1. Introduction

Drug addiction has become a pressing global health issue, with an estimated 39 million individuals worldwide affected by substance use disorders [1]. As different kinds of drugs become more available to the public, societies face mounting challenges in distinguishing between medically appropriate use, recreational consumption, and pathological abuse. Drug addiction is characterized by a compulsive, uncontrollable pattern of drug use that develops in a subset of individuals following repeated exposure [2]. In contrast to physical dependence, which is primarily physiological, addiction is largely driven by neurochemical changes, particularly those involving increased dopamine release. Addiction development begins with drug-induced neuroadaptive changes in the ventral tegmental area (VTA), which subsequently alter dopamine transmission in downstream brain regions [3].

Addiction emerges from a complex interaction among biological, psychological, and socio-cultural factors. Chronic stress, trauma, dysfunctional family dynamics, and adverse social environments can all contribute to increased vulnerability. For example, while positive social environments may act as protective factors, negative interpersonal experiences can increase the risk of substance use [4]. Early-life stress is also implicated in long-lasting impairments in inhibitory control by disrupting the mesolimbic dopamine system – an essential component of the brain’s reward network and a focal point in addiction research [5]. Despite the multifactorial complexity of its etiology, addiction remains a clinically manageable condition.

This paper aims to explore the multifactorial causes and consequences of drug addiction by reviewing findings from biopsychology, neuroscience, pharmacology, and public health. It highlights the dual nature of psychoactive substances as both therapeutic agents and potential sources of harm. A deeper understanding of addiction’s underlying mechanisms and contextual factors will inform clinical practice and support the development of comprehensive approaches to addressing substance use disorders.

2. The causes of addiction

2.1. Biological factors

The neurobiological basis of addiction is closely related to the brain’s reward circuitry, particularly involving the prefrontal cortex, ventral striatal areas, and nucleus accumbens [6]. Under normal physiological conditions, neurotransmitter activity is tightly controlled by regulatory processes such as reuptake, where excess neurotransmitters, like dopamine, are reabsorbed by presynaptic neurons to maintain homeostasis and prevent overstimulation. However, this balance is disrupted by drug use. In the case of opioids, for example, drug intake stimulates the VTA to release dopamine [3]. Opioids bind to specific receptors on neurons, inhibiting dopamine reuptake and accumulating dopamine in the nucleus accumbens, resulting in euphoric effects. Repeated exposure triggers neuroadaptive changes that reinforce drug-seeking. Ultimately, the prefrontal cortex, responsible for decision-making and self-control, becomes conditioned to associate opioid use with relaxation, further promoting continued [7].

Beyond neural mechanisms, two other physiological phenomena significantly contribute to the development of addiction: tolerance and withdrawal. Drug tolerance arises when repeated exposure to a substance reduces its efficacy, requiring progressively higher doses to achieve the same effect [8]. Studies on rats showed fentanyl tolerance increased required doses from 5 μg/kg to 500 μg/kg for the same pain relief [8].

Withdrawal symptoms emerge when drug use is abruptly discontinued after prolonged exposure [9]. As the brain develops dependent on the drug to maintain a neurochemical baseline, cessation leads to distress. Opioid withdrawal symptoms include nausea, cramps, insomnia, and anxiety [9]. These symptoms result from neuroadaptations in the reward system and often drive relapse to relieve discomfort. Together, these biological mechanisms underscore the powerful physiological basis of addiction and its resistance to voluntary cessation without medical or psychological intervention.

2.2. Psychological factors

Psychological vulnerabilities, particularly mood disorders such as depression, anxiety and bipolar disorder, can increase the risk of developing substance use disorders [10]. Individuals with these disorders may turn to drugs as a form of self-medication to alleviate emotional distress or numb psychological pain. Addiction develops through three psychological processes: learning, liking, and wanting [6]. Initially, individuals associate drug use with relief (learning), then begin to enjoy its effects (liking). Over time, neuroadaptations drive the “wanting” phase, marked by intense motivation to use drugs, even without pleasure. Mood disorders interact with this cycle. For instance, individuals experiencing a depressive episode may present with persistent sadness, fatigue, anhedonia, and social withdrawal [11]. Sufferers may discover that drugs provide temporary emotional relief, which evolves into dependency. This escalating cycle reinforces the psychological foundations of addiction and increases the likelihood of sustained substance use.

