Evolutionary Psych-Class 15

commonly abused substances

alcohol, nicotine, cannabis, opioids

alcohol

depressant, impairs cognition, anti-anxiety

nicotine

stimulant, highly addictive, affects dopamine

cannabis

alters perception, mood, and potential for misuse

opiods

pain relief, high addiction risk, overdose potential

effects of substance use

•

•Short-term: Euphoria, relaxation, altered perception

•Long-term: Dependence, tolerance, withdrawal

•Physical health: Organ damage, increased mortality risk

•Mental health: Depression, anxiety, psychosis risk

Substance Use Disorders (DSM-5-TR)

•Criteria: Impaired control, social impairment, risky use

•Tolerance: Need for more substance to achieve effect

•Withdrawal: Physical and psychological symptoms

•Severity: Mild, moderate, or severe based on criteria

Demographic Differences in Substance Use

•Higher rates in males than females for most substances

•Young adults have the highest prevalence of use

•Socioeconomic factors influence patterns of abuse

•Cultural norms shape substance use and stigma

Historical Use of Substances

•Prehistoric evidence of hallucinogens, opium, alcohol

•Ancient civilizations used substances for rituals, medicine

•Trade routes spread psychoactive substances globally

•Modern synthetic drugs have increased potency & risk

Evolutionary Perspective on Substance Abuse

•

•Why do humans seek out non-nutritional substances?

•Plants evolved neurotoxins to deter consumption

•Humans adapted to use some toxins beneficially

•Addiction arises from interaction with reward systems

Mismatch Models of Drug Use

•Brain reward systems evolved in different environments

•Modern substances exploit evolved pleasure pathways

•Mismatch between ancient adaptation & modern access

•Leads to high rates of misuse and addiction

Trade-off Theories in Addiction

•

•Substance use may have had fitness benefits

•Enhanced cognitive function, reduced fatigue

•Short-term benefits may outweigh long-term harm

•Explains persistence of drug use despite risks

Neurotoxin Regulation Hypothesis

•Plants produce toxins to deter consumption

•Humans developed mechanisms to tolerate some toxins

•Regulated exposure may have had evolutionary benefits

•Drug use may exploit these ancient adaptations

Pharmacophagy and Evolutionary Adaptations

•Some species consume plant toxins for health benefits

•Humans may have evolved similar behaviors

•Self-medication hypothesis suggests adaptive benefits

•Explains use of psychoactive plants in history

Risk-taking and substance use

•Risk-taking associated with reproductive success

•Adolescents have higher substance use rates

•Sensation-seeking and impulsivity play roles

•Cultural factors reinforce or discourage use

sexual selection and drug use

•Drug use may signal status, maturity, risk-taking

•Some evidence suggests increased mating success

•However, long-term effects on fitness are negative

•Sex differences exist in patterns of use

costly signaling and addiction

•Risky behaviors can act as fitness signals

•Drug use may demonstrate ability to handle toxins

•However, high costs suggest limited adaptive value

•More research needed on this hypothesis

Novel Psychoactive Subtances (NPS)

•Synthetic drugs evolving faster than human defenses

•Many mimic traditional substances with greater potency

•Increased risk of overdose and unknown health effects

•Challenge for regulation and public health

Genetic and Environmental Influences

•Addiction risk influenced by genetic factors

•Environmental exposure plays critical role

•Early use increases likelihood of dependence

•Gene-environment interactions shape outcomes

Social and Cultural Factors in Substance Use

•Peer influence and social norms shape use

•Media and advertising impact perceptions

•Legal status affects accessibility and use rates

•Cultural traditions influence substance choice

Cumulative Culture in Addiction Vulnerability

•Human learning and culture shape drug use

•Transmission of drug habits through generations

•Cultural practices influence addiction likelihood

•Public health efforts must account for culture

Plant Neurotoxins and their effects

•Many drugs originate from plant alkaloids

•Nicotine, morphine, cocaine as natural toxins

•Toxins can have medicinal and harmful effects

•Evolutionary trade-offs in plant-human interactions

self-medication hypothesis

•Some substance use driven by symptom relief

•Mental health conditions linked to higher use

•Temporary relief reinforces continued use

•Leads to cycle of dependence and harm

public health implications

•Understanding evolutionary factors informs policy

•Harm reduction approaches are more effective

•Treatment should address biological & social factors

•Preventive strategies must be evidence-based

critiques of the brain disease model

•Satel & Lilienfeld: Addiction is not purely a brain disease

•Emphasize the role of choice, meaning, and social context

•BDMA overstates neurobiological determinism

•Reduces agency, limiting treatment approaches

Addiction as a behavioural and social phenomenon

•Addiction influenced by values, goals, and environment

•Most people recover without medical intervention

•Psychological and social factors drive use and relapse

•Treatment should focus on motivation, not just biology

implications for policy and treament

•BDMA fosters over-reliance on medication-based treatments

•Alternative approaches stress personal responsibility

•Harm reduction, behavioural therapies more effective

•Addiction should be seen as a complex, multi-factorial issue

evolutionary pressures on drug use

•Environmental changes shape substance use patterns

•Different societies have varied substance norms

•Drug use influenced by social acceptance & prohibition

•Understanding evolution helps predict future trends

mental health comorbidities and addiction

•Substance use often coexists with mental disorders

•Anxiety, depression, PTSD linked to higher drug use

•Self-medication theory explains many substance habits

•Treatment must address underlying psychological distress

future research directions

•Integrating evolutionary psychology with addiction science

•Investigating genetic predispositions in modern contexts

•Exploring cultural adaptations to drug use

•Developing targeted interventions using evolutionary insights

policy and intervention strategies

•Policies should consider evolutionary motivations for use

•Harm reduction aligns with evolutionary perspectives

•Cognitive and social interventions over punitive measures

•Addressing root causes: stress, social instability, trauma