Thanks for posting the article Squiffy. I think the quote below is worth highlighting.
Nearly two-thirds of the marijuana smokers were classified as cognitively impaired based on a several psychological tests, such as information processing speed and verbal memory (all taken at least 12 hours after the patients had last used marijuana).
By comparison, only a third of the non-users had similar mental impairment. The effect was independent of other factors that might affect mental functioning - such as whether the participants drank alcohol or were depressed or anxious.
Moreover, the brain imaging work of Dr. Daniel Amen supports the above results. Dr. Amen is a psychologist who runs the Amen Clinics
which has several branches across the US. He has done extensive brain image scanning using Single Photon Emission Computed Tomography (SPECT). This type of scanning uses a radioisotope to measure blood flow in the brain and infers brain activity from the blood flow pattern. Read more about the basics of SPECT scanning
. A normal SPECT scan
shows the brain with a fairly smooth surface representing normal blood flow and normal brain activity. In contrast, the scans of even casual marijuana users reveal decreases in blow flow and brain activity. View a gallery of scans depicting the effects of drug use on brain activity
. The scans reveal swiss cheese style holes in the brain which represent areas of marked decreased blood flow and activity.
Dr. Amen's work raises an important issue. That is, it has been repeatedly published that MS patients have decreased cerebral blood flow
. Even casual drug use markedly decreases blood flow and it is difficult to imagine that neurons in the affected areas could be healthy. The combined effects of MS and drug use on blood flow could only be worse and seems counterintuitive, e.g., analogous to putting habanero pepper juice into an open cut. While there may be some compounds in marijuana that might be helpful for MS, until these are isolated and more is known about them, I suspect that marijuana use may not be in the best interest of MS patients.