Trauma, especially early-life trauma such as childhood abuse, neglect, or emotional abandonment, also plays a critical role in addiction vulnerability [12]. Maladaptive coping strategies developed in response to trauma are associated with an increased risk of depressive disorders and substance misuse later in life. Consequently, the unresolved emotional pain associated with trauma thus directly feeds into the psychological processes that underlie addiction.

Moreover, individual differences in impulse control represent another important psychological risk factor. Those with strong impulse control ability are better equipped to resist the temptation of drugs, even when exposed to triggers [13]. Conversely, individuals with weak impulse control are more likely to act on urges, especially after experiencing the pleasurable effects of a substance. Deficits in impulse control often precede drug use and may contribute to the initiation and escalation of addictive behaviors [13]. Continued drug uses impaired decision-making and inhibitory control, creating a self-perpetuating cycle of compulsive use.

2.3. Sociocultural factors

This section highlights three important sociocultural factors that may contribute to drug addiction development: social stress, social trends, and cross-cultural differences in societal norms.

2.3.1. Social stress

Social stress is increasingly prevalent in modern society, where individuals face mounting pressures from work, family, and daily life. While adaptive coping strategies, such as social interaction or physical activity, can mitigate stress and promote emotional resilience, chronic exposure to stress has detrimental neurobiological effects [14]. Persistent stress elevates cortisol levels, impairing cognitive function and emotional regulation. Individuals exposed to both chronic social stress and acute stressors exhibit structural and functional alterations in key brain regions implicated in addiction, including the prefrontal cortex, hippocampus, and amygdala [15]. These stress-related neuroadaptations can dysregulate the brain’s reward and decision-making systems, increasing vulnerability to substance use as a maladaptive coping mechanism. As a result, individuals who lack effective stress management strategies may resort to alcohol or drug use as a temporary escape from ongoing psychosocial burdens.

2.3.2. Social trends

Peer pressure and social trends are significant sociocultural determinant in the development of drug addiction. During early adolescence (ages 12-15), the prefrontal cortex is still developing. As a result, adolescents often struggle to differentiate between constructive and harmful behaviors and are more vulnerable to external influences. Peer groups, including friends, classmates, and social circles, shape behavior during this stage. However, susceptibility to social influence is not limited to adolescents. Adults may likewise conform to cultural or organizational norms that promote substance use. For example, in Japan, drinking is embedded in corporate culture, seen as a way to build loyalty and career ties [16]. Despite health risks, such behaviors are reinforced by social expectations. While positive peer influence can encourage healthy behaviors, exposure to peer groups that normalize drug use greatly increases addiction risk.

2.3.3. Cross-cultural differences

National norms and regulatory policies constitute a third key sociocultural factor influencing drug addiction. In some countries, societal attitudes and legal frameworks surrounding drug use is comparatively lenient, which can lead to higher rates of addiction. For instance, morphine is a powerful analgesic that, when regulated, can be used safely for medical purposes. In contrast, easy access without a doctor's supervision can increase the chances of abuse. Morphine, as an example, is a strong analgesic that usually requires a doctor's prescription to use. However, in places where there is no medical control, such as pharmacies, people have easy access to this drug and may therefore overdose or use it for non-medical reasons. Similarly, countries like the United States and Canada report high rates of daily cannabis use, with widespread perceptions that it is less harmful than cigarettes. Such perceptions, shaped in part by national discourse and legislation, contribute to increased acceptance and habitual use.

3. From treatment to addiction: managing medical drug use responsibly

While many drugs are commonly associated with recreational use and addiction, several also have legitimate and important medical applications. Drugs such as opioids, marijuana, and stimulants are widely used in clinical settings under the supervision of professionals to manage specific health conditions. The key is how these drugs are prescribed, monitored and regulated.

Opioids represent one of the most effective analgesics in modern medicine. Medications such as morphine, oxycodone and fentanyl are routinely prescribed for patients with acute or chronic pain, including those recovering from surgery or undergoing cancer treatment [17]. Similarly, some forms of cannabis are approved for medical use. Epidiolex, a purified cannabidiol (CBD) formulation, is used to treat rare epilepsies such as Dravet syndrome [18]. In some areas, medical marijuana is prescribed for chronic pain, chemotherapy-induced nausea, and multiple sclerosis [19]. Moreover, stimulants such as methylphenidate (Ritalin) and amphetamine (Adderall) are commonly prescribed for attention deficit hyperactivity disorder (ADHD), which improves attention and behavioral control in both children and adults [20].

