By Max Sargent


Cannabis has long been linked to low IQ, with a general reputation that it somehow makes people less smart. However, the issue is incredibly complex, and we do not yet know what the effects of cannabis on intelligence are. For that matter, we do not yet really know what intelligence is. However, studies are beginning to reveal that although there is a link between cannabis use and IQ, it may not be a causal one.

What Is IQ?

IQ stands for “intelligence quotient”, and serves as a quantifiable way of testing and measuring a person’s intelligence. It is considered by many a controversial measure, but more on this shortly.

IQ is measured by the famous IQ test. There are many versions of the IQ test, and some go by other names. However, they tend to be fairly standardised these days. They may test abstract reasoning, logical reasoning, verbal reasoning, general knowledge, and more.

Around two-thirds of participants will score between IQ 85 and IQ 115. About 2.5% will score above 130 or below 70.

What Does IQ Actually Tell Us?

Far from being a pure metric of intelligence, IQ has been examined for being influenced by many different factors, few of which directly tell us about the fundamental functions of someone’s brain, but rather about a host of interacting physical and environmental factors. What’s more, “intelligence” itself is an elusive concept, which makes measuring it very difficult.

While IQ tests may be a valid measure of a limited type of “academic intelligence”, they fail to tell us much about social intelligence or creativity. Therefore, even by placing stock in IQ, we can observe our own biases regarding intelligence and the culturally ingrained values we have surrounding it.

Moreover, the types of cognitive ability IQ measures have been strongly linked to environmental factors. While this does not mean that they don’t measure intelligence—there is no reason intelligence shouldn’t be a sociobiological interaction—it does mean that it brings biases with it, and perpetuates them. For instance, IQ tends to reward people like those who created it—middle-class white men.

Studies show that differences in average scores between different racial groups can be attributed to socioeconomic factors[1], rather than genetic ones. Indeed, a rapid closing of the gap[2] is clear evidence that environmental, rather than inherent, differences are the cause of such findings. What does this tell us? That IQ can be taken as a measure of someone’s background[3] as much as their intelligence.

What Does IQ Actually Tell Us?

  • Why Is This Important?

A little background of the flaws associated with IQ is important, as the correlation between cannabis use and reduced IQ may depend on these flaws. Simply put, cannabis use is related to lower IQ. However, upon closer inspection, it appears that cannabis use and low IQ may share similar causes, rather than one causing the other.

Does Weed Lower IQ?

Cannabis use, especially in adolescence, has long been said to cause a reduction in IQ over time. There are many studies that support this hypothesis. However, when you delve a little deeper, it transpires that cannabis may not be the cause after all.

Evidence That Marijuana Lowers IQ

It does seem to be the case that cannabis use in adolescence and a lower IQ are linked. For instance, a study by Meier et al.[4] tested the IQ of 1,037 participants at age 13, and again at 38. Between these ages, they were interviewed at 18, 21, 26, 32, and 38 in order to ascertain their cannabis use.

It was found that there was a statistically significant decline in IQ in users who were deemed to have “persistent” cannabis habits. Moreover, the decline was concentrated among those who began using cannabis during adolescence. Perhaps concerningly, it was also observed that cessation from cannabis use—even for long periods of time—did not reverse this decline. It was concluded that cannabis has neurotoxic effects on the developing adolescent brain.

More recently, a longitudinal study by Power et al.[5] found that persistent cannabis use in adolescence is linked to an average drop of two IQ points. This study screened 2,875 papers, and eventually conducted a meta-analysis on seven of them. These seven papers contained 808 cases and 5,308 controls. It is likely that this is the largest longitudinal meta-analysis regarding cannabis’ effects on IQ to date.

It found, as other studies have, that cannabis use in adolescence was linked to a drop in IQ, most prevalently to verbal IQ change.

However, while this study draws a clear correlation between cannabis use and IQ decline, it cannot point to cannabis being the cause of this decline. One important facet of all scientific testing: correlation does not equal causation.

There are many studies demonstrating that although cannabis use and declining IQ are connected, this does not mean that cannabis is necessarily the cause.

