Here’s some election news that’s not about Brexit, public services or strong and stable government: the Liberal Democrats have pledged a regulated cannabis market. Over 18s will be able to purchase small amounts of it as a recreational drug, like alcohol.

They argue it will undercut criminal activity and raise £1 billion a year for the exchequer. Some even argue that cannabis is less harmful than alcohol. Right or wrong, they are raising an important question about which drugs should be regulated for recreational use. But it leaves untouched the other side of the coin: which drugs should be regulated for non-recreational use?

There are Class A recreational drugs with a therapeutic potential for the most harrowing mental illnesses. My own brother has a prescription for what is technically a Class B drug to help him concentrate at school. And trendy Silicon Valley entrepreneurs are already experimenting with a whole new genre of substances, supposedly upgrading their intelligence and creativity. These are each very different forms of drug use. All three of them have provoked controversy. Are they a harmless means of medication and self-improvement? Or do they represent a slippery slope towards something darker?

Take the Class A drug, MDMA. Used recreationally, it is known as ‘ecstasy’. Used therapeutically, it might just be a breakthrough treatment for Post-Traumatic Stress Disorder (PTSD). The flashbacks it created by PTSD can be so lucid that sufferers feel as though they are literally reliving the trauma. I have never met anyone who suffers them, but I do remember a disturbing conversation with a psychiatrist who tried to treat them. One of the patients he worked with was a victim of the 7/7 bombings.

“If they have hidden dangers, we need to understand them before they reach the shelves. By then, it will already too late.”

She could not distinguish what was real from what was in her head. At times, she was convinced that she was still in the moments immediately after the explosion, and her psychiatric therapy was just an illusion. Even though the explosion was just a flashback, the experience was somehow more ‘real’ to her. “Taxing on the soul” was how he described his work. ‘Curing’ patients is regarded as rare: in most cases, the best you can hope for is to limit their suffering. Enter MDMA.

Recreational users chase the ‘ecstasy’ kick: the euphoria and the elation. For PTSD patients, the aim is to review their flashbacks whilst blocking the overwhelming emotional overload which shuts down the normal process of memory storage. Theoretically, their flashbacks can then be tamed and become normal memories. Theoretically, that is, because of the difficulties experimenters originally had in actually getting their hands on drug samples for clinical trials.

MDMA is a potentially lethal ‘Class A’ drug; applications for clinical trials had to convincingly separate its constructive therapeutic use from its dangerous recreational abuse. They were eventually approved, and are now showing promising results. But the initial inertia is arguably quite surprising. Morphine is basically the chemical cousin of heroine, but no-one would argue that it should therefore not be used. Why was it so difficult to apply the same logic to MDMA?

I would be kidding you if I pretended I was a history student who just happened to have a deep knowledge of the politics of clinical research applications. But deliberately interfering with the mind always seems to make people uneasy. A few years ago, my brother was diagnosed with something called Attention Deficit Hyperactivity Disorder (ADHD), which makes you more restless, impulsive and easily distracted than most people. Ritalin, a Class B drug, is often prescribed to temporarily suppress those traits and help concentration at school. At least, that’s how I would choose to describe it.

“For some, there might be something sinister in the principle of giving children drugs to alter their behaviour.”

Others prefer a very different vocabulary. I remember once being asked incredulously “so, you’re like, sedating these kids?” That may have been an understandable reaction given how Ritalin’s effects were exaggerated in the media. But as tempting as it is to use dramatic words like ‘tranquilise’ or ‘pacify’, its prescription format does not turn children into zombies. Nor does it upgrade them into a super-human, in the way a special item levels-up a video game character. It is disappointingly mundane, I’m afraid. The effects are so subtle that I normally can’t tell when my brother is on it. But there was a deeper unease here.

For some, there might be something sinister in the principle of giving children drugs to alter their behaviour, however mildly. As long as that unease lingers, fairly or unfairly, the question of non-recreational drug use will remain unresolved. This will become an issue soon, when drugs promising similar effects to Ritalin, marketed at people without any behavioural disorders whatsoever, hit the market.

These have been nicknamed ‘nootropics’. The hype would have you believe they are like the mushrooms from Mario, suddenly boosting your abilities in problem solving, creativity and even general intelligence. Imagine protein shakes, but for the brain. Silicon Valley entrepreneurs like to think they can induce the next ‘Eureka!’ moment and keep themselves ahead of the competitioan. The ultimate goal, according to the nootropic developer, Eric Matzner, is to create “a smarter, better populace to solve all the problems we have created.” It’s a noble purpose for drug consumption if there ever was one.

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But there is a lack of data available detailing their long term effects, and there is uncertainty as to the impact on young, developing brains. Pressure to attain the perfect body has already led to enough dangerous experimentation with steroids and weight loss pills. It’s far from inconceivable for any of us that similar risks wouldn’t be taken in pursuit of the perfect grades. Only three months ago, Oxford’s Student Union started setting up workshops for “exploring the reasons why people might take smart drugs, and suggesting safe and sustainable solutions.”

Understanding the risks involved in this kind of drug use is a task which needs to be taken seriously, as is exploring the potential rewards. The Liberal Democrats have opened a debate on which drugs should be regulated for recreational uses. The next step is working out which drugs should be regulated for non-recreational uses. If they have hidden dangers, we need to understand them before they reach the shelves. By then, it will already too late