A person is said to have physical opioid dependence if they have high 'tolerance' of opioids, meaning they need more of the opioid to get the desired effect. Opioid withdrawal symptoms occur when the substance is stopped. Most patients who seek treatment for opioid addiction also have some degree of physical dependence. However, physical opioid dependence alone is not sufficient to make a diagnosis of addiction. A person can be physically dependent - like a cancer patient might be when prescribed opioids for severe pain - and not be addicted. The term 'addiction' refers to certain behaviors.

What are the Symptoms of Opioid Withdrawal?

Opioid withdrawal can occur in both the addicted patient and the patient who has opioid dependence but is not experiencing total opioid addiction. When an opioid is stopped or the dose is suddenly reduced, both types of patients experience withdrawal symptoms - sweating, chills, muscle and joint pain, nausea, vomiting, diarrhea, restlessness and insomnia. 'Goosebumps', which commonly occur during opioid withdrawal, give rise to the term 'cold turkey'. Fear of these unpleasant and painful opioid withdrawal symptoms makes it difficult for the addict to stop using and begin the recovery process.

Who is Prone to Develop Opioid Dependence?

Although the specific causes vary from person to person, scientists believe that our heredity (our DNA) is the major factor in an individual's susceptibility to the development of the disease of addiction. We also know that psychological factors (feeling stressed, anxious or depressed) and our social environment also play important roles in the development of opioid addiction. The unpleasant effects of opioid withdrawal lead many users to continue abusing prescription or illegal opioids, leading to prolonged dependence.

Opioid abuse has risen dramatically in the United States over the past ten years. The National Institute of Drug Abuse (NIDA) reports that more than 5.2 million Americans misused a prescription painkiller in 2008 for non-medical reasons. Approximately 1 million people in the U.S. are addicted to heroin today. About 1 out of 8 people (13% of the population) who are exposed to a mood-altering substance that can cause an intense euphoric effect (like alcohol, opioids and other drugs of abuse) are prone to develop the behaviors of addiction with repeated use.

What Happens to the Brain in Addiction?

Opioid addiction is a disease of the brain. Repeated use of an opioid leading to opioid dependence causes long-term changes in both the structure (the architecture of the brain) and the way the brain functions (the biochemistry of the brain).

The most important structural or architectural change takes place in the circuitry of the brain - particularly in the wiring of the reward pathway. Our brains are wired to ensure that we will repeat life-sustaining activities - such as drinking water and eating food - by associating those activities with pleasure or reward. Whenever this reward circuit is activated, the brain records that experience making us likely to do it again. Memories that have an intense emotional component (like pleasure) may be permanently 'hard-wired'.

In the person with opioid dependence who is prone to opioid addiction, the excessive stimulation of the reward pathway by an opioid 'tricks' the brain into believing that an opioid is as necessary for survival as food and water. The effect of such a powerful reward motivates people to repeat that behavior again and again, even when it is clearly harmful to do so. This is why drug abuse is something the person prone to opioid addiction can learn to do very, very well.

Chemical changes also take place in the brain as it tries to adapt to the excessive stimulation of the reward pathway. During opioid dependence and opioid addiction, the brain tries to 'turn down the volume' and compensate for the vicious highs and lows that occur during repeated opioid use and opioid withdrawal by reducing the number of opioid receptors in the brain. This is what leads to tolerance in people with opioid addiction - more and more of the opioid is needed to achieve the same effect. The result is that eventually the addict may feel lifeless, depressed, and may be unable to enjoy activities that usually bring them pleasure. By the time most opioid addicts seek treatment they no longer get a euphoric effect from taking an opioid - they are taking opioids just to function normally.

To complicate matters further, the repeated use of an opioid has a profound impact on the intellectual portion of the human brain that is involved in judgment and decision making. Since this part of the brain is still developing in adolescence, opioid dependence leading to addiction which begins during the teen years is often more severe and more resistant to treatment. Unfortunately, the impairment in the thinking part of the brain - the part that serves as the 'brake pedal' for addiction - is so severe that the addict may flatly deny that they have a drug problem, try to justify their use to family and friends, or minimize the consequences of their behavior. A person with opioid addiction (and less often, opioid dependence) can find themselves saying or doing things they would never have believed themselves capable of - including lying to family members, stealing from loved ones, or even committing criminal acts - all in pursuit of the drug their brains are telling them they must have.

As a result of opioid dependence or opioid addiction, these changes in the structure and function of the brain result in powerful and long-lasting cravings for opioids. Cravings can last for months and even years after an addict has stopped using opioids, and has gone through the initial opioid withdrawal period. Persistent cravings explain why the relapse rate is so high with this disease. The need to satisfy cravings can be so intense that even people who try as hard as they can to remain abstinent find it difficult or impossible to do on their own.

Is Opioid Addiction Really a Disease?

Yes, opioid dependence can lead to opioid addiction, which is a chronic and progressive disease if untreated--just like heart disease, asthma and diabetes. These diseases have a lot in common with addiction--they are seen more frequently in those with a family history of the disease, they cause changes in the structure and function of a major organ system, they improve with behavior modification, they can be treated with medication, and they all require daily management. And like these other diseases, addiction is chronic - a condition for life, as there is no known cure. Fortunately, addiction can be managed, and a person suffering with opioid addiction can regain a healthy, productive life by seeking assistance with managed opioid withdrawal in an addiction treatment program.

The myth is that opioid addiction or opioid dependence is a result of poor will-power, a lack of self-control, or low moral standards. In reality, if it was that straightforward most people who are addicted would be able to stop using on their own. The changes in the structure and function of the brain are so powerful that stopping and remaining abstinent usually requires professional help.

How Serious is Opioid Dependence?

Opioid dependence is a behavior disorder that is potentially fatal. Sudden opioid withdrawal is an unpleasant experience, and many individuals continue to use opioids to avoid the negative physical effects. Individuals who use heroin intravenously are about 7 to 10 times more likely to die on any given day than someone of similar age who is not a user. Accidental overdoses are on the rise because the potency of street drugs like heroin are unpredictable from one dose to the next, and the potency continues to climb (7% purity in 1980 to 75% today). Overall, patients with opioid dependence die at a much higher rate than non-users from a number of medical complications. The incidence of Hepatitis C is on the rise due to the sharing of needles – even those that are supposedly 'recycled' and 'clean'. About 2% of those who are opioid-dependent die each year because they don't seek treatment or assistance for opioid withdrawal. The message here is that there is a good explanation for why we don't see a lot of old opioid addicts walking around.