I'm going to hit ten.

  

1. Physical Signs
Disregard for personal appearance: disheveled look, unkempt hair, etc.
Lack of energy or motivation
Unusual odors on breath, clothes, or body
Slow or impaired coordination or speech
Use of eye drops to hide red and bloodshot eyes, dilated or smaller pupils
Slowed reaction time
Changes in appetite
Sleep changes: insomnia, sleeping too much
Substance abusers show a mixture of these signs of drug use, but some physical signs will depend on the type of drug. For example, marijuana produces euphoric feelings, difficulty concentrating or remembering, and an increased appetite. Synthetic drugs may cause hallucinations, vomiting, chest pains, or confusion. Users may suffer panic attacks, become unusually sociable, or have a spike in energy. An extreme symptom is psychotic or violent behavior. Drug users snorting or inhaling drugs often have red or runny noses and/or nose sores.

2. Behavioral Signs
Secretive behavior: lying or hiding where they’re going, avoiding visitors
Withdrawing from family or friends or a drastic change in relationships
Financial difficulties: repeatedly asking for money without an explanation or a vague or unlikely reason, missing money and/or valuables
Poor work or academic performance, repeatedly calling off or skipping work without notice, loss of interest in work, significantly lower grades
Paranoid behavior
Changes in friend groups, activities, and interests
Risky behaviour: getting into fights or accidents, being arrested, engaging in illegal activities, etc.


3. Psychological Signs
Sudden change in personality
Mood swings, acting out, irritability, or agitation
Lethargy or absentmindedness
Anxiety or fearfulness for no apparent reason
Bouts of hyperactivity, periods of laughing or giddiness
Different drugs can have different effects on people. For more information on signs and symptoms related to specific drugs, visit Mayo Clinic’s website.