"Despite their relatively recent introduction, mobile mental health apps and websites have tremendous potential," Rego says.

Advantages he cites include their ability to extend the reach of mental health care beyond the clinic and be used as adjunct tools for therapy, making it more accessible and efficient.

The drawbacks include "effectiveness issues" - because the technology is outpacing the research, few apps have been studied. "Because of this, I'm hesitant to use them as a core part of the work I do as a clinical psychologist," says Rego.

"I do, however, encourage my patients to consider using some of the more well-established apps to augment the work we do together. In this way, apps could be considered the modern version of a good self-help book," he says, citing MoodKit and MindShift as apps that augment cognitive behavioural therapy, also called "talking therapy".

Hong Kong therapist Dr Melanie Bryan, who runs the mental health hub Mindmatters, also sees some potential in mental health apps. "If one has a minor problem, a mental health self-help app can give general guidance or information or ideas that can be useful," Bryan says.

Another possible plus of a mental health app is it can bring some relief through showing that you are not alone in dealing with an issue, according to Bryan, who adds that an app can potentially increase motivation to resolve a simple problem. Better yet, the cost is minimal.

However, she has her reservations. For starters, mental health apps may seem individualised but are, by definition, highly generalised, says Bryan. Worse, a mental health app could serve as a superficial way of dealing with a serious problem, making it unlikely to have great benefit.

"Just as a friend is not a therapist, neither is an app," she says.

According to therapist Dr Karen Phillip, who runs a virtual mental health site, apps are good for hypnotherapy but have no role to play in the complicated, dialogue-based realm of psychotherapy. The reason: they cannot read body language, emotions or voice tone.

In theory, communication breaks down into the following percentages: 7 per cent words, 38 per cent tonality, and 55 per cent physiology - posture, gesture and breathing, Phillip says. Therapists "match and mirror" in these areas.

Some apps provide minimal mental assistance, according to Phillip. The calming kind may provide brief relief from anxiety, she says, adding that any amount of help is good.

But "basic little apps" have severe limitations. Incapable of teaching the listener to adjust their thoughts, they have no place in treating trauma, anxiety or habit control issues, she says. She is sceptical of the idea that it is easier to be frank in front of a computer than a person. Many of her patients disclose confidential issues that have dogged them for decades within 30 minutes, "once rapport and trust are achieved", she says.

Digital entrepreneur Katie Harp, who offers a free mental health app called Resilient, also emphasises the value of human interaction.

"We'll always need human connection for reassurance, empathy, talking, and caring. An app will never replace that," Harp says.

Still, she adds, mental health apps can be a first step - a starting point for someone who feels depressed or anxious but is unsure what to do and afraid to seek help. "Sometimes, people struggle alone for a long time before they reach out to someone or get help," she says.

Harp founded Resilient after recovering from her own nine-year fight with depression. Her app, which she portrays as a pictorial social media platform for mental health, is designed to keep hope alive. Harp, whose app so far has about 1,500 users, she says, touts emails saying her innovation changed - even saved - someone's life.

Apps can inspire users to stay positive while gently guiding them to seek professional help if needed, according to Harp.

In a 2012 examination of 1,500 health apps that cost money and had been available since June 2011, the New England Centre for Investigative Reporting found that health apps in general fail to follow established medical guidelines. Worse, the centre found few had been tested through the kind of clinical research that is standard for other treatments.

Research conducted by the Australian mental health organisation The Black Dog Institute is more positive about mental health apps in particular.

"Results showed significant reductions in depression, stress, and substance use; these continued over time," the institute found.

It cited inherent advantages including real-time activity monitoring, personalised feedback and motivation support. Mobile phones are excellent devices for delivery of mental health programmes, the institute said.

Still, it noted many downsides including technical glitches and recommended therapy apps only for mild to moderate symptoms of anxiety or depression - as most industry observers do.

Despite their cheap, user-friendly charm, the worth of therapy apps remains unproven. But it is early days. The best therapy apps may be yet to come.

Meanwhile, good apps could reach millions of people who lack the money or inclination to engage in traditional therapy, which must be a positive. As Harp says, regardless of who you are, you deserve to get help, and you deserve to be happy.

Doctors call for long-term policy

Within Hong Kong's population of 7.2 million, an estimated 1 million to 1.7 million have a mental disorder and an estimated 70,000 to 200,000 suffer from severe mental illness, according to the Hospital Authority.

Last year, the Hong Kong Mental Health Council urged the government to set up a mental health commission to manage the problems of long-term patients and fill the gap left by a supposed lack of overall strategy.

In the past, psychiatrists have called repeatedly for a long-term mental health policy, especially after a string of family tragedies and violent episodes involving the mentally ill. Last year, the mental health of the city's youth declined to an extent described by one expert as "distressing".

Mental illness remains a deeply taboo subject in many Asian countries. Sufferers and their families are reluctant to acknowledge depression, anxiety and more serious conditions such as schizophrenia and bipolar disorder.

Such resistance is not confined to the region. A 2009 British study found people were more reluctant to reveal they had a mental illness than to come out as gay.