4.2

SUBSTANCE USE DISORDERS

  • Definition: Substance use disorder is defined by the DSM-5 as a compulsive pattern of drug use despite negative consequences.

    • Involves:
      • Physical dependence: Changes in normal bodily functions and withdrawal symptoms experienced upon cessation of use.
      • Psychological dependence: Emotional need for the drug.

  • Key Concepts:

    • Tolerance:
    • Definition: Occurs when a person requires more of a drug to achieve effects previously experienced at lower doses.
    • Linkage: Associated with physiological dependence.
    • Withdrawal:
    • Definition: Negative symptoms experienced when drug use is discontinued.
    • Credit: DSM5.

DRUG CATEGORIES

  • Categorization of Drugs: Various classes of drugs are identified, each having specific characteristics and effects.
    • Antipsychotics: e.g., Haldol, Risperdal, Seroquel.
    • Stimulants:
      • Examples: Amphetamines, Khat, Ritalin, Methylxanthines (e.g., Cocaine, Caffeine, Nicotine, Theophylline, Theobromine).
      • Include Marijuana as a separate class.
    • Depressants and Sedative Hypnotics.
    • Narcotic Analgesics: e.g., Opium, Codeine, Morphine, Heroin, Ketamine, DXM, PCP, Nitrous, Ibogaine, Amanitas, Salvinorum.
    • Psychedelics: e.g., MDMA, Mescaline, LSD, Psilocybin, AMT, DMT.
    • Minor Tranquilizers: e.g., Ativan, Valium, Xanax.
    • Alcohol: Includes Barbituates, Ether, GHB.

DRUGS AND THEIR EFFECTS

  • Drug Classifications and their Effects:
    • Stimulants:
      • Examples: Cocaine, amphetamines (including ADHD medications such as Adderall), methamphetamines, MDMA (“Ecstasy” or “Molly”).
      • Effects on the Body: Increased heart rate, blood pressure, body temperature.
      • Effects When Used: Increased alertness, mild euphoria, decreased appetite in low doses; high doses can cause agitation and paranoia, with potential hallucinations and heightened sensitivity to physical stimuli.
      • Severe effects: High doses of MDMA can cause brain toxicity and death.
      • Psychological Addiction: Yes.
    • Sedative-Hypnotics (Depressants):
      • Examples: Alcohol, barbiturates (e.g., secobarbital, pentobarbital), Benzodiazepines (e.g., Xanax).
      • Effects on the Body: Decreased heart rate and blood pressure.
      • Effects When Used: Low doses increase relaxation and decrease inhibitions; high doses can induce sleep, cause motor disturbance, memory loss, decreased respiratory function, and potentially death.
      • Psychological Addiction: Yes.
    • Opiates:
      • Examples: Opium, Heroin, Fentanyl, Morphine, Oxycodone, Vicoden, Methadone, and other prescription pain relievers.
      • Effects on the Body: Decreased pain, pupil dilation, decreased gut motility, decreased respiratory function.
      • Effects When Used: Pain relief, euphoria, sleepiness; high doses can cause death by respiratory depression.
      • Psychological Addiction: Yes.
    • Hallucinogens:
      • Examples: Marijuana, LSD, Peyote, mescaline, DMT, ketamine, PCP.
      • Effects on the Body: Increased heart rate and blood pressure, which may dissipate over time.
      • Effects When Used: Mild to intense perceptual changes with high variability in effects based on strain, method of ingestion, and individual differences.
      • Psychological Addiction: Yes.

DEPRESSANTS

  • Definition: Depressants are drugs that suppress central nervous system activity, commonly acting as GABA agonists which exert a quieting effect on the brain.

    • Mechanism: These drugs bind to GABA receptors, making neurons less likely to fire.
    • Included Drugs:
      • Alcohol
      • Barbiturates (used as anticonvulsants)
      • Benzodiazepines (used as anti-anxiety medication).

  • Effects of Alcohol:

    • Decreases reaction time and visual acuity.
    • Lowers levels of alertness and reduces behavioral control.
    • Potentially can result in complete loss of consciousness.

GABA

  • GABA Channel Mechanism: The GABA-gated chloride ($Cl^-$) channel is embedded in the cell membrane of specific neurons.
    • Function: The channel contains multiple receptor sites for substances such as alcohol, barbiturates, and benzodiazepines.
    • Process: Binding opens the chloride channel, allowing negatively charged chloride ions into the neuron's cell body, altering its charge negatively and inhibiting neuronal firing.
    • Outcome: Activating GABA neurons has a quieting effect on the brain.

STIMULANTS

  • Definition: Stimulants increase overall levels of neural activity, often functioning as dopamine agonists by preventing dopamine reuptake.
    • Included Drugs: Cocaine, Amphetamine, Cathinones (e.g., bath salts), MDMA.
    • Consumption Method: Crack rocks are typically smoked, enhancing the rapid onset of effects.
    • Side Effects: Nausea, elevated blood pressure, increased heart rate, anxiety, and potential hallucinations and paranoia.

DOPAMINE AGONISTS

  • Mechanism: Cocaine and amphetamines block the reuptake of dopamine from the synapse into the presynaptic cell, resulting in an increased availability of dopamine in the synapse.

NICOTINE AND CAFFEINE

  • Caffeine:
    • Mechanism: Antagonizes adenosine activity, increasing alertness and arousal.
  • Nicotine:
    • Mechanism: Interacts with acetylcholine receptors, highly addictive, and influences arousal and reward mechanisms.
    • Credit: Information from Wikipedia.

OPIOIDS

  • Function: Serve as analgesics (pain-relievers) through effects on the endogenous opioid neurotransmitter system.
    • Included Drugs: Heroine, Morphine, Methadone, Codeine.
    • Addictive Nature: Highly addictive.

HALLUCINOGENS

  • Description: Hallucinogens cause changes in sensory and perceptual experiences, often resulting in vivid hallucinations.
    • Neurotransmitter Interactions:
      • Mescaline and LSD act as serotonin agonists.
      • PCP and ketamine function as NMDA glutamate receptor antagonists.
    • Cultural Context: Medical marijuana shops are increasingly common in the United States.
    • Credit: Modified from “new 1lluminati”/Flickr.

OTHER STATES OF CONSCIOUSNESS: HYPNOSIS

  • Definition: Hypnosis involves an extreme focus on the self, particularly in relation to suggested changes in behavior and experience.
    • Clinical Application: Clinicians may use hypnosis to draw out information from a patient's memory, often utilizing relaxation and suggestion techniques.
    • Misconceptions: Unlike media portrayals, individuals under hypnosis maintain control over their behaviors and vary in susceptibility to hypnosis.
    • Applications: Used for pain management, treatment of depression and anxiety, assisting in quitting smoking, and weight loss.

OTHER STATES OF CONSCIOUSNESS: MEDITATION

  • Description: Meditation involves focusing on a single target, such as breath or a repeated sound, to enhance awareness of the moment.
    • Attributes: Characterized by relaxed, yet focused awareness.
    • Benefits: Demonstrates potential in managing stress, improving sleep quality, aiding in pain management, and treating mood and anxiety disorders.