NEW YORK (CNN/Money) - Paxil, a blockbuster antidepressant from British drug maker GlaxoSmithKline, increases the risk of suicide in adults, according to a study by Norwegian researchers

Patients taking Paxil, a $1.9 billion drug also known by its generic term paroxetine, attempted suicide seven times, compared to one suicide attempt in placebo studies, according to a report by Ivar Aursnes and other Norwegian researchers and published in BMC Medicine on Aug. 22.

"Summarizing the suicide attempts, there are seven among the patients on paroxetine and one among the patients on placebo," read the report, which said there were 16 studies conducted with 916 patients on Paxil and 550 on placebo.

GlaxoSmithKline (down $0.06 to $48.15, Research), a London-based drug maker with $39 billion in 2004 sales, criticized the study as "misleading" and based on outdated and "incorrectly selected" data.

"The company disagrees with the conclusion from the sub-analysis conducted by scientists based in Oslo," said GlaxoSmithKline in a prepared statement. "It serves only to cause confusion and unnecessary concern for patients using an SSRI (selective serotonin reuptake inhibitor,) such as paroxetine, for treatment of depression."

The suicidal side effects of antidepressants has raised concerns with the Food and Drug Administration, which now requires all antidepressants to carry warnings about the increased risk of suicide to children and teenagers. On June 30, the FDA said it is conducting a review of available data to determine whether there is an increased risk of suicidal thinking in adults who are taking antidepressants. The FDA expects to take at least a year to complete this review.

The scientists who conducted the Paxil study suggested that adults be included in regulatory warnings.

"We also conclude that the recommendation of restrictions on the use of paroxetine for children and adolescents recently conveyed by regulatory agencies should be extended to include usage by adults," read the report.

To read about the impact of antidepressant suicide risks and other factors on the drug industry's reputation, click here.