Evidence That Marijuana Lowers IQ

Evidence That Cannabis Does Not Cause a Low IQ

There is increasing evidence that the observed decline in the IQ of cannabis users has causes that predate cannabis use. Not only this, but cannabis use is thought to share these causes, explaining the strong correlation between what may be two effects of more difficult-to-identify causes.

Studies on twins are incredibly useful ways of distinguishing causes. Though averages can be gleaned from large populations, it can be difficult to apply these to any one individual, as you can’t know what that individual would have been like in any of their contingent futures.

In the context of cannabis, while it is possible to say that chronic smoker X has seen a two-point decline in IQ while non-smoker Y has not seen a decline, as persons X and Y are different, it’s hard to determine if person X would have seen this decline had they never smoked.

Studies on identical twins go some way to remove this problem, as one can work as the other’s control group. Due to genetic similarities and similarities in upbringing (this is the most contested aspect of twin studies—small differences can have big outcomes), it is deemed easier to isolate causes for differences between twins. In the case of cannabis use, if one twin uses cannabis and has a lower IQ than the other who doesn’t, and this is observed across twin pairs, the conclusion that cannabis use causes low IQ could be drawn.

Studies show this is not the case.

A longitudinal study by Jackson et al.,[6] which included many twin pairs, found that while cannabis use could be linked to a drop in IQ, this did not hold up with the twin pairs. In twin pairs in which one used cannabis during adolescence and the other did not, there was no significant difference in IQ between them at any point during the research.

From this they concluded that other factors, such as socioeconomic factors and familial factors, were responsible for the loss in IQ points, and not cannabis use.

Likewise, another study, again by Meier et al.[7], demonstrates the same findings. There were three important discoveries in this study. First, those who smoked cannabis were observed to have a lower IQ by age 12, prior to cannabis initiation. Second, while their IQs did drop over the proceeding years (during which they used cannabis), the drop was no greater than that observed in the participants who did not use cannabis. Third, the differences observed between users and abstainers were not observable in twin pairs where one used cannabis and the other did not. They too concluded that other factors were behind both cannabis dependency and a lower IQ.

It’s important to note that neither of these studies concluded that low IQ causes one to smoke cannabis.

Evidence That Cannabis Does Not Cause a Low IQ

Though more needs to be done, research seems to show that socioeconomic and environmental factors cause both a decline in IQ and persistent cannabis use in adolescence. Linking back to the beginning, as it has been shown that socioeconomic factors were the cause of racial differences between IQ scores, so too could they explain the differences between those who use cannabis and those who do not.

All that being said, we must not assume that cannabis use does not negatively impact IQ, especially in those who use it when their brains are still developing. It would be foolish to suggest there is no link between adolescent use and decline in IQ, even if the link is not a causal one. Therefore, we suggest not using cannabis until adulthood.

External Resources:
  1. Group differences in IQ are best understood as environmental in origin - PubMed https://pubmed.ncbi.nlm.nih.gov
  2. SAGE Journals: Your gateway to world-class journal research https://journals.sagepub.com
  3. IQ testing 101 : Kaufman, Alan S., 1944- : Free Download, Borrow, and Streaming : Internet Archive https://archive.org
  4. Persistent cannabis users show neuropsychological decline from childhood to midlife | PNAS https://www.pnas.org
  5. Intelligence quotient decline following frequent or dependent cannabis use in youth: a systematic review and meta-analysis of longitudinal studies | Psychological Medicine | Cambridge Core https://www.cambridge.org
  6. Impact of adolescent marijuana use on intelligence: Results from two longitudinal twin studies - PubMed https://pubmed.ncbi.nlm.nih.gov
  7. Associations between adolescent cannabis use and neuropsychological decline: a longitudinal co-twin control study - PubMed https://pubmed.ncbi.nlm.nih.gov
Disclaimer:
This content is for educational purposes only. The information provided is derived from research gathered from external sources.

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Privacy Policy - Royal Queen Seeds

To ensure a safe online environment and guarantee adequate data protection, we strictly comply with all legal requirements. In this privacy statement, we provide information about how and for what purpose data is collected, safety measures, storage periods and contact details.


