It’s Just Marijuana – It’s Still a Drug; It Still Affects the Brain

“It’s just marijuana!”

I can’t tell you how many times I hear this in my work with individuals and families. Many go on to defend using marijuana as safer, less harmful to self and others, than drinking alcohol. Of course the legalization of prescription marijuana confuses the issue because people think that makes it “safe.” As with all prescribed medications, if taken as prescribed, it can be safe (assuming there are no other complicating factors). The point of this post, however, is to address those who proclaim, “It’s just marijuana.”  Like all drugs of addiction and alcohol, which I’ll refer to as “drugs” going forward, marijuana changes the way the brain works. To better understand, let me first explain neural networks.

Neural Networks

Neural networks are the brain and body’s communication system. Basically it’s one cell talking to another cell. Neural networks in the brain control everything we think, feel, say and do via their talking to one another and to and from others in the body via the nervous system.

It's Just Marijuana - It's Still a Drug; It Still Affects the Brain

This is an illustration of a neural network. Like all drugs, marijuana affects the brain and its normal functioning because of its impact on neural networks – the brain and body’s communication system.


A few basics of a neural network describe in the above illustration, include:

  • Brain cells – neurons in the brain.
  • Branchlike extensions – carry the outgoing electrical signal (called an axon when it’s outgoing) or the incoming electrical signal (called a dendrite when it’s incoming).
  • Synapses – the gap between branchlike extensions.
  • Neurotransmitters – the chemical messenger that is triggered at the end of one brain cell’s branchlike extension (axon) that converts the electrical signaling into “something” that can float across the synapse.
  • Receptors – located on the receiving branchlike extension (axon) to accept the neurotransmitter. The neurotransmitters lock into these receptors like keys in a door lock. The receptors convert the message/signal back to an electrical signal that shoots up to the incoming branchlike extension on the receiving cell (neuron). That cell decides whether to continue or stop the messaging.

Each type of neurotransmitter has its own type of receptor and visa versa. Some of the commonly known neurotransmitters are dopamine, serotonin and norepinephrine. Having all components in a neural network healthy is what helps with the brain and body’s smooth, efficient communication system. Think of it as string after string of holiday lights. Pull out one – just a smidge – and the whole strand malfunctions.

What Drugs Do to Neural Networks

Drugs are chemicals and they all reach the brain via the bloodstream. This entry can be through the lungs if smoked, directly into the bloodstream if injected, or through the small intestine, as with alcohol, for example.

Once in the brain, the drug chemicals tap into the brain’s neural network communication system and interrupt how neurons normally send, receive and process information.  Take Marijuana for example.

In the case of marijuana, its main active ingredient is THC. THC binds to specific sites called cannabinoid receptors (CBRs). These receptors are found in high-density in areas of the brain that influence pleasure, memory, thinking, concentration, movement, coordination, and sensory and time perception.  

When someone smokes marijuana, THC stimulates the CBRs artificially. An overstimulation of these receptors in key brain areas produces the marijuana “high,” as well as other effects on mental processes. Over time, this overstimulation can alter the function of CBRs, which, along with other changes in the brain, can lead to addiction and to withdrawal symptoms when drug use stops.  NIDA’s “How Does Marijuana Produce Its Effects.”

Bottom Line

It doesn’t matter what the drug is – even if it’s just marijuana. There is an impact in the brain. To find out the specifics of individual drugs, check out NIDA for Teens: Facts on Drugs.

And check out NIDA’s Drugs, Brains, and Behavior: The Science of Addiction for even more information on the science that explains how drugs – regardless of the kind – change the brain. You may also be interested to read about marijuana’s effect on a person’s ability to drive safely.

Lisa Frederiksen

Lisa Frederiksen

Author | Speaker | Consultant | Founder at
Lisa is the author of hundreds of articles and 11 books, including "If You Loved Me, You'd Stop!," "Addiction Recovery: What Helps, What Doesn't," and "Secondhand Drinking: the Phenomenon That Affects Millions." She is a national keynote speaker with over 25 years speaking experience, consultant, and founder of She has spent more than 14 years studying 21st century brain research in order to write, speak, and consult on substance use disorders prevention, intervention and treatment; mental disorders; addiction (aka substance use disorders) as a brain disease; adolescent addiction treatment vs adult addiction treatment; effective treatment for co-occurring disorders (having both a substance use and mental disorder); secondhand drinking | drugging; help for the family; and related subjects. In 2015, she founded SHD Prevention, providing training and consulting to companies, public agencies, unions, nonprofits and other entities to address the workplace impacts of employee secondhand drinking and alcohol misuse.
Lisa Frederiksen

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27 Responses to It’s Just Marijuana – It’s Still a Drug; It Still Affects the Brain

  1. This is such a touchy subject, Lisa. I know a dear friend who is in constant pain from several illnesses and occasionally she is prescribed marijuana for pain. It makes her sleep but the few hours of not having pain, is worth it for her. I am not one to say what is right or not. I believe it is a choice that each individual must make. Unless we are in their shoes, who are we to judge. Thanks for sharing your views and providing links to more information. I pray that I’ll never be in a position where I have to decide to take drugs or meds.

