Physical symptoms
- Acting intoxicated
- Repressed physical development
- Bloodshot or red eyes, droopy eyelids
- Sudden appetite, especially for sweets
- Imprecise eye movement
- Unexplained weight loss or loss of appetite
- Wearing sunglasses at inappropriate times
- Neglect of personal appearance
- Abnormally pale complexion
- Changes in speech and vocabulary patterns

Behavioral symptoms
- Unexplained periods of moodiness
- Loss of motivation
- Depression, anxiety or irritability
- Lethargy, lack of energy or vitality
- Strongly inappropriate overreaction to mild criticism or simple request
- Loss of ability to assume responsibility
- Need for instant gratification
- Decreased interaction and communication with others
- Changes in values, ideas, beliefs
- Changes in friends, unwillingness to introduce friends to family
- Preoccupation with self, less concern for feelings of others
- Curfew Violation
- Loss of interest in previously important things such as hobbies and sports
- Noticeable increase or decrease in monetary status

School Changes
- Steady decline in academic performance; drop in grades
- Sleeping in class or meetings
- Less interest in appearance, dress, personal hygiene
- Reduced short-term memory, concentration, and attention span
- Slow to respond, forgetful, apathetic
- Increased discipline or behavioral problems
- Loss of motivation, interest, energy, participation in school activities
- Less interest in participation in classes and meetings
- Disappearance of money or items of value


Physical Evidence
- Odor of marijuana (like burnt rope) in room or on clothing
- "Bongs" (water pipes, usually glass or plastic)
- Incense or room deodorizers
- Small spoons, straws, razor blades
- Eye drops, mouth wash
- Marijuana cigarettes (rolled by hand and twisted at the ends)
- Stash cans (soft drink, beer, deodorant, and other cans that unscrew at the top or bottom)
- Powders, seeds, leaves, plants, mushrooms
- Unfamiliar small containers
- Capsules or tablets
- Cigarette rolling papers
- Plastic baggies or small glass vials
- Pipes, pipe filters, screens, strainer
- Drug-related books, magazines, comics
- "Roach clips" (metal clips to hold the butts of the marijuana "joint")

Occasionally, normal adolescence may include one or more of these behaviors.  However, it is important to take notice of the number of indicators and the frequency with which they occur.