German researchers want to give free marijuana to 25,000 stoners to study the long-term effects of getting high.
But there's a catch: participants have to be mentally sound and have no addictions. And yes, that includes an addiction to marijuana.
So it's perhaps no surprise there are few takers. Or is that tokers? So far only 2000 people have signed up.
"In Germany, several million people regularly get high with cannabis," Marko Dörre, managing director of the research initiative Cannabiskonsum, said. "It is time that science becomes more engaged with recreational use."
With the German government recently legalising marijuana for medical purposes and around 5 percent of Germans admitting to using the drug at least once a year, Mr Dörre says more needs to be known about its long-term effects.
If the study gets the green light from the authorities, participants will be provided with 30g of weed every month - slightly more than the traditional ounce, and enough for around 40 to 50 joints. They have to be over 18 and have a history of consumption - no first-timers.
"Cannabis as a drug has been largely neglected by research, with the exception of specific subgroups that are conspicuous in the health system, either by being addicted to cannabis or by a severe mental disorder," says research director Dr Thomas Schnel.
"Most consumers do not seem to develop either a dependency or a clinically relevant mental disorder, so the extent to which cannabis use is effective in these healthy consumers… should therefore be explored more intensively."
If you're in Germany and want to take part, applications are available on the Cannabiskonsum website.