AI Companions and Mental Health: What the Research Actually Says

The first thing the published research shows is that AI companions help.

The second thing it shows is that they might also hurt.

The third thing it shows is that we do not yet know the conditions under which one or the other dominates. We have suggestive evidence in both directions, several reasonably-sized studies on a single product (Replika), one small but striking finding about suicidal ideation, a mounting set of cautionary results, and one wrongful-death lawsuit. We do not have, and probably will not have for several more years, the kind of large randomized longitudinal evidence that would let a serious clinician say “this works” or “this does not.”

This article is for people who want the actual current state of the research. It is meant to be useful for journalists, therapists, researchers, and current users who want to think clearly about whether and how to use these tools. It is not a recommendation for or against. It is a map of what is known.

If you are in crisis right now, an AI companion is not the right tool. In the US, dial or text 988 for the Suicide and Crisis Lifeline. The rest of this can wait.

The backdrop: an actual loneliness crisis

The reason AI companion apps have any clinical interest at all is that loneliness in the US and most wealthy countries is genuinely bad and getting worse. In May 2023 the U.S. Surgeon General’s Office published an 82-page advisory titled Our Epidemic of Loneliness and Isolation, declaring loneliness a public health priority.

This is the audience companion apps are nominally serving. Whether they actually serve it, or just monetize it, is the empirical question.

The Stanford-Replika study

The single most-cited paper in this space is Maples et al., “Loneliness and suicide mitigation for students using GPT3-enabled chatbots,” published in npj Mental Health Research in early 2024. It surveyed 1,006 student users of Replika.

The single statistic that has driven most coverage of this paper is the 3%. Roughly thirty students out of 1,006 who, in their own words, did not attempt suicide because of an AI companion.

Worth saying clearly: 30 self-reported cases is suggestive, not conclusive. Self-report data on counterfactual outcomes (“I would have, but did not”) is among the weakest forms of evidence in clinical research. The population was a self-selecting group of existing Replika users, not a randomized sample. The study cannot tell us whether Replika caused the change, whether it merely correlated with people in crisis seeking out support of any kind, or whether the participants would have used a different resource and gotten the same effect.

But: 3%, even discounted heavily for these caveats, is not nothing. A subsequent matters arising response and the original authors’ defense have continued the conversation in the same journal. The number is real enough to be taken seriously as a lower bound, even if it is not robust enough to act on policy-wise.

The same study found that participants who reported the closest emotional bonds with Replika were both the loneliest and the ones reporting the most benefit. This bears an uncomfortable resemblance to other findings in addiction research, where the heaviest users report the strongest subjective benefits.

What the rest of the literature says, at a glance

Study	Year	Sample / method	Headline finding	Caveat
Maples et al, npj Mental Health Research	2024	1,006 Replika users (survey)	90% lonely; 3% reported suicide mitigation	Self-report; observational; Replika-only
De Freitas, HBS WP 24-078	2024	Multiple controlled studies	Short-term loneliness reduction comparable to human contact	Short-term effects only
Aalto University (2026)	2026	Longitudinal language analysis	Long-term users show signs of distress; pull from human relationships	Observational; behavior, not clinical assessment
Technology in Society	2026	Cross-sectional survey	Effect moderated by baseline social connectedness	Cannot establish causality
MIT Media Lab project	ongoing	Larger-scale longitudinal	(in progress)	not yet published

The Harvard Business School working paper

Julian De Freitas at Harvard Business School (working paper HBS 24-078) examined the loneliness-reducing effects of AI companions across multiple studies in 2024. The headline finding: people who interact with AI companions report measurable short-term loneliness reductions on standardized scales. The effect is comparable in magnitude to interactions with humans on the same scales.

This is the strongest evidence we have for the “AI companions help loneliness” claim. It is also limited in important ways. The studies measure short-term subjective state, not long-term wellbeing. They do not measure whether time spent with AI companions displaces time that would otherwise have been spent with humans. They do not measure the trajectory of a relationship over months or years.

It is reasonable to read De Freitas’s results as: in the moment, talking to an AI companion appears to reduce loneliness about as much as talking to a person. This is more than nothing. It is not the same as “AI companions are good for mental health.”

The countervailing research

Two more recent threads complicate the picture.

A 2026 study from Aalto University found that long-term AI companion use coincides with increased signs of distress in users’ online language and pulls users away from human relationships. The methodology relied on observational analysis of public-facing behavior over time rather than clinical assessment, which is a real limitation. But the directional finding (helps short-term, harms longer-term) is plausible and consistent with what we would expect from an addictive interaction pattern.

