Hi, thanks for joining us once again.
adventure and we are gradually completing the puzzle.
its types, physiology, and treatments.
the way in which it interacts with the body.
the effectiveness as an emerging pain therapy.
I treat many patients who experience different types of pain.
degree I expect the prescribed treatment to be effective.
effectiveness is subjective and difficult to quantify.
So what does effective mean?
Let's look at the study on the use of medical cannabis for neuropathic pain.
medical cannabis may be effective at ameliorating neuropathic pain.
All of whom had been exposed to cannabis prior to the study.
chronic lung disease, and severe depression.
three visits, with a minimum of three days between visits.
During each visit, they were asked to smoke a different cigarette.
One cigarette contains 7% THC, [SOUND] a relatively high concentration.
patient was aware of what was smoked at a given session.
is regarded as the most reliable means of conducting medical research.
then observed over a 3-hour period.
was tested in the two hours after the last two puffs were inhaled.
concentrations reduced pain intensity when compared to the placebo.
other 35 with medical cannabis.
No difference and the effect was reported between the two concentration of THC.
No effect on allodynia or hypersensitivity due to pain could be demonstrated.
a moment that you suffer from chronic neuropathic pain.
cannabis is indeed effective as a long-tern treatment for neuropathic pain?
Well, effectiveness is largely determined based on clinical trials.
Meaning studies that had been performed on patients and evaluated.
These studies can be conducted in many different ways.
Some are more reliable than others.
more importantly [SOUND] on the process used to obtain these results.
there are no clinical trials on with to base our evaluation.
should be administered, it relies purely on expert opinion.
but without any supporting evidence drawn from clinical studies.
it clearly represents the lowest level of scientific evidence.
Another type of evidence comes from case reports or case theories.
a certain treatment is interesting and worthwhile reporting.
A higher level of evidence emerges from retrospective studies.
patients who received a certain treatment for a given medical condition.
the doctor is asked if that medication is more efficacious and merits its price.
reports before and after treatment for his group of patients.
can he say if one medication is more effective that it to others.
The problem with this type of study comes from lack of uniformity in processes.
7 to 4 on a scale of 0 to 10.
And in another patient, a 30% reduction in pain was observed.
he may have requoted pain intervention from very severe to moderate.
a second medication to 30 patients, and a third to 50 patients.
as the scientific value of such data remains limited at best.
Prospective studies are more reliable.
patients, who are observed in a structured fashion for a determined period of time.
are typically aimed at proving a concept.
These studies do not have a control group or a control treatment.
And they are therefore called, open labeled studies.
should be regarded as complimentary to each other.
such as the American study I mentioned earlier.
And the other is called large scale prospective studies or registries.
Typically, the advantages of one are the disadvantages of the other.
one treatment to another or to a placebo in a highly selected group of patients.
this is typically based on one or more RCT's.
they include the most homogenous patient base possible.
Two, administered treatments resemble each other.
Three, patients are randomly assigned to receive one treatment or the other.
to draw sound clinical outcomes.
And five, study outcome is extremely well defined.
they also have some shortcomings.
rarely exceeding three months for pain trials.
Two, they may vary in quality.
on the small cannabis cigarettes for neuropathic pain.
The study included only 39 patients, a relatively small number.
And follow up lasted just three hours, a very short time.
And all patients had various forms of neuropathic pain.
So they were not really homogenous.
Overall, the study cannot be considered as high quality as it is.
One of the problems with RCT's is, that they strive for patient homogeneity.
after meeting strict inclusion criteria.
to shingles or neuropathic pain related to post-traumatic nerve injury.
we need many, many RCTs.
In some fields, numerous RCT's are conducted, and yield consistent results.
results can be conflicting, and even diametrically opposed.
This may confuse doctors who cannot tell if a tested treatment is indeed effective.
based on extraction of raw data from all relevant studies.
overcome some our cities-related problems.
are observe in the most structured way possible over a long period of time.
This long term studies last many month and sometimes even years.
real life conditions than are RCT's in which exclusion is central.
which factors predict the response to the treatment, and how safe the treatment is.
Such studies are required in areas where large gaps in knowledge exist.
This seems to be particularly relevant to medical cannabis.
This brings our lesson to its conclusion.