No Ill Effects For The Majority of Users
Despite anecdotal claims, a link between cannabis use and schizophrenia has yet to be proven. The majority of people who smoke cannabis suffers no ill effects, but a small proportion suffers from psychosis-like symptoms including paranoia.
There has long been a debate surrounding whether cannabis can lead to the development of schizophrenia. However, studies show that cannabis consumption is common while schizophrenia remains rare in the general population, affecting less that one percent of people.
Even if there was a causal link between cannabis and schizophrenia, and if it were to double the risk of developing symptoms, over 90 percent of cannabis users would not develop any.
Since the 60s the amount of THC in cannabis has risen dramatically, and high power types of cannabis are now incredibly common. If cannabis did contribute to the rate of schizophrenia in the population, then there would be a causal link between these new, more potent strains and a rising rate of schizoid symptoms. Though a huge amount of debate surrounds the link between schizophrenia and cannabis the evidence is still inconclusive one way or the other.
According to several studies, people who use cannabis are more likely to feel negative emotions and alienation. Brain scans have found that cannabis can increase the signal in the region of the brain that is linked to psychosis. Teenagers who smoke cannabis are found to be especially vulnerable to this as their brains are still developing.
It has been found that users who do experience psychotic symptoms after smoking cannabis are more likely to quit cannabis. The experience a user has with a particular substance tends to be predictive of whether they continue to use that substance or not, users who have a negative experience with cannabis are less likely to use it again.
This means that users who are at the highest risk are the least likely to continue using cannabis after a negative experience. The Debate is ongoing, but the evidence points towards the conclusion that there is no causal link between cannabis and schizophrenia.