http://news.bbc.co.uk/2/hi/health/5219646.stm
Mothballs are used to protect clothes from moth larvae
Huffing mothballs
An 18-year-old in Boston was hospitalized after her secret habit of huffing mothballs to get high resulted in a horrid rash, "unsteady gait," and "mental sluggishness. Turns out that her twin was also "bagging." Physicians report on these cases in the New England Journal of Medicine and suggest that the activity may be more common than people think. From the BBC News:It was discovered that the girls had been using the mothballs as a recreational drug when doctors found a bag of mothballs stashed in her room while she was being treated at the Hospital of Timone in Marseille.Link
Both girls had been "bagging" - inhaling mothball fumes - after encouragement from classmates.
The twin who was sickest had also been chewing half a mothball a day for two months.
She continued her habit in hospital because she did not think her symptoms were linked to the mothballs.