Article Review 3

Link:
Marijuana and driving in real-life situations

Summary 
 

The study that I used for this review was an interventionist study to determine the effects of marijuana on driving ability.  The causal hypothesis for this study is as follows:  marijuana impedes driving ability.   

According to the study, the smoking of marijuana by human subjects has a detrimental effect on driving skills and performance in a restricted driving area.  Furthermore, this effect is greater under normal driving conditions on city streets.  

While the effect of marijuana is not uniform in all subjects, the effect of smoking the substance is bidirectional.  Whether or not there was a significant decline depended on the subject’s ability to compensate and the dose of marijuana consumed. 

The street portion of this study tried to emulate regular driving conditions.  However, the actual driving experience on city streets was purely experimental.  The study provided for maximum safeguards which contained a dual control vehicle and a driver observer.  Also, subjects were professionally screened and were determined to be emotionally stable.   

The study concluded that driving under the influence of marijuana should be avoided as much as driving under the influence of alcohol. 

Details of the study after the break…

64 volunteers (43 men and 21 women) were assigned to three groups for the driving course portion of the study.  One group was given a high dose of the drug (14 men and 8 women), another group was given a low dose of the drug (13 men and 8 women), and a third group was given a placebo (16 men and five women). 

Of the volunteers, 38 (25 men and 13 women) participated in the street driving portion of the study.  There were four groups:  a group given a low dose of marijuana before and then a placebo prior to the second session (5 men and 4 women), a group given a placebo first and then a low dose before the second session (7 men and 3 women), a group given a high dose first and a placebo second (6 men and 2 women), and a group given a placebo first followed by a high dose (7 men and four women). 

The variable that constituted the intervention was as follows:  Takes drug [high dose, low dose, placebo]. 

The variables on which this intervention was acted upon were as follows:  Sex [male, female] and Driving [street, course, both]. 

While learning was likely to occur while driving on the course, taking the drug impeded this learning.  Scores after taking the drug worsened on average by 29 percent with the group taking a low dose of the drug and worsened by 54 percent by the people taking a high dose of the drug. 

For the street portion of the study, the 38 volunteers recorded 8 emergent situations while on the placebo.  There were 18 emergent situations when taking the drug.  The emergent situations that occured after smoking marijuana was unrelated to dose.   

As previously stated, the study showed that smoking marijuana should be avoided before driving.

Discussion 

I believe this study supported the causal hypothesis of smoking marijuana impedes driving ability.  The study took the necessary measures to control driving conditions while giving their subjects varying doses of the drug.  The conclusions drawn were concrete and clearly showed that consuming the drug has a devastating effect on driving ability. 

This study didn’t really support or discredit my causal hypothesis.  Due to its illegal nature, there are still few interventionist studies that I could find that included marijuana intake as a variable. 

However, those self-medicating with marijuana to treat for anxiety and depression will be more likely to drive while on the substance.  Encountering these emergent situations could have a harmful effect on those already suffering from depression and anxiety.  I will need to do a little more research to affect my opinion on my PIP topic. 

Some limitations from this study include a lack of night driving.  Night driving could provide for a more stressful environment.  Second, the doses of marijuana used were within the normal range of social marijuana usage.  A more “heroic” dosage might be taken before driving.  Finally, the effect of marijuana on reactions and decision making during high speeds was not  addressed.