Alliance for Substance Abuse Progress

Signs of Substance Use Disorder

Substance use disorder is a broad term that includes substance misuse, dependence and addiction to alcohol, legal and/or illegal substances.

Signs of a substance use disorder may include behavioral, physical and social changes. There are a number of warning signs to look for when you suspect someone might be struggling with a substance use disorder.

Addiction, the most severe level of substance use disorder, is a chronic disease characterized by continuing a behavior despite the harm and unintended consequences it may cause. Addiction causes changes in the brain that over time interfere with a person’s self-control and ability to resist cravings.

Warning Signs

There are a number of warning signs to look for when you suspect a loved one may be struggling with a substance use disorder:

These include behavioral and social changes, such as:

  • Drop in attendance or performance at work or school
  • Sudden lack of interest in favorite hobbies or activities
  • Frequently getting into trouble (fights, accidents, illegal activities)
  • Using substances in physically hazardous situations such as while driving or operating machinery
  • 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
  • Lack of motivation
  • Appearing fearful, anxious or paranoid with no reason
  • Sudden changes in friends, favorite hangouts and hobbies
  • Unexplained need for money

Physical Changes

Physical changes related to substance use disorder can include:

  • Bloodshot eyes and/or abnormally-sized pupils
  • Sudden weight loss or gain
  • Deterioration of physical appearance
  • Unusual smells on breath, body or clothing
  • Tremors, slurred speech or impaired coordination

Other signs to look for include:

  • Drug paraphernalia such as lighters, syringes, cotton balls, burnt spoons or bottle caps
  • Missing prescription medications or money


A series of toolkits with information specifically geared to parents, faith communities and other community leaders is available on this website. These toolkits provide guidance on appropriate topics and language when discussing the dangers of addiction or approaching someone who might be at risk.

For more information about recognizing the signs of substance use disorder, please see

Last modified on Friday, 3 April 2020 10:58