A brief reflection on the origins and techniques of Direct Cinema in the 1960's.

The prevalence of both alcohol and cannabis use and the high morbidity associated with motor vehicle crashes has lead to a plethora of research on the link between the two. Drunk drivers are involved in 25% of motor vehicle fatalities, and many accidents involve drivers who test positive for cannabis.

Cannabis and alcohol acutely impair several driving-related skills in a dose-related fashion, but the effects of cannabis vary more between individuals than they do with alcohol because of tolerance, differences in smoking technique, and different absorptions of Δ 9-tetrahydrocannabinol (THC), the active ingredient in marijuana. Detrimental effects of cannabis use vary in a dose-related fashion, and are more pronounced with highly automatic driving functions than with more complex tasks that require conscious control, whereas with alcohol produces an opposite pattern of impairment. Because of both this and an increased awareness that they are impaired, marijuana smokers tend to compensate effectively while driving by utilizing a variety of behavioral strategies. Combining marijuana with alcohol eliminates the ability to use such strategies effectively, however, and results in impairment even at doses which would be insignificant were they of either drug alone. Epidemiological studies have been inconclusive regarding whether cannabis use causes an increased risk of accidents; in contrast, unanimity exists that alcohol use increases crash risk. Furthermore, the risk from driving under the influence of both alcohol and cannabis is greater than the risk of driving under the influence of either alone.

Future research should focus on resolving contradictions posed by previous studies, and patients who smoke cannabis should be counseled to wait several hours before driving, and avoid combining the two drugs. IntroductionAccidents are the fifth leading cause of death in the US; nearly half are motor vehicle accidents, which according to the Fatality Analysis Reporting System (FARS) killed 38,588 people in 2006 alone. Motor vehicle accidents are the nation’s leading cause of death in those under 30. The contribution of drugs of abuse to this accident rate has attracted increasing attention in recent years because of the dramatic increase in drug use. In 2002, the National Survey on Drug Use and Health (NSDUH) estimated that 22 million Americans—9.4% of the population—have a substance use or dependence problem. As marijuana is the most commonly used drug of abuse, having been tried by 40% of the population, and is also smoked most commonly in the age group that also has the most road traffic accidents, the contribution of marijuana smoking to road traffic accidents is of great concern to both governments and clinicians responsible for counseling patients with substance abuse problems.

Moreover, given the paucity of data supporting marijuana’s acute toxicity, the most serious possible consequence of acute cannabis use is a road traffic accident from driving while intoxicated. The very high cost of crashes, both human and financial, underlines the importance of understanding the extent to which marijuana use contributes to such accidents. The purpose of this paper is to review the scientific evidence on the effects on driving while intoxicated with marijuana and contrast this with the effects of alcohol intoxication. Epidemiology of marijuana smoking and road traffic accidentsThe rising prevalence of cannabis use, its increased availability and potency, lower prices, widespread social tolerance, and earlier age of onset of use have combined to increase the number of users and hence the number of people subject to cannabis use disorders. Peak initiation is at age 18, and ten years later, 8% of users are marijuana-dependent.

Most cannabis use is intermittent and time-limited, however; users generally stop in their mid-to-late 20s, and only a small minority continue in daily use over a period of years.Young people also account for a disproportionate number of road traffic accidents. According to the National Center for Statistics and Analysis, the fatality rate for teenagers is four times that of drivers age 25 to 69, and drivers under age 25 account for a quarter of all traffic fatalities. Risk factors for having a fatal traffic accident include being a young man, having psychological characteristics such as thrill-seeking and overconfidence, driving at excessive speed, driving late at night, failing to wear a seatbelt, and lacking familiarity with the vehicle. The risk factors for adolescent marijuana use are somewhat overlapping—delinquency (vandalism, shoplifting, joyriding etc.), poor school performance, and substance use by self and peers.The National Highway Transportation Safety Administration (NHTSA) reported that in 25% of all motor vehicle crash fatalities, the driver had a blood alcohol concentration (BAC) of 0.01 g/dL (one eighth the legal limit) or greater, and in 21-year-old drivers, that figure rose to 39%. Drivers with a previous DWI (“Driving While Impaired”) conviction were responsible for 7.2% of all crashes involving alcohol.In comparison, the percentage of road traffic accidents in which one driver tested positive for marijuana ranges from 6% to 32%., In one study, 9.7% of cannabis smokers reported having driven under the influence in the previous year; those who did drove while intoxicated an average of 8.1 times during the year. Among those who seek treatment for cannabis problems, more than 50% report having driven while “stoned” at least once in the previous year.

