Border closures and movement restrictions in many countries to stem the spread of Covid-19 are also hindering the global supply of illegal drugs, with law-enforcement agencies seeing an increase in street prices of some drugs as a result.
One therapist from a private addictions clinic told The Straits Times that more people are finding it harder to buy drugs and are coming forward for help, although the Institute of Mental Health said it was unable to comment on trends.
"Anecdotally, the supplies of diverted medication such as opioids and benzodiazepines coming from Malaysia are now in shorter supply, and their costs have increased," said Mr Andrew da Roza, a psychotherapist at Promises Healthcare. "Other drugs (cannabis, meth and heroin) similarly seem to have become more expensive, although supplies appear to be available."
Circuit breaker measures were introduced in Singapore on April 7, clamping down on non-essential movement, services and gatherings.
Some drug addicts are managing withdrawal symptoms and cravings by substituting harder drugs with alcohol, new psychoactive substances (NPS) and over-the-counter medication, said Mr da Roza.
The clinic has seen a 25 per cent increase in patients, who are having a harder time managing compulsive behaviours, such as substance abuse, smoking and gambling, during the circuit breaker period.
Earlier this month, the United Nations Office on Drugs and Crime (UNODC) released a brief study on Covid-19 and the drug trade, noting that mobility restrictions and a drop in world trade may have disrupted supply chains.
"Overall, the Covid-19 measures do not seem to have affected drug production in Myanmar directly, but they may have limited opportunities to sell products to foreign buyers," the report said.
Myanmar is a major supplier of heroin and methamphetamine to South-east Asia.
A spokesman for the Central Narcotics Bureau (CNB) told ST: "It is inevitable that restrictions placed on the movement of people and goods affect the supply chain of drug trafficking syndicates, and we have started to see an increase in the street prices of drugs."
Still, drug and contraband syndicates continue to be active, as they search for new ways of getting drugs to the market. In March and last month, the CNB seized large quantities of heroin and NPS.
Likewise, Immigration and Checkpoints Authority officers discovered early last month more than 11,180 cartons of illicit cigarettes hidden in a container of "electrical control panels" at the Pasir Panjang Scanning Station.
They also found an e-vaporiser device and more than 1,100 e-vaporiser accessories in another seizure at Changi Airfreight Centre.
Drug and contraband cigarette networks in Malaysia, Ireland and Spain have adapted to Covid-19 restrictions by transporting their illicit wares in food delivery boxes, Interpol reported on April 30.
Locally, SG Vape, which sells banned vaping products, had to alter its delivery method when Malaysia extended its movement control order to June 9. On May 12, it told clients on Telegram that deliveries would now be done via international post.
While some clinics say more people are seeking help, We Care Community Services executive director Tham Yuen Han said it was hard to say if the Covid-19 situation was the cause. She told The Straits Times: "It's too early to tell because relapses happen for a multitude of factors - it's difficult to trace if they are happening now because of the circuit breaker."
But abusers may increasingly access the Dark Web in order to "overcome the effects of street control, and drug delivery by mail could become more popular", said UNODC.
Currently, many online drug vendors are offering discounts and reduced minimum orders, noted Mr Mikko Niemela, chief executive of Cyber Intelligence House.
Mr Niemela, who leads the Dark Net research team in UNODC, told The Straits Times that "since the start of the pandemic, a number of discussions on underground platforms are dedicated to the delay in orders and increased scrutiny by Customs and postal service officers".
According to Mr Niemela, a Dark Net vendor, NamasteLSD, informed customers about shipment delays to a list of countries including Singapore.
Mr Niemela added that customers had also complained about vendors who faced delays in shipping prescription opiates and painkillers.
UNODC observed a trend of abusers switching to pharmaceuticals in a May 7 report. "Some drug users have consequently been switching substances, for example, from heroin to synthetic opioids, and some are increasingly seeking access to drug treatment."