Check if the person is lying. One of the first signs of drug use is the person begins to lie. First of all, they are probably going to lie about any potential drug use. However, it does not stop there. While under the influence of drugs, a person begins to go through denial about their problem and they start lying about other things as well. The person's lies may seem obvious to you, but the user will see it differently.
Watch out for stealing. Much like a drug user starts lying, they also may start stealing. This does not mean that you will see them stealing from stores, but rather, and even more disappointing, they may steal from friends and family. If you live with someone whom you suspect to be a drug user, and begin to notice things missing, then there may be more to it. Often times a drug user steals to make money for their habit.
Notice if they have a lack of hygiene. Drug users begin to deteriorate on many levels and one of the things they truly stop caring about is how they look and their hygiene. Since they may spend a majority of their time on drugs, they do not notice their lack of appearance. You may start to see someone wearing the same clothes for days in a row, and stop showering. This will be hard to watch and will be an obvious sign that something is going on.
Keep an eye out for drugs and drug paraphernalia. This may be the most obvious sign of someone using drugs: if you find drugs or paraphernalia lying around. The person you suspect of using these drugs will probably deny that the stuff is theirs, and that is where some of the lying will come into play. If you start to see consistent drugs or items for using dugs, then the person you are worried about may be doing drugs.


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