Weed is great for paradoxes. It can help you contemplate whether the chicken or the age came first, whether we’re alone in the universe or surrounded by aliens, or whether that munchie craving you got is for chicken wings or gordita crunches. But weed itself has a couple of paradoxes. One of the biggest is probably: why does smoking it cause some people to get relaxed to the point of comatose and others to freak out like they belong in a psycho ward?

Luckily for us, the peeps over at VICE recently took a look at this phenomenon and compiled different experts’ theories upon it. What we found most interesting is that there seem to be several different variables that make the difference between couch potato and psychiatric ward.

The kind of weed

Any sophisticated stoner knows that different strains have different effects. So, it’s no big shock that some strains are more likely than others to bug you out. In the most simple terms, it breaks down to THC vs. CBD and sativa vs. indica. A study from Western Carolina University showed that while CBD has a calming effect on anxiety, THC can have the opposite effect and ramp up your anxiety level.

The cannabinoids in marijuana stimulate the endocannabinoid system of the body, which helps regulate our reactions to stress. THC can stimulate that system in ways which actually inhibit its ability to react calmly to stress or anxiety, which is why you might find yourself getting paranoid that the cops are following you because you see headlights a block away in your rearview. Since sativa has higher levels of THC than indica, you’ll find the freak-out reaction more common when puffing on sativa than other types of strains.

The amount

Low doses of cannabis are less likely to cause a freakout than high ones. According to Dr. Mohini Ranganathan, an assistant professor of psychiatry at Yale University, “as the dose increases, you become more and more likely to experience anxiety and panic.” This is related to the last point. If a little THC gives you a little anxiety, then a lot of THC can give you a lot of anxiety. That’s why people with low tolerances sometimes end up calling 911 after eating a high-dosage edible cookie.

The person

The biggest factor in whether weed makes an individual chill or ill may be the individual. There are many varieties of brain chemistry, and many reasons for that variety. Environmental factors like traumatic episodes or chronic stress have an impact on a person’s fear-processing system, and make them more likely to have an unpleasant reaction to cannabis.

These differences aren’t only seen from person to person, but can be seen in a single person over time. Someone who used to just chill out after a quadruple bongload might now get nervous after just a hit or two. Traumatic events can change brain chemistry, but so can aging in general. As a brain’s plasticity changes over time, so can its reaction to Gorilla Glue. Se la vie.