Substance abuse and addiction symptoms or behaviors include, among others1:
- Drop in attendance and performance at work or school
- Frequently getting into trouble (fights, accidents, illegal activities)
- Using substances in physically hazardous situations such as while driving or operating a machine
- Engaging in secretive or suspicious behaviors
- Changes in appetite or sleep patterns
- Unexplained change in personality or attitude
- Sudden mood swings, irritability, or angry outbursts
- Periods of unusual hyperactivity, agitation, or giddiness
- Lacking of motivation
- Appearing fearful, anxious, or paranoid, with no reason
1. U.S. Department of Health & Human Services