COMPANY NAME: SNORKEL SPAIN, SL (hereinafter ROYAL QUEEN SEEDS)

C/ Vilar d'Abdelà, 5 (nave 1) CP: 08170 de Montornès del Vallès

+34 937 379 846

support@royalqueenseeds.com


The present Privacy Policy sets out the terms on which we will treat personal data at ROYAL QUEEN SEEDS; this includes any personal data collected through our website https://www.royalqueenseeds.com/ as well as any other data we process in the course of our business activities.

ROYAL QUEEN SEEDS collects the following personal data for the purposes listed below:

SECTION 1 – PERSONAL INFORMATION WE COLLECT

1.1 Account purchases

Account purchases can only be made if you are in possession of a personal account. When you create an account or purchase something from our shop, as part of the buying and selling process we collect the following personal information that you provide to us:

This information is required for delivery. In addition, when you browse our shop, we automatically receive the Internet Protocol (IP) address of your computer. Based on this information, we can optimise your online experience and at the same time protect our online environment.

Purpose of data collection

We collect and store account-related data for the following purposes:

(a) to carry out obligations arising from any contracts between you and us, and to provide you with information, products and services that you may request from us;

(b) to set up, manage and communicate with you about your account and your orders;

(c) to conduct market research and analysis;

(d) to confirm your age and identity, and to detect and prevent fraud.

1.2 Newsletters

With your explicit permission, we may send you newsletters about our shop, new products and other updates. We send newsletters based on your explicit consent. In the event that you purchase a product, and in accordance with current regulations, we may send you commercial communications in accordance with the legitimate interest of our company, always about products or services similar to those you have purchased or contracted. In any case, you may exercise your right of opposition through the channels announced in this Privacy Policy. The following information is collected in relation to the newsletter:

We do not need to know the sex of the person in order to send the newsletter (data minimisation: by law we must ask for data that is strictly necessary to provide the service, and in this case knowing the sex is not necessary to send the newsletter).

Purpose of data collection

The data collected is used to:

(a) personalise our emails, including your name and gender;

(b) provide gender-specific content.

You can withdraw your consent at any time by using the link provided in the newsletter or the contact information provided in section 2.

1.3 Customer service and contact form

In order to provide appropriate support, our customer service employees have access to information related to the account. Consequently, their support will be highly effective and friendly. The data provided in our contact form is used by our CRM provider, SuperOffice. We will only use your details to respond to your message.

SECTION 2 – LEGITIMATE INTEREST

If you have purchased any of our products, please note that we may process your personal data for promotional purposes, based on Royal Queen Seeds' legitimate interest only to offer you products or services from our company and about products or services similar to those you have purchased. You may exercise your right to opt out of future messages by the means set out in this Privacy Policy or through any notification you receive.

2.1 How do you withdraw consent?

If you change your mind, you can withdraw your consent for us to contact you for the purpose of collecting, using, or disclosing your data at any time by reaching out to us at: support@royalqueenseeds.com.

SECTION 3 – DISCLOSURE

We may disclose your personal information if we are required to do so by law or if you breach our Terms of Service.

SECTION 4 – HOW LONG DO WE KEEP YOUR DATA?

At Royal Queen Seeds, we will not retain your data for longer than is necessary for the purposes described in this Policy. Different retention periods apply for different types of data; however, the longest period we will normally hold any personal data is 10 years.

4.1 Account information

Data relating to the account remains relevant for as long as the consumer is in possession of an account. Therefore, the data remains documented for as long as the account exists. When our customers delete an account, the associated data will be deleted within a reasonable period of time. Requests regarding the inspection or correction of stored personal data or the deletion of an account can be sent to support@royalqueenseeds.com.

4.2 Newsletters

In the event that you give us your consent to inform you about our products or services, we will keep your data until you express your wish not to receive any further communications from us. However, we regularly (every month) carry out a relevance check. Registered customers (and their personal information) will be deleted whenever customers do not reply to our request. In addition, our newsletter mailing has an opt-out feature. Consumers can withdraw their consent by using this opt-out feature.

SECTION 5 – COOKIES

Cookies are small information files that notify your computer of previous interactions with our website. These cookies are stored on your hard drive, not on our website. Essentially, when you use our website, your computer displays its cookies to us, informing our site that you have visited before. This allows our website to function more quickly and remember aspects related to your previous visits (such as your username), making your experience more convenient. At Royal Queen Seeds, we use two types of cookies: functional and analytical.

