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"Most people don't know how they're gonna feel from one moment to the next. But a dope fiend has a pretty good idea. All you gotta do is look at the labels on the little bottles."
- from the movie Drugstore Cowboy13

What is it that makes kicking heroin so hard?

Though with dependence you need heroin to stay well, it’s not dependence that makes quitting heroin so tough; it’s not dependence that causes cravings that can last for months or even years after abstinence.

To beat heroin addiction you need to understand what it does to your body and mind - when you understand why it makes you feel and act as you do you can make better choices that improve your health and well-being. Read on to learn:

  • What heroin does in the brain.
  • How addiction differs from dependence and how the brain changes of addiction doom many quit attempts to failure (fortunately, you can learn strategies to compensate for these brain changes.)
  • How to differentiate between abuse and addiction - and what types of people are most at risk to become addicted.
  • How heroin harms health and how treatment improves health and social functioning.

What Heroin Does in the Brain

When you take heroin, whether by injection, inhalation or insufflation (snorting) the drug enters the bloodstream and travels past the blood-brain barrier into the brain where it gets converted almost instantly into the active metabolites: morphine and monoacetylmorphine.*1

  1. The heroin metabolites then bond with mu opioid receptors in the brain’s pleasure centers, the ventral tegmental area and the substantial nigra.
  2. This binding also causes an inhibition of GABA suppression of dopamine – resulting in a secondary dopamine release.
  3. So the net result is that stimulating the mu opioid receptors causes pleasurable opioid effects and a flood of pleasure-spiking dopamine (most drugs of abuse cause the release of dopamine.)

*Why is heroin stronger than morphine if it gets converted to morphine in the brain?

Heroin’s smaller molecular structure enables it to pass more easily and quickly through the blood brain barrier, to where it can exert its effects. So when taking a similar amount of heroin or morphine, much more heroin gets through to the brain.2 

Physical Dependence Vs. Addiction

Both dependence and addiction lead to chronic use but they are 2 very distinct phenomena.

1. Physical Dependence

Physical dependence refers to:

  1. The development of drug tolerance.
  2. The presence of drug-specific withdrawal symptoms that arise predictably after a certain period of abstinence (with heroin use, withdrawal symptoms begin after only hours of complete abstinence).

Both tolerance and withdrawal symptoms develop after chronic use as the brain starts to down-regulate opioid receptors as a response to continual opioid oversupply. With fewer receptors available, a person needs to take increasing amounts of heroin to achieve the same high (tolerance) and with no heroin present in the brain, endogenous opioid levels aren’t sufficient and the person experiences unpleasant withdrawal symptoms (dope sickness).

With heroin, especially when used intravenously, physical dependence can develop quickly – within as little as 2 to 10 days of continuous use.3 Typical heroin withdrawal symptoms will appear within about 12 hours of the last dose and include:

Early Symptoms

  • Anxiety
  • Muscle aches and pains
  • Agitation and general discomfort
  • Runny nose and sweats
  • Yawning and tearing

Later Symptoms

  • Nausea and vomiting
  • Stomach cramps
  • Diarrhea
  • Goose-flesh

Withdrawal symptoms, which typically peak within about 2 days of complete abstinence and dissipate within about a week of abstinence, are uncomfortable but not dangerous (unlike alcohol or benzodiazepines withdrawal symptoms which can kill.) Although intense withdrawal symptoms dissipate within a week or so, many heroin users experience months or even years of low-grade secondary protracted withdrawals (Post Acute Withdrawal Syndrome or PAWS).4

Though sickness motivates use (you’ll hardly forget your need) tolerance and withdrawal alone don’t completely explain the difficulty most people have quitting heroin. After all, many people can make it through a week or 2 of detox and abstinence, but far fewer can stay clean for good.

The brain changes of addiction make longer periods of abstinence very difficult.

2. Heroin Addiction

Addiction is caused by changes to the brain’s memory, motivation, reward and impulse control systems – and it’s these changes that explain why people crave heroin for long after withdrawal symptoms dissipate, why people relapse back to use after long periods of abstinence and why people use heroin, even when they can see the tremendous damage it does to the body and mind.

Heroin addiction (not dependence) causes lasting changes in 4 areas of the brain:

  1. The nucleus accumbens and ventral palladium – results in changes to reward systems.
  2. The orbital prefrontal cortex – results in changes in motivation and drive.
  3. The amygdala and hippocampus – results in changes to memory and learning.
  4. The prefrontal cortex – results in changes to impulse control and behavioral regulation.5

These brain changes make it very difficult to stay clean, even after long periods of abstinence, and they explain why relapse is such a characteristic part of addiction. Some of the real-world consequences of these neural adaptations include:

  • Anything that reminds you of heroin use (even if you’re not consciously aware of it) will trigger drug cravings. Examples include people, places, things, certain emotional states, areas, smells…and many more. And though craving frequency will diminish with time and abstinence, you can expect cravings for many years – or even forever.
  • A dysregulated motivation system tricks your brain into thinking it needs heroin for survival – as a starving person needs food.
  • Stress stimulates reward pathways in the brain in ways that also trigger drug cravings (and since you can’t avoid stress, especially when trying to rebuild a heroin-damaged life, this is a tough one to overcome).
  • Changes to the prefrontal cortex limit your impulse control ability, so when you get a craving – you lack the ability you once had to delay gratification and curb your impulses.

When you sum and combine all of these changes, it’s no wonder that relapse is such a characteristic part of addiction. Fortunately, medications like Suboxone and methadone reduce drug cravings and compensatory techniques that you learn in addiction treatment or counseling can help you make-up for your diminished capacities.

