How Drugs Can Cause Schizophrenia: Mechanisms, Evidence, and Implications
Introduction
Schizophrenia is a disorder that consists of a complex set of diseases, including delusions, hallucinations, and a change in behavior. Schizophrenia comprises the following symptoms, such as speech impairments, etc. While this condition is caused by a number of factors, which include neurodevelopmental functions, environmental factors, and behavioral factors, etc., drugs can also alsoplay a major role in triggering and worsening this condition.
Scientific studies show that drugs have a great effect on a growing body; they are a cause of accelerated heart rate and psychosis and elevate the level of existing symptoms. In some cases, drugs even lead to the diagnosis of schizophrenia, but this happens under certain vulnerabilities. Now let’s take a deep dive into understanding the biological and psychological impact of drugs and their mechanism in prevention and intervention.
Understanding the Link: Drugs Psychosis
The drugs did not directly cause schizophrenia, but they can trigger its impact and also enhance its symptoms. On the other hand, the main cause of this disease is pathogens, e.g., retroviruses, HERV-W viruses, genetic, and environmental factors.
The effects of drugs on a human body work in two different ways: some drugs are used for medication, but the other drugs, or sometimes the same drugs, cause adverse effects and can cause disturbance of mental health.
Neurobiological Mechanisms Involved
When a human body takes in drugs, it reacts in various ways with the cells and different chemicals of the body and generates both positive and negative effects. In the same way, especially when discussing adverse effects of drugs, some chemicals react to produce psychosis. These drugs, when they react with thoughts, emotions, and perceptions, generate hormones like serotonin, dopamine, and glutamate. This causes dysfunction of the brain and triggers the symptoms of schizophrenia.
1. Dopamine Dysregulation
The dopamine hypothesis is one of the most widely accepted and well-explained models in terms of schizophrenia. It suggests that hyperactivity of dopamine transmission, particularly in the mesolimbic pathway, is responsible for positive symptoms like hallucinations and delusions. In other ways it enhances the intake of artificial dopamine metaphorically doing nothing and staying happy. Consequently, it reduces the activity of the prefrontal cortex, which is responsible for the generation of negative.
Following are the drugs that increase the levels of dopamine:
- Amphetamine
- Glutamine
- Cocaine
These drugs trigger the levels of physios. When these medicines were taken consistently, they mimicked the neurochemical state.
2. Glutamate and NMDA Receptor Hypofunction
Glutamate is one of the main types of neurotransmitters that is responsible for excitement. The intake of drugs casts negative impacts on NMDA receptors.
When we take substances like ketamine and phencyclidine, they produce paranoia and trigger schizophrenia in both healthy and sensitive persons. Repeated exposure can cause long lasting psychiatric effects, such as disrupting glutamate signaling and impair neuroplasticity.
3. Serotonin System Involvement
Drugs such as LSD and psilocybin primarily act on serotonin (5-HT2A) receptors. While these drugs cause temporary hallucinations, their impact on perception and reality testing mimics schizophrenia. When these drugs are taken in lesser quantities, they do not have any special impact on dopamine levels; prolonged or high-dose use—especially in those with underlying mental vulnerabilities—may destabilize brain function and induce psychosis.
Cannabis and Schizophrenia: A Special Case
Epidemiological Evidence
Cannabis is one of the most prohibited drugs worldwide and is considered to be the major factor causing psychosis. There are various long studies conducted that tell us about the use of cannabis, and later on they develop schizophrenia, especially when you use this medicine in adolescence.
A 2007 meta-analysis by Moore et al. found that cannabis users had a 40% increased risk of developing psychotic disorders compared to non-users. Importantly, the risk was dose-dependent—when these drugs are taken at an early age, the risk of getting schizophrenia increases.
Role of THC and Genetic Vulnerability
The psychoactive component of cannabis, delta-9-tetrahydrocannabinol (THC), interacts with the endocannabinoid system, which regulates mood, memory, and cognition. THC also increases dopamine activity in the brain, potentially triggering psychotic symptoms.
Research shows that individuals with certain genetic variants—particularly in the COMT and AKT1 genes—are more susceptible to the psychosis-inducing effects of cannabis. These findings support a gene-environment interaction model, where cannabis use interacts with biological vulnerability to produce schizophrenia.
Stimulants: Amphetamine- and Cocaine-Induced Psychosis
Amphetamines and cocaine are potent central nervous system stimulants that elevate dopamine and norepinephrine levels. High doses or chronic use can lead to amphetamine-induced psychosis (AIP) or cocaine-induced psychosis (CIP), which are often indistinguishable from acute schizophrenia. Studies suggest that 20–30% of individuals with methamphetamine-induced psychosis go on to develop chronic schizophrenia.
Risk Factors for Drug-Induced Schizophrenia
Not everyone who uses drugs will develop schizophrenia. Key risk factors include:
- Family history of schizophrenia or psychosis
- Early onset of drug use (especially during adolescence)
- High frequency or potency of drug use
- Co-occurring mental health disorders such as
- Childhood trauma
- Genetic predisposition (e.g., COMT gene variations)
Clinical and Public Health Implications
1. Prevention and Early Education
Increase the literacy levels and also set up campaigns about awareness in which people tell about the harmful effects of drugs, especially guiding the adolescent children. Because early-age drug use can interfere with critical periods of brain development, it increases the risk of psychiatric disorders later in life.
2. Screening and Genetic Counseling
Individuals with a family history of schizophrenia should be screened, and later on it is discovered that these families are more vulnerable to this disease. If we can do more research, then we can deep dive into recognizing the facts that cause schizophrenia more precisely.
3. Integrated Dual-Diagnosis Treatment
Patients with both schizophrenia and substance use disorder (SUD) often experience poorer outcomes. Integrated treatment models that address both conditions simultaneously are more effective than treating them separately.
Conclusion
In conclusion, I want to say that only drugs are not responsible for causing schizophrenia, while environmental factors, genetic factors, and family background also matter a lot. Although drugs also have a huge impact, especially the drugs which alter the pathway of hormones such as serotonin, glutamine, dopamine, etc.
This particular disease can be controlled by spreading awareness and taking action against the illegal drug vendors. Moreover, further research will reveal why some people are more vulnerable to schizophrenia and whether genetic and brain developmental factors lie behind it. This will provide us clarity on how we can measure precise and accurate steps to control it.