5.1 Functional Cookies

Functional cookies are used to enhance your online experience. Among other things, these cookies track what is added to your shopping cart. The use of these cookies does not require prior authorization.

5.2 Analytical Cookies

Analytical cookies are used for research and market analysis. The data collected with these analytical cookies is anonymous, making it unusable for third parties. The use of these cookies does not require prior authorization.

SECTION 5 – THIRD-PARTY SERVICES

Third-party services are required to conduct transactions and provide our services. In general, the third-party providers we use will only collect, use and disclose your information to the extent necessary to enable them to perform the services they provide to us.

However, certain third-party service providers, such as payment gateways and other payment transaction processors, have their own privacy policies regarding the information we must provide to them for your transactions.

We encourage you to read the privacy policies of these providers so that you can understand how these providers will handle your personal information.

In particular, certain suppliers may be located or have facilities located in a different jurisdiction than yours or ours. Therefore, if you choose to proceed with a transaction involving the services of a third party, your information may be subject to the laws of the jurisdiction in which that service provider or its facilities are located.

Once you leave our website or are redirected to a third-party website or application, you are no longer governed by this Privacy Policy or the Terms of Service of our website.

Web analytics service (anonymous data)

On this website we have integrated an element of a web analytics service (with anonymisation functionality). Web analytics can be defined as the gathering, processing and analysis of data about the behaviour of visitors to websites. An analytics service collects, among other things, data about which website a person came from (the so-called referrer), which sub-pages they visited or how often and for how long they visited a sub-page. Web analytics is mainly used for website optimisation and for a cost–benefit analysis of internet advertising.

Courier service

To complete deliveries we use a courier service. This courier service carries out the delivery between our company and the consumer's home. To complete these logistics, the company requires access to the consumer's name and address information.

Mailing service

Royal Queen Seeds uses a third-party mail service provider to send its newsletter. This provider has access to limited account information related to opt-in consent (e.g. email address).

Marketing services

Royal Queen Seeds has the support of a company that specialises in marketing and communication activities. Their access to personal information is very limited and mostly anonymous.

Payment services

At Royal Queen Seeds we use external payment services to handle our transactions (e.g. credit card payments).

SECTION 6 – SECURITY

To protect your personal information, we take reasonable precautions and follow industry standard best practices to ensure that it is not inappropriately lost, misused, accessed, disclosed, altered or destroyed.

If you provide us with your credit card information, the information is encrypted using secure socket layer technology (SSL) and stored using AES-256 encryption. Although no method of transmission over the internet or electronic storage is 100% secure, we follow all PCI-DSS requirements and implement additional industry standards that are commonly accepted. Information related to the account is protected with a hashing method. This method transforms the information into a generated hash. As a result, confidential information is protected and invisible, even to us. In addition, our databases are exceptionally protected against unauthorised access. For example, access to the database is only possible and permitted via approved IP addresses (e.g. from Royal Queen Seeds headquarters). Other attempts and addresses are rejected at all times.

Furthermore, data is anonymised as much as possible, so it cannot be directly linked to a specific consumer. With this data, however, we may be able to carry out market research and analysis. In addition, the third parties concerned (e.g. mailing service) are examined prior to our collaboration, comply with the GDPR from the EU and receive a processing agreement. Within Royal Queen Seeds, employees are assigned different access permissions. Specific permission provides access only to information that is strictly required to perform a task. Digital security measures are subject to change and must meet high requirements to ensure the safety of online customers. That is why, at Royal Queen Seeds, we appoint a security officer. Regular verification and improvement of security measures (where necessary) are part of the role.

SECTION 7 – CHANGES TO THIS PRIVACY POLICY

We reserve the right to modify this Privacy Policy at any time, so please check back regularly. Changes and clarifications will be effective immediately upon being published on the Website. If we make substantial changes to this policy, we will notify you here that it has been updated so you will know what information we collect, how we use it and under what circumstances, if any, we use and/or disclose it.

SECTION 8 – YOU HAVE THE RIGHT TO: