The term “opioids” refers to natural substances (for example, morphine) or synthetic substances (for example, heroin) that produce similar effects, primarily a state of profound calm progressing to loss of consciousness (narcosis), accompanied by a sensation of intense pleasure spreading throughout the body. The brain “detects” these substances through specific receptors and neural circuits that normally function in response to substances produced by the brain itself, known as endogenous morphines or endorphins.
In medicine, opioids were initially used as sedatives and painkillers, and more recently also as medications for cough.
Regular use produces tolerance to their effects, meaning that, on the one hand, increasing doses are required to reproduce the initial effects, while on the other hand the person experiences discomfort if the next dose is not taken within a certain period of time. This discomfort is the withdrawal syndrome. It does not occur only with opioids and is temporary (lasting days), although the initial phase is characterized by progressively increasing symptoms.
Repeated use carries a relatively high risk of triggering drug dependence. This risk applies to people who use opioids for pleasure, but also to those who use them for medical reasons. Drug dependence consists of loss of control over substance use, driven by an urgent and persistent craving that is relieved only after the substance has been taken.
Tolerance, with the associated problem of withdrawal, is not the mechanism underlying drug dependence. To eliminate the withdrawal problem, it would be sufficient to reduce the dose progressively, “going backwards,” and then return to normal use once tolerance had been eliminated. A person with drug dependence cannot carry out this process because they do not have control over the substance and cannot use it at “lower” doses, but rather tend to use increasingly higher doses.
People who use opioids usually do so for pleasure, although use may initially continue because of the beneficial effects of opioids on psychological distress or on actual psychiatric disorders (self-medication). The dependence that subsequently develops, however, is no longer linked to any particular reason. Instead, it reflects a stable change in the brain’s relationship with the substance, characterized by craving that does not disappear and, on the contrary, re-emerges even after long periods of abstinence.
Among all forms of drug dependence, opioid dependence—predominantly heroin dependence in our setting—is one of the most treatable. There is, in fact, a standard treatment suitable for most people with opioid dependence, consisting of a medication capable of suppressing and maintaining suppression of excessive craving for heroin.
In addition, residual craving tends to disappear because heroin no longer produces its usual effects, as these effects are “blocked” by the medication. For a small proportion of people dependent on heroin, blocking its effects is sufficient to achieve, over time and through regular treatment adherence, cessation of heroin use. For the majority, however, it is necessary to suppress the craving in order to interrupt the behavior.
The medications used for this purpose are opioid agonists (incorrectly referred to as “substitution” medications): methadone and buprenorphine.
In some countries, people dependent on heroin who do not wish to undergo treatment in other ways are provided with heroin by the state. This procedure does not eliminate the disorder; rather, it maintains it while controlling certain aspects of its consequences, such as criminal activity.
Methadone treatment (and treatment with other medications) is based on a fundamental difference between the medication and the drug of abuse: the medication reaches the brain “slowly” and does not produce a pleasurable effect similar to that produced by drugs of abuse, and therefore does not induce drug dependence.
Being dependent on methadone therefore simply means taking methadone as treatment in order to avoid relapse into heroin dependence. For the treatment to provide stable protection, it must be taken for long periods and at an adequate dose.