Marijuana and Memory
The illegal and legal use of marijuana is widespread, and for millions of people
all over the world, it is their recreational drug of choice. Marijuana is by far the
most widely available street drug and the compound of THC in cannabis
reportedly causes pleasure and euphoria among users. Although marijuana use
is most popular among teenagers and young adults, usage among older adults is
prevalent well into middle age. This is especially true with medical marijuana,
which is now legal in twenty states and is used widely for relief of pain, control of
epilepsy, help with nausea for chemotherapy in cancer patients, and a whole
host of other ailments. But how dangerous is marijuana and what effects does it
have on memory and basic functioning? Does marijuana irrevocably damage the
maturing brain in young people and act as a precursor for psychotic behavior and
conditions such as schizophrenia? Does marijuana affect I.Q.? And finally, does
the widespread legality of marijuana and ensuing problems with perception and
memory lead to reckless behavior, with disregard for physical and mental health,
especially leading to irresponsible and dangerous driving behind the wheel?
The scope of this analysis will focus on marijuana’s implications for memory
and cognitive abilities including IQ and the predilection for chronic disease such
as schizophrenia, the harm that marijuana has on development of the
development of adolescent brains and the social ramifications of that harm, and
finally, with the advent of medical marijuana, how cognitive deficits affect driving
and performing simple tasks, i.e., the long term implications for marijuana use.
The research is conclusive when it comes to cognitive difficulties with
marijuana, it does impair memory, especially working memory or short-term
memory. Working memory is responsible for managing immediate and current
information used for reasoning, perception, and comprehension. Short-term
memory affects verbal intelligence, reaction time and the completion of tasks
simultaneously or multi-tasking (Smith, Longo, Fried, Hogan, Matthew, &
Cameron, 2010). Using science in layman’s terms, marijuana negatively affects
memory by attacking neurons related to memory in the brain, causing them to
collapse and shrink thus causing disability.
Marijuana usage affects the frontal lobe of the brain, which affects making
decisions and solving problems and in turn causes attention and response
difficulties. The research used MRI technology to monitor blood flow to the
affected areas. Cannabis use, in short, decreases overall mental flexibility. Two
distinctions are important here, first, the age in which the individual started
smoking marijuana was an important factor, and second, how much marijuana is
smoked per week. In most studies, the targets studied were primarily heavy
users of cannabis with some exceptions. By far, the overwhelming opinion was
that the younger use or abuse was started, the worse the memory and related
cognitive problems.
Regarding marijuana affecting overall I.Q the research is mixed, but mostly
erring on the side that cannabis does affect I.Q. negatively as far as testing and
performance goes. This is because cannabis users often do poorly on the
memory and verbal sections of an I.Q. test. Long-range studies have shown that
individuals who used cannabis from an early age saw a downward spiral in I.Q.
scores for a period of twenty-five years. This trend was true even for those
individuals who has stopped smoking cannabis years before. Scientists say
cannabis use permanently weakens the network of specific memory brain
neurons and causes them to collapse on themselves, causing cognitive
problems. Many researchers hold that short-term memory loss as well as other
cognitive difficulties, directly affects intelligence (Dougherty, Mathias, Dawes,
Furr, Liguori, Shannon & Acheson 2013). The latter researchers believe that I.Q.
is at risk because the ability of the mind to properly assign importance to life’s
events and to memorize items and numbers in a sequence directly affects the
ability to solve problems. And this is true with both verbal problems and
numerical problems. Of course, whether this problem is short term, and goes
away with discontinued use of cannabis is an area for further study. One
important component of measuring intelligence is the age at which a given
individual started using cannabis. The earlier an individual used the drug, the
more pronounced the memory loss and motor function is (Hanson, Lucian 2010).
Low I.Q. has huge ramifications on a young person’s self esteem and affects
performance in school, performance in a job as well as future job choice and
success, the hallmarks of a young person’s future.
Another topic under discussion in the research is whether marijuana use and
the resulting loss of memory, perception, and motor function among young teens
can go a step further and precipitate mental illness, including psychotic disorders
such as schizophrenia. In short, can marijuana permanently damage the brain?
Schizophrenia usually strikes younger people and because a disproportionate
number of people with Schizophrenia have and continue to smoke marijuana,
corresponding studies have been made. The literature is divided as to whether
there is already a genetic factor present that could cause mental illness or if
marijuana itself causes the break in mental functioning (Balderston, Rhea, &
Crockford, 2014). There is similar brain activity in people with schizophrenia and
those with chronic marijuana abuse, and schizophrenia shares many of the same
tenants of marijuana use, loss of short-term memory, attention problems,
problem-solving difficulties and reaction time (Stern, 2014). The results most
often conclude that underlying illness factors and genetics were present prior to
marijuana use, but that cannabis use, with this particular affliction, makes the
symptoms worse (Malchow, Hasan, Fusar-Poli, Schmitt, Failai, & Wobrock
2014). The debate on this topic is still ongoing.
The final issue concerns how marijuana use affects society as a whole. With
the proliferation of medical marijuana, legal now in twenty states and totally legal
in two, Washington and Colorado, and the fact that marijuana usage grows
exponentially every year, there are dire consequences concerning health, and
specifically on reckless driving behind the wheel. The fact that medical
marijuana is more powerful now because of plant manipulation is troubling. The
diminishment of short-term memory and impaired judgment, poor decision
making, decreased motor function and planning that cannabis users demonstrate
in test after test lead to high risk behaviors that aren’t rational, and have huge
implications on mental and physical health. Surprisingly, smoking a marijuana
cigarette is ten times more damaging to the lungs than smoking one tobacco
cigarette and chronic use can cause lung cancer. And despite large-scale drug
prevention campaigns that start in grade school, the use of marijuana has not
decreased. Marijuana users show little concern for the potential dangers of
marijuana and only describe the positive effects of the drug (Alfonso & Dunn,
2007). In other words most users do not think of the future and possible dangers
of the drug.
Besides lack of concern regarding physical or mental health, individuals under
the influence of marijuana take part in dangerous sexual behavior, have poor
performance in school with a growing drop out rate (the batteries of tests telling
students they are “less than” don’t help), and tend to drive recklessly, having
trouble changing lanes and braking at an appropriate time, endangering both
themselves and others. There are serious, potential life-threatening problems
when individuals drive under the influence of marijuana. The poor spatial
memory, lack of flexibility, lack of movement coordination, lack of good motor
function, and poor reaction time, leads to accidents and driving poorly because of
poor coordination (Penning, Veldstra, Daamen, Oliver, & Verster 2010).
Marijuana does indeed cause short-term memory deficits and an array of
cognitive deficits as well. Marijuana use also negatively affects I.Q and test
taking in the areas of short-term memory and perception. In addition, marijuana
complicates the issue of further mental illness, and brain development. Finally,
marijuana use causes individuals to exhibit risky behavior, disregarding mental
and physical health. The latter point especially predicts poor driving performance
and places individuals, under the influence of marijuana, in serious danger of
having or causing traffic accidents. A question this study invites is whether the
discontinuation of marijuana use stops the short-term memory deprivation,
perception difficulties, and cognitive deficits so common in users of cannabis.
Many researchers say memory loss is permanent and I.Q. loss is persistently
lower than with individuals who have never used marijuana. No matter what the
further studies of the permanence of marijuana use prove, the fact that marijuana
usage, especially with chronic use and individuals beginning at an early age, is a
deterrent to the maturation of young minds and causes serious memory and
perception problems that seriously affect a young person’s array of choices for the future.
By Rhonda Morrison
First published in Psychology Today