One such case was revealed by Pulitzer Prize-winning investigative reporter Gary Webb, who wrote a series of stories in 1996 linking America's spy agency CIA to cocaine trafficking in Los Angeles. His series, Dark Alliance, which appeared in the San Jose Mercury News, revealed that the CIA had backed the transport of cocaine into the US by the Contras Nicaraguan rebel group.

The CIA's involvement with Contra rebels is largely political. After the overthrow of the dictator Anastasio Somoza Debayle in 1979, the Sandinista National Liberation Front (FSLN), a socialist party, came into power in Nicaragua. In 1981, US President Ronald Reagan was concerned that the FSLN would turn Nicaragua into a 'second Cuba', bringing Soviet-Cuban communist forces closer to the US. To suppress the socialists, Reagan directed the CIA to finance, arm and train the Contras, an anti-socialist group.

Webb wrote that Nicaraguan drug traffickers had sold and distributed cocaine in Los Angeles in the 1980s, and that the drug profits were used to fund the Contras. He reported that the CIA and White House officials knew about the cocaine deal and the rebel group's involvement.

Webb's investigation led to an inquiry in Washington led by US senator John Kerry. Two agents of the US Drug Enforcement Agency (DEA) told lawmakers that an official with the US National Security Council wanted to pay the Contras US$1.5 million from a Colombian drug cartel. The official, Oliver North, has consistently denied any involvement with drug trafficking.

North had said on Fox News television that 'nobody in the government of the United States ... ever had anything to do with running drugs to support the Nicaraguan resistance'.

But evidence suggested otherwise. In February 2004, North's diaries, e-mails and memos were posted online by the National Security Archive. The documents revealed that North and other senior officials created a privatised Contra network that attracted drug traffickers looking for cover for their operations. The officials then turned a blind eye to reports of drug smuggling related to the Contras, and actively worked with known drug smugglers to assist the Contras, the documents said.

Since the Nicaraguan Contras case, leaders have continued to struggle to stop drug-trafficking and cartels. In fact, three former presidents from Latin America have called the war on drugs a failure. In a 2009 opinion piece for the Wall Street Journal, they urge a different approach. The former presidents are Fernando Henrique Cardoso of Brazil, Cesar Gaviria of Colombia, and Ernesto Zedillo of Mexico.

Violence and organised crime associated with the narcotics trade is a serious problem in Latin America, the world's largest exporter of cocaine and marijuana, the leaders point out. Latin American countries are also becoming a major supplier of opium and heroin despite years of anti-drug efforts.

The former presidents suggested that drug policies focus on reducing harm caused by drugs, decreasing consumption through education and combatting organised crime. They said drug addicts should not be treated as criminals but as patients, to be cared for by the public health system.

What cocaine does to you

Cocaine stimulates the brain, making users feel 'high'. It works by changing the flow of dopamine, a chemical messenger in the brain associated with pleasure and movement. The build-up of dopamine makes cocaine users feel happy and excited.

Physically, cocaine use constricts blood vessels, dilates the pupils and increases the body temperature, heart rate and blood pressure.

When taken repeatedly at high doses, cocaine will make the user irritable, restless and paranoid. Drug users may lose touch with reality and hear things that are not there.

Cocaine use can alter heart rhythm and cause heart attacks, chest pain, respiratory failure, strokes, seizures, headaches, stomach pain and nausea. Many users are malnourished because the drug suppresses appetite.

Mixing cocaine with alcohol or with other drugs is extremely dangerous.

When cocaine and alcohol are combined, the liver produces a chemical called cocaethylene. It acts as a stimulant, but it also increases the risk of sudden death.

The mixture of cocaine and heroin, called speedball, has killed many entertainers. Combining the two - one a stimulant and the other a depressant - will cause uncontrolled and unco-ordinated motor skills. Because the effects of cocaine wear off far more quickly than heroin, respiratory depression - or lack of oxygen due to breathing problems - can occur and potentially kill a person.

The News

Largest-ever drug bust

Police seized 567kg of cocaine last month while investigating a recycling site in Tuen Mun, arresting five men and three women for suspected drug trafficking. The cocaine seizure is the largest ever in the city, worth HK$600 million.

Among the arrested were a Chinese man and his Colombian wife from Mexico, who were accused of using their infant son to help disguise the drug operations. The two-year-old was sent to a local orphanage, and Mexican diplomats say 'all the necessary steps' will be taken to ensure the child's safety after he returns to his hometown.

Acting on a tip-off, officers raided the 10,000 sq ft warehouse in the village at around 3.30am on September 16. The suspects were carrying bricks of cocaine in several suitcases and handbags. The drugs were stored in 1,241 containers designed for automatic transmission fluid for cars.

More than 100 narcotics officers sifted through recycled plastic containers used to conceal the drugs in the village of Fuk Hang Tsuen.

So far, 567kg of cocaine has been seized, including about 50kg found in four flats in Kwai Tsing and Mong Kok. Authorities believe the warehouse was the main storage centre for six months.

'We believe we have successfully neutralised the multinational syndicate,' said John Paul Ribeiro, chief superintendent of the bureau. He said the syndicate had been in contact with local dealers, but he believed only a small portion of the haul was sold locally.

'We can't rule out the drug would be sold to the mainland and other countries,' he added, when asked if the city was a major drug-trafficking hub.

The drug is believed to have come into Hong Kong by sea - usually from South American countries, such as Colombia, Peru and Bolivia.

This is an edited version of a South China Morning Post article by Joyce Ng which appeared on September 19

Cocaine abuse among HK youth on the rise

More people are using cocaine in the city because it's cheaper and easier to get, says the Action Committee Against Narcotics, which advises the government. The number of cocaine users in Hong Kong was rising along with an increase in supply, said Pong Oi-lan, chairwoman of a sub-committee in the narcotics advisory body.

In 2009, 4 per cent of new drug users had taken cocaine. In the first half of this year, that figure was up to 11per cent. Years ago, cocaine cost more and attracted only middle-class users on bigger salaries, Pong said, but now the drug is gaining popularity among youngsters seeking alternatives to ketamine.

Wilson Chan, of the Hong Kong Federation of Youth Groups, agrees that cocaine has become more popular among youths. 'Cocaine used to cost more than HK$1,000 per gram, but now it costs only around HK$300 to HK$400. Young people think it is a privilege to be able to afford cocaine, which offers more 'excitement' than ketamine.'

Police find it more difficult to track young drug users now, Chan said. Discos, clubs and stairwells in public housing estates used to be popular spots for youths to take drugs, but the police tightened surveillance in these places and drug users moved to motels and industrial buildings, he said.

This is an edited version of a South China Morning Post article by Dennis Chong which appeared on September 18