Addiction

Why Are Substance Use Disorders a Global Health Challenge?

Substance use disorders are not simply personal “vices,” but chronic brain and behavioral conditions that intertwine biology, psychology, and social context. The most recent estimates indicate that almost 300 million people worldwide use substances, with around 64 million experiencing a true substance use disorder, yet only a minority receive adequate treatment.

The impact is measured not only in terms of illness and mortality, but also in lost years of healthy life, disability, healthcare costs, reduced productivity, and strained family and community relationships. Substance use disorders thus become a mirror of collective vulnerabilities: economic inequalities, wars, forced migration, social exclusion, and cultural models that emphasize performance, speed, and instant gratification.

In many parts of the world, particularly high-income settings, substance use disorders are among the leading causes of lost healthy life years in adolescents and young adults, with millions of new cases each year. Discussing substance use disorders means considering brain and society together, individuals and public policy, intimate vulnerabilities and global dynamics.

How Do Drugs “Rewrite” the Brain?

To understand substance use disorders, it is essential to know how drugs alter brain circuits that regulate pleasure, motivationMotivation: a scientific perspective Motivation is a fundame... More, stressWhat is stress? From a clinical perspective, stress is a phy... More, and self-control. Psychoactive substances exploit the brain’s reward system, a network of areas and connections—including the ventral tegmental area, nucleus accumbens, and prefrontal cortex—that normally motivates us to seek what is useful for survival, such as food, relationships, and exploration. The main neurobiological mechanisms can be simplified as follows:

• Abnormal dopamineA neurotransmitter found in the brain and central nervous sy... More increase

Most drugs of abuse cause a rapid and intense release of dopamine in the nucleus accumbens, far exceeding that generated by natural rewards like eating or socializing. This “spike” signals the brain that the event is extraordinarily important, overpowering other sources of pleasure and interest. Over time, the brain adapts to these high levels: the same dose produces a weaker effect (tolerance), and the individual tends to increase the amount or frequency to chase the initial sensation.

• Reinforcement of habits and compulsions

Repeated drug exposure induces adaptations in pathways connecting the reward systemWith reward system, also called the gratification system, we... More with the striatum and motor areas, promoting the shift from “chosen” use to increasingly automatic and compulsive behaviors. Procuring and using the substance becomes a rigid habit, triggered by environmental cues (places, people, emotional states), even after periods of abstinence.

• Weakened executive control

The prefrontal cortex—the region involved in planning, decision-making, impulse inhibition, and evaluating consequences—shows structural and functional alterations in people with substance use disorders. This translates into difficulty resisting impulses, considering long-term risks, and maintaining coherent goals (like work, study, or self-care). The image of an “addict” continuing to use drugs despite knowing the dangers is not a moral weakness, but an expression of deeply altered self-control circuits.

• Stress, negative emotions, and “anti-reward”

Over time, the body not only adapts to the substance’s positive effects but develops an “anti-reward” system, based on stress circuits and neurochemical signals that generate anxietyAnxiety is an emotional response characterized by feelings o... More, irritability, and dysphoria when the drug is absent. The person no longer uses drugs solely to seek pleasure, but to avoid growing discomfort: this is a crucial shift from recreational use to addiction, where the substance becomes a sort of “medicine” against the void and distress it helped create.

Why Do Some People Become Addicted While Others Do Not?

Not everyone who tries a substance develops an addiction: this depends on a complex interplay of individual, family, and social factors. Science speaks of vulnerability: a terrain where drugs find easier entry, especially during developmental stages like adolescenceWhat is meant by adolescence? Adolescence is understood as t... More and early adulthood, when the brain is still maturing. Some recurring factors stand out:

• Genetic and biological factors

Studies of twins and families show that a significant portion of risk for substance use disorders is linked to genetic variants influencing reward sensitivity, drug metabolism, and regulation of anxiety and impulse control. This does not mean there is a “gene for addiction,” but rather that certain biological profiles may increase the likelihood of problematic use under stress, easy access to drugs, or traumatic experiences. Preexisting psychiatric conditions (mood disorders, ADHD, anxiety disorders) also increase risk, sometimes because substances are used as a form of dysfunctional “self-medication.”

• Age of onset and developmental stage

Early use—especially in adolescence, when emotional brain regions mature before control regions—is strongly associated with higher risk of substance use disorders in adulthood. Adolescents are particularly drawn to novelty and intense sensations while having limited ability to consider long-term consequences. This physiological imbalance makes early drug experiences more likely to alter brain circuits, solidifying use patterns that persist over time.

• Trauma, stress, and mental healthWhat is meant by mental health? According to the World Healt... More

Traumatic events (abuse, violence, loss, war, forced migration) and chronic stress (poverty, discrimination, housing or job insecurity) are powerful vulnerability factors. In these contexts, substances may seem like a shortcut to numb psychological pain, insomnia, or anxiety, or to feel temporarily integrated into a group. Addiction linked to intense emotional copingCoping is the ability to face and manage stress, challenges,... More is often more severe and resistant, with high relapse risk if trauma is not addressed specifically.

• Family, school, and social environment

Family conflict, parental substance misuse, neglect, or maltreatment greatly increase the risk of substance use in children. Conversely, stable relationships, open communication, consistent adult role models, positive school experiences, and prosocial group membership are protective. Urban context, local drug availability, policies, and degree of stigmaStigma towards mental health can be defined as prejudice and... More or inclusion of users significantly affect initiation and progression of substance use behaviors.

What Psychological and Social Effects Do Substance Use Disorders Have?

