LOS ANGELES—An expert witness, called by defendants in a high-stakes trial considering whether social media companies designed their platforms to be addictive to children despite known harms, on March 10 told a Los Angeles Superior Court jury that genetics and external stressors—not social media addiction—likely led a 20-year-old plaintiff to develop multiple psychiatric disorders.

Dr. Sonia Krishna, a child and adolescent psychiatrist based in Austin, Texas, told the court that the plaintiff, identified in court documents as “Kaley G.M.” or “K.G.M.,” did not in fact suffer from a clinical social media addiction, and that her mental health outcomes would have been the same without exposure to social media.

“I would not say she has a social media addiction,” Krishna said, acknowledging a period of “heavy use” but suggesting that there were “other reasons” that drove it.

“I don’t think she had impairment in her functioning. ... She was able to attend school every day.”

Learning disorders diagnosed since kindergarten, a volatile family life, genetically determined risk, difficulty with peer relationships, and bullying online and off all drove “Miss G.M.,” as defense attorneys called her, to develop anxiety, depression, and body dysmorphic disorders, according to Krishna.

“I think number one for most mental health disorders is genetics. ... And it sounds like it goes back to her grandparents,” Krishna said. The witness did not elaborate on an alleged history of mental illness among the plaintiff’s grandparents or on whether that information came from her medical records.

The current case, which names Instagram (parent company Meta) and YouTube (parent company Google) as defendants, is one of a handful of bellwether trials expected to have a profound impact on how thousands of related personal injury civil cases—brought by children, parents, school districts, and attorneys general across the country—will play out.

K.G.M. also sued Snapchat (parent company Snap Inc.) and TikTok (parent company ByteDance). Both companies settled privately days before the trial began, but they are still named in related cases.

To a contentious battle over the meaning and import of social media addiction—a relatively novel phenomenon that is by no means standardized in terms of diagnoses, treatment, or even an understanding of its true scope—the witness added a new take: the idea that problematic social media use is often a coping mechanism in response to underlying psychiatric illness.

“A lot of teens are on social media, so it comes up very often in my conversations,“ said Krishna, who sees patients remotely in her private practice. ”Most are able to have a healthy relationship with it, but some people use it too much. It’s usually because they’re trying to cope with an underlying psychiatric disorder.”

When she can treat that disorder, the compulsive social media use symptoms usually go away, Krishna said.

That contrasts with what witnesses for the plaintiff have called a “maladaptive coping mechanism” that itself became a debilitating illness for K.G.M.

Experts testified about skyrocketing rates of social media addiction among adolescents and about a growing body of research that points to an array of resulting psychological harms.

Defendants YouTube and Instagram, the plaintiff’s complaint alleges, have “borrowed heavily” from mechanisms used in slot machines to engineer features and algorithms that hook users and keep them trapped in a vicious cycle of addiction, withdrawal, and regret.

Adolescents, whose brains are developing until age 25 the “scaffolding” they will have for the rest of their lives, are especially vulnerable to triggers and tricks that tap into primitive reward pathways in the brain and keep users returning, even in the face of obvious and mounting harms, plaintiff’s experts argued.

Behavioral addiction, including social media addiction, they contend, is virtually indistinguishable from substance addiction.

Krishna argued on March 10 that when underlying issues such as learning disabilities were addressed in high school, K.G.M.’s long history of poor grades finally began to change. Those disabilities, including attention-deficit disorder (inattention type) and a specific impairment in mathematics, would have been something the plaintiff was born with, and were documented before she began using social media, Krishna said.

K.G.M. testified earlier in the trial that she began using YouTube at age 6 and found herself routinely ensnared by app features such as “infinite scroll” that would keep her engaged far longer than she wanted to be, including at night and during school. Even in the face of bullying and feelings of low self-esteem exacerbated by her use of beauty filters, K.G.M. said, she could not stay away.

Krishna argued that the plaintiff’s anxiety began before she began using social media. She based her evaluation on both a three-hour interview with K.G.M. and on more than 200 medical records dating back to early childhood.

