[...] : :: I'll finish with another Quote from New Scientist that surprised me. : ::                             Other research suggests that ::                               evidence of dramatic mental decline ::                               is unlikely to be found, even as a ::                               result of long-term heavy use. Over ::                               the past 25 years, Jack Fletcher at ::                               the University of Texas in Houston ::                               and his colleagues have been visiting ::                               Costa Rica to test the mental skills of ::                               very heavy users. Although some of ::                               them have smoked 10 joints a day ::                               for more than 30 years, their ability ::                               to learn and remember lists of words ::                               is only mildly impaired (see diagram ::                               below). And even when struggling ::                               with more demanding tasks, such as ::                               recalling information while pressing a ::                               tapper as fast as possible, their ::                               scores fall well within the normal ::                               range. : :Here we must be careful that they are not only relating the tasks which :were not impaired. : :What is the effect on the saccades, the catch up jumps which the eyes :make when following a moving _object_? That is controlled by the frontal :brain. Schizophrenics make too many catch up jumps when following an :_object_ at certains speeds, though not at all speeds. : :Marijuana users report that they have to concentrate harder when doing :co-ordination requiring tasks (driving). : resumably the people in the study you quote have adjusted to marijuana. :That does not mean that all will be able to. The study is not adequately :controlled. It only says that some can partly override the impairment, :though it does not say at what expense, either. [...] A study on saccades - eye tracking has now come through: *******************      Pharmacol Biochem Behav 1998 Aug;60(4):777-84 Acute and residual effects of marijuana in humans.     Fant RV, Heishman SJ, Bunker EB, Pickworth WB   [...] The    current study sought to examine both acute and residual subjective.    physiologic, and performance effects of smoking a single marijuana    cigarette. Ten healthy male volunteers who reported recent use of    marijuana resided on a residential research ward. On three separate    days, subjects smoked one NIDA marijuana cigarette containing either    0%, 1.8%, or 3.6% delta9-tetrahydrocannabinol (THC) according to a    paced puffing procedure. [...] A new finding was that marijuana smoking acutely produced    decrements in smooth pursuit eye tracking. Although robust acute    effects of marijuana were found on subjective and physiological    measures, and on smooth pursuit eye tracking performance,[...] ******************* So cannabis is putting a similar load on the brain to what is hampered in schizophrenia. I submit a study ought to be done, somehow or other, to find whether people who have previously coped and had no schizophrenic episodes begin with cannabis use to have them. The claim that cannabis agravates schizophrenia is agreed, but if the symptoms were not showing till the first use then is that just aggravation? Maybe in some proportion of people they never would have produced trouble without cannabis. Aidan speaks of the losers. He seems to want there to be losers. Well if you do not wish to be a loser I suggest that you have an eye pursuit test before cannabis use to see whether your nervous system is anywhere near having difficulty coping. It would not be conclusive of course. Brian Sandle

produced trouble without cannabis....... as i have said before ..the majority of cannabis users are normal well employed level headed people..much like drinkers.. a glass of wine with dinner etc .....you can sway arguement by applying facts which affect a few to the entire group of users...something of which you are doing here.... let those who wish to reduce harm to their bodies do so by the use of cannabis instead of alcohol and cigs....

So cannabis is putting a similar load on the brain to what is hampered in schizophrenia. I submit a study ought to be done, somehow or other, to find whether people who have previously coped and had no schizophrenic episodes begin with cannabis use to have them. There is certainly an anecdotal _link_age. Eric Stevens There are two classes of people. Those who divide people into two classes, and those who don't. I belong to the second class.

