(gentle music)
- [Narrator] Cannabis is becoming increasingly mainstream
as many states legalize consumption,
but for some, especially young people,
use may come with a risk to their mental health
and there may even be a link to psychosis.
- I started using cannabis when I was 15 years old
and in my college years, multiple times a day.
I started getting really paranoid about things,
I started feeling like people were following me.
I was hearing voices
and I was too afraid with all the paranoia
and thinking people were listening to me
like through the telephone, through the TV,
that I really started considering suicide.
My mom was like, "Callan, what's going on?"
I was like, "Mom, there are things that are talking to me."
And she's like, "We have to go to the hospital."
(dramatic music)
- [Narrator] Callan was eventually diagnosed
with schizophrenia, a chronic brain disorder
that often appears in early adulthood.
Symptoms include hallucinations, delusions, and paranoia,
which often can be managed with medications.
- [Deepak] What about side effects from the medicines?
- They make me very tired, which is like very hard.
I take 11 pills in the morning and 10 before I go to bed.
- There's a lot of epidemiological evidence
suggesting that exposure to cannabis,
especially in young adulthood and adolescents,
increases one's risk for the development of this disorder.
Cannabis is not necessary or sufficient
to cause schizophrenia.
There may be many factors that together
lead to tipping the person over the edge,
having the right genes, social stress,
all those could contribute to that.
- [Narrator] Some research suggests
frequent use of high-potency cannabis
could play a role in the early onset of schizophrenia.
One study analyzed 900 cases of first psychotic episodes
across Europe and Brazil,
and found that high-potency cannabis
might have contributed to an increase of psychosis.
In Denmark, a nationwide study of health records
of more than seven million individuals
suggested there's a link
between the increased availability of high-potency cannabis
and an increase in the rate of schizophrenia
associated with cannabis use disorder.
- Two of my paternal relatives have had psychotic symptoms.
It can change your life so dramatically.
Here I am eight years later at 30,
and I'm still living with the repercussions
of smoking marijuana.
- The overwhelming majority of people who use cannabis
on a very sporadic basis don't experience harmful effects.
The same as alcohol,
the overwhelming majority of people who use alcohol don't,
but everyone knows of somebody
who has a problem with alcohol.
At the present time, we can't do much about our genes,
but we can do something about cannabis,
just we've done with tobacco.
We've convinced young people
that tobacco smoking is harmful.
If we can have young people delay their use of cannabis
until after their brain has developed
and after they're past the risk of psychosis,
that would be amazing because it's a lifelong illness.
The cost of schizophrenia is massive
because not only in the cost of treating someone
with a lifelong disorder,
but since many people are unable to work,
they remain wards of the state on disability
for their entire life.
- [Narrator] In high doses,
cannabis can cause temporary psychotic-like experiences
like hallucinations and delusions.
- So we do know that with individuals,
if you give them very high doses of THC,
individuals can undergo a transient psychotic episode,
and that can be true of other drugs as well.
We know methamphetamine and stimulants
can also trigger psychotic episodes,
but that is not the same as schizophrenia as a disease.
- [Narrator] We need more data to understand the link
between cannabis use and psychotic experiences,
and the role genetics plays.
- I think, realistically, we're not going to ever resolve
the exact nature of this relationship because in some cases,
it may be for some people, it is causal,
and for some people, it may be that they are using cannabis
as a means to medicate some symptoms, and for some people,
it may just be this genetic association,
and it's unrelated to the disease per se,
but the two phenomenon occur in tandem.