<p>I discovered a study relating to a <strong>longitudinal study</strong> of a cohort of 45 570 Swedish conscripts covering a 15 year difference in between the first testing of and after. They covered the Swedish conscripts who had taken cannabis ( Who used cannabis on more than '50 occasions' )  and the others who haven't and came to the conclusion that the subjects that taken cannabis had a higher likelihood of developing schizophrenic symptoms than their counterparts. In their own words,</p>
<blockquote>
<p>&quot;Persistence of the association after allowance for other psychiatric
illness and social background indicated that cannabis is an
independent risk factor for schizophrenia&quot;</p>
</blockquote>
<p>The study is here: <a href="https://www.sciencedirect.com/science/article/abs/pii/S0140673687926201" rel="nofollow noreferrer">https://www.sciencedirect.com/science/article/abs/pii/S0140673687926201</a></p>

CC BY-SA 4.0
2022-07-29T21:56:32.970Z
2022-07-29T21:58:17.283Z
2022-07-29T21:58:17.283Z
chipotlechumdum
<p>I've heard that cannabis exposure during teenage years increases the probability of developing schizophrenia-like symptoms later in life. What evidence is there that this is causal and not correlational?</p>

<p>Current references I'm reading and will try to form into an answer:</p>

<ul>
<li><a href="https://www.ncbi.nlm.nih.gov/m/pubmed/26733534/" rel="nofollow noreferrer">https://www.ncbi.nlm.nih.gov/m/pubmed/26733534/</a></li>
<li><a href="https://www.ncbi.nlm.nih.gov/m/pubmed/28392208/" rel="nofollow noreferrer">https://www.ncbi.nlm.nih.gov/m/pubmed/28392208/</a></li>
<li><a href="https://www.ncbi.nlm.nih.gov/m/pubmed/28285022/" rel="nofollow noreferrer">https://www.ncbi.nlm.nih.gov/m/pubmed/28285022/</a></li>
<li><a href="https://www.ncbi.nlm.nih.gov/m/pubmed/28443616/" rel="nofollow noreferrer">https://www.ncbi.nlm.nih.gov/m/pubmed/28443616/</a></li>
</ul>

CC BY-SA 3.0
2017-06-27T09:42:16.077Z
A couple of things: 1) Psychotic patients make more use of cannabis than non-psychotic patients 2) people who consume cannabis between 15-18 are more likely to display psychotic symptoms at 26 3) relevant paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2864503/
Ebbinghaus
CC BY-SA 3.0
2017-07-10T17:18:15.793Z
1. your best bet would be twin studies (concordance rate between MZ and DZ twins with/without cannabis exposure. 2. since i last checked, there is at least one study with evidence that cannabis has anti-psychotic properties in a group of treatment refractory individuals with schizophrenia. 3. you should clarify your term "schizophrenia-like" -- do you also consider schizotypy to fit this criterion.
faustus
<abnormal-psychology><psychopharmacology>
Evidence of cannabis exposure causing schizophrenia?
Seanny123
# Evidence of cannabis exposure causing schizophrenia?

(Asked by: username_0 on 2017-06-23)

I've heard that cannabis exposure during teenage years increases the probability of developing schizophrenia-like symptoms later in life. What evidence is there that this is causal and not correlational?

Current references I'm reading and will try to form into an answer:

* <https://www.ncbi.nlm.nih.gov/m/pubmed/26733534/>
* <https://www.ncbi.nlm.nih.gov/m/pubmed/28392208/>
* <https://www.ncbi.nlm.nih.gov/m/pubmed/28285022/>
* <https://www.ncbi.nlm.nih.gov/m/pubmed/28443616/>

**Tags:** abnormal-psychology, psychopharmacology

> **Comments:**
> **username_1**: A couple of things: 1) Psychotic patients make more use of cannabis than non-psychotic patients 2) people who consume cannabis between 15-18 are more likely to display psychotic symptoms at 26 3) relevant paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2864503/  
> **username_2**: 1. your best bet would be twin studies (concordance rate between MZ and DZ twins with/without cannabis exposure. 2. since i last checked, there is at least one study with evidence that cannabis has anti-psychotic properties in a group of treatment refractory individuals with schizophrenia. 3. you should clarify your term "schizophrenia-like" -- do you also consider schizotypy to fit this criterion.  

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## 1 answers

### Answer by username_3 on 2022-07-29. Score: 2

I discovered a study relating to a **longitudinal study** of a cohort of 45 570 Swedish conscripts covering a 15 year difference in between the first testing of and after. They covered the Swedish conscripts who had taken cannabis ( Who used cannabis on more than '50 occasions' ) and the others who haven't and came to the conclusion that the subjects that taken cannabis had a higher likelihood of developing schizophrenic symptoms than their counterparts. In their own words,

> "Persistence of the association after allowance for other psychiatric
> illness and social background indicated that cannabis is an
> independent risk factor for schizophrenia"

The study is here: <https://www.sciencedirect.com/science/article/abs/pii/S0140673687926201>


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