Letter to Sven Andreasson on his longitudinal study of Swedish conscripts and confounding data

I have done some research in nuclear medicine on this subject and there are a number of confounding factors that I believe you have left criminally unaccounted for in your research. To begin with, in states with legal marijuana, such as Canada, use of 5 grams and less per day is associated with an increase in IQ of 5 points. My own research in nuclear medicine looking at the blood flow of the brain supports this, after half a pack of marijuana cigarettes over 6 months most of my brain was normal, with one area with increased activity. According to MRI studies there has been little change in the brain observed, though conclusive evidence exists that the size of the amygdala increases and some indication that the part of the brain associated with addictive behaviour becomes less prominent, here a benefit, though this was not substantial enough to say for certain. Ultimately, biologically what is claimed about marijuana in this longitudinal study is in conflict with studies in Canada that had a high level of accuracy that followed users from 12-17 to 25 and later points in life as well as the most recent SPECT and MRI imaging studies.
The most important confounding piece of evidence does not rely on new technology, or different methodology, however, and it is quite sad that this was not accounted for in this expensive research costing the Swedish government severely. According to the CDC the majority (between 65% and 86%) of schizophrenia can be attributed to the parasite toxoplasmosis gondii. To suggest that something without a logical biological explanation is responsible when it is quite simple how the microbe targets brain and muscle tissue to lay its eggs and the body’s protective cysts disrupt bloodflow is quite unethical. The explanation for how it goes in uneven amounts in marijuana users is quite simple, a cat defecating into a potted marijuana plant will contaminate the product for up to a year later.
I do not know the statistics in Sweden off the top of my head, but in the United States 22.5% of people are infected in their lifetime with t. gondii. Of these 25% (5-6% of the general population) get flu-like fatigue and fever, other psychotic symptoms for one week to as long as a month or three months. 6% will have latent symptoms, lasting longer than 6 months and will be diagnosed as schizophrenic. This is the majority of the 1.2% diagnosed with schizophrenia in the USA. It is dose dependant, and getting exposed to the parasite later in life or going thru a period of immunosuppression will cause a recurrence of behaviour.
Please provide an addendum to your research as I have done mine (this came up only as I was publishing, at first I thought to say there were some mild changes, nothing significant from marijuana, luckily I had prefaced my research by emphasizing that marijuana was decriminalized or illegal and the results may be different in a legal setting, as they indeed turned out to be) providing for these confounding factors.
Thank you,
Paul Fischer

Effect of under-regulated Marijuana or Alcohol on blood flow (circulation) of the brain

Effects of under-regulated or decriminalized regular or light marijuana, alcohol, and tobacco use on the brain – Single Photon Emission Computed Tomography

These are the brains of various substance users, including the marijuana user, center in states with illegal or decriminalized marijuana laws. On the right are alcoholic and various other drug users. Using four times a week over the period of three years, this heavy user’s brain is scalloped out, and damage to the blood circulation in the brain is apparent. In a normal person without any substance use and in continued sobriety, seen at the top, there is no damage to the circulation of the brain. Due to statistics suggesting infection from toxoplasmosis, the information provided here regarding marijuana, which is frequently homegrown may be incorrect. An addendum is provided at the end explaining this. The scan remains an excellent example of light alcohol use as well as the impact of potential parasitic infection or pesticide exposure from using marijuana in a decriminalized or illegal setting.

With the alcohol and other drug users, this looks like swiss or cottage cheese after decades or years of abuse. Interestingly and significantly, an example of a weekend only drinker is provided. The brain still looks completely decimated by the alcohol use, dismissing the concept that just sometimes using alcohol limits or reduces the damage done by the neuro-toxins present in alcoholic beverages. I wondered what might occur with light marijuana use (and much less alcohol use).
After about a year of sobriety (enough time for the circulation of the brain to return completely to normal), this experiment involved use of one half to one full ounce of marijuana and around 36 beers over a 6 month period and getting a single photon emission computed tomography scan which accurately shows brain function and substance use.


Source: The Hanley Center, Amen Clinic, Siemens

Over a six month period, occasional use of around 36 beers, seen following, moderate non-consecutive use and between one half and one full ounce of marijuana, medium quality consumed less than one half of a gram at a time. The damage to blood flow in the brain is clearly beginning in the same areas as that exhibited by an alcohol and marijuana user, though only a fraction of the levels as displayed through heavy use. This indicates positively that light substance use has a legitimate and severe negative impact on multiple areas of cognitive and motor skill functioning as well as emotional processing. It must be noted, however, that in a legal setting the impact of pesticide and parasite free marijuana may be completely different from alcohol, and some studies have connected current light marijuana use with an increase in IQ (though alcohol remains negative regardless of legality). The scalloping seen on the top of the head is light, and most likely caused by alcohol consumption, along with reduced circulation to decision making and memory functions which are likely caused and exacerbated by marijuana consumption as well. Full recovery is expected in less than six months, if in keeping with other subjects. There is currently no permanent structural damage, as expected as well. No significant history of physical brain trauma, ie. head injury or medical problems to rule out. Some prior use of hallucinogens including absinthe, but several years past and not apparent in this scan. Use of marijuana in this scan is after 7 years, and is normal in comparison to a caffeinated scan obtained later from another, non-substance using individual (see above).

Imaging by Eclipse Nuclear Medicine
Facility: The Hanley Center

Addendum: Due to information on infection from toxoplasma gondii and resulting psychosis and schizophrenia that has only been compiled in a meta-analysis in 2014, the impact of marijuana on the IQ may be incorrect in places with legalized marijuana industries. It would appear that the perceived effects of marijuana are in actuality the effect of a small parasite that is present in many cats, the fece of which will infect soil and crops in a home-grow operation for up to a year. The information provided here on the impact of illegal or decriminalized marijuana holds, however, as these laws encourage home grown operations meaning many users will contract the parasite as they will buy from a cat owner at some point. Also please remember that psychosis is pursuant to nearly all child abuse cases, and in 50% of students who were victims of bullying.


Amen, Daniel G., and Martin Waugh. “High resolution brain SPECT imaging of marijuana smokers with AD/HD.” Journal of psychoactive drugs 30.2 (1998): 209-214.

Callender, Thomas James, Lisa Morrow, and Kodanallur Subramanian. “Evaluation of chronic neurological sequelae after acute pesticide exposure using SPECT brain scans.” Journal of Toxicology and Environmental Health, Part A Current Issues 41.3 (1994): 275-284.

Fried, Peter et al. “Current and Former Marijuana Use: Preliminary Findings of a Longitudinal Study of Effects on IQ in Young Adults.” CMAJ: Canadian Medical Association Journal 166.7 (2002): 887–891. Print.

Mariani, Giuliano, et al. “A review on the clinical uses of SPECT/CT.” European journal of nuclear medicine and molecular imaging 37.10 (2010): 1959-1985.

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