Research
Original studies and whitepapers from our team
Predicting Exercise Preferences Using Sport Similarity
Ming Xuan Samuel Tan
82.7% of users engaged in sports similar to their preferences — validating a similarity-based approach to fitness class recommendations across 499 users.
A Framework for Assessing Mental Wellbeing from Activity and Sleep Data
Ming Xuan Samuel Tan
How activity and sleep patterns connect to mental wellbeing — and how Sahha's Mental Well-Being Score quantifies that relationship.
What Can Smartphones and Wearables Reveal About Behavior?
Balkaran Singh
A review of behavioral inference from phone and wearable sensor data — covering mental state, lifestyle, personality, and cognition.
How Daily Step Count Relates to Depression, Anxiety, and Stress
Ming Xuan Samuel Tan
Every 1,000 extra daily steps linked to lower DASS-21 depression, anxiety, and stress scores across 301 participants.
Detecting Stress from Smartphone Activity and Sleep Patterns
Gurleen Singh, Sugam Budhraja
Logistic regression achieves AUC 0.76 for stress detection using smartphone-derived steps, sleep, and phone unlock data from 820 participants across 15 countries.
Smartphone Activity Patterns as Markers of Depression
Ming Xuan Samuel Tan, Sugam Budhraja, Vidusha Tewari, Gurleen Singh, Aleksander Dahlberg, Nathan Berg
In 2,068 participants, smartphone-derived activity patterns — including nighttime activity and sleep regularity — were significantly associated with depression levels, with sex-specific differences.
The Case for Passive Digital Phenotyping in Mental Health
Vidusha Tewari, Sugam Budhraja
Self-report mental health apps suffer from engagement and accuracy problems. This review examines the evidence for passive digital phenotyping as a scalable, objective alternative.
Sleep Disturbances as Early Predictors of Depression
Vidusha Tewari, Sugam Budhraja
Insomnia doubles the risk of developing depression. This review examines how sleep disturbances precede depressive episodes and how passive monitoring could enable early detection.
Sahha Research Study: Design, Data Collection, and Ethical Framework
Aleksander Dahlberg, Nathan Berg
The protocol behind Sahha's longitudinal mental health study — covering recruitment across 17 countries, passive data collection, psychometric validation, and ethical safeguards.