Can Cannabis Cause Mental Illnesses



The psychoactive effect starts to take effect a few minutes after the cannabis is used and continues for approximately 1-2 hours. However, the THC substance remains in the body for a longer period of time (can be detected even after a month in cases of chronic use). Some of the side effects of this substance can be listed as short-term memory loss, dry mouth, flushing, weakening of perception, decreased motor ability and loss of appetite. A person who uses cannabis may become addicted to this substance and as a result, may have to go through some different mental and physical processes.



Some people are more likely to develop certain mental disorders due to their nervous system, genetic characteristics, life experiences, and personality structures. Similarly, a number of psychotic disorders that the person has but are “asleep” can occur at the same time with cannabis use. No one can give us assurance of how a person will behave after the next use of cannabis. Drug use and its consequences are everyone’s own responsibility. Sometimes people can close their eyes and ignore some facts. However, it is an undeniable fact that drug use changes our mental, emotional and physical state. It is not possible for us to really escape this problem that we may actually encounter every day.

The potential beneficial effects of cannabis and the fact that in some patients it is used as a therapeutic option in the context of clinical and pharmacology – keeping its dosage and concentration in a controlled and balanced manner – does not necessarily mean that cannabis is a useful substance. The effects of the condition, also known as pathological intoxication or “bad trip” may cause various disorders such as anxiety disorder, loss of self, perception of unrelated emotions, intense sense of panic, paranoia, the emergence of disorders in motor abilities, paralysis or sensory-perception changes. Some clinical findings related to cannabis use and the mental disorders they cause are listed below:

  • Anxiety disorder: The occurrence of anxiety symptoms and/or panic disorders after cannabis consumption is quite common.
  • Depression: There is an increased risk of developing depressive disorders and suicide attempts.
  • Bipolar disorder: Cannabis use can cause psychotic symptoms, trigger manic stages, and lead to an increase in the number of relapses.
  • Amotivation syndrome: May cause loss of energy, reluctance, apathy, and cognitive deficits.
  • Cognitive impairment: Weakness and loss of abilities such as reaction, perception, memory, problem-solving, concentration, attention, etc. can be seen.
  • Psychosis: There are several studies showing that cannabis use doubles the likelihood of a psychotic explosion. In this context, there may be short-term psychotic disorders as well as longer-term and chronic psychosis. Cannabis use is severely prevalent in people with severe mental disorders such as schizophrenia.
  • Re-living: Even in cases where cannabis is not used, the situation of re-living the same experience can occur.


  • Loss of unconsciousness: Transient reactions can be seen in people who use cannabis, such as delusion, concussion, agitation, fear, deep sleep, hallucination and the like. Although uncommon, such conditions may develop in connection with consumption at high doses.
  • Effects on sleep: The THC substance triggers sleep and causes a change in the sleep-wake pattern.
  • Effects of cannabis in the context of nutritional status: In rare and occasional use of cannabis, appetite gain is observed. However, in the case of continuous use, on the contrary, appetite loss and unwillingness to eat may be experienced. In addition, the use of the substance can cause the body to accumulate fat.

It is not possible to predict what awaits the person after the use of cannabis. In this context, mental disorders may occur and there is a possibility of serious irreversible problems. Drugs are considered to be the largest harmful substances with chain-destructive effects. These substances start to affect you when you don’t give yourself the value you need; then it ends by dragging you into the abyss with all your loved ones.

Why Cannabis Causes Mental Disorders?


Recent studies provide more information on how long-term cannabis use has adverse effects on mental health but provides important evidence that cannabis increases the negative emotions and reduces motivation by changing the brain reward system. Dopamine is a neurotransmitter that plays a key role in learning, movement, motivation, emotion and reward systems in the brain. Studies suggest that there is sufficient evidence that cannabis use reduces dopamine levels in the brain.



Low dopamine levels are associated with mood changes, fatigue, depression and lack of motivation; dopamine deficiency may present in many neurological and psychiatric disorders such as Parkinson’s disease and attention deficit hyperactivity disorder (ADHD). Long-term cannabis use has been associated with many mental disorders such as schizophrenia, anxiety, and depression, but the mechanisms underlying this relationship have not yet been elucidated.

