13.4 Drug abuse, dependence, and addiction
5 min read•august 16, 2024
, dependence, and are complex issues with far-reaching consequences. This topic explores the definitions, diagnostic criteria, and neurobiology behind substance use disorders. It also covers common drugs of abuse and their effects on the brain and body.
Understanding the signs of drug abuse is crucial for early intervention. The notes delve into treatment options, including medications and behavioral therapies, highlighting the importance of integrated approaches in addressing addiction. This knowledge is essential for healthcare professionals working with diverse patient populations.
Defining drug abuse, dependence, and addiction
Key Concepts and Definitions
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- Drug abuse involves harmful use of psychoactive substances leading to significant impairment or distress
- creates physiological adaptation characterized by and
- Addiction manifests as a chronic, relapsing disorder with compulsive drug seeking despite consequences
- Abuse and addiction differ in symptom severity and degree of control over drug use
- DSM-5 combines substance abuse and dependence into a single disorder on a mild to severe continuum
- Physical dependence can occur without addiction in some medical treatments
- Addiction always involves a psychological component
Diagnostic Criteria and Clinical Implications
- DSM-5 criteria for substance use disorders include impaired control, social impairment, risky use, and pharmacological criteria
- Tolerance develops as higher doses are needed to achieve the same effect
- Withdrawal symptoms emerge when drug use is discontinued (nausea, sweating, anxiety)
- involves intense desire or urge to use the substance
- Continued use despite physical or psychological problems caused or exacerbated by the substance
- Clinical assessment involves comprehensive evaluation of substance use patterns, medical history, and psychosocial factors
Common drug classes associated with abuse
Central Nervous System (CNS) Depressants
- Alcohol depresses CNS activity leading to relaxation and reduced inhibitions
- Benzodiazepines (Xanax, Valium) enhance GABA neurotransmission causing sedation and anxiolysis
- Barbiturates (phenobarbital) also enhance GABA activity but carry higher risk of overdose
- GHB produces euphoria and sedation by acting on GABA and GHB receptors
- Abuse potential stems from pleasurable effects and risk of physical dependence
Stimulants and Psychostimulants
- Cocaine blocks dopamine reuptake creating intense euphoria and increased energy
- Amphetamines (Adderall) and methamphetamine increase dopamine and norepinephrine release
- MDMA (ecstasy) causes serotonin release leading to empathogenic and stimulant effects
- Caffeine mildly stimulates the CNS by blocking adenosine receptors
- Nicotine activates nicotinic acetylcholine receptors producing stimulation and relaxation
Opioids and Analgesics
- Heroin rapidly crosses the blood-brain barrier producing intense euphoria
- Prescription opioids (oxycodone, hydrocodone) bind to opioid receptors for pain relief
- Fentanyl is a potent synthetic opioid with high abuse potential and overdose risk
- Kratom contains opioid-like compounds with stimulant effects at low doses
- Tramadol has both opioid and serotonergic activity leading to analgesic effects
Hallucinogens and Dissociatives
- LSD activates serotonin receptors causing powerful alterations in perception and cognition
- Psilocybin (magic mushrooms) produces similar effects to LSD but with shorter duration
- Ketamine acts as an NMDA receptor antagonist causing dissociation and analgesia
- PCP also antagonizes NMDA receptors leading to more intense dissociative effects
- Salvia divinorum activates kappa opioid receptors causing brief but intense hallucinations
Neurobiology of drug addiction
Reward Pathway and Dopamine Signaling
- Mesolimbic dopamine system mediates reinforcing effects of drugs of abuse
- Ventral tegmental area (VTA) projects dopamine neurons to nucleus accumbens (NAc)
- Drugs increase dopamine release in NAc creating pleasure and reinforcing behavior
- Natural rewards (food, sex) also activate this pathway but to a lesser extent
- Repeated drug use leads to neuroadaptations reducing sensitivity to natural rewards
- Drug-related cues trigger dopamine release and craving even in absence of drug
Neuroplasticity and Synaptic Changes
- Long-term potentiation (LTP) strengthens synaptic connections associated with drug use
- AMPA receptor trafficking increases excitatory transmission in NAc
- Dendritic spine density changes alter synaptic plasticity and learning
- Brain-derived neurotrophic factor (BDNF) signaling contributes to drug-induced plasticity
- Epigenetic modifications lead to persistent changes in gene expression
- Synaptic pruning in prefrontal cortex impairs executive function and decision-making
Tolerance and Withdrawal Mechanisms
- Downregulation of receptors reduces drug sensitivity requiring higher doses
- Upregulation of cAMP pathway contributes to tolerance development
- Homeostatic adaptations in neurotransmitter systems oppose drug effects
- Withdrawal results from rebound effects when drug is removed from system
- Glutamate signaling plays key role in withdrawal and drug-seeking behavior
- Stress hormone systems become dysregulated contributing to negative affect
Recognizing signs and symptoms of drug abuse
Physical Manifestations
- Changes in sleep patterns (insomnia or hypersomnia) disrupt circadian rhythms
- Appetite fluctuations lead to unexplained weight loss or gain
- Deterioration in personal hygiene and grooming habits becomes noticeable
- Bloodshot eyes, dilated or constricted pupils indicate recent drug use
- Track marks or injection sites may be visible on arms or legs
- Frequent nosebleeds can result from intranasal drug administration
