Over the years, with a shortage of other effective psychiatric medications, Seroquel has been prescribed for children with schizophrenia, and bipolar disorder, and for adults with anxiety and depression.

Dr. Alex Walley, a substance abuse specialist with the Boston Public Health Commission, said Seroquel gained street value as the tablets began filling the medicine cabinets of a broader cross-section of psychiatric patients. Even though the Food and Drug Administration has approved Seroquel for adults with schizophrenia and bipolar disorder, psychiatrists are allowed to use their judgment and prescribe “off-label’’ for other purposes.

In Lawrence, police are investigating relatives’ accounts in the death of 32-year-old Roberto Plaza last month that may have been related to his efforts to get Seroquel to help him sleep. He died of gunshot wounds near a house associated with drug trafficking.

There are no statistics to measure the abuse of the drug, but many clinicians who work in drug treatment programs said they noticed an uptick in Massachusetts over the past five years.

In a 2007 letter published in the American Journal of Psychiatry, Dr. Emil Pinta, who worked with drug abusers in an Ohio prison, said some inmates were known to fake psychotic symptoms just to continue a Seroquel habit to help them sleep. He urged clinicians to be more wary in prescribing this medication, known by its chemical name of quetiapine, and urged studies “to explore the addiction potential’’ of the drug.

Nicknamed Susie Q, Quell, Q, or Squirrel, these pills appear so far to be more psychologically than physically addictive. The drug, made by AstraZeneca , is often sought on the street by former drug addicts or inmates who were first prescribed them to reduce anxiety while confined in institutional settings.

The street use of Seroquel as a sedative is yet another example of how many prescription drugs cross over into the illicit drug market, creating incentives for dealers to illegally obtain the drug and dangers for users ignorant of its side effects. If misused, doctors say, Seroquel can heighten the risk of diabetes, heart and blood pressure problems, involuntary twitches, and rapid weight gain.

“Seroquel puts you to sleep,’’ said Luis Lopez, 28, a patient at Men’s Addiction Treatment Center in Brockton who used to buy Seroquel tablets from drug dealers. “We all know from the streets that’s how it works.’’

But these days, the use of Seroquel is growing in popularity in a different group: men and women living on the margins who simply want a good night’s rest.

Seroquel debuted 12 years ago as a novel drug for adult patients with schizophrenia and bipolar disorder, a powerful pill that would help stabilize their emotional lives. Psychiatrists began prescribing these tablets to others - children with serious mental illnesses and adults with anxiety or depression.

FDA advisory panels, in fact, this year have recommended broadening the authorized uses of Seroquel.

Dr. Joseph Glenmullen, a psychiatrist and clinical instructor at Harvard Medical School, said Seroquel’s emergence as a street drug is further proof that psychiatrists have to be more careful with their prescription pads, resisting the trend in which “antipsychotics are being overprescribed for off-label uses.’’

Some clinicians say they are profoundly saddened by the idea that people on the streets are using a powerful antipsychotic drug just to fall asleep; even some schizophrenics loathe the drug, saying it makes them feel like a zombie.

“It’s not thought of as a fun drug,’’ said Michael Otto, director of the Center for Anxiety and Related Disorders at Boston University.

But Seroquel has its appeal, said a 30-year-old from Webster who asked to remain anonymous because of his past illegal drug use. He said he bought Seroquel off the streets because it’s strong enough to “take you out of your element.’’ He said some people mix Seroquel with other recreational drugs to achieve a more calm, measured high.

When he bought Seroquel illegally, it cost about $3 to $5 for a 200 milligram pill, and was relatively easy to get on the streets compared with other prescription drugs. The retail price of a 200 milligram pill of Seroquel is about $10, though most people obtain it for far less through insurance or treatment centers.

In New England, the prescription drugs most commonly abused are OxyContin, Xanax, and Vicodin, all of which are controlled substances, said Nancy Coffey, diversion program manager of the Drug Enforcement Administration in New England. She said the DEA does not monitor Seroquel because it is not a controlled substance.

Officials at AstraZeneca condemned the misuse of Seroquel, which is one of the top-selling drugs worldwide, with more than $4 billion in sales last year.

“Unfortunately, drug abuse extends not just to illicit substances, but also to medicines that are safe, effective, and necessary when used according to doctors’ prescriptions and advice,’’ said Kirsten Evraire, a spokeswoman for the company. She said AstraZeneca supports the efforts of government enforcers to work on the “misuse and abuse of prescription medicines.’’

Clinicians at many drug treatment programs and prisons have begun to curb Seroquel prescriptions to minimize abuse. Nicholas Tenaglia, program director of Men’s Addiction Treatment Center in Brockton, said the staff noticed a few months ago that many patients were selling their pills, so now they have drastically cut back orders for Seroquel. The motivation to secretly acquire the pills, he said, is sleep.

“That’s what I get 99 percent of the time when I ask someone why they abuse Seroquel,’’ he said. “They say it’s not to get high - it’s to knock them out.’’

Patricia Wen can be reached at wen@globe.com.

© Copyright 2009 Globe Newspaper Company.