Cannabis users 500% more like to develop schizophrenia than someone who has never smoked it, Increased Risk from Alcohol and Other illegal Drugs Also

This is an important and large new study that again confirms the increased risk of psychosis for young people using cannabis, but also many other street drugs, including alcohol. (Note, we’ve included the full research paper at the end of this post).

As one researcher / clinician out of Harvard has noted:

Dr. Dost Öngür, chief of the Psychotic Disorders Division at Harvard-affiliated McLean Hospital, recently presented a sweeping slide-talk on complex current issues in treating psychosis, but it was one simple line of his that most stayed with me:

“I tell my students: Smoke all the pot you want — after you’re 30.”

In this new study the report:

Regular cannabis users are more than five times more likely to develop a serious mental disorder.
Cannabis creates a greater mental health risk than any other substance, including class A drugs, scientists have found.

Those who abuse the drug – now more potent than ever in the form of super-strength ‘skunk’ – are 5.2 times as likely to develop schizophrenia as someone who had never smoked it.

This compares to 1.9 times higher risk for users of hallucinogenic drugs and 1.24 times for amphetamines.

Danish researchers trawled more than 3.1 million people’s medical records to ascertain the link between cannabis use and schizophrenia.

In research presented to the International Early Psychosis Association, they suggested the pleasure hormone dopamine, released by the drug, could trigger the disorder in people susceptible to its effects.

Increased Risk of Schizophrenia from Alcohol and drugs:

  • Cannabis: 5.2 times
  • Alcohol: 3.4 times
  • Hallucinogenic drugs: 1.9 times
  • Sedatives: 1.7 times
  • Amphetamines: 1.24 times
  • Other substances: 2.8 times

In a second study they discovered that pregnant women who abused cannabis gave birth to children six times more likely to become schizophrenics. This suggests the physical effects of the drug could be passed on in the womb.

For paternal cannabis abuse, there was a 5.5 times increased risk of schizophrenia in the child whether diagnosed before or after the birth.

Maternal alcohol abuse diagnosed before the birth of the child was associated with a 5.6 times increased risk of schizophrenia in the child, but this fell to twice the risk if the diagnosis of alcohol abuse was after the birth, with a similar relationship for fathers (4.4 times increased risk with a pre-birth diagnosis versus 1.8 times for a diagnosis after the birth).

Read more:

A Good Interview with the study leader:

See the full interview at this link:

What is the background for this study? What are the main findings?

Response: Several studies have tested whether use of substances can cause schizophrenia. However due to methodological limitations in the existing literature, uncertainties still remains. We aimed to investigate the association between several types of substance abuses and the risk of developing schizophrenia later in life. We did a nationwide, prospective cohort study using the detailed Danish registers, which enabled us to address some of the limitations from prior findings. Our cohort consisted of more than 3.13 mio. individuals, that we were able to follow up for more than 104 mio. years at risk. We found that dealing with a substance abuse increased the overall risk of developing schizophrenia by 6 times, with abuse of cannabis and alcohol presenting the highest associations (5 and 3 times increased risk). The risk was found to be significant even 10-15 years prior to a diagnosis of substance abuse. What should readers take away from your report?

Response: Our findings confirm the association between abuse of cannabis and schizophrenia found in previous studies. However, we found an association between almost any type of substance abuse and the risk of developing schizophrenia, with alcohol abuse as the most surprising result, as there has not been much evidence of this before. What recommendations do you have for future research as a result of this study?

Response: I believe our findings opens up for many interesting studies regarding the association between alcohol abuse and schizophrenia. Alcohol is one of the substances most used in the world, however I believe it has not been thoroughly examined in the association with psychosis. We are currently looking at parental substance abuse and the offsprings risk of developing schizophrenia later in life.

Additional Reading:




Association-between-abuse-of-substances-and-the-risk-of-schizophrenia_2016_October.pdf (909.6 KB)


I can show you posts I made on the shroomery I made from a year ago where I said I didn’t think it was the hallucinogens that caused my sz, but rather the massive amounts of cannabis I smoked during my hallucinogenic experiences. That said there’s a million other factors too… Like alcohol users are 3x more likely to develop schizophrenia than non users (from the same study, but not included in your article) but drinking alcohol definitely played a factor in causing my sz.

I can tell you that as someone who dedicated his entire adolescence to the pursuit of the pot culture, even deciding to go to college in the mountains where the pot was the best. Marijuana had to have been responsible for me developing this illness. That’s not to say that everyone who smokes will get this but if you have any kind of vulnerability like I did, it’s a recipe for disaster.

Geez, kinda too late now :frowning:

I’m sure genetics, and stress comes into play, but Pot definitely activated this disease for me.

The only thing I got out of this article that was beneficial is that all the cocaine and stimulants that I did didn’t have any negative effect lol

1 Like

From another article

Cannabis: 5.2 times
Alcohol: 3.4 times
Hallucinogenic drugs: 1.9 times
Sedatives: 1.7 times
Amphetamines: 1.24 times
Other substances: 2.8 times.

So pretty much, the more fun you have, the more likely you are to develop sz. Us addicts have no choice.

Surprised that sedatives are higher than amphetamines??? I am!

1 Like

Can you post a link to that article? Thanks.

its called ‘‘weed’’ for a reason, it certainly isn’t a flower


I had trouble copying and pasting 2 things in one post my bad! But there it is.


GMO pot causes schizophrenia huh?? I’m not really too ready to buy it. This is all a war against a decent medicine and we all know that it’s not exactly true. I’ve heard many people once again demonizing weed like they did in the 40s. It’s just disgusting to think that a plant like this has to take the blame for all of the governments problems. I’m not buying it for a second, and neither should anyone else. It’s all propaganda.

1 Like

For alcohol, maternal abuse diagnosed before the birth of the infant was associated with a 5.6 times increase in schizophrenia risk, but if diagnosed after the birth, this dropped by roughly 50 percent. Similarly, in fathers, pre- and post-birth risk were 4.4 times and 1.8 times, respectively.

This is interesting to know, maybe my father’s alcoholism had something to do with me having Sz.

1 Like

Weeds can be flowers. It’s called weed cuz it grows wildly and abundantly without any help from humans, etc… But the part you can smoke is the flower. :wink:

1 Like

can you imagine how stupid this is? (don’t drink or have fun or else you’ll be 500% more likely to get a mental illness)…I mean it’s just plain retarded. Addiction would for me play a minor factor in my illness. Trauma is the most heavy in my illness not addiction.

Having fun doesn’t necessarily mean drinking alcohol or doing drugs, you can have plenty of fun without it.

Substance abuse is a mental illness and should be regarded as such.


Its the abuse, not the use. Regular consumption within recommended guidelines seems to be fine - its when you drink so much, or use drugs so much, that its on your health care records (or should be) - that it becomes an issue.


Agreed - and mental illness, when not treated, can lead to more mental illness, and more problems.


Exactly, some of us here are the living proof of that.

If only I knew how?! Socialization would make me happy but ive been disincluded my whole life…long before I started drugs/drinking…long before I said NO to drugs and drinking. Hug

The way I see it, in our situation, we have to put our mental health first, that’s the priority. Then all rest falls into place. Learning how to be social without substances is a good step. Took me a while, but it’s possible.


Unfortunately it’s s huge part of our culture here in the states. Especially pot and other drugs. Certain places more so than others but I got introduced to drugs in 8th grade and I wasn’t even looking. It’s like they found me.