Social Media Judge Eyes Users’ Authority to Testify on Distress

Expert testimony—that social media users say is critical in a sprawling case against platforms like Meta Platforms Inc., Snap Inc., and Google LLC—may not be necessary to establish harm, a Los Angeles judge said Wednesday.

Without testimony from general causation experts on the science of social media addiction, it’s unclear whether key claims can proceed in the case. The question hung heavy over the courtroom during the hearing in California Superior Court, Los Angeles County. Lawyers for the companies indicated its exclusion could be the end of the road for hundreds of plaintiffs seeking to put big tech on trial starting in November.

Defense counsel argued the experts aren’t reliable, and the evidence they’d use runs afoul of the federal Communications Decency Act’s Section 230, the legal shield for online platforms that bars suits based on user content. Plaintiffs’ attorneys said doctors and researchers should be allowed to testify so long as they aren’t trying to hold companies liable as the publishers of that information.

Judge Carolyn B. Kuhl uncharacteristically asked no substantial questions for the first hour of arguments.

Then, she asked whether, if the opinions of general causation experts are excluded, lay people might be able to testify that social media caused some level of their emotional distress.

“Nobody really digs down on this,” she said.

She asked whether there’s a distinction between the coordinated proceeding in California Superior Court and federal litigation involving the drug Lipitor, where a court excluded general causation expert testimony and said plaintiffs couldn’t testify that the drug caused their diabetes, later granting summary judgment to Pfizer Inc.

Kuhl also said lawyers should be reminded that under state procedural law, motions such as the one at hand—to exclude expert testimony— “cannot come cloaked as a motion in limine but in fact be a motion for summary judgment.”

Section 230

Social media companies argued in court filings that allowing experts to speak to studies that are content-based would run afoul of Section 230—the boundaries and complications of which have marked many of the major skirmishes in the case so far.

Kuhl in January ruled the companies could be sued for the design of their websites under a novel non-product negligent failure-to-warn theory.

She said they may be liable for reasonably predicting the platforms could be addictive to young users and not warning them.

Attorney Jonathan Blavin of Munger, Tolles & Olson LLP, representing Snap, showed deposition recordings Wednesday of several plaintiffs’ experts saying it’s difficult to separate user-created content from features created by the platforms, such as algorithms and endless scroll.

No studies show the impact of features independently, Blavin said.

The companies also argue that because there is no recognized medical diagnosis for “social media addiction,” the experts on causation don’t meet California state law standards for reliability.

“Despite hundreds of studies cited in this litigation, there is no scientific consensus that social media causes ‘addiction’ or the other psychiatric disorders Plaintiffs allege, let alone that content-agnostic social media features—as opposed to the content made available on such platforms—causes those harm,” the companies said in court filings.

The plaintiffs, on the other hand, argue Section 230 isn’t an evidentiary rule, and that evidence discussing content can be admitted so long as they aren’t trying to hold the companies liable as a publisher of that information. They also say medical diagnoses aren’t needed to establish injury under state law.

“A harm can have multiple causes,” said plaintiffs’ attorney Josh Autry of Morgan & Morgan.

“As this Court has held, there is no ‘but for’ test that would require Plaintiffs’ case to be entirely divorced from social media content,” the plaintiffs argued in filings. “Rather, the question is whether features are a substantial factor in the harm.”

The first bellwether trial is scheduled to begin in November.

The case is Social Media Cases JCCP, Cal. Super. Ct., No. JCCP5255, 9/17/25.