By R. Ryan S Patel DO, FAPA OSU-CCS Psychiatrist

As of 2016, about 37 million individuals in the United States reported using cannabis / marijuana in the last year (1).

This is projected to increase in the future as many states move to legalize medicinal and or recreational cannabis or marijuana use.

As with many things like excessive junk food, excessive alcohol, tobacco, etc. being legal does NOT ALWAYS mean being  healthy.

For example, a recent study looked at cannabis and false memories (2), while another study looked at memory changes after stopping cannabis (3).

What was the first study? (2)

  • 23 healthy people aged 18 to 29 with and without tetrahydrocannabinol (THC).
  • They were asked to learn material while sober.
  • 2 days later, researchers compared memory recall among those who had used cannabis vs those who had not 2 hours before the test.

What were the study results of the first study (2)

In the first study, subjects who used cannabis 2 hours prior to the test were more likely to have false recognition of words and pictures that had not been presented during the sober study session (2).

What does this mean?

This small study suggests that cannabis use might impact academic performance (2), though further study is needed.

What was the second study (3)?

  • 88 individuals (Average age 21 years) who used cannabis at least weekly were randomized to 30 days of abstinence or to a control group, abstinence confirmed through biochemical testing (3).
  • Participants underwent cognitive testing at baseline and then weekly for 4 weeks.

What were the results of the second study? (3)

This 4 week study showed that improvements in memory started at week 1 and continued improvement through week 4. (3)

What does this mean?

  • This small study implies stopping cannabis may improve memory; and further longer, larger studies are underway (3).
  • Subjects used cannabis atleast weekly, and it is unclear if there is a difference in benefit among heavy vs light users.
  • These studies suggest that Cannabis or Marijuana may impact your ability to remember, and may cause false recall during tests; as well as memory improvement after stopping cannabis use.  A previous postshowed that cannabis may increase alcohol intake (4).

How else is cannabis impacting you?

What are some useful resources regarding cannabis?

Drug treatment group at OSU Office of Student Life Counseling and Consultation Service.

Treatment Facilities in the Columbus, Ohio area:

Disclaimer: This article is intended to be informative only. It is advised that you check with your own physician/mental health provider before implementing any changes. With this article, the author is not rendering medical advice, nor diagnosing, prescribing, or treating any condition, or injury; and therefore claims no responsibility to any person or entity for any liability, loss, or injury caused directly or indirectly as a result of the use, application, or interpretation of the material presented.


  1. Center for Behavioral Health Statistics and Quality, 2016 National Survey on Drug Use and Health: Detailed Tables, Substance Abuse and Mental Health Services Administration, Rockville 2017.
  2. Doss MK et al. Δ9-Tetrahydrocannibinol at retrieval drives false recollection of neutral and emotional memories. Biol Psychiatry 2018 May 9; [e-pub]. ( .
  3. Schuster RM, Gilman J, Schoenfeld D, et al. One month of cannabis abstinence in adolescents and young adults is associated with improved memory. J Clin Psychiatry. 2018;79(6):17m11977 .

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