- Dental problems (meth mouth) occur with prolonged stimulant abuse
Behavioral and Psychological Changes
- Increased secrecy and social withdrawal from family and friends
- Financial problems due to spending money on drugs
- Neglect of responsibilities at work, school, or home
- Mood swings, irritability, anxiety, or depression become more frequent
- Paranoia or psychotic symptoms may emerge with certain substances
- Loss of interest in previously enjoyed activities (anhedonia)
- Impaired cognitive function affects memory, attention, and decision-making
Drug-Seeking and Use Patterns
- Preoccupation with obtaining and using drugs becomes primary focus
- Doctor shopping to obtain multiple prescriptions for
- Using medications in ways other than prescribed (crushing, snorting, injecting)
- Stealing or borrowing medications from others
- Continued use despite negative consequences (health, legal, relationship issues)
- Inability to cut down or control substance use despite attempts
- Experiencing withdrawal symptoms when attempting to stop or reduce use
Treatments for drug addiction
Pharmacological Interventions
- Agonist therapies (methadone) activate opioid receptors to reduce cravings
- Partial agonists (buprenorphine) provide limited opioid effects with lower abuse potential
- Antagonists (naltrexone) block opioid receptors preventing reinforcing effects
- Acamprosate reduces alcohol cravings by modulating glutamate and GABA systems
- Disulfiram causes unpleasant reaction when alcohol is consumed as deterrent
- Nicotine replacement therapy (patches, gum) eases withdrawal from tobacco
- Varenicline acts as partial agonist at nicotinic receptors to reduce smoking urges
Behavioral and Psychosocial Approaches
- (CBT) addresses drug-related thoughts and behaviors
- Motivational interviewing enhances intrinsic motivation for change
- Contingency management uses positive reinforcement to encourage abstinence
- Mindfulness-based relapse prevention integrates meditation practices
- Family therapy improves communication and support systems
- 12-step facilitation therapy connects individuals with peer support groups
- Dialectical behavior therapy (DBT) teaches emotional regulation and distress tolerance
Integrated Treatment Models
- (MAT) combines pharmacotherapy with behavioral interventions
- Dual diagnosis treatment addresses co-occurring mental health and substance use disorders
- Therapeutic communities provide long-term residential treatment and social support
- Intensive outpatient programs (IOP) offer structured treatment while living at home
- approaches focus on minimizing negative consequences of drug use
- Telemedicine and mobile health applications expand access to addiction treatment
- Recovery-oriented systems of care provide comprehensive, person-centered support
Key Terms to Review (21)
Addiction: Addiction is a chronic, relapsing disorder characterized by compulsive drug seeking, continued use despite harmful consequences, and long-lasting changes in the brain. It involves a complex interplay of genetic, environmental, and psychological factors that can lead to substance abuse and dependence, ultimately disrupting normal functioning and quality of life.
Alcohol dependence: Alcohol dependence is a chronic condition characterized by a strong craving for alcohol, loss of control over its use, and the presence of withdrawal symptoms when not consuming it. This condition is often linked to significant impairment in social, occupational, or recreational activities and is classified as a type of substance use disorder. Individuals with alcohol dependence may find it increasingly difficult to reduce or control their drinking despite experiencing negative consequences.
Brain reward system: The brain reward system is a group of structures in the brain that are activated by rewarding stimuli, which leads to feelings of pleasure and reinforcement of behaviors. This system plays a crucial role in motivating individuals to repeat activities that bring joy or satisfaction, such as eating, socializing, and engaging in certain substances. Understanding this system is key to grasping the mechanisms behind drug abuse, dependence, and addiction.
Cognitive-behavioral therapy: Cognitive-behavioral therapy (CBT) is a psychotherapeutic approach that focuses on identifying and changing negative thought patterns and behaviors that contribute to emotional distress. This therapy is particularly effective in treating various mental health disorders, including those associated with drug abuse, dependence, and addiction, by helping individuals develop healthier coping mechanisms and problem-solving skills.
Compulsion: Compulsion refers to a strong, often irresistible urge to engage in certain behaviors, even when an individual is aware that these actions may be harmful or counterproductive. In the context of drug abuse, dependence, and addiction, compulsion manifests as a driving force that leads individuals to seek out and use substances despite negative consequences, illustrating the struggle between desire and rational choice.
Controlled substances: Controlled substances are drugs that are regulated by law due to their potential for abuse, dependence, and addiction. These substances are categorized into schedules based on their medical use, safety, and potential for abuse, with stricter regulations placed on those deemed more dangerous. Understanding controlled substances is essential in grasping their role in managing anxiety disorders and the risks associated with drug misuse.
Craving: Craving is an intense desire or urge for a substance or experience that often occurs in individuals with drug abuse, dependence, or addiction. This phenomenon can lead to compulsive behaviors and is a significant factor in maintaining substance use disorders. Cravings can be triggered by various environmental cues, emotional states, or even specific memories associated with the drug or behavior.