“In psychiatry I wouldn’t use the term [social media] addiction, it’s not even in the [Diagnostic and Statistical Manual of Mental Disorders] for other diagnoses, it’s stigmatizing,“ Krishna said. ”They’re called use disorders.”

During cross-examination, plaintiff’s attorney Mark Lanier grilled the witness over both her qualifications and the ethics of her testimony.

Defense attorneys had attempted to impugn the qualifications of Dr. Kara Bagot, a witness for the plaintiff who is a coinvestigator in a landmark National Institutes of Health-funded study tracking how social media and other childhood experiences are affecting the brains of nearly 12,000 children. Lanier went after Krishna’s lack of addiction research experience.

“You don’t have any addiction expertise, do you?” he asked. Krishna responded that she has not done a fellowship in addiction but that she sees patients who suffer from addiction disorders in her private practice.

Lanier read from transcripts of Krishna’s evaluation interview with K.G.M., in which Krishna asked her whether she thought that difficulties with friends and school led her to seek out social media to make more friends. Lanier then suggested that Krishna led the patient to a biased conclusion after attending multiple strategy meetings with defense attorneys.

“You told her to describe it as a coping mechanism,” he said. “You were asking lawyer-quality leading questions, weren’t you?”

Krishna said she also asked a lot of open-ended questions throughout the interview.

“I tried my best to understand her symptoms,” she said.

When Lanier suggested that Krishna’s evaluation differed from those of all K.G.M.’s previous therapists and doctors, who all said social media in some way contributed to her mental health challenges, the psychiatrist pushed back.

“They clearly describe in their records so many risk factors, and they never once did an intervention for social media,” Krishna said, stressing that it was treatment for underlying conditions that resulted in improvements in the patient’s life.

Krishna acknowledged that social media may have adversely affected K.G.M. in terms of online bullying, which she described as “content,” but said it did not play a part in her psychiatric diagnoses.

The case is narrowly focused on the design and function of platform features and algorithms, rather than third-party content, which is broadly protected by the First Amendment and Section 230 of the 1996 Communications Decency Act.

Codefendants also played a videotaped deposition of Kristin Hendrix, formerly a director of product design and user experience research at Meta, who testified that the company was unique in the tech world for giving research “a seat at the table.”

Hendrix said safety features the company introduced in the past several years—the “take a break” function, nighttime quiet mode, and “nudges”—were responses to user experience research.

“We developed these features even though we know it would potentially upset teens in terms of their experiences and preferences because they were safer settings,” she said.

Also in a videotaped deposition presented to the jury, Elena Davis, a user experience manager for Meta, testified about research she presented shortly after being hired in 2018 that contested emerging claims of social media addiction, and suggested reframing the “addiction narrative” to differentiate social media from substance abuse.

Meta CEO Mark Zuckerberg, Instagram chief Adam Mosseri, and YouTube’s top engineer, Cristos Goodrow, have all denied that their products are engineered to be addictive.

In a call with reporters on March 10, YouTube representatives reiterated a distinction presented throughout trial—that the platform is a video streaming app like Netflix, not a social media platform in the functional sense that Instagram, Snapchat, or TikTok are.

The company also argued that there has been no medical evidence presented in the trial to prove that K.G.M. had an addiction to the platform. It said that in thousands of pages of K.G.M.’s medical records, references to the app were only references to benign uses, such as watching videos to help her sleep.

During the trial, attorneys for the plaintiff have highlighted internal YouTube documents in which executives, project managers, and engineers suggested that the company’s mission was to make it “more like an addictive experience” that people would keep returning to, such that the goal is “not viewership, it’s viewer addiction.”

Both sides are expected to conclude closing arguments on March 12, and a verdict could come as soon as March 13.

If one or both codefendants are found liable, and the jury finds that they acted with malice by committing fraud or oppression, a second phase to determine punitive damage would follow. If there is no punitive finding, the jury could set a dollar amount when they deliver the verdict.

Separate verdict forms will be given to the jury for Meta and Google; if both are found liable, jurors may allocate which party is more responsible than the other.

Nine out of 12 jurors must vote in order for one or both defendants to be found liable.

Correction: A previous version of this article misspelled the name of Meta user experience manager Elena Davis. The Epoch Times regrets the error.