Every drug has a different effect on each user. For example, marijuana makes some users act outgoing and talkative, while other users become withdrawn and quiet. Even the same user can respond dramatically different when taking the same amount of drug than he or she did before. This is because the effects depend on several different things:
How much of the drug is being taken? What is the strength of the drug? It is very hard to tell the exact strength of a drug. Drugs may become weaker because they change chemically as time passes. Where a drug is made or grown will also influence its strength. Drugs manufactured on the street may be very strong or very weak. In addition, drugs may be mixed with other drugs or other substances.
Mood and Expectation
A person’s mood and expectation may have significant impact on the response to a drug. When a person is happy, sad or angry, for example, the body reacts by altering the heart rate, pulse, blood pressure, and hormone secretion. This in turn impacts the response to a drug.
The setting or environment includes both the physical place where the drug is taken and the psychosocial circumstances surrounding its use. A person will react differently when taking a drug out on the street when compared to taking it in a controlled setting with protective friends for example.
How is the drug being taken? There are a variety of ways that drugs can enter the bloodstream. Some drugs can be injected, others can be inhaled or smoked, and some can be swallowed. The fastest way into the bloodstream is through injecting the drug with a needle. It usually takes a longer period of time for a drug to reach the bloodstream when inhaled and even longer if it is swallowed.
Individual Body Type
Every person is different and therefore has a different reaction to drugs. For example, our bodies are different sizes and respond to drugs differently. In addition, if a person has used drugs before or on a regular basis, his or her body may require more of the drug to produce the desired effect. This is called tolerance. Experienced users may be able to take a dose of some drug that would kill an inexperienced user.