WASHINGTON -- Data on which doctors are prescribing which drugs is speech that is protected by the First Amendment, and pharmaceutical companies have every right to buy that information and use it to target their marketing efforts, the Supreme Court has ruled.

The nation's high court handed down a verdict Thursday in the Sorrell v. IMS Health case, striking down by a 6-3 vote a 2007 Vermont law that that bans the practice of data mining -- the sale and use of prescriber-identifiable information for marketing or promoting a drug, including drug detailing -- unless a physician specifically gives his or her permission to use the information.

Vermont argued that selling prescriber-identifying information is "conduct," not "speech," but the Supreme Court didn't buy that and ruled that "the creation and dissemination of information are speech for First Amendment purposes."

When filling prescriptions, Vermont pharmacies collect information, including the prescribing physician's name and address; the name, dosage, and quantity of the medication; the date and place where the prescription was filled; and the patient's age and gender. Pharmacies sell this "prescriber information" to data-mining companies, including the three appellants in the case: IMS Health, Verispan (now SDI), and Source Healthcare Analytics.

Pharmaceutical companies are the primary purchasers of the data, using the information to better target their marketing to individual physicians. Aside from marketing, drug companies say the information helps them direct safety messages to doctors, to track disease progression, to aid law enforcement, to implement risk-mitigation programs, and to do postmarketing surveillance required by the FDA.

When the law was passed, the Vermont legislature said it was intended to protect the privacy of doctors and their prescribing practices, to promote public health, and to bring costs down "through the promotion of less costly drugs," i.e., generics, which aren't marketed and detailed in the same fashion as pricier brand-name drugs.

Writing for the majority, Justice Anthony Kennedy said the goal of lowering the costs of medical services and protecting public health are laudable goals, but that the law doesn't advance those goals.

"Vermont seeks to achieve those objectives through the indirect means of restraining certain speech by certain speakers -- i.e., by diminishing detailers' ability to influence prescription decisions," he wrote. "But 'the fear that people would make bad decisions if given truthful information' cannot justify content-based burdens on speech."

Justices John Roberts, Clarence Thomas, Sonia Sotomayor, Antonin Scalia, and Samuel Alito joined Kennedy in the majority opinion.

Dissenting were Justices Stephen Breyer, Elena Kagan, and Ruth Bader Ginsburg, who argued that the Vermont law affects expression "in one, and only one way" -- by depriving data-mining companies of data that "could help pharmaceutical companies create better sales messages." That is more linked to legal government effort to regulate a commercial enterprise, and not speech protected under the First Amendment, wrote Justice Breyer.

Doctors' groups, including the American College of Physicians and the American Medical Association (AMA), have historically opposed the use of physician prescribing data for marketing purposes.

The AMA called the decision "important."

The Supreme Court's decision upholds an appeals court decision that found Vermont's Prescription Confidentiality Law is a violation of First Amendment rights because it restricts commercial speech, and that it is a violation of the Commerce Clause of the Constitution because it impinges on interstate commerce, since data-mining companies sell the prescriber information in states other than Vermont.

Similar laws in New Hampshire and Maine have been declared unconstitutional by appeals courts.