Studies relevant to marijuana and smokingThree types of studies are generally performed to help assess the risk that smoking marijuana may increase the probability of having a fatal traffic accident. The first are cognitive studies that measure the effects of smoking marijuana on cognitive processes that are considered to be integral to safe driving. The second are experimental studies on the collision risk of people under the influence of marijuana. The third are descriptive and analytic epidemiological studies on the relationship between cannabis use and accidents, usually performed through drug testing of injured drivers. 3.1 Cognitive studiesAttentiveness, vigilance, perception of time and speed, and use of acquired knowledge are all affected by marijuana; – in fact, a meta-analysis of 60 studies concluded that marijuana causes impairment in every performance area that can reasonably be connected with safe driving of a vehicle, such as tracking, motor coordination, visual functions, and particularly complex tasks that require divided attention, although studies on marijuana’s effects on reaction time have been contradictory. Similar conclusions have been reached by other reviewers.

Worse still, marijuana and alcohol, when used together, have additive or even multiplicative effects on impairment. Consequently, on the basis of cognitive studies, it seems reasonable to propose that smoking marijuana may increase the risk of having a fatal traffic accident.Alcohol at 0.75 g/kg (slightly less than four standard drinks) causes high levels of impairment in psychomotor performance and medium-to-high levels of impairment in such tasks as critical flicker fusion and short-term memory. 3.2.2 Studies that show impairmentNot all deficits can be compensated for through the use of behavioral strategies, however.

Both alcohol and marijuana use increase reaction time and the number of incorrect responses to emergencies. Drivers under the influence of marijuana were not able to compensate for standard deviation of lateral position (SDLP, a measure of staying within lane), which increased with increasing doses of THC.

This is a measure that is not subject to conscious compensatory mechanisms in the way that other aspects of driving are. Other studies have found poorer monitoring of the speedometer under the influence of marijuana, increased decision time when passing, increased time needed to brake when a light suddenly changes, and increased time to respond to a changing light, or sudden sound. Drivers also crashed more frequently into a sudden obstacle on a high dose of marijuana, although this did not happen at a low dose.Meta-analyses of over 120 studies have found that in general, the higher the estimated concentration of THC in blood, the greater the driving impairment, but that more frequent users of marijuana show less impairment than infrequent users at the same dose, either because of physiological tolerance or learned compensatory behavior. Maximal impairment is found 20 to 40 minutes after smoking, but the impairment has vanished 2.5 hours later, at least in those who smoke 18 mg THC or less (the dose often used experimentally to duplicate a single joint).,With increasing doses of alcohol, however, there is general dose-dependent lowering of both sustained attention and overall attentional capacity, with consequently more concentration paid to the main component of a complex skill (steering, for example), and less and less attention paid to secondary tasks (such as speed or driving skill). Functional imaging on the effects of increasing doses of alcohol up to a BAC of 0.08% in simulated driving has demonstrated that orbitofrontal areas (subsuming judgment) and motor areas are affected first, then cerebellar areas controlling coordination show functional deterioration, and finally, at high doses, global cognitive networks and simulated driving performance are impaired.Interestingly, three reports indicate that chronic marijuana smokers are less susceptible to impairment from alcohol on some measures compared with nonsmokers or infrequent smokers. As far back as 1970, Reese Jones noticed that alcohol’s effects were diminished in heavy cannabis smokers.

A subsequent study showed that regular cannabis smokers demonstrate less of a decrement in peripheral signal detection under the influence of alcohol than do infrequent users, and a later study still found that regular cannabis users given alcohol alone showed less of a decrement in tracking accuracy and dizziness ratings than infrequent users given the same alcohol dose. The reason for this is unclear, but is hypothesized to result from either pharmacological or behavioral cross-tolerance between marijuana and alcohol.

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3.2.3 Summary of experimental studiesIt appears that cannabis use may impair some driving skills (automatic functions such as tracking) at smoked doses as low as 6.25 mg (a third of a joint), but different skills (complex functions that require conscious control) are not impaired until higher doses, and cannabis users tend to compensate effectively for their deficits by driving more carefully. Unexpected events are still difficult to handle under the influence of marijuana, however, and the combination of low-dose alcohol and low-dose cannabis causes much more impairment than either drug used alone., Alcohol appears to impair tasks requiring cognitive control more than it does automatic functions, whereas marijuana at a comparable dose impairs automatic functions more than those requiring cognitive control. Together, the effects on impairment are additive and may even be synergistic. Chronic marijuana smokers are less impaired by both alcohol and marijuana than would be expected, however. 3.3 EpidemiologicalstudiesOne weakness of driving studies is that subjects are aware of being observed and assessed, so such studies are generally a better measure of what drivers are capable of doing rather than what they actually do. Epidemiological studies attempt to assess the actual risk that a driver may cause an accident under the influence of a drug, relative to that of a sober person driving under similar conditions.

