Difficulty: Introductory | Prerequisites: Consciousness and Awareness notes
Psychoactive drugs alter consciousness by changing brain chemistry. They fall into three main categories: depressants (slow the CNS), stimulants (speed it up), and hallucinogens (distort perception). Repeated use can lead to tolerance, physical dependence, psychological dependence, or full addiction. Hypnosis and meditation are non-chemical ways of altering consciousness, and psychologists disagree about whether hypnosis is a genuinely altered state (Hilgard's divided consciousness view) or a product of social expectations (the social cognitive view).
Psychoactive drugs
Drugs that act on the nervous system to alter consciousness, modify perception, and change mood. Think of it as any substance that changes how your brain processes the world.
Tolerance
The need to take increasing amounts of a drug to achieve the same effect. In simple terms, the brain adapts and the original dose stops working as well.
Physical dependence
The physiological need for a drug, shown by unpleasant withdrawal symptoms (sweating, tremors, nausea, pain) when the drug is discontinued. Think of it as your body "expecting" the drug and protesting when it does not arrive.
Psychological dependence
The strong desire to repeat drug use for emotional reasons, such as stress relief or a feeling of well-being. In simple terms, the craving is in the mind rather than the body, but it can be just as powerful.
Addiction
Either a physical or psychological dependence (or both) on a drug, characterised by compulsive drug seeking and use despite harmful consequences.
Depressants
Psychoactive drugs that slow down central nervous system activity, leading to relaxation, drowsiness, and reduced anxiety. Examples: alcohol, tranquilisers, barbiturates.
Stimulants
Psychoactive drugs that increase central nervous system activity, elevating alertness, attention, and energy. Examples: caffeine, nicotine, amphetamines, cocaine.
Hallucinogens
Psychoactive drugs that modify perceptual experiences and can produce visual or auditory images that are not real. Examples: LSD, psilocybin.
Tranquilisers (benzodiazepines)
Depressant drugs such as Valium and Xanax prescribed for anxiety and panic disorders. They enhance the effect of GABA, an inhibitory neurotransmitter.
Barbiturates
Depressant drugs such as Nembutal and Seconal that decrease CNS activity. Now less commonly prescribed due to high overdose and addiction risk.
Alcoholism (alcohol use disorder)
A chronic disorder involving long-term, compulsive, uncontrolled drinking that impairs health and social relationships.
Hypnosis
An altered state of consciousness (or a psychological state of altered attention and expectation) in which a person is unusually receptive to suggestions.
Meditation
The practice of focused attention, deep breathing, and mindfulness to achieve mental calmness and clarity, without being consumed by worry.
Act on the central nervous system by influencing neurotransmitter activity
Classified by their primary effect on the CNS: depressants slow it down, stimulants speed it up, hallucinogens distort perception
Can be used recreationally, medicinally, or illicitly
All carry risks of dependence and adverse effects
Develops through neuroadaptations: the brain adjusts its receptor sensitivity to compensate for the drug's presence
The same dose produces a weaker effect over time, pushing users towards higher doses
Increases the risk of both dependence and overdose
Physical dependence: the body has adapted to the drug. Stopping or reducing use triggers withdrawal symptoms (sweating, tremors, nausea, pain). The body's protest is physiological.
Psychological dependence: the mind craves the drug for its emotional effects (stress relief, euphoria, escape). Can persist long after physical withdrawal has passed.
Both can coexist, and both drive the cycle of addiction.
Compulsive drug seeking and use despite negative consequences
Involves a complex interplay of biological factors (genetics, neurotransmitter systems), psychological factors (coping patterns, mental health), and environmental factors (peer influence, stress, availability)
Often requires comprehensive treatment: therapy, support groups, and sometimes medication
Reduce CNS activity, producing relaxation, drowsiness, and decreased anxiety
Alcohol: the most widely used depressant. Impairs judgement, coordination, and reaction time. Chronic misuse leads to alcoholism (loss of control over drinking, tolerance, withdrawal, liver disease, cardiovascular damage).
Tranquilisers (benzodiazepines): Valium, Xanax. Prescribed for anxiety and panic disorders. Work by enhancing GABA, the brain's main inhibitory neurotransmitter. Risk of dependence and withdrawal.
Barbiturates: Nembutal, Seconal. Older class, now less commonly prescribed. High overdose potential; depress neural activity and can cause respiratory depression.
Increase CNS activity by boosting dopamine, norepinephrine, and other neurotransmitters
Caffeine: the most commonly consumed stimulant worldwide. Blocks adenosine receptors, promoting wakefulness.
Nicotine: highly addictive. Triggers dopamine release in the brain's reward pathway.
Amphetamines and cocaine: powerful stimulants that flood the brain with dopamine. Enhance alertness and energy temporarily but carry high risk of dependence, cardiovascular problems, and crashes when effects wear off.
