Influences on Psychoactive Drug Effects
A given drug doesn’t always have the same effect. If ten people drink beer one evening, they all may have different experiences. The effect of a drug depends on many different factors:
- The amount of the drug
- The potency of the drug
- How the drug is administered
- How much previous experience a user has with the drug
- The user’s age and body weight
- The user’s mood, personality, and motivation
- The environment in which the drug is used
- The user’s expectations about the drug’s effects
Chronic Use of Psychoactive Drugs
When people regularly use a drug, they may develop a tolerance to it. As time goes on, people with a tolerance need more and more of the drug to get the same effect.
When people stop using a drug after a long period of regular use, they often experience withdrawal symptoms. Different drugs produce different kinds of withdrawal symptoms. Not all drugs are addictive.
With chronic use, people can get physically or psychologically dependent on a drug. Physical dependence happens when a person must take the drug to avoid withdrawal symptoms. Psychological dependence is when a person keeps taking the drug because of cravings. A drug can be both physically and psychologically addictive.
Drug use can be dangerous for several reasons. Heavy or frequent use of drugs can damage body tissues and organs. Overdoses of some drugs, including sedatives, stimulants, and narcotics, can be lethal. Drugs can have dangerous indirect effects by causing people to behave in risky, accident-prone, or unhealthy ways.