The relative risk is expressed in the form of an “odds ratio” (OR), which is the multiplier for the increased accident risk from driving under the influence of marijuana. Two approaches are taken. The first is culpability studies, which classify drivers who have crashed according to their degree of responsibility for the crash, then compare drug use in each category.

If there is greater use of the drug in those culpable for crashes, then the drug is judged to be responsible for a greater crash risk. The second is case control studies. We will discuss both in turn. 3.3.1.1 Studies that do not show culpabilitySome reviewers have concluded that there is no evidence that cannabis alone increases the risk of culpability for crashes, and may actually reduce risk. Drummer’s review of blood samples of traffic fatalities in Australia found that drivers testing positive for marijuana were actually less likely to have been judged responsible for the accident.

Several other studies have found no increase in crash risk with cannabis. – Williams’ California study of 440 male traffic accident deaths found that while alcohol use was related to crash culpability, cannabis use was not. Terhune’s study of 1882 motor vehicle deaths calculated an OR of 0.7 for cannabis use, 7.4 for alcohol use, and 8.4 for cannabis and alcohol use combined. Lowenstein and Koziol-McLain’s study of 414 injured drivers admitted to a Colorado E/R found an OR of 1.1, indicating that marijuana use was not associated with increased crash responsibility. Drummer’s later and more extensive ten-year study of 3400 traffic fatalities in three Australian states found that drivers with blood THC levels less than 5 ng/mL, and those with only carboxy-THC present (THC-COOH, a metabolite that is excreted in the urine for weeks and is thus more likely to indicate past use than current use), had an OR of 1.0, but those with serum levels greater than 5 ng/mL had an OR of 6.6, the same as that for a BAC of 0.15%. In all 30 cases in this study in which one driver had a serum level of THC greater than 10 ng/mL, that driver was judged to have been responsible for the accident. When marijuana was combined with alcohol, the risk was higher still.

A later reanalysis of the same data that adjusted for the age and sex of the fatalities found that OR of crashing for cannabis use alone dropped to 0.6 (not significantly different from 1.0), versus 7.6 for alcohol. Laumon’s study of 10,748 French motor vehicle fatalities found that although rates of alcohol and cannabis intoxication were similar (nearly 3%), ten times as many crashes were associated with alcohol as with cannabis; however, investigators noted a dose-dependent effect on OR with increasing THC serum levels, confirming Drummer’s observation by calculating an OR of 4.72 for THC levels greater than 5 ng/mL. 3.3.1.2 Studies that show culpabilitySeveral studies have found that cannabis users are more likely to be responsible for crashes (OR 1.7).

– Crouch found that marijuana use contributed to the demise of 168 fatally-injured truckers in all cases in which the serum concentration of THC exceeded 1 ng/mL. Terhune’s study of 497 road traffic accidents found that cannabis users had a responsibility rate of 76% versus 42.5% for the control group. A later, larger study by the same author on 1882 drivers killed in seven US states found no difference between responsibility rates, however, and it is unclear why the conclusions of the two studies differed.Unfortunately, many positive studies fail to take into consideration interactions with other drugs, – and since alcohol and cannabis in combination cause more impairment than either drug alone, failure to control for concurrent alcohol use represents a significant limitation. Lack of blinding can also be a problem, as knowledge by the raters of drug use influences assignment of culpability. This was likely a confound in Crouch’s study. 3.3.1.3 Summary of culpability studiesAlthough the results of culpability studies have therefore been somewhat contradictory, all find that the combination of alcohol and cannabis has worse consequences than use of cannabis alone., In general, culpability studies suffer from two main confounds. The first is delay to sampling, which classifies some THC users who were impaired at the time of the accident into the non-use group, and the second is use of the metabolite carboxy-THC to identify marijuana-users, which can mistakenly classify some non-impaired drivers in the impaired group.

3.3.2.2 Studies that show increased riskIn contrast, some case-control studies have indicated increased risk. Gerberich, in a large retrospective study of 64,657 health plan members in Northern California, found an OR of 2.3 for motor vehicle injuries among male cannabis users versus nonusers. Mura’s French study of injured drivers in the emergency room calculated an OR of 2.5 for marijuana users versus sober controls, which rose to 4.6 when alcohol was combined with marijuana. 3.3.3 Summary of epidemiological studiesThe validity of case-control studies rests entirely on careful matching of cases with controls, which is hard to do.

