Signs of drug abuse Sudden change of mood / temper Lack of appetite Bouts of drowsiness or sleeplessness Abnormal behavior Nausea and body pain Spending long house in toilet Tendency to tell lies Losing inerst in job or in extra- curricular activities Increasing demand for money / stealing Presence of tablets , capsules , scorched tinfoil , cigarettes , syringes etc . in the roo m or in the belongings .