Alcohol can also rapidly alter eating habits and, like marijuana which increases appetite, a side effect can be weight gain as well as loss.
Drug abuse will leave physical signs on the body, varying from track marks and bruises to sores and burns. Track marks from heroin or other intravenous drugs range from small red marks to sores and bruises, and they form clusters down the inside of the arm.
However, it is also worth remembering that it is not uncommon for teenagers to drastically alter their appearance or to want to look deliberately disheveled!
Burns on the hands and around the mouth can be a sign of crack and meth abuse: too-hot pipes and scorching smoke can cause burns on the lips.
Drug users often overlook hygiene and a drug habit can lead to complacency about appearance. Drug users often overlook normal hygiene habits (showering, brushing teeth) but other habits, such as spraying perfume or cologne, can be picked up.
Drugs users may wear sunglasses at odd times to conceal bloodshot eyes, or wear long-sleeved garments in an attempt to hide possible track marks. Fixation on a drug habit can lead to complacency in other areas of life and appearance is often one of them: people who previously took a lot of pride in their exterior appearance and in the clothes they wore can lose all interest.
Use and abuse of these drugs can cause several physical and behavioral problems.
Location can also influence which substances a young adult uses.