Now that the festive season is in full swing, many West Australians will look for ways to let their hair down and celebrate the end of the year. 
Most will be satisfied with indulging in a wine or two at the annual office Christmas party, or hitting a post-exam shindig, but others will look for a bigger high.
Last year, the United Nations World Drug Report listed Australia as having the highest proportion of recreational drug users in the world, with numbers continuing to rise at a steady rate.
For many years, health workers have had their hands full dealing with the fallout of problems caused by established illicit drugs such as methamphetamine, cocaine and ecstasy.
Methamphetamine in particular has been in the spotlight for several years, with health workers and authorities reporting its use at an all-time high and families being forced to cope with the never-ending effects that present when a loved one becomes addicted.
And the serious health risks associated with ecstasy use have also received plenty of attention because of a recent spate of deaths at music festivals around the country.
The State Government has responded to the increasing use of established illicit drugs by implementing a range of educational and treatment programs and upgrading facilities.
But a new class of recreational drugs is now causing added concern for health professionals, policy makers and parents.
And with different varieties of these new compounds, known as synthetic drugs or new psychoactive substances constantly hitting the streets, experts say WA's illicit drug problem seems more difficult than ever to contain.
According to the Australian Drug Foundation, new psychoactive substances (NPS) are a range of drugs that have been designed to mimic illicit drugs such as cannabis, cocaine, ecstasy and LSD.
"Manufacturers of these drugs develop new chemicals to replace those that are banned, which means that the chemical structures of the drugs are constantly changing to try to stay ahead of the law," the foundation's national policy manager, Geoff Munro, said.
 "New psychoactive substances are being developed at an unprecedented rate."
The European Monitoring Centre for Drugs and Drug Addiction and Europol monitor more than 450 NPS, which is close to double the number of substances controlled under the UN international drug- control conventions. More than half of these have been reported in the past three years.
A spokesperson for the WA Mental Health Commission said synthetic drugs caused a wide range of adverse short- term health effects and there was concern because not enough was known about the long-term effects.
"New psychoactive substances, also known as synthetic drugs, can pose serious health risks with potentially harmful side- effects," the spokesperson said.
"Because these substances are new, there is little known about long-term health effects. It is important to understand that in some cases, these substances were developed for research purposes and abandoned for their unwanted side-effects and health harms."
In   May, WA mental health minister Helen Morton announced new legislation to help clamp down on the promotion, sale and supply of new synthetic drugs.
"People manufacturing these drugs have continued to introduce new chemical derivatives of substances which have been banned resulting in governments around the world having to catch up using existing legislation," Mrs Morton said.
"These drugs can cause serious health problems including tremors, chest pains, increased heart rate and blood pressure, seizures and an altered mental state.
"We've been proactive by banning a number of these specific substances already, however, the new legislation further strengthens our response and helps remove extremely dangerous substances from circulation."
Mr Munro said NPS or synthetic drugs had a range of street names including legal highs, herbal highs, party pills, synthetic cocaine, synthetic cannabis, herbal ecstasy, bath salts, plant fertiliser, herbal incense, room deodoriser, social tonics, NEDs and research chemicals.
He said one of the biggest misconceptions about NPS was that they were safer than other recreational drugs, and people probably got that idea because NPS were sometimes advertised or promoted as being legal.
"Given how rapidly new drugs are emerging, it is difficult to know the common effects of these drugs and what dose causes what effects," he said.
"NPS do not typically come with a recommended dosage printed on the label. 
"They are unregulated and untested. Given the chemicals in these drugs are constantly changing to try to stay ahead of the law, it's possible to receive a very different product from batch to batch, even if the packaging and name are the same.
"NPS are relatively new, so there is limited information available about their short and long-term effects.
 "However, synthetic cannabis has been reported to have more serious side-effects than cannabis."
'Given how rapidly new drugs are emerging, it is difficult to know the common effects of these drugs and what dose causes what effects.'
Geoff Munro 
Common side-effects of synthetic drugs include aggressive behaviour, anxiety, confusion, dehydration and overheating, dizziness and headaches, increased alertness, increased energy, insomnia, involuntary jaw clenching and teeth grinding, psychosis, rapid or irregular heartbeat, stomach pains, nausea, twitches, tremors and visual distortions.
Regular use can lead to tolerance and dependence.