Long term heroin use even seems to change the shape and packaging of DNA in the ventral and dorsal striatum. In one study, researchers found that lengthy heroin use caused changes to genes that regulate glutamate in the brain, and that longer use caused greater alterations. These changes  likely play a role in explaining how the brain functioning changes with addiction in ways that make quitting very tough to do.6

Heroin Addiction Signs

It’s easy to recognize dependence (you can’t fail to notice dope-sickness) but you cross from abuse to addiction silently and most people don’t recognize this transition as it happens.

While withdrawal symptoms make it easy to self-diagnose dependence, even with withdrawal symptoms, you could theoretically be dependent but not addicted.

So if you’re not sure about your addiction status, consider the following warning signs. The more questions you answer yes to, the more likely you are addicted.7

  • Are you spending less time on activities and interests that used to be enjoyable in favor of time spent getting, using and recovering from heroin?
  • Do you think about heroin a lot when not using? Do you feel a strong desire to get high?
  • Do you neglect your responsibilities so you can get high?
  • Do you have a hard time controlling how much you use or when you use?
  • Do you continue to use heroin despite observing negative consequences from your habit, whether psychological, physical or social?

Who Is Most at Risk?

As an intensely addictive drug, virtually anyone who uses heroin regularly will develop addiction and physical dependence. Though nobody's immune to addiction, some people are at higher risk of a quicker progression from recreational use to full-blown addiction. Susceptible people include:

  • Anyone with a personal history of drug or alcohol abuse or addiction (any substance).
  • Anyone with a family history of addiction.
  • Anyone with a history of childhood sexual abuse.
  • Anyone with psychiatric illness.
  • Anyone with very easy access to opioids.

Health Consequences

Using street-heroin and living the heroin lifestyle isn’t conducive to good health and longevity, in fact, active intravenous heroin users are 7 times more likely to die on any particular day than non heroin users of a similar age group.8

But beyond fatal overdose, other potential health consequences of regular heroin use include:9

  • Clogged blood vessels (from additives used to cut heroin). This can lead to diminished blood flow and kidney, liver, heart, brain and other organ damage.
  • An increased risk of pneumonia and other pulmonary infections. These occur as a combination result of heroin’s effects on respiration and the generally poor health of heroin users.
  • An increased risk of HIV, hepatitis C and other infectious diseases (from shared injection equipment).
  • Collapsed veins.
  • Infections of the heart’s lining and valves.
  • Skin abscesses.
  • Constipation.
  • Spontaneous abortion.
  • Poor nutrition and dental decay.
  • Memory or cognition problems.

Other Consequences

Heroin isn’t detrimental to health alone. Other consequences associated with heroin addiction include:

  • Homelessness.
  • Social exclusion.
  • Legal problems or imprisonment.
  • Family welfare issues and social services involvement -  loss of children in the household.
  • Criminality or involvement in the sex trade.
  • Increasingly marginal legal status (loss of driver’s license, credit cards, etc.)
  • Increased guilt, anxiety and fear.3

Treatment Benefits

Opiate addiction is a chronic condition that’s characterized by recurrent bouts of relapse and treatment-need over a lifetime, but this doesn’t mean that treatment doesn’t work or isn’t useful.

And though complete heroin abstinence is an excellent treatment goal, you don’t have to to achieve 100% success to still benefit from treatment participation. Some of the many benefits of treatment include:10

  • Heroin use during treatment tends to fall dramatically or even stop completely, and the longer a person sticks with treatment the lower heroin use tends to get (such as with long-term methadone use).
  • A reduced risk of overdose death.
  • Improved general physical health.
  • Improved emotional health.
  • Reduced criminality and other antisocial behaviors linked to drug seeking.
  • Increased employment stability and better relationship stability.

Basically, with treatment you have a great chance to stop using heroin completely, and even if you don’t, your heroin use will almost certainly decrease. With either abstinence or decreased heroin use you will experience improved quality of life. 

Treatment Gap

Most heroin addicted people do not seek or receive treatment. Of the estimated 810 000 heroin addicted people in America, only 20% seek or receive treatment.11

Quit Attempts, Relapse and Overdose Risks


With quit attempts and even a few days of abstinence your opiate tolerance can decrease dramatically. After a short period of abstinence, using the same dose as you were using prior to your quit attempt could result in overdose, respiratory depression and even death.

If you intend on quitting for good, you can reduce your risks of relapse and relapse-overdose by using an opiate substitution medication, like buprenorphine or methadone, stabilizing for a year or more on this medication, and then either continuing to take this medication indefinitely, or gradually tapering down when ready.

Take-Home Summary

  • It’s not just about dependence – Though the withdrawal symptoms associated with physical dependence can be extremely uncomfortable, getting past the detox phase isn’t the hard part – avoiding relapse in the weeks, month and years that follow is what most people have the toughest time with.
  • Though your body recovers (mostly) from physical dependence in a week or more, the brain changes of addiction last for much longer. These brain changes can leave you craving heroin for years after abstinence. Fortunately, you can learn compensatory strategies to help manage these cravings.
  • Treatment works – Though complete abstinence is an excellent goal, treatment can also help people achieve other goals that also increase health and quality of life, such as reducing health problems and risks of overdose death, improving social and psychological functioning, reducing criminal behaviors and facilitating a return to the workforce or to school. Treatment statistics show that addiction treatment works about as well as treatment for other chronic diseases, such as diabetes, but when you take into account all of the benefits of treatment that go beyond achieving complete abstinence, treatment starts to look like a very good idea.12
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Page last updated Feb 18, 2014

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