Alter perceptions and consciousness, often producing vivid visual or auditory hallucinations
LSD and psilocybin: act primarily on serotonin receptors
Can induce profound changes in thought, emotion, and perception
Effects are unpredictable and can sometimes trigger psychological distress ("bad trips")
Real-world connection: psilocybin is currently being researched as a treatment for depression and PTSD, though this work is still in clinical-trial stages
A state of focused attention, reduced peripheral awareness, and increased suggestibility
Can be used therapeutically for pain management, habit change (e.g. smoking cessation), and psychological treatment
Hypnotic susceptibility varies widely between individuals
Hypnosis splits consciousness into two streams: one follows the hypnotist's commands, the other acts as a "hidden observer" that remains aware of what is happening
Emphasises the dissociative nature of hypnosis
Evidence: in cold-pressor experiments, hypnotised participants report no pain verbally but the "hidden observer" (accessed through a separate channel) reports awareness of pain
Hypnosis is not a special altered state at all
The hypnotised person behaves in line with their expectations about what hypnotised behaviour should look like
Driven by social and cognitive factors: motivation, expectation, and the power of suggestion
Essentially a form of role-playing, not dissociation
Involves focused attention, deep breathing, and mindfulness practices
Goal: mental calmness and clarity, attending to thoughts and feelings without being consumed by them
Reduces stress, enhances concentration, and promotes emotional well-being
Regular practice can alter brain activity (e.g. increased activity in areas associated with attention and emotional regulation)
Real-world connection: mindfulness-based stress reduction (MBSR) programmes are now used in clinical settings for anxiety, chronic pain, and depression
Students often confuse physical and psychological dependence. Physical dependence is defined by withdrawal symptoms when the drug is stopped. Psychological dependence is defined by craving for emotional reasons. A person can have one without the other, or both.
Tolerance is sometimes confused with addiction. Tolerance is a neurological adaptation (needing more of the drug for the same effect). Addiction is compulsive use despite negative consequences. Tolerance can develop without addiction (e.g. regular caffeine drinkers develop tolerance but are not typically "addicted" in the clinical sense).
Hypnosis is often believed to give the hypnotist total control over the subject. In reality, people under hypnosis cannot be made to act against their core values or beliefs. Susceptibility varies, and the social cognitive view argues it is closer to voluntary role-playing.
Barbiturates and tranquilisers are sometimes treated as interchangeable. They are both depressants, but barbiturates carry a much higher overdose risk and are now rarely prescribed, while benzodiazepines (tranquilisers) remain commonly used.
⚠️ Be able to classify drugs into the three categories (depressants, stimulants, hallucinogens) and give examples of each. This is a staple multiple-choice item.
⚠️ Know the difference between tolerance, physical dependence, psychological dependence, and addiction. Exam questions frequently present scenarios and ask you to identify which concept applies.
⚠️ Understand how tranquilisers work at the neurotransmitter level (enhance GABA). This links to the biological bases of behaviour unit.
⚠️ The two views of hypnosis (Hilgard's divided consciousness vs. the social cognitive view) are a classic compare-and-contrast question. Be ready to explain each and name their key proponents.
⚠️ Meditation's measurable effects on brain activity and stress reduction are increasingly tested in applied-psychology questions.
Depressants ______ central nervous system activity, while stimulants ______ it. (Slow down / decrease; speed up / increase)
True or False: Psychological dependence always involves physical withdrawal symptoms. (False. Psychological dependence is driven by emotional cravings and can exist without physical withdrawal.)
Tranquilisers like Valium work by enhancing the neurotransmitter ______. (GABA / gamma-aminobutyric acid)
True or False: According to the social cognitive view, hypnosis is a genuine altered state of consciousness. (False. The social cognitive view holds that hypnosis is a normal state driven by expectations and role-playing.)
Name one hallucinogen and the neurotransmitter system it primarily affects. (LSD or psilocybin; serotonin)
Q: Explain the difference between physical dependence and psychological dependence, using alcohol as an example.
A: Physical dependence on alcohol means the body has adapted to its presence, and stopping use triggers withdrawal symptoms such as tremors, sweating, and nausea. Psychological dependence means the person craves alcohol for emotional reasons, such as stress relief or social comfort. A person can be psychologically dependent (craving a drink after a hard day) without yet having physical withdrawal symptoms, and vice versa.
Q: Compare Hilgard's divided consciousness view and the social cognitive behaviour view of hypnosis.
A: Hilgard argues that hypnosis splits consciousness into two streams: one follows the hypnotist's suggestions, while a "hidden observer" remains aware of what is happening. This frames hypnosis as a genuine dissociative state. The social cognitive view argues hypnosis is not a special state at all; the person is acting in line with their expectations about hypnotised behaviour, driven by motivation and social cues, similar to role-playing.
Q: A person has been drinking coffee daily for years and now needs three cups to feel alert in the morning, whereas one cup used to be sufficient. Which concept does this illustrate?
A: Tolerance. Repeated caffeine consumption has led to neuroadaptations that reduce the drug's effect, requiring a larger dose to achieve the original level of alertness.
Q: Why are barbiturates now less commonly prescribed than benzodiazepines, even though both are depressants?
A: Barbiturates have a much higher risk of overdose (they can cause fatal respiratory depression) and a higher addiction potential compared to benzodiazepines. Benzodiazepines are considered safer, though they still carry dependence and withdrawal risks.
Q: How does meditation alter brain activity, and what practical benefits has research linked to regular practice?
A: Regular meditation increases activity in brain regions associated with attention and emotional regulation. Practical benefits include reduced stress, improved concentration, greater emotional well-being, and, in clinical settings, relief from anxiety, chronic pain, and depressive symptoms.
Psychoactive drugs connect to the biological bases of behaviour unit: understanding neurotransmitters (dopamine, serotonin, GABA, norepinephrine) is essential for grasping how each drug category works. Addiction ties into the learning chapter (operant conditioning, reinforcement) and health psychology (stress, coping). Hypnosis and meditation link back to the consciousness unit and forward to therapeutic approaches in the clinical psychology section.
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