In Movig’s study, which assessed marijuana use through both urine and blood testing, urine testing (which measures carboxy-THC) was performed on twice as many controls (85%) as accident victims (39%), likely overestimating the prevalence of marijuana use in the control group and artificially depressing the OR. Dussault and Breault’s study also only measured carboxy-THC, so the calculated OR was really for the risk of accidents given marijuana use at all rather than for marijuana use while driving. In addition, 15.4% of their roadside survey control group refused testing, and since this was the subset of the group that was more than likely to have been using illicit drugs, the refusals probably depressed the incidence of marijuana use in the control group and artificially increased the OR. The control group in Mura’s study was comprised of non-trauma patients at the hospital, rather than drivers who had not crashed, making the odds ratio an incorrect calculation.

In addition, non-trauma hospital patients are not representative of the population and arguably may have had a lower rate of marijuana smoking, again distorting the OR.Because of these difficulties, epidemiological studies have also shown inconsistent effects, some finding decreased or no risk from driving while smoking marijuana, and others increased risk. Most studies are fraught with methodological problems that could lead to underreporting of drug use or misclassification of experimental subjects into or out of the marijuana-using category, confounding results.In contrast, epidemiological studies on the relationship between alcohol consumption and accident have been clear-cut and consistent, demonstrating that the risk of a motor vehicle accident increases significantly with BAC 0.05%. Summary of effects of marijuana on driving performanceAlthough cognitive studies suggest that cannabis use may lead to unsafe driving, experimental studies have suggested that it can have the opposite effect. Epidemiological studies have themselves been inconsistent, and thus have not resolved the question. One possibility is that people who smoke marijuana share qualities—being young, male, and risk-taking—that would increase their risk of road traffic accidents even in the absence of marijuana use. It has been suggested that there is a single factor that underlies adolescent “problem behaviors” such as illicit drug use, precocious sexual intercourse, and problem drinking.

Two epidemiological studies in New Zealand that attempted to address this hypothesis found that the significant relationship that existed between self-reported cannabis use and self-reported accidents (OR 1.6 and 3.9, respectively) disappeared after risky driver behaviors and unsafe driver attitudes were controlled for., A follow-up study found that the crash risk for driving under the influence of cannabis more than 20 times in one year (OR 2.25) was halved and reduced to marginal significance when distance driven and self-reported risky driving behaviors were controlled for. Correlation between THC concentration in whole blood and accident risk (from Grotenhermen et al. (2007) based on data from Drummer et al. ).Future research should concentrate on resolving contradictions posed by previous studies by more tightly controlling for methodological problems. Experimental studies could focus on measuring blood levels consistently or developing more accurate methods of measuring THC levels in the CNS, as well as examining residual effects that persist for more than one hour after smoking.

This would permit construction of a better dose-impairment curve for THC. It would also be interesting to know whether the improved performance of experienced users is because of physiological tolerance or because of behavioral strategies that can be taught to infrequent users. Epidemiological studies should use serum THC levels rather than urinary metabolites, develop techniques to compensate for the time delay between the accident and the blood test, and use non-fatally injured drivers for a control group. Cutting list software.

Issue #49, Summer 2013Picturing the Personal Essay: A Visual Guide Picturing the Personal Essay: A Visual GuideA design professor from Denmark once drew for me a picture of the creative process, which had been the subject of his doctoral dissertation. “Here,” he said. “This is what it looks like”:Aha, I thought, as we discussed parallels in the writing process. Although I may start an essay with a notion of where I am headed, inevitably I veer away as I get new ideas or encounter dead ends. Sometimes I even seem to go backward, losing all direction.Nothing is wasted though, said the design professor, because every bend in the process is helping you to arrive at your necessary structure. By trying a different angle or creating a composite of past approaches, you get closer and closer to what you intend.

You begin to delineate the organic form that will match your content.The remarkable thing about personal essays, which openly mimic this exploratory process, is that they can be so quirky in their “shape.” No diagram matches the exact form that evolves, and that is because the best essayists resist predictable approaches. They refuse to limit themselves to generic forms, which, like mannequins, can be tricked out in personal clothing.

Nevertheless, recognizing a few basic underlying structures may help an essay writer invent a more personal, more unique form. Here, then, are several main options.Narrative with a liftNarrative is the natural starting place since narrative is a natural structure for telling others about personal events. We instinctively turn to chronology as a way to recreate the past, putting our lives into a neat moment-by-moment order. Beware, though. The march of time can be methodical—first this, then this, then this.