Despite their therapeutic efficacy, these medications pose significant risks of misuse. Prescription drug abuse, including unsupervised use, dose escalation, or diversion, could become a major public health concern. Medications initially used for therapeutic purposes may still lead to dependence, tolerance, and serious health consequences if taken inappropriately [21]. Therefore, distinguishing between medical use and abuse is critical. Appropriate medical supervision, controlled access to prescription drugs and increased public awareness are essential to maximize the therapeutic benefits of these medicines while minimize the probability of addiction and abuse.

4. Biopsychosocial consequences of drug addiction

Although these substances have recognized medical applications, their misuse or unsupervised use can lead to severe physical, psychological, and social consequences. Long-term drug use can cause cardiovascular diseases, cognitive decline, mood swings, and memory degradation [22]. Neuroimaging shows reward and memory circuits are hyperactive during drug cues but less active in normal tasks [22]. Illicit drugs can cause abdominal pain, vomiting, or in severe cases, intestinal ischemia and perforation [23].

Addiction may cause or worsen dissociative disorders like amnesia, depersonalization, or identity disruption [24]. Similarly, dissociation plays a critical role in the development of substance use disorders following trauma exposure [25]. People with depression, PTSD, or anxiety face higher risks of both dissociation and addiction. Moreover, substance use may exacerbate dissociative symptoms, creating a self-perpetuating cycle of psychological deterioration.

Socially, addiction leads to isolation and marginalization. It is associated with crime, unemployment, and educational dropout. In addition, interpersonal relationships often deteriorate as trust erodes, communication breaks down, and addicts can become socially isolated. Together, these cascading consequences highlight the barriers to social integration that drug addiction can create.

5. From stigma to support: reforming addiction policy

Addiction remains an extremely difficult problem to address, largely due to its biological, psychological and social complexity. Although the scientific community is increasingly recognizing addiction as a chronic brain disease, public perceptions often lag, leading to continued stigmatization. The persistent stigma, coupled with fragmented coordination between the healthcare and criminal justice systems, frequently prevents access to appropriate treatment, especially for recently incarcerated individuals [26]. Despite the availability of evidence-based approaches such as medication-assisted treatment (MAT), their implementation remains limited, especially in prison settings, only 11% of criminal justice agencies provide MAT upon reentry into the community, with common barriers including staff bias, legal liability issues, and limited awareness of MAT’s effectiveness [27].

A central point of debate in addiction treatment policy nowadays is whether drug use should be considered as a medical issue or a criminal offense [28]. While MAT programs have demonstrated clear efficacy, they often encounter resistance in systems that prioritize punishment over rehabilitation. However, community-based treatment programs shows significant reductions in substance use among previous addicts, highlighting the potential of therapeutic approaches to promote recovery [28].

Moving forward, the implementation of a comprehensive interdisciplinary strategy is imperative. This includes expanding access to evidence-based treatments, training justice and healthcare professionals, integrating services across agencies and promoting public education to reduce stigma. Reframing addiction as a treatable medical condition rather than a moral failing could be a critical step toward more humane policies.

6. Conclusion

Drug addiction is a multifaceted disease influenced by biological, psychological and sociocultural factors. This paper emphasizes how neurochemical alterations - particularly in the dopamine reward system - interact with emotional vulnerability and social context to lead to drug addiction. While some drugs have important medical uses, the line between therapeutic use and abuse highlights the need for responsible provision of prescription drugs and public awareness. Addiction is not a consequence of personal weakness or moral failure, but a complex condition shaped by trauma, impaired impulse control, chronic stress, peer influence and prevailing social norms.

This research has practical implications for psychology, neuroscience, and public health, as it synthesizes biological, psychological, and sociocultural perspectives to provide a more comprehensive understanding of addiction. By exploring the multifaceted nature of addiction, this study emphasizes the need for more nuanced prevention and intervention strategies beyond medical treatment alone. However, this study was limited by its reliance on secondary sources and a literature review, which may limit the depth of empirical analysis and affect the generalizability of the findings. Further study could focus on marginalized populations or cross-cultural comparisons to explore how addiction manifests under different social conditions.

Overall, this study provides new perspectives for understanding the complex causes and consequences of addiction and emphasizes the importance of interdisciplinary approaches in addressing substance use disorders. Reframing addiction as a health issue is essential to building systems that support recovery reintegration.