THE total number of drug abusers fell last year but a disturbing blip stood out in the latest annual drug statistics: Heroin has re-emerged as the most commonly abused drug type in Singapore for the first time in six years.

Nearly half of the 1,855 drug abusers caught last year were heroin addicts.

In 2003, synthetic drugs like Ecstasy, Ice and ketamine became the drug type of choice among local abusers, bumping heroin off its long-time perch.

In 2007, the most commonly abused drug here was Subutex - a pill which was meant to wean heroin addicts off the white powder but ended up getting them hooked on the substitute instead.

Heroin arrests started to escalate after Subutex was banned by the authorities in August 2006.

Last year, 859 heroin abusers were caught compared to 690 in 2007.

At a briefing yesterday on last year's drug scene, the Central Narcotics Bureau (CNB) said three in 10 heroin abusers caught were formerly users of Subutex.

Since the ban on Subutex, enforcement against abusers of both drugs had been stepped up.

The bureau's deputy director Ng Ser Song said: 'Naturally, if you step up enforcement, you bring in more abusers...and inevitably, there'll be some recalcitrants who will go back to heroin.'

Mr Ng also said the rise could be due to a swell in heroin supply in the region.

'In some ways, you can say that it (the increase in supply) will induce a little bit of demand,' he said.

But this effect was limited because the heroin supply was 'not really flowing down to the street', Mr Ng added. Seizures have ensured that the price of the drug remain constant at $50 per 0.2g straw.

The number of heroin arrests last year was the highest since 2002, the year Subutex was introduced. The following year, the number of heroin abusers - which had already been dropping since the mid-1990s - fell to just 567, the first time since the 1970s that the figure was below 1,000.

Allaying concerns that the heroin scourge was returning, Mr Ng stressed that the numbers caught were 'definitely not' in the league of 'the bad old days'. More than 6,000 heroin addicts were busted in 1994.

Since those days, there had been a 'dramatic drop', he said, adding: 'When you look at the numbers over time, the rate of increase is tapering off.'

Nine in 10 of those caught for heroin abuse last year were repeat offenders, the majority of whom have since been sentenced to jail terms of at least five years under what is called the long-term imprisonment regime.

This scheme puts repeat drug abusers in jail for between five and 13 years.

Their imprisonment means they will not abuse the drug again or influence others to try heroin for the first time, said Mr Ng, who expressed confidence that the situation could be brought under control.

Halfway houses that The Straits Times spoke to said the comeback was worrying but felt that the rise would not reach the alarming levels of the 1970s to 1990s.

Meanwhile, Subutex arrests dropped by over half last year to 354, compared to 841 in 2007.

Asked if the ban on Subutex was the right move, Mr Ng said: 'I think we did a good thing. We bit the bullet and took the problem head-on. If you look at the figures, they're either dropping or tapering off. We'll continue with the enforcement action.'

joolin@sph.com.sg