Cannabis triggers paranoid thinking

Article: Cannabis really can trigger paranoia

Wow. Well-written, with all parts well explained. Terms defined as well:

“Paranoid” in this context means the unfounded or excessive fear that other people are trying to harm us.

The authors note that in any given month, half of people have paranoid thoughts, so they are not talking about full-blown mental illness. Just something that is common, although it exists on a spectrum from mild to severe.

To discover whether cannabis really does cause paranoia in vulnerable individuals, we carried out the largest ever study of the effects of THC (∆9-tetrahydrocannabinol, the drug’s principal psychoactive ingredient). We recruited 121 volunteers, all of whom had taken cannabis at least once before, and all of whom reported having experienced paranoid thoughts in the previous month (which is typical of half the population). None had been diagnosed with a mental illness. The volunteers were randomly chosen to receive an intravenous 1.5mg dose of either THC (the equivalent of a strong joint) or a placebo (saline).

So the researchers deliberately chose people who had already had paranoid thoughts. This makes sense.

Like most psychological experiences, there is a spectrum of paranoia within the population: many people have a few, relatively mild paranoid thoughts, while for a few people those thoughts are numerous, persistent, and profoundly unsettling. Cannabis users are more likely to be at the problematic end of that spectrum.

Still, is this cause or effect? Correlation does not equal causation. The authors go on to show that cannibis does cause paranoid thinking in susceptible persons.

Experts generally agree that regular use of cannabis starting from an early age is an accurate predictor of later severe mental health problems, but what hasn’t been established is whether the drug causes paranoid thoughts. Maybe people suffering from paranoia are more likely to start taking cannabis; or perhaps the drug use and the suspicious thoughts are independent consequences of another factor entirely.

Excellent analysis. The authors do not fall into the "correlation does not equal causation" trap.

This does point towards possible, future experiments. There are known, genetic risk factors for schizophrenia (one of the "severe mental health problems" noted above). There must be some brain chemistry involved in both the regular use of (that is, need for) pot and mental problems.

THC also produced other unsettling psychological effects, such as anxiety, worry, lowered mood, and negative thoughts about the self. Short-term memory was impaired. And the THC sparked a range of what psychologists call “anomalous experiences”: sounds seemed louder than usual and colours brighter; thoughts appeared to echo in the individuals’ minds; and time seemed to be distorted.

THC is a psychoactive drug. Of course it is going to have pyschological side effects.

Why is cannabis such a potent trigger for paranoia? Our statistical analysis showed that in our experiment the culprits were THC’s negative effects on the individual’s mood and view of the self, and the anomalous sensory experiences it can produce. Negative emotions leave us feeling down and vulnerable. Worry leads us to the worst conclusions. So when we try to make sense of the anomalous experiences – when we try, in other words, to understand what’s happening to us – the world can appear a weird, frightening and hostile place. Hence the paranoia.  

Perhaps most importantly, the research shines a light on the psychological processes underlying paranoia in general. When we worry, think negatively about ourselves and experience perceptual disturbances, it’s much more likely that we will feel needlessly suspicious of others.

"Psychological effects such as anxiety, worry, lowered mood, and negative thoughts about the self." I would think that further study would show that people who already have this as a problem would have them make worse by pot use. This is probably why "cannabis users are more likely to be at the problematic end of [the] spectrum."

Placebo effect: Gotta love the placebo effect: "Interestingly, the placebo produced extraordinary effects in certain individuals. They were convinced they were stoned, and acted accordingly. Because at the time we didn’t know who had been given the drug, we assumed they were high too."

As a political aside, let us perform a thought experiment. A psychoactive drug is brought to the market (an Ambien or a Zoloft). It is found to be associated with paranoid thinking, intoxication when used normally, and have a wide-spread, illegal-usage associated with "severe mental health problems." Would it continued to be used? Or would it be pulled from the shelves and its manufacturers sued into oblivion?