Schizophrenia is a severe mental health illness, characterised by a range of symptoms like hallucinations, delusions and unorganised thoughts and behaviour.

It is known in the wider culture for being one of the most severe conditions to live with. But a question that not many know the answer to is – can street drugs cause schizophrenia?

Some street drugs have been linked to Schizophrenia

What is Schizophrenia?

Schizophrenia: Schizophrenia is a severe and long-term mental health condition characterised by a range of symptoms, normally revolving around a difficulty in understanding reality, due to changes in the way someone thinks, feels and acts. The condition usually involves a breakdown in the connection between thoughts, emotions and behaviour – leading to psychotic symptoms. While the exact symptoms range from case to case, generally delusions, hallucinations, disorganised speech, catatonia, poor concentration and a lack of interest may be displayed. With the right treatment, support and lifestyle, it is possible for symptoms to be controlled more.

The contribution of street drugs

While the understanding of Schizophrenia has come a long way in the last few decades, the exact causes of the condition aren’t yet known.

It is widely believed that there are numerous potential causes and risk factors for Schizophrenic-related conditions. So where do street drugs fit into this?

The term “street drugs” is rather broad. But in general, they refer to illegal drugs that are widely sold and traded illegally, often “on the streets”.

Some street drugs are worse than others. For instance, Cannabis has been particularly linked to Schizophrenia [1].

Moreover, hallucinogenic drugs like LSD, the stimulant Methamphetamine, and the psychedelic Phencyclidine (PCP) have also all been linked to Schizophrenia [2].

Where is the link to schizophrenia?

What links several street drugs to psychotic experiences 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 has the potential to cause psychosis – which is the hallmark of Schizophrenia.

Perhaps one of the key risks involved is that when someone uses street drugs at an early age, their brain is still developing.

The drugs can cause the brain to fail to develop as it should. In later life, this may contribute to the onset of Schizophrenia.


So while these street drugs may not ‘cause’ Schizophrenia per se, they certainly have the potential to contribute to the onset of the condition.

At the very least, they make users more vulnerable to developing the condition in later life. For those already at risk – such as through experiencing a traumatic event or genetically – these street drugs do little good.

See Also


This website should be used purely for informational purposes, and does not intend to, nor should it ever, be used as a replacement for professional medical advice.

We strive to keep all of our pages updated, and ensure that our website is full of factual and in-depth information. However, we encourage you to browse this website with care.

As a reminder, this website and all content within it cannot and should not replace the advice of a trained medical professional. You can read our full disclaimer at this link.


If you are struggling with your mental health, help is available. With the right support and treatment, you can make a recovery. For information on helplines, or if you are in a state of crisis, please visit our crisis page by clicking on the relevant link for your geographical location (United Kingdom), (United States), (International). You can also see how to get mental health treatment and the process involved by clicking this link.


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

[2] Cortes-Briones, J. A., Cahill, J. D., Skosnik, P. D., Mathalon, D. H., Williams, A., Sewell, R. A., Roach, B. J., Ford, J. M., Ranganathan, M., & D’Souza, D. C. (2015). The psychosis-like effects of Δ(9)-tetrahydrocannabinol are associated with increased cortical noise in healthy humans. Biological Psychiatry. 1 (11): p805-813. DOI: