Cannabis, a triggering factor  

Cannabis use can, in itself, cause hallucinations, depersonalisation, or ‘bad trips’ – but not for everyone. “We are not all equal when it comes to the effects of cannabis; some people overreact, while others experience fewer effects.”

The link between cannabis and schizophrenia is now established. "Cannabis clearly has an aggravating effect: it increases or maintains symptoms in people with psychosis," explains Philippe Conus. But it can also play a role earlier in the process. For someone at risk of developing schizophrenia (e.g. family history), cannabis use may be the triggering factor.

Finally, population-based studies show that young people who start using cannabis between the ages of 12 and 14 are four times more likely to develop a psychotic disorder. The adolescent brain undergoes major reorganisation. "At this age, the brain has a certain flexibility in neural connections; an increase in dopamine or the effect of cannabis can interfere with the smooth running of this important reorganisation and contribute to the emergence of a psychotic disorder." Cannabis can therefore disrupt a balance that is still fragile and developing. "Before the age of 18, the causal link between cannabis use and schizophrenia is much clearer; it is no longer found in the same way among those who start smoking later." 

Beyond age, other factors come into play. The genetic component is also important, as are exposure to trauma, violence, sexual and physical abuse, and even abandonment, which are risk factors. These factors create a vulnerability on which cannabis can act as a trigger.

Identifying warning signs

It is possible to detect certain high-risk mental states. "These may be young people who have mild symptoms such as odd perceptions, slowed thinking, anxiety, and depression." In such contexts, specialised programmes offer appropriate preventive care. "Psychological or neuroprotective approaches – such as the prescription of omega-3 – are being studied and seem to slow or prevent the development of the disorder." 

For Philippe Conus, young people’s awareness of the risks of cannabis remains insufficient. He advocates a simple, guilt-free, reality-based message: avoid early cannabis use; be attentive to unusual reactions, such as paranoia or malaise; and seek help if you feel your cannabis use is becoming a need. Psychiatric therapy is particularly effective in addressing this problem. "In most cases, brief treatment is sufficient. By consulting quickly, it is easier to find ways to solve the problem. We need a democratisation of consultations to understand where the trouble comes from and act quickly: it is important. Otherwise, the situation may worsen and require longer, more complex treatments. The brain is a complex organ. Around half the population will experience a mental health disorder at some point in their lives. The sooner we deal with it, the better we understand its causes and the greater the chance of recovery.” 

Cannabis, a triggering factor  

Cannabis use can, in itself, cause hallucinations, depersonalisation, or ‘bad trips’ – but not for everyone. “We are not all equal when it comes to the effects of cannabis; some people overreact, while others experience fewer effects.”

The link between cannabis and schizophrenia is now established. "Cannabis clearly has an aggravating effect: it increases or maintains symptoms in people with psychosis," explains Philippe Conus. But it can also play a role earlier in the process. For someone at risk of developing schizophrenia (e.g. family history), cannabis use may be the triggering factor.

Finally, population-based studies show that young people who start using cannabis between the ages of 12 and 14 are four times more likely to develop a psychotic disorder. The adolescent brain undergoes major reorganisation. "At this age, the brain has a certain flexibility in neural connections; an increase in dopamine or the effect of cannabis can interfere with the smooth running of this important reorganisation and contribute to the emergence of a psychotic disorder." Cannabis can therefore disrupt a balance that is still fragile and developing. "Before the age of 18, the causal link between cannabis use and schizophrenia is much clearer; it is no longer found in the same way among those who start smoking later." 

Beyond age, other factors come into play. The genetic component is also important, as are exposure to trauma, violence, sexual and physical abuse, and even abandonment, which are risk factors. These factors create a vulnerability on which cannabis can act as a trigger.

Identifying warning signs

It is possible to detect certain high-risk mental states. "These may be young people who have mild symptoms such as odd perceptions, slowed thinking, anxiety, and depression." In such contexts, specialised programmes offer appropriate preventive care. "Psychological or neuroprotective approaches – such as the prescription of omega-3 – are being studied and seem to slow or prevent the development of the disorder." 

For Philippe Conus, young people’s awareness of the risks of cannabis remains insufficient. He advocates a simple, guilt-free, reality-based message: avoid early cannabis use; be attentive to unusual reactions, such as paranoia or malaise; and seek help if you feel your cannabis use is becoming a need. Psychiatric therapy is particularly effective in addressing this problem. "In most cases, brief treatment is sufficient. By consulting quickly, it is easier to find ways to solve the problem. We need a democratisation of consultations to understand where the trouble comes from and act quickly: it is important. Otherwise, the situation may worsen and require longer, more complex treatments. The brain is a complex organ. Around half the population will experience a mental health disorder at some point in their lives. The sooner we deal with it, the better we understand its causes and the greater the chance of recovery.”