THC and Psychotic Symptoms in the Young

Good day to all of you in marijuana world-

Dr. Lee here with a new blog post about marijuana and psychosis! Marijuana usage is in-fact related to the development of acute psychotic symptoms (like auditory hallucinations), and is also implicated in long-term psychiatric illness. This risk seems to be particularly potent for young people (especially those aged 13-18).

I have actually had a few patients come to me to share this experience! A few young guys have developed auditory hallucinations, and they can usually identify a big exposure. These high-THC exposures can be dabbing, or they can be occupational- one young man described being exposed by an industrial oven filled with marijuana that was scorched and smoking.

I decided to write a blog post about it. This information is particularly important for other providers, who may be certifying patients for marijuana. With all medications, it’s best to share the downsides and limitations. Marijuana is no exception!


Why does this matter? 

Because we need to protect the kids!

Marijuana is becoming increasingly available, and increasingly accepted both recreationally as a treatment for medical conditions. We also know that marijuana usage in adolescence in increasing as availability increases! We already know that the onset of psychotic illness is generally in adolescence- it differs by gender, but in general psychotic illnesses like schizophrenia debut in the patients’ teens to early 20s. Psychotic illnesses are many in number and vary, but common symptoms include hallucinations or paranoia.

The age range of 12-18 is crucial for psychiatric development, and we know that brain structures (famously the frontal lobe) continue to develop into the early 20s. Marijuana exposure changes your risk of psychotic illness during this crucial period! We don’t really know why yet, but the human neurological system does have plenty of endocannabinoid receptors. These endocannabanoid receptors are well characterized and distributed on a bunch of organs, and present as early as 18 weeks of gestation. It’s not that much of a stretch to expect THC to play a role in brain development.

It also seems like outcomes for patients that start marijuana use as adolescents are worse than those that start marijuana use at a later age- peep this study from 2012 (1): it describes long-term neurological and psychiatric outcomes on daily marijuana users. It notes that marijuana users that started frequent use in adolescence expressed worse outcomes.

“Impairment was concentrated among adolescent-onset cannabis users, with more persistent use associated with greater decline. Further, cessation of cannabis use did not fully restore neuropsychological functioning among adolescent-onset cannabis users. Findings are suggestive of a neurotoxic effect of cannabis on the adolescent brain and highlight the importance of prevention and policy efforts targeting adolescents.”


What’s the evidence?

I would describe the evidence on this topic as robust. To summarize, we’ve known that cannabis has a weird link to psychotic illness for a long time. Observationally, at least for several decades. But, patients with psychiatric illness always use more substances, so causation has been a bit more difficult.

Here’s an example of an early study, published in Lancet in 2007 showed that marijuana use during adolescence increased lifetime incidence of psychiatric illness (2). It’s findings, summarized, state that:

“There was an increased risk of any psychotic outcome in individuals who had ever used cannabis (pooled adjusted odds ratio=1.41, 95% CI 1.20-1.65). Findings were consistent with a dose-response effect, with greater risk in people who used cannabis most frequently (2.09, 1.54-2.84).”

I think this study is interesting because it notes that it’s dose-dependent- the more you smoke, the more risk of psychotic illness you have! Again, it shows that using marijuana as a youth has long-lasting consequences- it increases your risk of developing psychiatric illness lifelong!

More recently, a study performed by Pittsburgh public schools and published in 2016 showed that utilizing marijuana between the ages of 13-18 resulted in the increased incidence of subclinical psychotic symptoms, described here as auditory hallucinations and paranoia (3). Personally, there’s auditory hallucinations don’t seem super ‘subclinical’ but that’s semantics. Here’s a startling quote:

“For each year adolescents engaged in regular marijuana use, their expected level of subsequent subclinical psychotic symptoms rose by 21% (p <.05)”

I note that this study was performed prospectively, and followed the same group of American students for six years. It’s a rather high-quality study and at this point I think it’s pretty clear that marijuana use during adolescence should be discouraged. We have all the evidence we need!


Now I heard that them there Dabs might be involved…

We really don’t know why THC is associated with psychotic symptoms, but there are some patterns. (I actually had a whole section about the reasons why but I figured that ‘hypothalamic neuroplasticity’ wasn’t a super relatable topic). High THC products like dabs seem to be particularly implicated in the onset of psychotic symptoms! Isn’t that funny to think about! These products are definitely aimed at the young, and are potentially hazardous to their health in particular.

THC percentages in products just keep going up and up, and these high THC products are definitely more likely to cause a psychotic episode than normal marijuana use. This case report is great, and easy to read (4). It describes a patient that dabbed, had auditory hallucinations, and then had ongoing hallucinations for several years! 


Clinical Implications- WHAT’S NEXT?!

Anyone with a pre-existing disposition to psychotic illness (Family history, pre-existing psychiatric illness) needs to be counseled on the potential for psychotic illnesses. Youths using marijuana need to be counseled on the potential to develop these symptoms, and what to do if they develop them. They should immediately stop using marijuana, and start taking a low dose antipsychotic medication until all of their symptoms abate.

Also…Personally I feel that dabs and (really all concentrates that you need a crack pipe to smoke) are less than medical, and this is just further evidence for me that providers should probably be actively counseling against them.


Dr. Lee



  1. Meier MH, Caspi A, Ambler A, et al. Persistent cannabis users show neuropsychological decline from childhood to midlife. Proc Natl Acad Sci U S A. 2012;109(40):E2657-E2664. doi:10.1073/pnas.1206820109
  2. Moore TH, Zammit S, Lingford-Hughes A, Barnes TR, Jones PB, Burke M, Lewis G. Cannabis use and risk of psychotic or affective mental health outcomes: a systematic review. Lancet. 2007 Jul 28;370(9584):319-28. doi: 10.1016/S0140-6736(07)61162-3. PMID: 17662880.