The impact of cannabis on cognitive function has been debated for years, but new evidence suggests the long-term use of cannabis may have negative effects. This article will look at what has been studied so far and how these findings could affect our understanding of the potential effects of cannabis on our brains.
Effects on memory
Cannabis has been shown to cause short-term memory problems, but the effects of long-term cannabis use are still unknown. Scientists are worried that chronic marijuana use can lead to cognitive impairment that lasts for weeks after users are no longer high.
Heavy cannabis users have reported a range of cognitive difficulties, including decreased processing speed, difficulties focusing and poor verbal learning skills. Some research suggests that these effects could persist for months, even years after the person has stopped using marijuana.
The impact of cannabis on memory is particularly concerning among adolescent users. This is because their brains are still developing.
Researchers have found that the negative effects of cannabis on memory can be severe, affecting as much as 25% of a person’s cognitive function, especially if they’ve used the drug frequently. And these effects can linger for weeks after they’ve been removed from the drug, according to a recent study.
However, a new study suggests that these effects can be reversed with abstinence. It also found that people who have recently used cannabis had an increased risk of developing mental health problems.
This study evaluated the impacts of cannabis products on memory and cognitive function after ad libitum acute administration of different legal market forms of the herb, each with varying THC:CBD ratios. Participants completed a verbal recognition memory task before (pretest) and shortly after (posttest) ad libitum ingesting their product.
Results from the study show that cannabis products containing mainly THC significantly decrease memory accuracy (d’) after use, while those containing both THC and CBD have no measurable effect on memory performance. Furthermore, d’ was negatively correlated with blood THC levels but not with CBD levels.
Effects on attention
Long-term use of cannabis has been shown to impair attention, concentration and executive function. These deficits are most evident among heavy cannabis users but they can also be seen in occasional users.
Several studies have shown that the effects of cannabis on attention and cognitive function remit with sustained abstinence. However, there is evidence that these effects may persist if frequent or heavy use occurred during adolescence and executive function development was not fully completed at the time of use.
This is because of the way cannabis impacts the brain. The psychedelic compound tetrahydrocannabinol (THC) has been shown to cause changes in the way brain cells are stimulated. These changes can lead to impaired cognitive function and even dementia later in life.
Although there is a large body of research on the short-term impact of cannabis on cognition, most studies are observational and use cross-sectional between-subject designs which do not allow for inferences on causality. Consequently, these findings should be interpreted cautiously.
There are many different hypotheses about the relationship between cannabis and cognitive functioning, most of which do not involve a causal relationship between cannabis use and cognitive deficits. Hence, adequate longitudinal population-based and genetically-informed (co-twin designs) studies are needed to examine the relationship between cannabis and cognitive function more accurately.
The most common hypothesis is the cognitive vulnerability hypothesis, which posits that prior to cannabis use onset, future cannabis users already exhibit mild cognitive deficits. This may be due to unknown common factors, such as genetics or shared environment factors, that could explain the emergence of these deficits.
In addition, the concurrent cannabis impairing hypothesis suggests that cannabis use exacerbates already existing cognitive deficits. This is particularly true for memory.
Effects on decision-making
The impact of cannabis on cognitive function is complex. It can affect memory, attention, decision-making, and learning. It can also cause psychosis and other mental health issues, including anxiety, delusions, hallucinations, and panic.
Adolescents who smoke marijuana may be at increased risk for developing schizophrenia, according to a study. It’s a good idea for teens to use it in moderation, though, to avoid problems later in life.
It can also reduce the ability to concentrate and pay attention, as well as causing a loss of short-term memory and body movement. In addition, it can increase anxiety and paranoia, leading to depression.
Moreover, it can have adverse effects on memory and cognition in those who have a history of mental illness, such as schizophrenia. The drug can also lead to changes in mood, impulsivity and decision-making.
For example, a recent study showed that long-term users of cannabis had smaller IQs than nonusers. They also had more difficulty learning new information and processing speed.
The researchers found that cannabis-related impairments were reversible after a period of abstinence. However, they still remained in many people who had been using cannabis for a long time.
The researchers used an MRI to scan the brains of 799 adolescents in Germany, Ireland and England before they started smoking marijuana, and again 5 years after they stopped. They found that the area most responsible for making decisions – the prefrontal cortex – was significantly damaged in those who had smoked pot during adolescence.
Effects on impulsivity
Despite its reputation for being a drug of abuse, cannabis has shown significant effects on the brain and can alter the way people think. Its effects can include a loss of executive control and impulsivity, which can lead to problems with memory, attention and decision making.
It also has been shown to have a direct impact on the psyche, with some studies showing a link between cannabis use and psychosis. In one study, it was found to increase the risk of developing schizophrenia.
This may be due to the changes in brain structures in chronic marijuana users, including reduced fractional anisotropy (FA) and increased diffusivity of axons in the frontal cortex, cingulum and dlPFC [37, 41]. These alterations could be linked with impulsive behavior and have also been observed in young cannabis users compared to non-users.
To assess the acute effects of a single dose of cannabis on impulsivity, 37 subjects were tested on four behavioral measures of impulsivity before and after a double-blind trial. They were administered capsules containing placebo, 7.5 or 15 mg THC in randomized order for three sessions.
The results showed that THC increased impulsive responding on the Stop task but did not meaningfully affect performance on the Go/no-go or Delay discounting tasks. These findings are important as they suggest that a number of processes are involved in impulsive behavior and that THC affects only some of these processes.
The lack of effects on several of the impulsivity tasks was also confounded by the fact that the subjects in this study were not high on trait impulsivity. In addition, the subjects used a variety of personality questionnaires to assess their level of impulsivity before the experiment and also after the drug was given. This may have led to an underestimation of the effects of cannabis on these tasks.
Effects on verbal fluency
The plant Cannabis sativa and its derivatives (such as hemp) contain chemicals called cannabinoids that cause drug-like effects all over the body, including in the brain. The chemicals bind to cannabinoid receptors in the brain and influence how it works.
The main psychoactive chemical in cannabis is tetrahydrocannabinol (THC). It has a wide range of effects on the brain, including affecting emotions and memory. It is also used to treat nausea and pain.
Studies have shown that long-term use of cannabis can have negative effects on verbal fluency. It is important to note that these effects are only temporary and reversible.
Some researchers have found that using a high-concentration of cannabidiol (CBD) can have positive effects on memory and attention. However, it is essential to remember that CBD is not the only compound in marijuana.
To examine the effect of cannabis on verbal fluency, researchers have used a variety of tests. Some measure working memory, while others focus on attention. The Symbol Digit Modalities Test (SDMT) and the Paced Auditory Serial Addition Test (PASAT) are two of the most commonly used.
Other studies examined the impact of cannabis on processing speed. Some of them found that the drug improved processing speed in both dominant and non-dominant hands, but the effect was not significant after one or four hours.
These findings suggest that the long-term impact of cannabis use on cognitive function might be relatively small, but they have important implications for research on this subject. This suggests that future studies need to be designed with a more experimental approach to investigate the effects of cannabis on cognitive function. For example, researchers should design studies to measure the residual effects of cannabis on multiple domains, which will allow for inferences about causality.
