The effects of drugs and other substances can vary significantly depending on several personal factors of the driver.

- **Age:** Both medications and alcohol and drugs can affect differently depending on the driver's age. For example, alcohol tends to have a greater impact on people under 18 and over 65 years old.

- **Consumption habit:** The way a person consumes substances like alcohol or drugs influences their effects. Factors such as the amount consumed, the speed of consumption, and whether it is consumed on an empty stomach can alter the blood alcohol level and the effects of drugs.

- **Physical condition:** The driver's physical condition, including their weight and personal circumstances such as stress or illnesses, can also modify how these substances affect them. For example, alcohol tends to affect people with lower weight more.

These combined factors determine how a driver can be affected by medications, alcohol, or drugs, influencing their ability to drive safely.