The state of New York sued the giant British pharmaceutical company, GlaxoSmithKline, on Wednesday claiming the company had illegally suppressed studies that showed its popular drug, Paxil, was not only ineffective in treating children but that it may have caused children to suffer from an increased risk of suicidal thoughts. A year ago the British government banned the use of Paxil for most minors but the Food and Drug Administration in Washington has not gone further than issuing warnings against its use among some children.