Substance use disorders affect not only the body but also emotional life, relationships, and community participation. Many people experience progressive narrowing of interests, social isolation, and loss of meaning regarding social roles: parent, partner, worker, student. Over time, drugs occupy increasing space in the mind and daily life, becoming central to thoughts, choices, and relationships. Common psychological and social impacts include:

• Mental health and emotional well-being impairment

DepressionDepression is a disorder characterized by persistent sadness... More, anxiety, irritability, mood swings, and reduced pleasure in daily activities (anhedonia) are common in people with substance use disorders. It can be difficult to determine causality: preexisting symptoms may favor drug use, or chronic use may trigger or worsen mental health disorders. Either way, perceived quality of life drops: guilt, shame, hopelessness, and reduced confidence in change increase.

• Deterioration of family and social relationships

Families and partners experience fear, anger, frustration, helplessness, and often social stigma. Conflicts over money, lies, absences, unpredictable or violent behaviors erode trust. Roles may shift: children become “parents” of parents, siblings feel neglected, partners oscillate between over-control and detachment. Socially, friendships with non-users may be lost, replaced by fragile ties centered on substance use.

• Impact on school, work, and civic participation

Substance use disorders are linked to lower academic performance, school dropout‘School dropout’ refers to the phenomenon in which a you... More, poor concentrationWhat concentration really is and why it’s so hard to maint..., absenteeism, and workplace accidents. Job loss or insecurity, combined with legal issues (possession, trafficking, impaired driving), creates a vicious cycle of socioeconomic marginalization. This burden extends beyond the individual, increasing healthcare costs, reducing productivity, and worsening poverty and inequality.

• Stigma, discrimination, and self-stigma

In many cultures, people with addictions are labeled “weak,” “spoiled,” or “dangerous” rather than recognized as having a complex disease requiring care. External stigma often becomes self-stigma: internalized negative judgments, loss of self-esteemThe term self-esteem literally refers to the evaluation of o... More, and reluctance to seek help for fear of exclusion or judgment. Societies aiming to reduce drug harms must address this symbolic level, recognizing dignity and potential for change.

Can Substance Use Disorders Really Be Treated?

Scientific research shows recovery is possible: substance use disorders are treatable, not irreversible sentences. Treatment is not a single miracle intervention, but a phased process of prevention, early diagnosis, integrated treatments, and long-term support, often including relapses that should be seen as part of recovery, not failure. Key strategies include:

• Targeted medical and pharmacological interventions

For some addictions—especially opioids and alcohol—effective medications reduce cravings, ease withdrawal symptoms, and lower overdose risk. Integrated into structured programs, these treatments stabilize the individual, creating space to address psychological and social aspects. Medical care for physical complications (infections, cardiovascular, liver, respiratory issues) is essential to halt physical deterioration and boost motivation for change.

• Psychotherapy, psychosocial interventions, and rehabilitation

Evidence-based therapies—cognitive-behavioral therapy, motivational interviewing, family interventions, community reinforcement—help identify triggers, develop alternatives, rebuild social networks, and process trauma. Residential and semi-residential programs, therapeutic communities, and local services offer protected spaces to “detoxify” habits, routines, and life perspectives. Rehabilitation may include training, job support, expressive workshops, sports, and volunteeringVolunteering is an activity of help and service carried out ... More, restoring belonging and social utility.

• Harm reduction and public health policies

Needle exchange programs, supervised consumption sites, naloxone distribution, and information on substance interactions are harm reduction interventions that preserve life and health while complementing treatment. Policies such as accessible nonjudgmental services, decriminalization of personal use, regulated legal markets (e.g., alcohol), and integrated mental health and addiction services are crucial.

• Long-term support and relapse prevention

Because brain and behavioral changes can last years, long-term support—self-help groups, outpatient follow-ups, home interventions, peer networks of recovered individuals—is essential. Relapses should be viewed as signs of active vulnerabilities to address, not reasons for exclusion. A recovery-centered approach focuses on the whole person: not just abstinence, but quality of relationships, meaningful work, physical health, and future planning.

What Does “Global Well-Being” Mean in the Era of Addiction?

In a world of easy access to substances—legal and illegal—and diversified drug markets, discussing substance use disorders involves questioning the model of well-being a society pursues. “Global healthWhat is the definition of health proposed by the WHO in 1948... More” encourages moving beyond a simple “use vs. abstinence” view to embrace a perspective including physical health, mental balance, relationship quality, social participation, environmental sustainability, and social justice. Key directions for integrated well-being include:

• Life skills and emotional literacy promotion

Schools, adolescent/family services, and local communities can prevent substance misuse not by scaring with harm, but by fostering stress management, problem solving, critical thinkingWhat happens in our mind when we “think critically”? Beh... More, emotion regulation, and meaningful relationships. Evidence-based programs show early socio-emotional education reduces problematic use, improves academic performance, and strengthens resilienceWhat is meant by resilience? According to the American Psych... More.

• Reducing inequalities and risky contexts

Substance use often clusters in areas marked by poverty, unemployment, segregation, violence, and lack of services. Housing, income support, job protection, and equitable access to education and healthcare are preventive measures against problematic use. A less unequal society is less vulnerable to addiction.

• Building inclusive, non-stigmatizing communities

Global well-being sees people with addictions as rights-bearing citizens, not just patients or problems. Housing-first projects, co-production workshops, cultural initiatives, and media narratives giving voice to those with lived experience help repair social ties. Respectful, evidence-based language in media and online platforms can transform collective perceptions.

Ultimately, discussing substance use disorders today is about defining a good life: not just the absence of drugs, but presence of safe relationships, real opportunities, meaningful spaces, and social participation. A society that treats addictions also heals its deepest wounds.