Depending on the drug you may notice the following.

Stimulants

(medications used to speed up brain activity causing increased alertness, attention,

and energy that come with elevated blood pressure, increased heart rate and breathing)

• Hyperactivity
• Shaking
• Sweating
•  Dilated pupils
•  Fast or irregular heart beat
•  Elevated body temperature
• Seizures
• Paranoia/nervousness
• Repetitive behaviors
• Loss of appetite or sudden and unexplained weight loss

 

Sedatives/depressants

(medications used to slow down or “depress” the functions of the brain and central nervous system)

• Loss of coordination
• Respiratory depression
• Slowed reflexes
• Slurred speech
• Coma

 

Opioid analgesics

(medications used to treat moderate-to-severe pain)

• Sleep deprivation or “nodding”
• Pinpoint/constricted pupils, watery or droopy eyes
• Nausea, vomiting, constipation
• Slow slurred speech
• Slow gait
• Dry skin, itching, skin infections
• Constant flu-like symptoms
• Track marks (bruised skin around injection sites)

Behavioral Signs

Behavior changes may include:

• Sudden mood changes, including irritability, negative attitude, personality change
• Extreme changes in groups of friends or hangout locations
• Forgetfulness or clumsiness
• Lying or being deceitful, unaccounted time away from home/missed school days,
• avoiding eye contact
• Losing interest in personal appearance, extracurricular activities or sports
• Unusually poor performance in school, on the field, in debate club or other activities
• Borrowing money or having extra cash
• Acting especially angry or abusive, or engaging in reckless behavior
• Visiting pro-drug website

 

Sourced : National Institute on Drug Abuse