    • Oh gosh, Alexandra, I didn’t mean for it to come across judgmental — I absolutely agree we can never be the judge for what does and does not work for someone. My point was the legalization is often what people cite as the reason it’s safe to use. As with all prescribed medications, it should be used as prescribed. The point of my post was that all drugs (marijuana included) impact the brain and how that impact takes place — even if it is “just marijuana.” I appreciate you adding your comment and will try clarify this in the post for future readers.

      Note to all readers: I have gone back and revised the opening to make this point more clearly (I hope).

  2. Solvita says:

    Thank you, Lisa. This is good to know for those, who use the drug. Every drug is so harmful to our health and well being, so sad to see people getting trapped and addicted. It is great; you are building up more awareness about this issue, in a such an educational way. Love it!

  3. Martha Giffen says:

    So sad. ANY drug that alters the brain is dangerous. When will folks “get” it??

  4. I’m with you. It needs to be used for heath and pain management nit for recreation. Thank you for writing and publishing such fact backed articles. The use of drugs and substance can be very damaging to a relationship too! Many good relationships are ruined by so called “not” harmful substances.. It matters.

    • You are so right, Barbara! The brain changes caused by substance abuse change how the brain works, which in turn causes behavioral changes that are extremely detrimental to a relationship. Thanks for adding your comment!

  5. Lisa, this was an excellent explanation as to why marijuana is just as dangerous as any substance. People really don’t realize how damaging it can be. thanks!

  6. I love that you are educating people, Lisa! I, too, have a reaction whenever I hear “it’s just marijuana.” I tweeted this and hope lots will read it.

  7. Great post, Lisa! I agree with Alexandra though, there are times when someone needs it for medical reasons. A few years back when my son was having chemo that was the only thing that seemed to help him to be able to eat. He did have a prescription for it. Thanks for sharing your wisdom and knowledge 🙂

    • Thanks so much, Susan! And I appreciate the point you and Alexandra make that taking drugs (marijuana, included) as prescribed can be incredibly helpful and important for patient health.

  8. Marie Leslie says:

    I have never been an advocate of any kind of “recreational” drug use–and the “it’s just marijuana” drives me crazy. I have seen great potential wasted by some who bought into that lie. All drugs, whether used to treat illness or for other reasons have the potential for abuse.

    I believe marijuana has some definite medical benefits and I wish they would find a better way to control and distribute it for legitimate medical purposes than our current “dispensary” system, which is a disaster.

  9. Hi Lisa,

    Thank you for this much needed post! Saying that it is “just marijuana” is really being in denial about the danger of any drug use. The brain changes affect how we function in the world, as well as affect our ability to reach our full potential.

    The struggle with marijuana is that many people can function on some level, so they are not as willing to admit they have a drug problem.

    Appreciate the information. Take care and have a great weekend!

    • Thank you, Cathy. And I agree with your comment that the struggle with marijuana is that many people can function on some level, which is the similar problem with alcohol. Hopefully people will better appreciate it doesn’t matter the drug – in moderation, it can work fine — it’s when a person abuses it that the trouble with structural and chemical changes in the brain begins. You have a great week-end, as well. Take care.

  10. MK says:

    I believe marijuana is a bit less harmful than alcohol – but that does not mean it is harmless. So go ahead and relax with a toke on the weekend or after a hard day at work. But, if you are ‘waking and baking’ or doing it everyday, remember it is a drug and it will affect you and your life. Written with loving kindness, not judgement.

    PS – Of course, it does have real, valid medicinal uses – like many drugs. But, like many drugs, it is valuable to the person with the medical need, yet harmful to the healthy person who ingests it. Imagine taking your friends heart medication when your heart is just fine. You wouldn’t do that, would you?

  11. Good info. Thx for posting 🙂

  12. Sharon O'Day says:

    I really appreciate the explanation of the mechanical impact of drugs … which removes any doubt of the destructive impact of the substances. Even when used for pain relief, as marijuana may be, the destruction is still there … but is simply being weighed against the benefit.

  13. […] It’s Just Marijuana – It’s Still a Drug; It Still Affects the Brain, Lisa Frederiksen […]

  14. Jim says:

    You make Marijuana out to be harmful and addicting. That’s simply not the case, as any previous or current marijuana user could tell you. You compare Marijuana with other prescription drugs and alcohol.. both of which can easily kill/harm you when taken recklessly. Marijuana cannot harm anyone physically and certainly cannot kill someone. You are tarnishing the reputation of a beautiful drug with no serious dangers to the normal healthy minded person. YOU are doing harm.

    • Thanks for your comment and sharing your views, Jim. This source from the National Institute on Drug Abuse (NIDA) shares some of the science about marijuana. For example, “Many people don’t think of marijuana as addictive—they are wrong. About 9 percent of people who use marijuana become dependent on it. The number increases to about one in six among those who start using it at a young age, and to 25 to 50 percent among daily users,” quoting from this link: This is not to say that all people who use will be come addicted, just as not all people who drink become alcoholics.

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