*******************    Pharmacol Biochem Behav 1998 Aug;60(4):777-84 Acute and residual effects of marijuana in humans.     Fant RV, Heishman SJ, Bunker EB, Pickworth WB   [...] The    current study sought to examine both acute and residual subjective.    physiologic, and performance effects of smoking a single marijuana    cigarette. Ten healthy male volunteers who reported recent use of    marijuana resided on a residential research ward. On three separate    days, subjects smoked one NIDA marijuana cigarette containing either    0%, 1.8%, or 3.6% delta9-tetrahydrocannabinol (THC) according to a    paced puffing procedure. [...] A new finding was that marijuana smoking acutely produced    decrements in smooth pursuit eye tracking. Although robust acute    effects of marijuana were found on subjective and physiological    measures, and on smooth pursuit eye tracking performance,[...] ******************* Let's finish the abstract shall we. Although robust acute effects of marijuana were found on subjective and physiological measures, and on smooth pursuit eye tracking performance, no effects were evident the day following administration, indicating that the residual effects of smoking a single marijuana cigarette are minimal. It almost appears as if you are trying to be dishonest here.

: [...] : : : :: I'll finish with another Quote from New Scientist that surprised me. : : : ::                             Other research suggests that : ::                               evidence of dramatic mental decline : ::                               is unlikely to be found, even as a : ::                               result of long-term heavy use. Over : ::                               the past 25 years, Jack Fletcher at : ::                               the University of Texas in Houston : ::                               and his colleagues have been visiting : ::                               Costa Rica to test the mental skills of : ::                               very heavy users. Although some of : ::                               them have smoked 10 joints a day : ::                               for more than 30 years, their ability : ::                               to learn and remember lists of words : ::                               is only mildly impaired (see diagram : ::                               below). And even when struggling : ::                               with more demanding tasks, such as : ::                               recalling information while pressing a : ::                               tapper as fast as possible, their : ::                               scores fall well within the normal : ::                               range. : : : :Here we must be careful that they are not only relating the tasks which : :were not impaired. :   Implying, of course, that since their results demonstrated a lack of any : hard evidence for cognitive deficits in any major domain, they must have : fudged their results (since it disagrees with Brians biases). Fudged their results if they have found problem areas but only reported the areas where there were minimal troubles. But I did not claim fudged. But for a start it needs to be more explicit. You like to have exact wording. What is a normal range? Take the normal range for height, 4 feet to 7 feet. So anyone with a height of 6 1/2 feet falls well within the normal range. Sure they are nothing like fourteen feet. They need to show that the _distribution_ of scores is close to that of the non-using population who have not been offered the drug. It is not fair to compare them against left-overs - the ones left out of use. The left-outs may have a reason for being left out. May they have been less sociable and so may have other deficits? The next point is that the ones who have smoked so heavily (I do not know the strength of cannabis there, though - they are going by number of joints - not dose) are the ones who have been able to continue in their lives while doing that. Therefore they may have been special types. These people have not had their abilites impaired to a degree which has put their living ability badly below average. Ones who may have had their abilities spoiled would not be in the study because they would not have been able to keep at it. Now do you consider decision making and planning to be major cognitve domains and were they tested for? : : : :What is the effect on the saccades, the catch up jumps which the eyes : :make when following a moving _object_? That is controlled by the frontal : :brain. Schizophrenics make too many catch up jumps when following an : :_object_ at certains speeds, though not at all speeds. :    Yes. I've read the literature. Smooth-pursuit eye-tracking has been : investigated across several editions of the DSM, and has yet to be included as : one of the diagnostic criteria for the so-called 'disease' of schizophrenia. One of the problems may be that then employers/insurers could then start demanding the tests. : : : :Marijuana users report that they have to concentrate harder when doing : :co-ordination requiring tasks (driving). :    Who said that? I know literally dozens of