THC is the active chemical substance of cannabis. According to the researchers, there is “very important” evidence that long-term exposure to THC leads to a decrease in dopamine levels in animal and human studies. Low dopamine levels may be the reason some users develop some mental disorders.

“Current evidence suggests that THC exposure has complex, widespread and potential long-term effects on the dopamine system” the authors state. “These include nerve cell activation in response to acute THC uptake, increased dopamine release, and dopaminergic blunting in relation to long-term use.” In animal models, recent studies have shown that cannabis use initially increases dopamine levels, thus causing a sense of reward. An explanation may be given that this substance is addictive.

How Does Cannabis and Alcohol Use Affect Our Brain?


Addiction is a brain disease. In other words, when addictive substances are used for a long time, they cause different effects and changes in brain cells. People often start drinking alcohol and smoking cannabis, thinking they can control it. However, after a while, the use of alcohol and cannabis gets out of control, even if the person does not want to use them, their brain asks them to continue to use them.



With intense alcohol and cannabis use, the brain’s self-stop mechanism is disrupted, and when alcohol and cannabis are encountered, the brain only gives the message “go and use” and not the “stop” message. Thus, even if the person does not enjoy the “go and use” message from his brain, he continues to use it. Our brain is made up of nerve cells and our perception of our environment takes place through these nerve cells. Alcohol and drug use disrupts the communication between nerve cells and causes many negative effects on our brain.

The use of alcohol reduces brain function, weakens memory, leads to balance disorders and dementia. Many studies have shown that regular alcohol use triggers dementia even if it is not high. Drugs mechanize the brain by disturbing the normal functioning of the brain. Some substances cause blockage in the veins of the brain, causing paralysis. In addition, hearing sounds in the brain and the onset of mental disorders are the effects of drugs on the brain. Research shows that cannabis use increases the risk of schizophrenia 7 times.

Alcohol and substance use interferes with the communication between nerve cells, thus slowing the brain’s work. One has difficulty in learning new things and solving problems. Research with brain imaging techniques revealed that alcohol and substance use slows the brain with brain images. These studies also showed that alcohol and substance use causes changes in the structure of the brain. Since alcohol and substance use severely disrupts reflexes, it is very inconvenient to carry out work that requires attention under the influence of these substances. In addition, the negative effects and changes of certain drugs on the brain are known to cause sudden deaths.



Changes in brain structure and deterioration of nerve cells do not improve as soon as alcohol and substance use is discontinued. The recovery may take a long time. It should not be forgotten that addiction is a brain disease beyond the control and will of the person. It is important to stay away from both alcohol, cannabis, and other substances and reminders of these things in order for your brain to recover.

The Effect of Cannabis Use on Intelligence: Does Cannabis Stupify?


Many changes have been witnessed throughout human history. Imagine how normal a war at a time? How helpless you are in the face of many diseases? Today, relatively, the world is dominated by peace. We have drugs and technology that can fight diseases. So much so that the viruses that killed millions of people in the past are not even on earth today. We develop and become conscious both in technological and educational terms. Wheat, which is indispensable to the tables, is a subject of debate about health hazards today. Opponents of the vaccine stand against science all over the world. While the immune system of a generation has been suppressed with antibiotics, today there are serious restrictions on antibiotic use. Cannabis is also a topic of debate, with its benefits and harms, positioned differently throughout human history. In order to put an end to these discussions, I have compiled the results of some researches from past to present.



You must have heard the thesis that using cannabis makes people stupid. Especially those who grew up in the 80s and 90s know well, that was the message of many anti-drug NGOs. This argument was updated in 2012 by a study by Duke University that “cannabis used during adolescence and youth causes a serious decline in IQ.” Another study, whose methods have been criticized by many researchers since then, revealed that the original study did not take into account a number of important factors that could affect cognitive development, such as smoking and alcohol use, mental illness, and socioeconomic status.

