Having difficult conversations is beneficial in relationships. (Chay_Tee/Shutterstock)
Study shows six distinct facial muscle movements, mainly around the eyes and mouth, linked to higher depression scores
In A Nutshell
Mild depression was linked to subtle changes in facial muscle activity, especially around the eyes and mouth.
Strangers rated these faces as less expressive, friendly, and likable after just 10 seconds.
Six facial patterns appeared more often, and five correlated with depression scores.
Results suggest early depressive symptoms may show in expressions, but findings are limited to Japanese students.
SHINJUKU, Japan — You may notice when someone seems “off,” even if they have not said anything about how they feel. New research from Japan suggests that instinct is sometimes right. A team at Waseda University found that people with early depressive symptoms show subtle differences in their facial expressions. These differences shape how strangers see them within seconds, even before any diagnosis is made.
The study focused on “subthreshold depression,” which refers to mild depressive symptoms that do not meet the criteria for clinical depression but can increase the risk of developing it later. Using a mix of human ratings and computer analysis, the researchers showed that students with subthreshold depression were judged as less expressive, friendly, natural, and likable compared to peers without such symptoms.
Interestingly, while their outward expressions were different, their ability to evaluate others’ faces was no weaker than that of healthy students.
How Researchers Connected Facial Expressions to Depression
The researchers recruited 127 Japanese undergraduates and measured their symptoms using the Beck Depression Inventory-II (BDI-II). Students scoring between 1 and 10 were classified as healthy, while those scoring 11 to 20 were grouped as having subthreshold depression.
The project unfolded in two stages. In the first stage, 64 students recorded short, 10-second self-introduction videos under identical conditions: the same room, lighting, and clothing. A year and a half later, a separate group of 63 students viewed the silent clips and quickly rated each person on seven traits, including expressiveness, friendliness, and stiffness.
At the same time, the videos were run through OpenFace 2.0, a facial recognition program that detects specific muscle movements known as action units (AUs). The software tracked 18 possible AUs, from eyebrow lifts to mouth openings, across each frame.
Researchers say signs of mild depression can show on facial expressions, with six in particular showing a stronger correlation. (Photo by voronaman on Shutterstock)
6 Facial Patterns Linked to Mild Depression
The differences were clear. Students with mild symptoms consistently received lower ratings on positive traits such as being expressive, natural, friendly, and likable. Statistical tests showed these were not small fluctuations but meaningful differences in first impressions.
Computer analysis revealed which muscles drove those impressions. Six action units appeared more often in the subthreshold depression group:
AU01 (inner brow raiser)
AU05 (upper lid raiser)
AU20 (lip stretcher)
AU25 (lips part)
AU26 (jaw drop)
AU28 (lip suck)
Five of these facial movements also correlated with students’ depression scores. That means the more symptoms someone reported, the more likely those specific movements appeared.
Earlier studies have linked some of these same muscle combinations to tension, discomfort, and forced or “fake” smiles. Another research group even mapped a set of action units to fear expressions in both depressed and non-depressed people. In the current study, six of those fear-related movements were also elevated in the mildly depressed group. This overlap led the authors to speculate that early depression may share biological ties with fear responses. They stress, however, that this idea is still a hypothesis, not a confirmed explanation.
Why Cultural Context Shapes Interpretation
The fact that this study was conducted in Japan is important. Cross-cultural research shows that East Asian individuals often display lower baseline levels of facial expressivity compared to Western populations. This difference in typical expressiveness may influence how depression-related facial cues appear across cultures.
Previous research has shown that people with clinical depression often display fewer positive expressions, such as smiling. The new findings suggest this reduction in visible positivity may begin earlier, during milder stages of depression.
Yet, one finding was notably absent: participants with subthreshold depression did not show any bias in how they judged others’ faces. Both groups of raters, healthy and mildly depressed, gave similar scores to the same videos. That suggests the main difference lies in outward expression, not in social perception.
Could Facial Analysis Help Spot Depression Early?
Because both strangers and computer software picked up on consistent differences, the researchers believe facial analysis might someday help flag people at risk of depression. Automated screening tools, if carefully developed, could provide an early signal for those who might benefit from support.
