Scientists have identified many types and types of schizophrenia, described hundreds of symptoms and developed dozens of treatment methods. However, the exact causes of schizophrenia have not yet been identified. In the majority of cases, the issue is genetic activity. For a long time, schizophrenia could be a consequence of substance use. Today, drug addiction is excluded from the causes of schizophrenic disorders. However, there is still a connection between the two. Let us explore this topic in more detail.


Schizophrenia and drugs


Relation between Drugs and Schizophrenia

When psychiatric disorders are diagnosed, doctors try to rule out drug addiction. According to the International Classification of Diseases, tenth revision (ICD-10), drug addiction can cause the development of such diagnoses, but schizophrenia is not on this list. A schizophrenic-like condition may occur due to drug use, but it is not a schizophrenic disorder by definition or by the set of symptoms.

As for schizophrenia itself, its true causes are unknown. Psychiatrists and scientists name only disposable factors that can provoke psychopathology. These include genetic conditioning, trauma, gene mutations, and alcohol and drug use. However, after the manifestation of schizophrenia, it is almost impossible to reveal a clear connection between a trigger and symptomatology.

In other words, drugs are not a direct cause of schizophrenic spectrum disorders. But one cannot rule out its harm in the presence of schizophrenia either. Moreover, there is a risk that a patient with psychopathology will become addicted to drugs or alcohol. This is linked to the fact that a person with schizophrenia may experience severe anxiety. It is known that sometimes people resort to taking psychoactive substances to relieve stress and relax.

See Also: Smoking and Schizophrenia – Should a Schizophrenic Give up Cigarettes?

This is especially true for patients with the indolent form of schizophrenia. It progresses weakly with a small set of symptoms. Many patients do not go to doctors and are not registered at all. They try to solve their “psychological problems” by other means, including drugs and alcohol, which quickly become addictive. As a result, one pathology can lead to another mental condition.

The mechanism of substitution of notions is quite simple. When treating schizophrenia, psychoactive drugs are often prescribed that do not provoke hallucinations and delusions but inhibit mental processes. There are many kinds of such medications. Some are used for relaxation, some to intensify the thought process, and some to form vivid experiences. All of them are prohibited.

Doctors chronologically separate drug addiction in patients with schizophrenia and schizophrenic disorders in people addicted to drugs. If a person uses psychoactive substances for a long time, he sooner or later develops delusions and hallucinations. But in this case, the mental disorder of schizophrenic type develops, which is not schizophrenia directly.

If a patient with a current diagnosis or manifestations of schizophrenic spectrum disorders has also developed a drug addiction, the underlying disease remains psychiatric. Addiction intensifies the symptoms. However, addiction is formed in the background of the current pathological process and does not act as a direct cause of it.



A young man who used drugs came to see a narcologist. He told the doctor that he had only tried them three times. He did not like the state the psychoactive substances caused in him, so he gave them up quickly and easily. However, sometime later, he began to experience delusions and hallucinations. His parents thought he had lied to them and continued using drugs.

The drug doctor, who understood that a large dose could only provoke hallucinations from drug addiction, decided to conduct a thorough examination. It turned out that the young man had been experiencing negative symptoms of schizophrenia for several years. Before the visit to the doctor, an aggravation began, that is, a seizure. As a result, he was diagnosed with paranoid schizophrenia.

The patient’s parents initially did not want to believe that their child had schizophrenia. Often it is easier for relatives to admit that their loved one is an addict but not “crazy.” But it turned out the man did not lie to his family and did not use drugs.

In this case, it could not say that schizophrenia resulted from the triple use of psychoactive substances. Most likely, it developed over a long period. But also, it is not excluded that drugs served as an impetus for splitting of mind when the disorder had already developed.



The relationship between drug addiction and mental illness has long been investigated. For example, in the 50-the 60s of the last century, only 2-4% of patients with schizophrenia who were addicted to drugs were registered. In the 1970s, this figure rose to 25-30%. According to a 2008 study, 24.9% of 257 schizophrenic patients used cannabinoids. Those with two diagnoses, schizophrenia and substance abuse, were dominated by people who used marijuana (62%) and cocaine (51%).

Some doctors claim that people with schizophrenia have an unconscious craving for psychoactive drugs. It is not surprising since schizophrenic disorders are treated with them. They allow stopping positive symptoms of psychopathology – delirium and hallucinations. But only the doctor can determine which medicine is suitable for the patient and in what dose.


Schizophrenia and Smoking

According to the ICD-10, smoking or nicotine addiction is a physiological, behavioural disorder. It is associated with smoking, that is, psychoactive substances. Tobacco is also a drug but not as powerful as heroin, cocaine, etc.

It is proven through research that people with schizophrenia are more prone to this kind of addiction. More than 80 per cent of schizophrenic patients smoke and are “heavy smokers”. The same figure for the general population is only 40%.

The money that comes from cigarettes in the UK can cover anywhere from ⅕ to ⅓ of the cost of treating schizophrenia.

The reason people with schizophrenia depend on tobacco is understandable. In this psychopathology, the person overreacts to external stimuli but cannot block unnecessary signals from the outside world in a particular situation. A high dose of nicotine can slow down this process, blocking a part of the receptors.

It is why people with schizophrenia not only smoke a lot but also choose cigarettes with a high tar content, that is, strong tobacco varieties. However, they do not know that. In this case, they need a lot of nicotine to get the effect that alleviates the symptomatology of the pathology. Cigarettes cannot provide it.

As a result, smokers don’t get cigarette therapeutic help in schizophrenia fight but get comorbidities connected with vascular lesions and other systems of an organism.


LSD and Schizophrenia

LSD is a substance in the lysergamide family. It is considered the best psychedelic, sometimes used in meditations and various mystical practices. There was a surge of interest in such substances in the 1960s. Today, however, research has been suspended. It is because it is still unclear whether LSD strongly affects the brain and what consequences it may cause. It is forbidden to conduct such research on people.

Schizophrenia can slowly progress over the years. Any factor – alcohol, illness, trauma, drugs, etc. – can trigger a seizure.

The data we were able to obtain half a century ago show that there is no direct connection between schizophrenia and LSD intake. Psychoactive substances are not the cause of pathology development, even though hallucinations often accompany their use.

Moreover, some scientists have called for treating psychiatric disorders, including children, with the help of such drugs. For most physicians and researchers, the question remains open.



Drugs cannot cause schizophrenia in a healthy person, but a patient with a mental disorder should eliminate psychoactive substances from his life.