IT was as if she woke up one day and decades of her life had disappeared.

Joyce, 52 and a writer in Manhattan, started smoking pot when she was 15, and for years it was a pleasant escape, a calming protective cloud. Then it became an obsession, something she needed to get through the day. She found herself hiding her addiction from her family, friends and co-workers.

“I would come home from work, close my door, have my bong, my food, my music and my dog, and I wouldn’t see another person until I went to work the next day,” said Joyce, who like most others in this article asked that her full name not be published, because she does not want people to know about her past drug use.

“What kind of life is that? I did that for 20 years.”

She tried to stop, but was anxious, irritable, sleepless and lost. At one point, to soothe her cravings, she took morphine that she found at her dying father’s bedside. She almost overdosed.

Two years ago, she checked into the Caron Foundation, a treatment center in Wernersville, Pa. Even there, she said, some other addicts  cocaine and heroin users or alcoholics  downplayed her dependence on marijuana.