1. Introduction to Psychopharmacology
Psychopharmacology is the study of the effects of chemical substances (such as medications and drugs) on:
Behavior
Mood
Cognition
Neurological functions
Importance in understanding drugs:
Analyzing acute and chronic effects
Understanding the biological basis of addiction
Developing therapeutic methods
| Type | Examples | Primary Effect |
|---|
| Natural | Cannabis, Opium | CNS inhibition/stimulation |
| Semi-Synthetic | Heroin, Cocaine | Modulating neurotransmitters |
| Synthetic | Methamphetamine, Ecstasy | Dopamine release stimulation |
Depressants (Alcohol, Benzodiazepines)
Stimulants (Amphetamines, Nicotine)
Hallucinogens (LSD, Psilocybin Mushrooms)
Opioids (Morphine, Tramadol)
Role of the Reward System:Dopaminergic pathway (Mesolimbic pathway):Nucleus accumbens (NAc)
Ventral tegmental area (VTA)
Reinforcement Mechanisms:Positive reinforcement (dopamine increase)
Negative reinforcement (relief from withdrawal symptoms)
Chronic Neural Changes:Reduction of D2 dopamine receptors
Synaptic plasticity alterations
Prefrontal cortex dysfunction (reduced impulse control)
| Substance | Affected Neurotransmitter | Mechanism | Psychological Effect |
|---|
| Cocaine | Dopamine | Blocks reuptake | Euphoria, increased energy |
| Heroin | Opioid receptors | μ-opioid receptor activation | Relaxation, pain relief |
| Alcohol | GABA | Enhances inhibitory transmission | Sedation, balance loss |
| Nicotine | Acetylcholine | Activates nAChRs | Increased attention, addiction |
2. Classification of Drugs
3. Neural Mechanisms of Addiction
4. Effects of Drugs on Neurotransmitters
5. Psychiatric Disorders Associated with Addiction
Amphetamine-Induced Psychosis
Hallucinogen Persisting Perception Disorder (HPPD)
Cocaine withdrawal depression
Anxiety related to benzodiazepine withdrawal
Panic attacks during alcohol withdrawal
Link between borderline personality disorder and substance abuse
6. Psychological Models Explaining Addiction
Biological Factors: Genetic predisposition (e.g., DRD2 genes)
Psychological Factors: Self-control, stress
Social Factors: Stimulating environments
Classical Conditioning: Environmental cues → craving
Negative Reinforcement: Using substances to avoid withdrawal
Cognitive distortions: "I can control my use."
Erroneous beliefs about the benefits of drugs
7. Pharmacological and Psychological Treatment of Addiction
| Substance | Medications Used | Mechanism |
|---|
| Opioids | Methadone, Buprenorphine | Partial receptor activation |
| Alcohol | Disulfiram, Naltrexone | Alcohol metabolism inhibition |
| Nicotine | Nicotine patches | Nicotine replacement |
Cognitive Behavioral Therapy (CBT):Identifying triggers
Developing coping strategies
Motivational Interviewing (MI):Enhancing the desire for change
Group Therapy:12-Step Programs (e.g., AA)
8. Addiction Prevention within the Framework of Mental Health
Primary prevention: Adolescent education (school programs)
Secondary prevention: Early detection of users
Tertiary prevention: Relapse prevention
Understanding biological risk factors
Developing vaccines against certain drugs (e.g., cocaine vaccine)
9. Drug-Related Medical Conditions: A Neuropsychological Perspective
A. Amphetamine-Induced Psychosis
Cause: Chronic/high-dose methamphetamine or cocaine use
Symptoms:
Auditory and visual hallucinations
Paranoid delusions
Aggressive behavior
Mechanism:
Hyperactive dopamine transmission in the mesolimbic pathway
Neuronal damage in the prefrontal cortex
Case Study:
A 24-year-old male experiencing "bugs crawling under his skin" hallucinations after one week of crystal meth use, displaying aggressive behavior toward family members. Differential diagnosis: schizophrenia vs. substance-induced psychosis.
B. Cannabis-Induced Psychosis
Risk Factors:
Genetic predisposition (e.g., AKT1 gene)
Early adolescence cannabis use
Clinical Features:
Psychomotor retardation
Distinct visual hallucinations
A. Post-Cocaine Depression
Pathophysiology:
Dopamine depletion
Dysfunction of the reward system
Characteristics:
Lasts 2–4 weeks post-cessation
High suicide risk
Comparison Table:
| Criterion | Typical Depression | Post-Cocaine Depression |
|---|
| Onset | Gradual | Sudden after cessation |
| Treatment Response | 4–6 weeks | 2–3 weeks |
| Hallucinations | Rare | Possible (especially auditory) |
B. Bipolar Disorder and Drugs
Bidirectional Relationship:60% of individuals with bipolar disorder also suffer from substance use disorders
Drugs can trigger manic episodes
Wet Brain Syndrome
Cause: Chronic thiamine deficiency (Alcoholism)
Stages:
Wernicke's Encephalopathy:
Confusion
Ophthalmoplegia
Korsakoff’s Psychosis:
Severe short-term memory loss
Confabulation
Mechanisms of Damage:
Degeneration of mammillary bodies in the thalamus
Mammillary body atrophy
A. Panic Attacks During Withdrawal
Substances:
Benzodiazepines
Alcohol
Mechanism:
Sympathetic nervous system hyperactivity
Decreased GABAergic inhibition
B. Social Anxiety and Alcohol
Pattern of Use:
"Self-medication" for symptoms
Long-term exacerbation of anxiety
A. Fetal Alcohol Syndrome (FAS)
Manifestations:
Microcephaly
Characteristic facial deformities
Intellectual disability
Mechanism:
Neuronal growth inhibition
Disruption of cell migration during fetal development
B. Persistent Drug-Induced Psychosis
Diagnostic Criteria:
Symptoms persist >1 month after cessation
Excluding schizophrenia
Causative Substances:
Hallucinogens (especially PCP)
Stimulants
Case 1: Opioid Addiction and Depression
32-year-old woman with chronic pain started with tramadol use, later switching to heroin.
Presenting features:
Social withdrawal
Suicidal ideation
Anhedonia
Suggested Interventions:
Pharmacological: Buprenorphine/Naloxone
Psychological: CBT for depression and addiction
Pain management therapy
Case 2: Alcohol Use Disorder with Neurological Damage
45-year-old man with a 20-year history of alcohol use presenting with:
Short-term memory loss
Ataxia
Disorientation in time and place
Recommended Investigations:
MRI: To exclude cerebellar degeneration
Blood thiamine level testing
Executive function assessment
Organic Disorders Caused by Substance Abuse
| System | Causative Substance | Disorder |
|---|
| Nervous | Alcohol | Peripheral neuropathy |
| Hepatic | Steroids | Fatty liver hepatitis |
| Cardiac | Cocaine | Myocardial infarction |
Conclusion
The study of drugs within the framework of psychopharmacology requires the integration of:
Neurosciences
Psychological models
Social perspectives
Effective treatment requires a multidisciplinary approach combining pharmacological interventions and psychological support.