If unrelieved, it becomes the ticking clock in the jail or, worse, the flat line of death. Savvy essayists, as a result, twist their chronology, beginning at the end or breaking to a moment in the past, even weaving together several timelines. More crucial, though, is their use of tension, which changes the flat line of chronology into a rising line—a plot.

Such tension forces the reader into a climb, muscles contracting. It raises anticipation. Will we reach the top? And what will we see from there?Take, for example, Jo Ann Beard’s essay “The Fourth State of Matter.” The narrator, abandoned by her husband, is caring for a dying dog and going to work at a university office to which an angry graduate student has brought a gun. The sequence of scenes matches roughly the unfolding of real events, but there is suspense to pull us along, represented by questions we want answered.

In fact, within Beard’s narrative, two sets of questions, correlating to parallel subplots, create a kind of double tension. When the setting is Beard’s house, we wonder, “Will she find a way to let go of the dying dog, not to mention her failing marriage?” And when she’s at work, we find ourselves asking, “What about the guy with the gun? How will he impact her one ‘safe place’?”Narrative essays keep us engaged because we want answers to such questions. The tension begs for resolution. We keep on reading unless the writer stops stair-stepping upward toward the critical moment when change becomes necessary. If she flatlines on an emotional plateau, not raising the tension, then we are likely to lose interest and walk away. “Readers do not want to put their foot on the same step twice” is the way veteran essayist Bill Kittredge put it while swapping ideas at a writing conference.

He had learned this principle from screenwriters in Hollywood and insisted, “Think what you want, those guys know how plots work.”One interesting side note: trauma, which is a common source for personal essays, can easily cause an author to get stuck on the sort of plateau Kittredge described. Jo Ann Beard, while clearly wrestling with the immobilizing impact of her own trauma, found a way to keep the reader moving both forward and upward, until the rising tension reached its inevitable climax: the graduate student firing his gun. I have seen less-experienced writers who, by contrast, seem almost to jog in place emotionally, clutching at a kind of post-traumatic scar tissue.The whorl of reflectionLet’s set aside narrative, though, since it is not the only mode for a personal essay. In fact, most essays are more topical or reflective, which means they don’t move through time in a linear fashion as short stories do.Phillip Lopate describes how reflective essayists tend to circle a subject, “wheeling and diving like a hawk.” Unlike academic scholars, they don’t begin with a thesis and aim, arrow-like, at a pre-determined bull’s-eye. Instead, they meander around their subject until arriving, often to the side of what was expected.One of the benefits of such a circling approach is that it seems more organic, just like the mind’s creative process. It also allows for a wider variety of perspectives—illuminating the subject from multiple angles.

A classic example would be “Under the Influence,” Scott Russell Sanders’s essay about his alcoholic father. Instead of luring us up the chronological slope of plot, Sanders spirals around his father’s drinking, leading us to a wide range of realizations about alcoholism: how it gets portrayed in films, how it compares to demon-possession in the Bible, how it results in violence in other families, how it raises the author’s need for control, and even how it influences the next generation through his workaholic over-compensation. We don’t read an essay like this out of plot-driven suspense so much as for the pleasure of being surprised, again and again, by new perspective and new insight.The formal limits of focusMy own theory is that most personal essayists, because of a natural ability to extrapolate, do not struggle to find subjects to write about. Writer’s block is not their problem since their minds overflow with remembered experiences and related ideas. While a fiction writer may need to invent from scratch, adding and adding, the essayist usually needs to do the opposite, deleting and deleting. As a result, nonfiction creativity is best demonstrated by what has been left out.

The essay is a figure locked in a too-large-lump of personal experience, and the good essayist chisels away all unnecessary material.One helpful way to understand this principle of deletion is to think of the essayist looking through a viewfinder to limit the reader’s focus. The act of framing a selected portion of raw experience from the chronological mess we call “life” fundamentally limits the reader’s attention to a manageable time and place, excluding all events that are not integrally related.

What appears in the written “picture,” like any good painting, has wholeness because the essayist was disciplined enough to remove everything else.Virginia Woolf’s “Street Haunting” is an odd but useful model. She limits that essay to a single evening walk in London, ostensibly taken to buy a pencil. I suspect Woolf gave herself permission to combine incidents from several walks in London, but no matter. The essay feels “brought together” by the imposed limits of time and place.As it happens, “Street Haunting” is also an interesting prototype for a kind of essay quite popular today: the segmented essay.

Although the work is unified by the frame of a single evening stroll, it can also be seen as a combination of many individual framed moments.