If you suspect that someone you know is smoking marijuana, there are a few telltale signs you can look for. While the presence of one or more of these indicators is not necessarily proof that the individual is using marijuana, it can provide a strong suspicion that the individual is under the influence.
The clearest indicator that an individual is using marijuana is the presence of marijuana paraphernalia in his possession or home. This is the easiest method of detection for parents, as they will have access to a child's living space. Small glass pipes, glass bongs, cigarette rolling papers or other homemade smoking devices all indicate a marijuana smoker. Look for a sticky residue on smoking devices, as this indicates the presence of burned marijuana.
While under the effects of marijuana, individuals generally have an increased appetite, especially for sweets or snacks. An individual who is generally a picky eater will become more open to different types of food, and will also eat larger quantities of food while under the influence of marijuana. An increased appetite may also indicate a variety of other physical states, so this feature alone is generally not a sign of marijuana use. However, you will typically see a larger appetite along with other signs.
Red or sleepy-looking eyes are also an indicator of marijuana use. Red eyes are caused either by irritation from the marijuana smoke, or by the effects of blood vessels in the eyes relaxing—called vasodilation—which makes the blood vessels in the eye fill with blood. The pupils also tend to relax and dilate while the individual is under the effects of marijuana. While smokers may use eye drops to lessen the effects of red eyes, droopy eyelids and dilated pupils will remain. Additionally, excessive use of eye drops may be a sign of marijuana use if the individual does not normally suffer from dry eyes.
Poor Time Sense
Someone using marijuana generally suffers from the inability to accurately gauge the passage of time. This usually manifests in the user as a feeling of time going by slowly, but some individuals may overcompensate for the feeling and perceive events as going by more quickly than they are. To test an individual's perception of time, ask her to indicate when she believes one minute has gone by. Someone under the influence of marijuana will have difficulty with this task, and may believe the minute has elapsed when in reality only a few seconds have passed.