Two recent reports have examined the relationship between marijuana use and intelligence from two perspectives: one examines the life curves of 2,235 British young people aged 8-16 years, and the other examines the differences between the same twin brothers who use cannabis and the other do not. Although they are conducted using different methods, both of the researches reach the same conclusion; There is no evidence that cannabis use at a young age causes any decrease in intelligence. Another study argues that cannabis use alone during adolescence does not cause any mental retardation or decrease in school performance, and should be evaluated together with factors such as maternal health, mental health and the use of other substances.

Researchers in this study emphasize that their findings do not completely invalidate the findings of the paper presented by Duke University in 2012. Because the previous research focused on long-term and continuous use of heavy amounts of cannabis, while the recent study examines only low to moderate amounts of cannabis use. “Cannabis addiction and long-term cannabis use have a negative impact on IQ, but cannabis use alone does not seem to have an effect on the intelligence level of young people,” the researchers said.



Research on American twins, however, is completely in contradiction with the findings of Duke University. There is no cognitive difference between the same twins, one using cannabis and the other not using cannabis. Since the genetic structure of the twin siblings and the home environments where the developmental periods are the same, the results of such comparisons and analyzes on identical twins are considered very important.

Of course, none of this does mean that you can use cannabis as much as you want. There are many negative physical and mental health problems associated with the use of cannabis, especially with large amounts of cannabis. Some studies even suggest that intense cannabis use may increase the risk of psychosis or suicide. These risks are even greater for people who start using marijuana at an early age. Intense cannabis users or those who start using cannabis at an early age are also at high risk of gaining drug addiction. Cannabis is a kind of drug substance, in the end. Just like cannabis, such as alcohol, nicotine, and caffeine, has both risks and benefits. Unfortunately, neither exaggerating these risks nor these benefits does not help anyone to create smarter policies.

Does Cannabis Use Trigger Schizophrenia


Underlining that the use of cannabis is becoming widespread all over the world, experts said that the wrong information that cannabis does not make addiction causes one to see cannabis as a harmless drug. Experts emphasize that marijuana is addictive, just like cigarettes, underlining that there is one aspect of marijuana that needs attention more than addiction.



Beyond being addictive, another aspect of cannabis that needs attention is its relationship with psychotic pictures. Studies show that the onset of schizophrenia-like psychotic conditions in regular cannabis users is accelerating. Especially if there is a genetic predisposition to psychotic diseases in the family, the emergence of psychosis is accelerating. In recent years, the proportion of adolescents who have met cannabis has increased. Adolescence is a period in which the brain undergoes rapid structural changes.

Therefore, fluctuations occur in the emotional state of the adolescent and behavior disorders are observed. Thus, it may be easier to turn to a “forbidden” substance such as cannabis. The fact that impulse control in adolescence is not yet sufficiently developed prepares the ground for even easier and unlimited use of cannabis. In this case, the emergence of diseases such as psychosis, which deteriorate the connection of the person with reality and impair social and occupational functionality, has started to age at an earlier age. The lifetime course of early-onset psychosis is more negative than late-onset. Education life is negatively affected. Therefore, efforts to prevent the spread of cannabis are of great importance. Families and schools should inform children and adolescents about substances. The information on the substance should be provided by the experts, preferably emphasizing the adverse effects of the substance on the brain and body.

Schizophrenia Due to the Cannabis Use


Experts who believe that substance use is necessarily accompanied by a psychiatric disease state that substance use leads to schizophrenia and psychotic attacks, especially if there is a genetic predisposition. Experts emphasize that the substances that make the person addicted increase dopamine in the brain. Increased dopamine in the brain causes many other psychiatric disorders, especially schizophrenia or what we call psychosis is associated with increased dopamine in the brain.



According to a study published in the journal Cerebral Cortex, especially in adolescence and after cannabis use can cause schizophrenia. Statistics show that 15 percent of 8th-grade students in the United States have tried cannabis at least once, and more than 1 percent use it every day. The use of marijuana can create a sense of comfort, but it can also produce feelings of panic, anxiety, insecurity, and fear. In the short term, cannabis use causes memory loss, impaired perception, and disability in reasoning, but also lacks performance at work and at school.

