What is the primary difference between physical and psychological dependence?

Physical dependence is a physiological adaptation resulting in withdrawal symptoms upon cessation, while psychological dependence is a mental compulsion to use a substance for its pleasurable effects or emotional relief.

How does metabolic tolerance differ from cellular tolerance?

Metabolic tolerance occurs when the body breaks down a substance faster, while cellular tolerance involves neurons becoming less responsive to the substance as the brain tries to maintain homeostasis.

How does the concept of homeostasis explain the development of tolerance?

The brain naturally seeks a state of balance; when a substance disrupts this balance, the brain readjusts its 'normal' level to include the substance, requiring higher doses to achieve the same initial disruption (the high).

Why is it a misconception to say addiction is purely a choice or a lack of willpower?

Addiction involves significant physical changes in brain chemistry and structure (such as cellular tolerance) that impair an individual's ability to regulate behavior and resist compulsions.

What is the 'opposite effect' rule in withdrawal syndrome?

Withdrawal symptoms are typically the physiological opposite of the drug's effects; for example, withdrawing from a stimulant (which increases energy) often results in extreme fatigue and depression.

What error occurs when a student treats 'tolerance' and 'withdrawal' as the same concept?

Tolerance is the process of needing more of a substance to get an effect, whereas withdrawal is the negative physical/mental reaction that occurs when the substance is removed.

Define 'Withdrawal Syndrome'.

A set of unpleasant physical and psychological symptoms that occur when an addictive substance is discontinued or reduced, often acting as a motivation to continue use.

What are the behavioral indicators that distinguish addiction from regular use?

Key indicators include the inability to stop despite wanting to, neglecting social or occupational obligations, and continuing use even when aware of physical or psychological harm.

In the context of addiction, what does 'nature' refer to in the nature vs. nurture debate?

Nature refers to the biological and genetic factors, such as innate brain chemistry, the physiological mechanisms of tolerance, and the hereditary predisposition to dependence.

Why might a light smoker still be classified as 'addicted' according to recent research?

Addiction is defined by the compulsion and inability to quit rather than just the quantity consumed; even low-frequency users can show signs of dependence and struggle to stop.

What is Addiction? | AQA A-Level Psychology

Addiction: Option Topic (Section D)

What is Addiction?

Summary

Addiction is a complex condition characterized by physical and psychological dependence on substances or behaviors. It involves physiological adaptations such as tolerance and withdrawal, driven by the brain's attempt to maintain homeostasis, alongside cognitive compulsions that persist despite negative consequences.

1. Definition & Core Concepts

Addiction is defined as a state of physical and/or psychological dependence on a substance (e.g., nicotine, alcohol) or a specific behavior (e.g., gambling, shopping).
Physical dependence refers to a physiological state where the body has adapted to the presence of a substance, making its continued use necessary for 'normal' functioning.
Psychological dependence involves a mental compulsion or obsession with the substance or behavior to achieve a pleasurable effect or avoid emotional distress.
Key behavioral indicators of addiction include over-use, persistence despite known harm, and an inability to fulfill daily responsibilities or stop the behavior voluntarily.

2. The Mechanism of Tolerance

Tolerance occurs when the brain and body adjust to the regular presence of a substance, requiring increasingly larger doses to achieve the original effect.
This process is driven by homeostasis, the biological drive to maintain a stable internal environment; the brain 'rebalances' itself to function alongside the drug.
Metabolic tolerance occurs when the body becomes more efficient at breaking down and eliminating the substance, reducing its duration in the bloodstream.
Cellular tolerance involves changes in the sensitivity or number of neuronal receptors, meaning the brain's cells become less responsive to the same amount of the chemical.

Diagram showing the shift in homeostasis over time. Initial use causes a high peak, but repeated exposure leads to a lower baseline response as the brain adapts, illustrating the development of tolerance.

3. Withdrawal Syndrome

Withdrawal syndrome is a collection of physical and psychological symptoms that emerge when an individual suddenly stops or significantly reduces substance intake.
The symptoms are typically the physiological opposite of the drug's effects; for example, stopping a sedative may lead to extreme agitation and tremors.
Withdrawal provides a powerful negative reinforcement, as the discomfort of the symptoms often motivates the individual to resume use to find relief.
The severity and duration of withdrawal vary by substance, ranging from a few days of nausea (alcohol) to several weeks of irritability and weight gain (nicotine).

4. Key Distinctions

5. Exam Strategy & Tips

6. Common Pitfalls & Misconceptions