In the first weeks of the pandemic in 2020, when China imposed strict controls on the movement of its citizens, technology became the main means of responding to anxiety and depression. Cellphones provided crucial support to Chinese citizens in lockdown, from counseling through chat services to online self-help. WeChat, Weibo and TikTok, the country’s giant social networks, sprang into action, offering education and mental health services.

More intriguingly, artificial intelligence (AI) was also used. Weibo posts were used to find individuals at risk of suicide and volunteers were alerted to intervene. Using AI to search social media for signs of mental illness raises obvious privacy concerns. But overall, China has made impressive use of technology to manage the diagnosis and treatment of depression, anxiety and stress.

Interest in mental health technology had been growing even before the pandemic. Today there are between 10,000 and 20,000 of these apps available for download. Their quality is questionable and the dangers of bias built into algorithms are well known. The privacy risks, and not just in China, are serious. Yet the US National Institutes of Health consider technology to have opened “new frontiers” in mental health support. It seems certain that robots will play an important role in the evaluation and treatment of mental health problems.

There is an immense global need for care that goes unanswered, as the World Health Organization (WHO) global report on mental health published on June 17 makes clear. The study, the largest of its kind in 20 years, paints a sorry picture. In 2019, 1 billion people were living with mental health problems, the most common of which were anxiety and depression. The pandemic, the economic downturn and social polarization have made things worse. In the first year of covid, the prevalence of anxiety and depression increased by 25% in the world. In Britain, annual spending on antidepressants increased 66% during the pandemic.

However, according to the WHO, on average, governments dedicated only 2% of their health budgets to mental health treatment and prevention. Even if they could get more money, they would face a desperate global shortage of health personnel. There are few specialized mental health nurses and psychiatric social workers. Half of the world’s population lives in a country where there is less than one psychiatrist for every 200,000 people. Ordinary doctors and nurses in many cases do not have the training to recognize patients with mental health problems.

Although mobile networks cover 85% of the population, half of the world does not have access to the Internet; in low-income countries the percentage drops to 20 percent. But that also represents an opportunity: governments seeking to help the mental health of their citizens have a choice in the form of lending or financing cell phones.

However, there is much work ahead. Privacy and security policies need to be much stricter and require better oversight: a data privacy breach could reveal the private thoughts of deeply vulnerable people. Some apps share information with their advertisers. Governments and regulators have to work much harder to identify good online deals and weed out bad ones.

And complicated ethical issues abound. AI could diagnose people online without their permission; Few want to be told that an algorithm has concluded that they have depression. If an algorithm decides that someone could be killed, what should be done?

This technology could be misused in the 20 countries where suicide is still considered a crime, since online tools can often uncover intentions. With powerful tools come great responsibilities. But the benefits to humanity of using technology to tackle mental health problems could be huge.