In adolescents, cannabis use has a negative and long-term impact on cognitive development, damaging the developing brain systems. The use of cannabis at high doses can cause acute psychosis, including hallucinations, delusion, and loss of self-perception. Cannabis-induced disorders can be transient, but you can lose your mental health as a result of cannabis use by making a long-lasting effect. Experts in particular point to the link between schizophrenia and cannabis use. The feeling of numbness after cannabis use is caused by a chemical found in marijuana: Delta-9-Tetrahydro-Cannabinol (THC).



A group of researchers from the Canadian-based Western University found important findings on the long-term effects of THC on the brains of adolescents. These findings suggest that behavioral, neuronal, and molecular changes that are unique to neuropsychiatric disorders such as schizophrenia arise from cannabis use. It is stated that adolescents who have been exposed to THC – as a result of cannabis use – have withdrawn from the social world, withdrawn, have excessive anxiety and cognitive disruptions and carry dopamine at abnormal levels. These symptoms are the common features of schizophrenia. Although there is no evidence of such long-term negative symptoms in adult brains exposed to THC, they are found to have deficiencies in memory and social comprehension.

Rates and Predictors of Drug-induced Psychosis Conversion to Schizophrenia or Bipolar Disorder


In this study, the rates of conversion of drug-induced psychosis to schizophrenia or bipolar disorder and the main predictors of this transformation were investigated (https://ajp.psychiatryonline.org/doi/abs/10.1176/appi.ajp.2017.17020223).

All patients (n = 6788) diagnosed with drug-induced psychosis between 1994 and 2014 using Danish national registry systems were included in the study. Exclusion criteria were that patients were previously diagnosed with schizophrenia or bipolar disorder. Patients included in the study were followed up on the basis of certain criteria (until the diagnosis of schizophrenia or bipolar disorder, until August 2014, until death or migration).



Using the Kaplan-Meier method, the cumulative probability of conversion of drug-induced psychosis to schizophrenia or bipolar disorder was calculated. In addition, hazard ratios were calculated for all variables.

It was reported that 75% of the patients included in the study were male, 34% of the psychoses were due to alcohol, 22% to cannabis, and 27% due to mixed / other substance use. The age of onset of psychosis varies according to the substance used; The mean age of onset of alcohol, opiate and sedative use was found to be above 45 years of age, while other substances were below 30 years of age.

In general, the rate of conversion of these patients to schizophrenia or bipolar disorder was 32.2%. This rate is 26.0% for schizophrenia and 8.4% for bipolar disorder. When analyzed by substance types, conversion rates ranged from 22% to 47%. The highest rate was determined for cannabis-related psychosis, and the most common cannabis-induced psychosis was found to be schizophrenia (41.2%).



When the risk factors were examined, an early age (especially 16-25 age range) was found to be a risk factor for the development of schizophrenia. The presence of self-destructive behavior after psychosis was found to be risky for both schizophrenia and bipolar disorder. The hazard rate for schizophrenia was 77.3, the highest rate was 101.7 for cannabis psychosis and the lowest rate was 23.4 for opiate psychosis. The overall hazard ratio for bipolar disorder was reported as 24.4. Approximately half of the patients had schizophrenia in the first 3 years after psychosis, and bipolar disorder was seen in the first 5 years. For the development of schizophrenia, personality disorder, eating disorder and substance use disorder were predicted, and bipolar disorder, personality disorder, unipolar depression, and anxiety disorder were predictive.

Although the nature of the relationship between drug-induced psychosis and future psychiatric disorders is not clear, this study has once again demonstrated that cannabis-induced psychosis is an important risk factor for schizophrenia and bipolar disorder. As a cohort study by examining the registry systems, factors such as the amount of substance use and the substance use status of the patients after psychosis could not be examined are the main limitations of the study. Considering the effects of early diagnosis and treatment on the course of these psychiatric disorders, the results of the study suggest that patients with substance use-related psychosis should be followed for a long time.

Savaş Ateş

I like cannabis. I read a lot about cannabis usage in the medical field. I researched a lot about planting it. I have started a cannabis business and i want to share my experiences with you.

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