THC and paranoia

Paranoia. It is that term you often heard associated with smoking weed all your life, and perhaps have even experienced it. A study in 2014 set out to find out if THC is the cause of paranoia, as well as if THC could help identify the mechanisms that contribute to paranoia. 121 participants ages 21 to 50, with paranoid ideation received a placebo, THC, or THC preceded by a cognitive awareness explanation, in which participants were educated about possible effects prior to administration (Antley et al., 2014).

Paranoia in this study was defined as the individual experiencing an anomalous internal state, which includes changes in sensory intensity, distorted sensory, thought echo and hallucinations. One of the major factors in paranoia was a negative affective state, which is believed to underscore their belief of harm, fear, jumping to conclusions and delusion (Antley et al.).

A psychiatrist, blind to the treatments analyzed the participants and injected either THC or a placebo intravenously. The cognitive awareness condition group also received a 5-minute educational explanation of the effects of THC. Paranoia was then assessed by survey that compared baseline paranoia with scores after receiving injection, as well as a walk around a virtual reality testing room, which they were exposed to a virtual reality social environment.

Results from this study showed that THC significantly increases paranoia, and that previous explanation of the effects did not necessarily decrease feelings of paranoia. Previous cannabis use did not seem to affect the results. Although THC did lead to increased paranoia, this effect seemed to be mediated by simply reducing negative emotion associated with the paranoia. Although changes in working memory were detected, this did not seem to be responsible for paranoia occurring.

Interestingly, although the group that was made aware of THC paranoia did not experience statistically significant decrease in paranoia and many displayed an increased sensitivity to paranoid thoughts, and were even aware that this was due to cannabis.

Although THC does seem to explicitly increase feelings of paranoia, with or without explanation of the fact that it will do so, having a positive nature, and being exposed to more positive experiences may tone this down. There is also evidence mounting that CBD, THC’S non-psychoactive counterpart can do a lot to counter effect feelings of paranoia, should this get too intense for the THC user.


Antley, A., Brenneisen, R., Cornish, R., Cowen, P., Dunn, G., Di Simplicio, M., Freeman, D., Harmer, C.J., Harrison, P.J., Godlewska, B., Igoumenou, A., Lister, R., Murray, R.M., Morrison, P.D., Slater, M., Turnbridge, E.M., Williams, J., 2014. How cannabis causes paranoia: using the intravenous administration of THC to identify key cognitive mechanisms leading to paranoia. Schizophr Bull, (2015) 41 (2): 391-399. DOI:

Erin Warwick has experimented with medicinal plants for over 20 years and is currently studying for her Master’s Degree in Herbal Therapeutics at Maryland University of Integrative Health. On top of this, she is a fitness expert and Personal Trainer who received a degree in Kinesiology from the University of Illinois. When not immersed in plant matters, she can be found running heavy-duty obstacle coarse races or hanging out with her kids and pets. She thrives to help others obtain full body, mind and spirit health and wellness, and is particularly interested in unlocking the medicinal powers of cannabis and other amazing plants.