Normally, a “gut feel” is never wrong. As they say, where there is smoke, there is fire. However, the following observable behaviors may help you determine substance use/abuse: Reversed sleeping patterns; erratic eating habits resulting in drastic weight loss; episodes of irrational behavior; inability to keep commitments; neglect of personal hygiene; always in need of money while unable to maintain expenses; loss of personal belongings; hanging around with known drug abusers. It is also important to search for illicit substances such as: tablets; capsules, powder-like substances; packets of dried (marijuana) leaves; joints (sticks of marijuana); roaches (marijuana butts) and so on. Search also for common paraphernalia such as: strips of aluminum foil; rolled tissue; glass straws; mini bottles; syringes; razor blades; modified lighters, etc.