949.htm
[2] http://opiumproject7d.wordpress.com/
[3] http://www.painpolicy.wisc.edu/internat/DCAM/Mayet_Psychosocial_treatment.pdf
[4] http://www.webmd.com/drugs/drug-93960-Opium+Tincture+Oral.aspx?drugid=93960
[5] http://alcoholism.about.com/od/heroin/a/opium.htm