A middle-aged man had to be taken away from his home last year as volunteers cleared piles of trash from his Housing Board (HDB) flat after an intervention from the town council - the sight of his "belongings" being discarded was too much for him to bear.

Elsewhere, a retired engineer hoarded numerous electrical items even though they were spoilt or backdated. He insisted he would refurbish them and make them into useful items once more.

In yet another case, an elderly widow collected stacks of newspapers, filling her home with them. It mattered little that she would never read them - the newspapers were a reminder of her late husband and keeping the papers was how she continued to remember him.

These are just three cases of hoarding that Singapore agencies such as Habitat for Humanity Singapore and the Institute of Mental Health (IMH) have dealt with in recent years.

The problem made the headlines recently after a woman and her daughter were reported to have spent the past two years sleeping and washing their dishes outside their four-room Ang Mo Kio flat, as a result of the clutter they had accumulated inside.

The Nee Soon town council and HDB were alerted to the situation after complaints from neighbours.

There has been increased recognition of the condition and engagement, says Dr Kelvin Ng, a consultant from the department of community psychiatry at IMH.

It is one of the conditions receiving attention over the last few years as part of the National Mental Health Blueprint and Community Mental Health initiatives.

Hoarding has long been considered a subtype or a manifestation of obsessive-compulsive disorder, but Dr Ng says it can also occur in groups of people who have no mental or developmental disorders.

Even though hoarding tendencies can be seen in a spectrum of illnesses, including schizophrenia and dementia, the more severe problems involve an irrational reluctance to let go - often because the hoarders are scared to throw out something they might need later for practical or nostalgic purposes.

"Persons who hoard have usually experienced loss or stress in the past, which causes them to have a 'vacuum' in their hearts, which they try to fill with the hoard," says Dr Ng.

"They also may not be able to articulate why they feel the way they do, as the reason that triggered them to hoard may have been forgotten. So the hallmark of a hoarder would be the difficulty or distress they exhibit when they have to clear the hoard."

A study conducted in 2010 by the Research Division at IMH found that one in 50 people in Singapore will display hoarding behaviours.

However, experts say the problem is under-reported here. Cases rarely come to light unless the situation is so severe that the spillover either affects family members or neighbours or the home becomes a serious fire and health hazard.

Of the 800 cases the IMH's Mobile Crisis Team has been activated to handle in the past three years, only 15 are related to hoarding issues.

Similarly, at the HDB, the number of complaints about hoarding is low. According to an HDB spokesman, it received 35 and 30 cases in 2014 and last year, respectively, of feedback on hoarding in HDB flats. From January to June this year, it received 16 cases of such feedback.

But the low numbers may not be a true reflection of the hoarding situation in Singapore because hoarding can also occur within private properties, which are not under the purview of the HDB.

A lot of hoarding also takes place in a home, which means neighbours may be unaware of the issue until belongings spill out into a common corridor or they have to deal with resultant pest infestations.

Moreover, it takes hoarders time to accumulate an amount big enough to be a problem. Until then, their hoarding tendencies may remain unknown to others. This is often also why many severe cases of hoarding involve the elderly - their tendency to hoard may worsen as the years pass.

Still, thanks to the efforts of various agencies in Singapore, including referrals from medical social workers and senior activity centres, it seems more cases are coming to light.

At Habitat for Humanity Singapore, which runs the decade-old Project HomeWorks to improve the living conditions of the elderly, the sick and the disabled in one- and two-room rental flats across the island, at least two or three cases of hoarding are dealt with every month.

Clinical psychologists in private practice such as Ms Agnes Teo of Think Psychological Services have also noticed a rise in the number of clients referred to them for hoarding over the past three years.

Treating underlying mental illnesses such as schizophrenia with medication can sometimes reduce hoarding behaviours.

Psychotherapy - specifically cognitive behavioural therapy - is also increasingly recognised to be an effective way to treat hoarding behaviours. It involves talking to a trained therapist to examine the root of problems and dealing with troublesome habits such as hoarding.

According to Mr Yong Teck Meng, national director of Habitat for Humanity, the hoarding problem is an uphill battle that requires long- term concerted efforts on the part of agencies to rehabilitate hoarders.

Volunteers at his organisation are trained to clean out the homes of hoarders. Often, these jobs are completed only after three or four visits.

"In most cases, the hoarders get very agitated when they see their stuff being taken away, even if these are oranges from Chinese New Year two years ago," he says.

"Helping to clear their home therefore is a long-term process, which requires not only distracting them when the home is being cleaned, but also keeping in contact with them to ensure they do not bring back all the clutter to their home."