Could the next prescription from your doctor be for an app? A raft of apps in use or under development can now detect or monitor mental and physical disorders autonomously or directly administer therapies. Collectively known as digital medicines, the software can both enhance traditional medical care and support patients when access to health care is limited—a need that the COVID-19 crisis has exacerbated.

Many detection aids rely on mobile devices to record such features as users' voices, locations, facial expressions, exercise, sleep and texting activity; then they apply artificial intelligence to flag the possible onset or exacerbation of a condition. Some smart watches, for instance, contain a sensor that automatically detects and alerts people to atrial fibrillation, a dangerous heart rhythm. Similar tools are in the works to screen for breathing disorders, depression, Parkinson's, Alzheimer's, autism and other conditions. These detection, or “digital phenotyping,” aids will not replace a doctor any time soon but can be helpful partners in highlighting concerns that need follow-up. Detection aids can also take the form of ingestible, sensor-bearing pills, called microbioelectronic devices. Some are being developed to detect things such as cancerous DNA, gases emitted by gut microbes, stomach bleeds, body temperature and oxygen levels. The sensors relay the data to apps for recording.

The therapeutic apps are likewise designed for a variety of disorders. The first prescription digital therapeutic to gain FDA approval was Pear Therapeutics's reSET technology for substance use disorder. Okayed in 2018 as an adjunct to care from a health professional, reSET provides 24/7 cognitive-behavioral therapy (CBT) and gives clinicians real-time data on their patients' cravings and triggers. Somryst, an insomnia therapy app, and EndeavorRX, the first therapy delivered as a video game for children with attention deficit hyperactivity disorder, received FDA clearance earlier this year.

Looking ahead, Luminopia, a children's health start-up, has designed a virtual-reality app to treat amblyopia (lazy eye)—an alternative to an eye patch.* One day college students might receive alerts from a smart watch suggesting they seek help for mild depression after the watch detects changes in speech and socializing patterns; then they might turn to the Woebot chat bot for CBT counseling.

Not all wellness apps qualify as digital medicines. For the most part, those intended to diagnose or treat disorders must be proved safe and effective in clinical trials and earn regulatory approval; some may need a doctor's prescription. (In April, to help with the COVID-19 pandemic, the FDA made temporary exceptions for low-risk mental health devices.)

COVID-19 highlighted the importance of digital medicine. As the outbreak unfolded, dozens of apps for detecting depression and providing counseling became available. Additionally, hospitals and government agencies across the globe deployed variations of Microsoft's Healthcare Bot service. Instead of waiting on hold with a call center or risking a trip to the emergency room, people concerned about experiencing, say, coughing and fever could chat with a bot, which used natural-language processing to ask about symptoms and, based on AI analyses, could describe possible causes or begin a telemedicine session for assessment by a physician. By late April the bots had already fielded more than 200 million inquiries about COVID symptoms and treatments. Such interventions greatly reduced the strain on health systems.

Clearly, society must move into the future of digital medicine with care—ensuring that the tools undergo rigorous testing, protect privacy and integrate smoothly into doctors' workflows. With such protections in place, digital phenotyping and therapeutics could save health care costs by flagging unhealthy behaviors and helping people to make changes before diseases set in. Moreover, applying AI to the big data sets that will be generated by digital phenotyping and therapeutic apps should help to personalize patient care. The patterns that emerge will also provide researchers with novel ideas for how best to build healthier habits and prevent disease.

*Editor’s Note (11/11/20): This sentence has been revised after posting to update the name of the company.