* Verdict could affect thousands of similar cases against

tech companies

* Plaintiffs' focus on platform design may make liability

harder to avert for companies

* Mounting criticism over child safety shifts debate to

courts, state governments

* Meta says "respectfully disagree" with verdict

* Shares of both companies little changed after verdict

By Dawn Chmielewski

LOS ANGELES, March 25 (Reuters) - A Los Angeles jury

found Alphabet's Google and Meta liable for

$3 million in damages on Wednesday in a landmark social media

addiction lawsuit.

The outcome could influence thousands of similar cases

against the tech companies brought by parents, attorneys general

and school districts. At least half of American teens use

YouTube or Instagram daily, according to the

Pew Research Center

.

The Los Angeles case involves a 20-year-old woman who said she

became addicted to the apps at a young age because of their

attention-grabbing design. The plaintiffs in the Los Angeles

proceeding focused on platform design rather than content,

making it harder for the companies to avert liability.

Snap and TikTok were also defendants in the trial. Both settled

with the plaintiff before it began. Terms of the agreements were

not disclosed.

Shares of Meta Platforms ( META ) were up 1% and Alphabet slightly

higher after the verdict, little changed on the news.

A Meta spokesperson said "We respectfully disagree with the

verdict and are evaluating our legal options." Google did not

have an immediate comment.

MOUNTING CRITICISM

Large technology companies in the U.S. have faced mounting

criticism in the last decade over child and teen safety. The

debate has now shifted to courts and state governments. The U.S.

Congress has declined to pass comprehensive legislation

regulating social media.

At least 20 states enacted laws last year on social media usage

and children, according to the nonpartisan National Conference

of State Legislatures, an organization that tracks state laws.

The legislation includes bills that regulate the use of

cellphones in schools and require users to verify their ages to

open a social media account. NetChoice, a trade association

backed by tech companies such as Meta and Google, is seeking to

invalidate age verification requirements in court.

A separate social media addiction case brought by several states

and school districts against technology companies is expected to

go to trial this summer in federal court in Oakland, California.

Another state trial is slated to begin in Los Angeles in

July, said Matthew Bergman, one of the attorneys leading the

cases for the plaintiffs. It will involve Instagram, YouTube,

TikTok and Snapchat.

Separately, a New Mexico jury on Tuesday found Meta violated

state law in a lawsuit brought by the state's attorney general,

who accused the company of misleading users about the safety of

Facebook, Instagram and WhatsApp and of enabling child sexual

exploitation on those platforms.