Decriminalization: Decriminalization refers to the process of removing criminal penalties associated with certain behaviors, particularly in relation to drug use and possession. This approach shifts the focus from punitive measures to a public health perspective, aiming to reduce stigma and facilitate access to treatment and harm reduction services for individuals struggling with substance use issues.
Dopaminergic pathways: Dopaminergic pathways are neural circuits in the brain that utilize dopamine as their primary neurotransmitter. These pathways are crucial for regulating mood, motivation, reward, and motor control. When it comes to substance use, these pathways become particularly relevant as many drugs can hijack the brain's natural reward system, leading to abuse and addiction.
Drug abuse: Drug abuse refers to the inappropriate or harmful use of drugs, leading to detrimental consequences for the individual and society. This behavior often involves taking substances in a manner not prescribed or intended, resulting in physical, psychological, and social issues. Drug abuse can lead to dependence and addiction, where users develop a compulsion to seek out and use substances despite negative outcomes.
Drug dependence: Drug dependence refers to a state in which an individual has developed a reliance on a substance, characterized by compulsive use, tolerance, and withdrawal symptoms when not using the drug. This condition is often associated with drug abuse and can lead to significant impairments in social, occupational, and other important areas of functioning. Understanding drug dependence is crucial for recognizing the broader issues of addiction and the need for effective treatment strategies.
Drug policy: Drug policy refers to the principles and regulations that govern the control, distribution, and use of drugs within a society. This includes laws and practices aimed at preventing drug abuse, managing drug dependence, and addressing addiction. Drug policies are shaped by various factors including health concerns, societal values, and economic considerations, influencing how substances are regulated and treated within communities.
Harm reduction: Harm reduction refers to a set of strategies and principles aimed at minimizing the negative health, social, and economic consequences associated with drug use and addiction. It emphasizes a pragmatic approach that accepts drug use as a part of society while focusing on reducing harm rather than solely aiming for abstinence. This approach includes various interventions such as needle exchange programs, supervised consumption spaces, and access to addiction treatment services, all of which aim to improve the well-being of individuals who use drugs.
Medication-assisted treatment: Medication-assisted treatment (MAT) is a comprehensive approach to treating substance use disorders, particularly opioid addiction, by combining medications with counseling and behavioral therapies. This method addresses both the physiological and psychological aspects of addiction, providing a holistic approach to recovery and helping individuals reduce cravings and withdrawal symptoms while engaging in therapy for sustainable recovery.
Neuroplasticity: Neuroplasticity is the brain's ability to reorganize itself by forming new neural connections throughout life. This adaptability enables the brain to adjust to new experiences, learn new information, and recover from injuries. Neuroplasticity plays a critical role in how individuals respond to drug abuse and addiction, as it can influence behaviors, cravings, and the brain's reward system.
Opioid addiction: Opioid addiction is a chronic, relapsing disorder characterized by compulsive drug seeking and use despite harmful consequences, stemming from the misuse of opioid medications or illicit opioids. This condition often develops due to the brain's adaptation to these drugs, leading to physical dependence and a strong psychological urge to use them. Understanding opioid addiction is crucial for addressing the broader issues of drug abuse, dependence, and addiction in society.
Schedule I drugs: Schedule I drugs are substances that are classified by the Controlled Substances Act as having a high potential for abuse and no accepted medical use in the United States. These drugs are considered the most dangerous, leading to severe psychological or physical dependence. The classification reflects concerns about their potential for addiction and the lack of medical benefits, making them illegal to manufacture, distribute, or possess.
Serotonin receptor agonists: Serotonin receptor agonists are compounds that bind to and activate serotonin receptors, mimicking the effects of serotonin in the brain. These agonists can influence mood, anxiety, and various physiological functions, making them important in the context of drug abuse, dependence, and addiction, as they may be used to treat disorders like depression and anxiety or may be misused for their euphoric effects.
Substance use disorder: Substance use disorder is a medical condition characterized by an individual's compulsive pattern of using substances, such as drugs or alcohol, despite negative consequences. This disorder encompasses both abuse and dependence, often leading to significant impairment in various aspects of life, including social, occupational, and psychological functioning. It highlights the complex interplay between biological, psychological, and environmental factors that contribute to addiction.
Tolerance: Tolerance refers to a decreased response to a drug after repeated use, meaning higher doses are required to achieve the same effect. This phenomenon is particularly important in understanding how drugs interact with receptors in the body and plays a critical role in the contexts of substance use and dependence. Over time, as the body adapts to the presence of a drug, both pharmacodynamic changes (like receptor desensitization) and pharmacokinetic changes (like altered metabolism) can contribute to tolerance.
Withdrawal symptoms: Withdrawal symptoms are physical and psychological reactions that occur when a person stops using a substance they are dependent on. These symptoms can range from mild to severe and can include anxiety, sweating, nausea, tremors, and more, depending on the substance involved. Understanding withdrawal symptoms is crucial in recognizing the challenges of drug dependence and addiction, as they play a significant role in the cycle of substance use and recovery.