What schedule should marijuana be classified?

In many cases, snake venoms are also used as medicine. Many items used in our daily life can be fatal if taken in overdose.
So, in this case too there is no difficulty or panic in using marijuana as a narcotic drug if it (the patient's dose) is maintained properly.

Europe

High potential for abuse and severe psychological or physical dependence

As per any herbal product there are concerns about variability of the product of natural origin and therefore any medical use should be restricted to the well-standardized extracts, possibly pure components only. As any psychoactive substance including alcohol it should be treated with utmost care and with an assumption of high potential of dependence and possibility of abuse. There should labels issuing warnings against driving a car and operating machines after the use. Ban on use for children, pregnant women etc.

There is a wealth of scientific evidence demonstrating that THC in marijuana, in isolation, is not inherently capable of inducing chemical dependence or drug abuse. However, from a neurological perspective, any form of rewarding stimulus prompts our brain to develop a dependency. Much like how an individual can become addicted to chocolate, sex, shopping, or extreme sports, for instance, the pleasurable sensation offered by the use of marijuana can lead to dependence and substance abuse.

Concurrently, caution should be exercised in the use of this substance due to substantial evidence indicating an increased incidence of schizophrenia and manic psychosis in individuals who regularly partake in marijuana consumption.

The potential for abuse is low but it should not be available without prescription to avoid excessive exposures and thus related risks!