Blog entry
Marijuana Impaired Driving
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For alcohol we have a driving per se limit: 0.08 g/dl. This means that if a driver has a BAC at or above 0.08 g/dl, he/she is presumed impaired and can be charged with DUI. But for marijuana, we have no such limit. So while high school seniors are more likely to report driving after smoking marijuana than driving after heavy drinking (O'Malley & Johnston, 2007), enforcement is hampered by vague guidelines for impairment.
Indeed there are perceptions among some in our target population that marijuana does not impair driving at all. Some claim that the tendency of marijuana users to drive slowly makes them better drivers. But recent research contradicts this belief, and there is general consensus that driving under the influence of cannabis is a serious public health concern.
A few years ago, a panel of experts came together to study the issue of THC limits for driving. Their report (see Grotenhermen et al., 2007) offers a nice overview of the research that has documented the crash risks associated with various THC blood levels. It’s clear that marijuana researchers have the work cut out for them; while we have roadside alcohol breath tests since the late 1930’s, there is still no good roadside equivalent for THC. However, the panel was able to make some very specific recommendations based upon laboratory research as well as sound epidemiological data. They recommend a per se limit of between 7 and 10 ng/ml THC blood level.
So this means we should be informing our students about the risks of marijuana impaired driving. To avoid driving over the safe limit, a marijuana user must allow for the passage of time. Using marijuana is different than drinking alcohol. Almost any use of cannabis will cause a spike well above 7 ng/ml. But that spike will dissipate rather quickly. By waiting 3 hours from the last use, the driver will likely be well below the recommended limit and also likely not still be experiencing any substantial impairments.
Finally, the limits recommended for THC change dramatically with even low levels of concurrent alcohol use. Mixing alcohol with marijuana substantially increases crash risk. Students should be explicitly warned about this, and encouraged to use designated drivers who will remain completely sober to assure everyone get’s home safely.
References
Grotenhermen, F., Leson, G., Berghaus, G., Drummer, O. H., Krüger, H., Longo, M., Moskowitz, H., et al. (2007). Developing limits for driving under cannabis. Addiction, 102(12), 1910-1917.
O'Malley, P. M., & Johnston, L. D. (2007). Drugs and driving by American high school seniors, 2001-2006. Journal of Studies on Alcohol and Drugs, 68(6), 834-842.
Changing Injunctive Norms
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In a new study that will be appearing in the November edition of the publication Addictive Behaviors, Mark Prince and Kate Carey explore the ability of normative feedback to change existing injunctive norms (Prince & Carey, 2010). Before talking about that study, let’s step back a bit and explain the difference between injunctive and descriptive norms. A descriptive norm is the degree of uniformity within a group for a certain behavior. For example, if most men wear hats, then the descriptive norm is for men to wear hats. An injunctive norm concerns the opinion or approval of a behavior held by group members. So if most men feel wearing a hat is good, then the injunctive norm is to approve of hat wearing.
There are some studies that have explored the difference between injunctive and descriptive norms within the college alcohol literature. Those that have (e.g., Larimer, Turner, Mallett, & Geisner, 2004) have indicated that there may be some gain to thinking of them separately. However, clearly the two are going to be related. It would be strange, for instance, for the perceived descriptive norm to favor a behavior, while the perceived injunctive norm objects to it. One presumably often infers the injunctive norm based upon the perceived descriptive norms.
What Prince and Carey have done in their relatively simple experiment is expose some students to computer-generated feedback that attempted to modify perceived injunctive norms; other students (the control) received no corrective feedback. Then both descriptive and injunctive norms regarding alcohol use were measured. As predicted, they found that the feedback produced a lowered injunctive norm perception for alcohol approval. Beyond that, correcting injunctive norms appeared to also affect perceived descriptive norms.
So this means interventions that seek to change misperceptions of normative beliefs through individualized normative feedback should consider including not just descriptive norms, but injunctive corrections as well. Since these norms are indeed changeable through such feedback, broadening the focus may yield changes in meaningful beliefs that could be regulating drinking behavior.
However, the caveat within the study is that the effect was found within general student norms, and not within beliefs about the subjects' friends. Since we know that closer peer relations have greater impact on actual behavior (Reed, Lange, Ketchie, & Clapp, 2007), the impact of this intervention may be limited unless it can become more personally relevant to the targeted student.
References
Larimer, M., Turner, A., Mallett, K., & Geisner, I. (2004). Predicting drinking behavior and alcohol-related problems among fraternity and sorority members: examining the role of descriptive and injunctive norms. Psychology of addictive behaviors: journal of the Society of Psychologists in Addictive Behaviors., 18(3), 203-212.
Prince, M. A., & Carey, K. B. (2010). The malleability of injunctive norms among college students. Addictive Behaviors, 35(11), 940-947. doi:doi: DOI: 10.1016/j.addbeh.2010.06.006
Reed, M. B., Lange, J. E., Ketchie, J. M., & Clapp, J. D. (2007). The relationship between social identity, normative information, and college student drinking. Social Influence, 2(4), 269. doi:10.1080/15534510701476617
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Anxious, Sad, same thing... NOT!
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Emotional differentiation was the variable of interest for researchers at George Mason, and SUNY Buffalo and Albany (Kashdan, Ferssizidis, Collins, & Muraven, 2010) . They found that underage drinkers differ on how well they label their emotions; some make fine-grain distinctions (like anxious, angry or sad), while others tend to lump all the negatives into one category. Further, it turns out that at times when the drinkers were feeling low, subjects who differentiated between sour moods drank less than those who did not.
Of course, it’s hard to make causal inferences from such research, but their findings fit the theory that some drinking occurs in order to cope with negative emotions; and further, those who are skilled at differentiating between types of emotions will have more nondrinking coping tools and would therefore drink less.
Knowing this may help broaden the perspective of the AOD prevention professionals on campus. It speaks to the idea that global prevention strategies may have a place in an educational environment. Given that a university generally seeks to foster graduates who are best equipped to adapt and cope with a changing world, focusing a bit on their emotional management fits within the educational goals of the university. But it may also fit our prevention objectives.
There are other examples of prevention efforts that benefit from broader academic objectives. For instance, Residential Learning Communities are being used at many campuses throughout the nation. They are generally thought of as a way to better foster student’s academic engagement. But research suggests they may also have an AOD preventive effect (Cranford et al., 2009).
So this means that those in the AOD prevention office need to remain open to supporting efforts that foster more general academic and personal growth, since research is emerging that those efforts may indeed be an important component to AOD prevention itself.
References
Cranford, J. A., McCabe, S. E., Boyd, C. J., Lange, J. E., Reed, M. B., & Scott, M. S. (2009). Effects of residential learning communities on drinking trajectories during the first two years of college. Journal of Studies on Alcohol and Drugs. Supplement, (16), 86-95.
Kashdan, T. B., Ferssizidis, P., Collins, R. L., & Muraven, M. (2010). Emotion Differentiation as Resilience Against Excessive Alcohol Use. Psychological Science, Psychological Science OnlineFirst, published on August 9, 2010, -. doi:10.1177/0956797610379863