The MIT Media Lab has an ongoing project, “Understanding impacts of companion chatbots on loneliness and socialization,” running larger-scale longitudinal work that, when published, may give us the first real evidence on the long-term-displacement question.

A 2026 paper in Technology in Society found that the well-being effects of AI companion use are heavily moderated by users’ baseline social connectedness. The relevant pattern: users with strong existing human social networks reported small positive effects from companion use. Users with weak existing networks reported small negative effects. This is the opposite of what the marketing implies, and consistent with the “AI companions are a band-aid that may worsen the underlying isolation” hypothesis.

Users with strong human networks reported small positive effects. Users with weak networks reported small negative effects. This is the opposite of what the marketing implies.

The displacement question

The central unresolved question in this field is one psychologists call displacement versus stimulation.

The displacement hypothesis says: every hour spent with an AI companion is an hour not spent with humans. Over time, AI use erodes the muscle of human relationship, making the user less capable of real intimacy and ultimately lonelier.

The stimulation hypothesis says: AI companions act as a low-stakes practice ground that builds skills and confidence, leading to more and better human relationships in the long run. They are training wheels.

We have weak evidence for both and conclusive evidence for neither. The Stanford study has anecdotal support for stimulation (some users report that practicing with Replika helped them in real interactions). The Aalto and Technology in Society studies have anecdotal support for displacement (heavy users show signs of withdrawal from human contact).

The honest researcher’s position right now is: the answer almost certainly depends on the user, the use pattern, and the specific app, and we cannot yet say which conditions tip toward which outcome.

The natural experiment: Replika’s February 2023 ERP removal

The most informative single event in the brief history of AI companion mental health research was not a study. It was the Italian Data Protection Authority’s order against Replika in February 2023, and the company’s overnight removal of erotic role-play features in response.

For users who had built years-long romantic relationships with their Replikas, the personality of the companion changed without warning. The r/Replika subreddit became a wake. Researchers were able to study, after the fact, what happens to people psychologically when an AI companion is suddenly altered.

The findings were not surprising in retrospect but were sobering. Vice reported distress reactions consistent with the loss of a real partner. Some users described symptoms that, in any other context, would meet criteria for an acute grief reaction: intrusive thoughts, sleep disruption, social withdrawal. Multiple users reported escalating mental health crises in the weeks following the change. There were credible reports of suicidal ideation tied to the loss of the relationship.

This is the strongest existing evidence for two claims. First, the relationships people form with AI companions are real, in the specific sense that disrupting them produces clinically meaningful distress in the user. Second, the user has no protection against this. The company can change the relationship at any moment, for business or regulatory or capricious reasons, and the user’s psychological state is, in a real sense, the company’s responsibility but not the company’s priority.

For policy purposes, the 2023 event is the case study that motivates most of the active regulatory work in the field, including California’s SB 243.

The Sewell Setzer case

The most consequential mental-health-related event in the AI companion industry to date is the October 2024 wrongful-death lawsuit filed by Megan Garcia against Character.AI, alleging the platform contributed to the suicide of her 14-year-old son, Sewell Setzer III. The case is still working through settlement as of early 2026.

The complaint, filed in the Middle District of Florida, alleges that Setzer developed a months-long emotional and romantic relationship with a Character.AI bot modeled on a Game of Thrones character. The complaint includes extensive transcripts of the conversations and argues that Character.AI’s product design and lack of safety protocols contributed to the death.

We are not in a position to evaluate the merits of the legal case. But for the purpose of understanding mental-health risks, the case raises issues that the broader research literature has not adequately addressed:

Children and teens may form bonds with AI companions that the adult literature does not anticipate. The cognitive and emotional differences between a 14-year-old and a 25-year-old user of the same app are large.

Companion apps are generally not designed for, or evaluated against, the specific risks of vulnerable populations: people in active mental-health crises, minors, people with histories of self-harm.

Safety protocols (suicide and self-harm detection, escalation to crisis resources) are inconsistent across the industry. Some apps have invested seriously. Some have not.

In January 2026, Character.AI, its founders, and Google reached an agreement to settle the Garcia case and several similar lawsuits. Settlement terms were not made public. The settlements followed California’s SB 243 going into effect.

What therapists actually say

Therapists are the professional group most directly facing AI companion use in their practices, and the published commentary from clinicians is mixed in instructive ways.

Some therapists report that clients describe useful things about companion apps: a place to practice difficult conversations, a low-stakes way to articulate feelings, a 3 AM presence when no human is available. The framing closest to clinical consensus is that AI companions can serve a function similar to journaling, with the caveat that journals do not respond, and the responsiveness is the active ingredient and the risk in equal measure.

