Overview

Signs that a person is using substances such as drugs or alcohol include behavior changes and physical changes. Substance use is more likely to cause changes in behavior than physical signs.

Behavior changes

These may include:

• Changes in sleeping or eating habits or having less interest in sex.
• Paying less attention to dressing and grooming.
• Up-and-down moods, a mood or attitude that is getting worse, or not caring about the future.
• Sneaky behavior, lying, or stealing.
• Poor family relationships, or relationships that are getting worse.
• New problems at work or school, or problems with the law.
• Not keeping up with old friends and activities. The person may find new friends and not want old friends to meet them.

These signs don't always mean that a person is using substances. The behavior could be due to work or school stress. Or it could be a sign of depression or another medical condition. But behavior changes like these are common in people who use substances.

Physical changes

These may include:

• Red eyes, a sore throat, a dry cough, and feeling tired.
• Needle marks on the arm or other area of the body.
• Small "pinpoint" pupils in the eyes.
• Losing weight without trying to, or not feeling like eating.
• Seeing things that don't exist (hallucinations).