My question:

What are some real word diseases, disorders, drugs, effects, etc. that interfere with a person's thinking-ability (but do not cause blackout)? I am creating a magic system in which I want to create spells that interfere with another person's ability to think clearly. These spells should mimic real world sources of mental impairment. Which is why I have tagged this question as science based.

Some off-the-top-of-my-head examples of inducing mental impairment are nausea from spinning, or poor perception from alcohol poisoning. I am not looking for an exhaustive list of things that can interfere with thinking, but a few examples of chemically induced mental impairment, and a few examples of disease induced mental impairment.

Background of my magic system as extra information:

This is extra information so you can understand why I want to interfere with someone's ability to think.

The magic system I am creating uses willpower, imagination to power spells. So far I have come up with certain abilities; like you can heal wounds, diseases, and regrow limbs if you have a thorough understanding of how the muscles and bones are structured and how a disease works, but not if you don't. So a person's ability to think critically is crucial.

You can also “enchant” things such as shields by willing them to be much more resistant to certain things like fire, but that requires a mixture of a certain magical paste infused with an item related to your desired enchantment, or knowledge of how to restructure the shield's properties. Willing is focusing your attention and imagination onto something, and changing it methodically. Your willpower is based on your upbringing, education and discipline.

So I imagine a scenario where spellcasters battling each other hurl mind altering hexes at each other to disrupt each other's ability to focus, concentrate, remember details, etc.

  • 1
    $\begingroup$ The range of things that impair thinking is immense. Acquired and congenital, toxins, infections, trauma, deficiencies. Diseases including seizures, dementia, strokes, and illnesses of other parts of the body which impair thinking because you are sick. The scope of your request needs to be narrower. $\endgroup$
    – Willk
    Nov 12, 2018 at 1:55

3 Answers 3


You could just plainly give them head trauma one mind effectively punches another's as concussions limit your ability depending on how severe it is. You can find it hard to track moving objects, think beyond simple terms, hearing can be impaired to the point a person must talk very slowly and you still take forever to unwind the words they said (because it come into your head backwards) and then piece what they said into some jumbled not quite sure thing, speaking can be impaired, ect.

You could also just go hyper imagination as well. If a person has too much going on they can do one off super powerful things or it could fail because they're to squirrel brained to keep their attention long finding it boring mid process, ect.

As far as drugs are concerned you could do drugs or gas products or just make it up. Laughing gas distorts your ability to reason amongst other things. But I could force your mind to produce its own internal ill effects too. We know drugs target spaces in the brain to cause issues so really you don't need drugs you need the mage whose harming the other to pick a hormone and amplify it to achieve an imbalanced state this causes the victim to hallucinate or degenerate in other ways.

If creativity and imagination is apart of the process starving them of the ability can take out their potency like lack of nutrients limits the 3rd eye harming creativity and vision so does a state of depression or deprivation of stimulus. trapped in a room with your own mind (no one to talk to or those who are there ignore and/or neglect you) can only help you for so long eventually you spool through all your inner creativity and have no new stimulus to use as an imagination restore.

EMF waves for those who are sensitive to them cause issues with the mind for concentration, create sickness, headaches, dizziness, ect. Don't forget the squawk box was also similar in low vibrations making someone ill but in higher notes caused death. In this case it changes in waves and vibrations.

Another thing for the sensative that causes disruption you may not think of would be grouping select stones together and pointing them at someone (stick them on a wand) it changes energies and can harm the person as they are giving off vibrations and in select forms create waves unpleasant to the body sickness or pain can occur.

You just want to look at things that are disruptive to the human senses or physical energy not just diseases and mental injury.


Hydrocephalus. The brain needs to drain fluids on a regular basis. If the ventricular system is blocked, the brain will lose function over time. This is a real-life disease that usually affects infants. Sometimes there is so much extra fluid that their skulls swell.

A friend of mine has it and the solution is artificial shunts. I saw what happened to her when her shunt needed replacing (as they do every few decades) and her insurance company delayed the surgery. All the problems you're looking for. Trouble with details and memory plus headaches of course.

It took a few weeks for the fluid to build up so she stopped working, then driving, and was starting to have trouble walking and using her muscles. Thankfully, the approval came through, she had the surgery, and all the symptoms went away. After a while, stuff like this can be permanent.

In your case, you can make the fluid buildup happen a lot faster by moving fluids in unnatural ways. You won't have to wait weeks as the brain tries and fails to move out fluid it no longer needs.

Interfere with their detoxification systems. This is chemical sensitivity and one of the common systems is brain fog. Yes, that's a technical term. Overlaps with fibromyalgia (sometimes called "fibro-fog") and Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Any "everyday" exposures to toxins (both human-made and natural) will act as if they were exposed to huge amounts. This includes things like making alcohol and drugs much more potent.

Interfere with their sleep. You don't say if you want the effects to be immediate or not (just that they hurl hexes at each other). If not, then you can mess up their actual sleep. If you want immediate effects, then change brain waves such that they are in a light sleep state, but still awake. This will really mess up their thinking.

I don't know how the brain knows that the body got enough sleep the night before...are there markers to mess with? Is it related to HGH/IGF-1 levels? I'm not sure. But that might be fertile ground to work with.

Human Growth Hormone. Keeping someone's body from producing growth hormone (which happens during sleep) will make them tired and spacey and make it hard to focus on anything. But you won't see symptoms for a few days to weeks.

Pain. Being in pain makes it pretty much impossible to focus on things and it leads to actual (temporary) mental impairment (lots of studies about that). Pain has a lot of components and you can have non-traditional pain that gives you side effects but maybe doesn't feel like pain (sorry to be vague...my college neurology class on this topic was too long ago to remember details).


Thiamin deficiency.

Thiamin is B1. It can cause all sorts of mental problems. I have seen in in animals but not in humans - but humans do get it!.

It makes them act very weird. it can cause delirium, hallucinations, memory loss, confusion etc. It can be caused primarily by bad diet or alcoholism, but also has some other causes.

As a sidenote, experiencing some of these symptoms in a very mild way, from mild thiamin deficiency can also cause depression. so eat well folks - eat your greens and real good fresh healthy foods eh!

Heres more than enough info on thiamin deficiancy:



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