Still, the authors were cautious about overextending their results. The study had several limits:
All participants were Japanese college students, which restricts generalizability to other cultures and age groups.
Depression levels were measured by self-report surveys, not clinical interviews.
The sample sizes, while adequate for statistical testing, were relatively small.
The study looked only at subthreshold depression, not at moderate or severe cases.
The researchers emphasized that while mild depressive symptoms may be part of a continuum that leads to clinical depression, their findings cannot be applied directly to diagnosed depression without further evidence.
What This Means for Everyday Life
For the millions of people experiencing mild depressive symptoms worldwide, this research suggests their struggles may sometimes be visible to others, even if they are unaware themselves. Rather than a cause for stigma, this visibility could help open doors to earlier recognition and support.
The findings also highlight how social impressions are formed quickly and unconsciously. A slight shift in facial expressivity can change how someone is perceived, not by making them seem more negative, but by making their positive qualities less noticeable.
This study adds detail to the long-standing belief that “the face reveals the mind.” It shows that the connection is not just cultural wisdom but can be measured and analyzed with scientific tools. Yet the researchers are clear: this work is an early step. Broader studies, across cultures and age groups, are needed before any clinical or technological application can be trusted.
What To Look For: Facial Signs That May Signal Early Depression
While this study focused on subtle muscle movements detected by computer software, there are observable changes family and friends might notice:
People with mild depression showed more frequent eyebrow raising, upper eyelid lifting, lip stretching, and mouth opening
These movements often relate to tension, forced smiles, or expressions of discomfort
What You Might Notice:
Smiles that seem strained or don’t reach the eyes
Less animated facial expressions overall
A “flat” or withdrawn appearance during conversations
Subtle signs of tension around the eyebrows and mouth
Reduced overall expressiveness, even when talking about positive things
If You’re Concerned: Pay attention to changes in someone’s usual expression patterns rather than isolated moments. Depression affects much more than facial expressions; look for shifts in sleep, appetite, energy, and interest in activities they once enjoyed.
Remember: Facial expressions alone cannot diagnose depression. If you’re worried about a loved one, encourage them to speak with a healthcare professional. Early support can make a significant difference in preventing mild symptoms from developing into clinical depression.
Disclaimer: This article is for general informational purposes only and should not be taken as medical advice. If you are concerned about depression, please seek help from a qualified professional.
Paper Summary
Methodology
Researchers recruited 127 Japanese university students and used the Beck Depression Inventory-II to divide them into healthy (scores 1–10) and subthreshold depression (scores 11–20) groups. In the first phase, 64 students recorded standardized 10-second self-introduction videos. In the second phase, conducted 1.5 years later, 63 different students watched silent versions of these videos and rated each person on seven traits using five-point scales. Videos were also analyzed using OpenFace 2.0 software to detect 18 different facial action units (specific muscle movements that create expressions).
Results
Students with subthreshold depression received significantly lower ratings on positive traits (expressive, natural, friendly, likable) but showed no differences on negative traits (stiff, nervous, fake). Automated analysis identified six facial action units that were more prominent in the subthreshold depression group, particularly movements around the eyes and mouth. Five of these facial patterns correlated directly with depression severity scores. People with subthreshold depression showed no bias in their ability to rate others’ faces.
Limitations
The study involved only Japanese university students, limiting generalizability to other populations. Depression assessment relied solely on self-report rather than clinical interviews. Sample sizes were modest, and the research could not establish causal relationships between specific facial movements and social impressions. Cultural factors specific to East Asian expressivity norms may also limit broader applications.
Funding and Disclosures
This research was supported by The Jacob and Malka Goldfarb Charitable Foundation. The authors declared no competing interests. Writing and editing assistance was provided by Dr. Katrin Ishii-Schrade of Dmed under contract with the authors.
Publication Information
Sugimori, E., & Yamaguchi, M. “Subthreshold depression is associated with altered facial expression and impression formation via subjective ratings and action unit analysis,” published in Scientific Reports, 15, Article number: 30761, August 25, 2025.