A new drug called kush is wreaking havoc in west Africa, particularly in Sierra Leone where it is estimated to kill around a dozen people each week and hospitalise thousands.
The drug, taken mostly by men aged 18 to 25, causes people to fall asleep while walking, to fall over, to bang their heads against hard surfaces and to walk into moving traffic.
Kush should not be confused with the drug of the same name found in the US, which is a mixture of "an ever-changing host of chemicals" sprayed on plant matter and smoked.
Kush in Sierra Leone is quite different; it is a mixture of cannabis, fentanyl, tramadol, formaldehyde and – according to some – ground down human bones.
It is mixed by local criminal gangs, but the constituent drugs have international sources, facilitated no doubt by the internet and digital communications.
While cannabis is widely grown in Sierra Leone, the fentanyl is thought to originate in clandestine laboratories in China where the drug is manufactured illegally and shipped to west Africa.
Tramadol has a similar source, namely illegal laboratories across Asia. Formaldehyde, which can cause hallucinations, is also reported in this mixture.
As for ground human bones, there is no definitive answer about whether or not they occur in the drug, where such bones would come from, or why they might be incorporated into the drug.
Some people say that grave robbers provide the bones, but there is no direct evidence of this.
But why would bones be incorporated into the drug? Some suggest that the sulphur content of the bones causes a high. Another reason might be the drug content of the bones themselves, if the deceased was a fentanyl or tramadol user.
However, both are unlikely. Sulphur levels in bones are not high. Smoking sulphur would result in highly toxic sulphur dioxide being produced and inhaled. Any drug content in bones is orders of magnitude less than that required to cause a physiological effect.
Where is the drug found?
The drug is reported in both Guinea and Liberia, which share porous land borders with Sierra Leone, making drug trafficking easy.
Kush costs around five leones (20 UK pence) per joint, which may be used by two or three people, with up to 40 joints being consumed in a day.
This represents a massive spend on drugs and illustrates the addictive nature of the mixture, in a country where the annual income per capita is around £500.
The effects of the drug vary and depend on the user and the drug content. Cannabis causes a wide variety of effects, which include euphoria, relaxation and an altered state of consciousness.
Fentanyl, an extremely potent opioid, produces euphoria and confusion and causes sleepiness among a wide range of other side-effects.
Similarly, tramadol, which is also an opioid but less potent than fentanyl (100mg tramadol has the same effect as 10mg morphine) results in users becoming sleepy and "spaced out" – disconnected from things happening around them.
The danger of the drug is twofold: the risk of self-injury to the drug taker and the highly addictive nature of the drug itself. A further problem is the need to finance the next dose, often achieved through prostitution or criminal activity.
Joining the ranks of existing polydrugs
Kush is another example of polydrug mixtures of which forensic scientists are becoming increasingly aware. Another tobacco and cannabis-based drug, nyaope, otherwise known as whoonga, is found in South Africa.
This time the tobacco and cannabis are mixed with heroin and antiretroviral drugs used to treat Aids, some of which are hallucinogenic.
A further polydrug, "white pipe", a mixture of methaqualone (Mandrax), cannabis and tobacco, is smoked in southern Africa.
These drugs are inexpensive and provide an escape from unemployment, the drudgery of poverty, sexual and physical abuse, and the effect, in some cases, especially in west Africa, from having been a child soldier.
So what can be done about these drugs? The effectiveness of legislation alone is questionable, and many of those who attend the very limited rehabilitation centres return to drug use.
Perhaps what is required is an integrated forensic healthcare system where legislative control is backed up by properly resourced rehabilitation centres coupled with a public health and employment programme. What changes are made in response to this epidemic remains to be seen.
Michael Cole, Professor of Forensic Science, Anglia Ruskin University
This article is republished from The Conversation under a Creative Commons license. Read the original article.