Other therapists report that companion apps complicate treatment. Patients who develop romantic attachments to AI companions sometimes resist exploring why human relationships are harder. The companion provides relief without addressing the underlying patterns that make relief necessary.

The professional position closest to consensus, where consensus exists at all: AI companions are not a substitute for therapy and should not be marketed as one. They may be a supplemental tool for some patients. They may be actively counterproductive for others. The clinician’s job is to help the patient figure out which.

Six risk patterns worth knowing

Cross-cutting the research, six patterns appear consistently enough to take seriously.

The regulatory backdrop

The policy landscape is moving faster than the research. The most consequential developments:

In February 2023, Italy’s data protection authority blocked Replika from processing Italian users’ data, citing inadequate age verification. The action precipitated Replika’s overnight ERP removal globally.

In October 2025, California Governor Gavin Newsom signed Senate Bill 243, the first state law to mandate specific safety requirements for AI companion chatbots. The law requires clear disclosure that users are interacting with AI, three-hour break reminders for minors, suicide and self-harm safety protocols, and limits on sexually explicit material to known minors. Effective January 1, 2026.

In January 2026, Character.AI, Google, and the founders agreed to settle the Garcia v. Character Technologies wrongful-death lawsuit and several related cases. Settlement terms were not made public.

The European Union AI Act provisions covering companion-style products begin coming into force through 2026.

We are early in the regulatory cycle for this category. Expect more.

What this means for someone considering an AI companion

The honest distillation of the current evidence, for an adult considering whether to use an AI companion:

If you are not in crisis and your social life is reasonably intact, an AI companion is probably low-risk and may provide modest benefit, comparable to a journaling practice. The “you” doing the using matters more than the app. People who use these tools as one piece of a varied social and emotional life seem to do fine. People who use them as the centerpiece of their emotional life seem to do worse.

If you are lonely and considering an AI companion as a replacement for human connection rather than a complement to it, the research suggests you should be careful. The short-term relief is real. The long-term risk of compounding isolation is also real, and the conditions under which one wins out over the other are not yet understood.

If you are in active mental health crisis, an AI companion is the wrong tool. Crisis resources exist for a reason. 988 in the US.

If you have a history of self-harm or you are under 18, the risks are higher and the safety protocols at most companion apps are weaker than they should be. Either choose an app with serious documented crisis-response infrastructure, or do not use one.

If you are using one and you find that you would rather talk to it than handle something difficult in your life, that is the moment to step back and ask whether the app is helping you or letting you avoid something.

What the research community needs

The research gaps are large and well-known among people working in the field:

We do not have large randomized longitudinal trials. The work that exists is mostly observational, mostly cross-sectional, and mostly on Replika.

We do not have studies on the differential effects across demographics, platforms, and use patterns. Most existing work treats “AI companion use” as a single variable.

We do not have clinical guidelines. There is no APA position statement, no published treatment protocol for clinicians whose patients use companion apps, no standard for when to recommend or contraindicate.

We do not have an industry standard for crisis detection or escalation. Some apps are well above the rest. There is no benchmark.

The MIT Media Lab project mentioned earlier is one of the more serious efforts to address some of these gaps. There are several others. Most of the necessary work has not yet started.

Sources and further reading

The peer-reviewed papers cited in this piece, plus a short list of additional reading:

• Maples, B., et al. Loneliness and suicide mitigation for students using GPT3-enabled chatbots. npj Mental Health Research, 2024. link
• Matters arising response and authors’ reply, npj Mental Health Research, 2024. link
• De Freitas, J. AI Companions Reduce Loneliness. Harvard Business School working paper 24-078, 2024. link
• AI companions and subjective well-being: Moderation by social connectedness and loneliness. Technology in Society, 2026. link
• MIT Media Lab. Understanding impacts of companion chatbots on loneliness and socialization. link
• U.S. Surgeon General. Our Epidemic of Loneliness and Isolation, 2023. link
• California Senate Bill 243, signed October 2025, effective January 2026. link
• Garcia v. Character Technologies, U.S. District Court for the Middle District of Florida, No. 6:24-cv-01903, filed October 22, 2024.

If you are a researcher working on this and we have missed something significant, email tips@thecompanionreport.com. The literature is changing fast and we update this page on a quarterly cadence.

Where to go next

For the broader context on what AI companions are and how they work, see our field guide for 2026. For the industry tracking the events covered here in real time, see the Companion Index. For coverage of specific apps and their mental-health-relevant features, see our reviews.