marijuana smokers who report no : decrement in driving ability. I think you made this one up. One argument was that because they had been using they take more care - they are concentrating harder. : : : resumably the people in the study you quote have adjusted to marijuana. :   Well, to be quite honest, yes. If they hadn't, and were suffering because : of their lack of adjustment, that would help your argument. If they hadn't adjusted to it they would not be using it now. They are the ones who are survivors of its rigours. We do not know how bright they might have become without it. We do not know of the fates of the ones who got excluded. :    Try and argue consistently. ??? : :That does not mean that all will be able to. :    You're asking AGAIN whether a negative can be proven (i.e., 'are you sure : that will never happen'?), an amateur's tactic. In this case we know that a lot do not wish to continue. It has been unpleasant for them. The argument is like producing a group of people who do not get sun burnt after being in the sun a lot. I say that does not prove that everyone can be in the sun a lot without getting burnt. You say that I may be wrong. But I say it is still a good idea to warn people about sunburn. If people go your way then it may make extra work for certain doctors. :    If you knew anything about the philosophy of the scientific method, you'd : understand that you are asking for a logical impossibility. Try again. : The study is not adequately : :controlled. :   _base_d on what? Sorry, unless these researchers were egregiously : irresponsible (in which case it would have never made it past peer-review) : they compared the results of their studies to non-users. We have talked of peer-review lack with the recent Lancet pro-cannabis legalisation article having a faulted 1990 schizophrenia incidence study by Der as a major king-pin. : It only says that some can partly override the impairment, : :though it does not say at what expense, either. :   Um, again, you're merely saying, 'this study has got to be wrong, because : it disagrees with me'. No I am not. I am saying it looks that it is a study of a special group. Its conclusions can only apply to a similarly select group. Besides that I question, as I said, the meaning given to falling within a normal range.  That's fine, but you haven't made any sensible : arguments yet as to why we should believe you. Keep thinking. : [...] : : A study on saccades - eye tracking has now come through: :   They've been churning out replications and non-replications of the saccades : and schizophrenia stuff for a little while now. I was learning about it in : psychobiology class back in '95. I know that, it is the researching of the relationship to cannabis that is new. For interest here is a bit of a post of mine under an earlier address: ********************* From This e-mail address is being protected from spam bots, you need JavaScript enabled to view it Sat Apr 22 14:54:27 1995 Subject: ECT 10 Journal Abstracts (Was: Re: Reject ECT treatment) Newsgroups: misc.health.alternative,sci.psychology [...] TI: Eye coordination and vestibular testing in electroconvulsive therapy. AU: Kolev,-Ognyan-I.; Tanchev,-Ognyan; Peykova,-Margarita; Ivanov,-Ivan-A. IN: Medical Academy, Inst of Neurology, Psychiatry & Neurosurgery, Sofia, Bulgaria JN: Convulsive-Therapy; 1991 Dec Vol 7(4) 275-279 AB: Nine female depressive Ss were examined before bilateral electroconvulsive shock therapy (ECT), immediately after ECT, and 2 days later with saccadic, pursuit tracking, and Hallpike caloric vestibular tests. Before ECT, all tests showed normal results. Immediately after ECT, the saccadic test displayed dysmetria of the fast eye movements in 6 Ss. The pursuit tracking test showed decreased gain of the slow eye movements with compensatory saccades in 7 Ss. These findings were for both directions in the horizontal plane. In the caloric vestibular test, changes were not significant. Two days after ECT, the eye coordination and vestibular testing showed normal function, suggesting that eye coordination and vestibular function disturbances induced by ECT are transitory. (PsycLIT Data_base_ Copyright 1992 American Psychological Assn, all rights reserved) [...] ******************* And in a more brainstorming session: ******************* From bsandle Wed Nov 29 03:18:53 1995 Subject: Re: Music,oblique astigmatism,(Was: Re: Eye Muscle) Newsgroups: sci.med.vision [...] Saccades are the catch up jerks which eyes make as they follow a moving _object_ [...] With some trepidation I draw attention to research that saccadic production has been found different in some tests on schizophrenics: following moving _object_s (travelling at certain speeds only) they produce more saccades. This might point to frontal brain trouble being involved. So paying more attention to astigmatic idiosynchrosy, how well to check any variation and correct for that, may have other payoffs? [...] ****************** : : ******************* :    Pharmacol Biochem Behav 1998 Aug;60(4):777-84 : : Acute and residual effects of marijuana in humans. : :  
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