what do I do if I find that my sister is on drugs?!
Angry outbursts, mood swings, irritability, manic behavior, or overall attitude change
Talking incoherently or making inappropriate remarks
Risky behavior, such as driving under the influence of drugs, starting a fight, or engaging in unprotected sex
Secretive or suspicious behavior: frequent trips to the restroom, basement, or other isolated areas for privacy while using drugs
Deterioration of physical appearance and grooming
Wearing sunglasses and/or long-sleeved shirts frequently or at inappropriate times Frequent absences from work or school; drop-off in quality of work or grades
Neglect of family responsibilities
Evidence of money problems: frequent borrowing, selling possessions, or stealing items from employer, home, or school
Legal problems rooted in drug use: arrest for driving under the influence, possession of a controlled substance, disorderly conduct, or stealing
if any two of these are there,u can suspect a drug abuse...
Talk to your parents about it. You're not her parent, and your parents will be able to discuss it with her in a rational, mature fashion.