Cannabis is a popular street drug which is known for its sedating and calming effect among its users.

While it is often seen as one of the “milder” recreational drugs, it has the potential to cause long-term problems. High strength Cannabis is particularly dangerous in terms of endangering mental health.

In this article, we explore the link between Cannabis and Psychosis, as well as the psychotic disorder Schizophrenia.

Hearing voices is a common example of psychosis


Cannabis is also known by a variety of “street” names too. For example, these include ‘weed’, ‘skunk’, ‘pot’, ‘hash’, ‘grass’, ‘ganja’ and ‘dope’ among others.

While people commonly take Cannabis to feel relaxed, there are a host of unwanted side effects – such as anxiety, paranoia, confusion and sickness. Despite this, it is a popular drug to abuse.

The link between cannabis and psychosis

Unfortunately, cannabis is linked heavily to psychosis, as well as psychotic disorders like Schizophrenia. The link between cannabis and Psychosis has been linked time and time again through multiple research studies.

For example, one study found that cannabis directly increases the risk of psychotic symptoms [1]. Another study suggests that using cannabis in adolescence appears to significantly heighten the risk of schizophrenia or schizophreniform disorder [2].

At the least it can make someone more vulnerable to experience psychosis, and at worst it can directly cause a psychotic experience.

High strength cannabis is a particular risk – in terms of there being a high level of the active ingredient THC being present. Another key ingredient CBD, can help to mitigate the power of THC, but it isn’t often included in high enough quantities.

Therefore, THC, which can directly cause hallucinations – is typically seen in high levels in high strength versions of the drug.

Heavy users of cannabis see their risk of psychosis rising around a staggering 600% [3] – underlining how dangerous it can be.

The cannabis circulating on the streets in this day and age is significantly stronger than the cannabis of a decade or so ago. High-strength “skunk” is also being linked to psychosis.

The cause of the connection

What links Cannabis and psychosis is actually a chemical in the brain called dopamine. Many recreational drugs like Cannabis, cocaine and amphetamines will increase the level of dopamine in the brain. Scientists believe an excess amount of dopamine in the brain can trigger the symptoms of psychosis.

That is why antipsychotics seem to work – as they block the action of dopamine. But this doesn’t mean that as long as someone takes antipsychotics that they will be fine, as it counteracts the effect of Cannabis.

That simply isn’t correct. Instead, the consumption of Cannabis will mean the effect of the antipsychotic won’t be felt.


While Cannabis is used by many people as a way of relaxation – it is important to know that there are risks involved.

The higher the strength of the Cannabis – the further the risk involved is. In the worst cases, there is a clear link to severe mental illness.

See Also


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[1] Fergusson, D. M. (2005). Tests of causal linkages between cannabis use and psychotic symptoms. Addiction. 100 (3): p354-366. DOI:

[2] Arseneault, L., Cannon, M., Witton, J., & Murray, R. M. (2004). Causal association between cannabis and psychosis: examination of the evidence. British Journal of Psychiatry. 184 (2): p110-117. DOI:

[3] Andréasson, S, Allebeck, P & Rydberg, U. (1987). Cannabis and Schizophrenia, A Longitudinal Study of Swedish Conscripts. The Lancet Psychiatry. 330 (8574): p1483-1486. DOI: