Why Do People Respond Differently to Drugs?

Content medically reviewed by Vicky Magobet, PMHNP-BC, on January 30, 2019.

The effects of drugs vary from person to person. Two people can take the same amount of a substance and feel different results. Do you ever wonder why people have unique responses to drugs or why some people have a higher chance of getting addicted than others? Multiple factors come into play.

5 Reasons People Respond Differently to Drugs

1. Tolerance

Someone who takes a drug on a regular basis can build a tolerance. When this happens, they feel fewer effects from the drug over time. The body adapts to its presence and needs a higher amount for the person to feel the same results. Taking certain drugs can cause you to develop a tolerance at a faster rate than others. For example, the way opioids interact with the body creates a tolerance in a short time.

2. Body Mass

A person's size and amount of fat and muscle impact their reaction to a drug. Larger people also have larger vascular systems, meaning that a substance must travel in more blood. The higher volume of blood dilutes the drug, so its effects aren't as strong.

There are also fat-soluble drugs stay that in the system for a long time when the person has a high amount of fat tissue, with effects that are less pronounced. Meanwhile, non-fat-soluble substances focus on muscle mass and have a stronger impact on those with less muscle.

3. Age

As someone gets older, they need less of a drug to feel its effects. They develop more fat tissue in relation to muscle, so a drug lasts for a long time. The liver reduces in size and effectiveness over the years as well, so its capacity to absorb and filter various drugs decreases. An older person's receptors also become more sensitive as they age.

4. Sex

Most people have hormones and body sizes dependent on their biological sex. Men tend to have bigger body sizes and lower fat tissue proportions than women, so various drugs affect them in different ways.

For women, even different phases of the menstrual cycle can change someone's sensitivity to certain drugs. For example, certain phases can cause a stronger reaction to stimulant drugs than others.

5. Genetics

Someone's genetic makeup influences the way they absorb drugs. Genes determine the activity of the enzymes that help the body metabolize drugs. Most gene differences create small changes, but some types of genetic coding prevent the enzymes from working. In some cases, genes cause someone to process drugs at a rapid rate, creating an unpleasant response.

Factors Behind Substance Abuse

Some people have a higher chance of developing an addiction or substance abuse than others due to biological and social factors. Since the way we react to drugs has genetic causes, people with family histories of addiction have a risk of also getting addicted. Trauma and mental health issues also contribute to someone's likelihood of substance abuse. In certain cases, the person dealing with substance abuse started using a drug to self-medicate without realizing it.

At Diamond House Detox, we specialize in finding these underlying factors and addressing them so you can heal. Our dual diagnosis approach allows us to treat the causes and results of your substance abuse. If you need a partner in your journey to recovery, let us help. We welcome you to contact our team today. Call today for same day admittance at (800) 205-6107.