Blackouts among college students

For many people, the environment
plays a key role in determining
current drinking habits.  One
environment in which excessive
drinking is often tolerated, if not
supported, is the college campus
(Keeling, 2002).  As might be
expected given the drinking habits
of some college students. blackouts
are not uncommon in this population. 
In 1993, 1997, 1999, and 2001, the
Harvard School of Public Health
surveyed roughly 15,000 students
from over 100 colleges in the U.S.
about their drinking habits
and experiences (2002).  An item in
the survey asked students if, during
the previous year, they had forgotten
what they did or where they went as
a result of drinking.  In 1993, almost
25% of the students who consumed alcohol in the year before the survey indicated having had such an experience during this time period.  The percentage of students reporting blackouts in the previous year increased slightly, but significantly, to roughly 27% in 1997, 1999, and 2001.  The significant increase in the prevalence of blackouts paralleled, or more likely followed, a significant increase in rates of heavy episodic drinking and an increase in self-reported rates of drinking with the intent to get drunk.
        White et al. (2002) recently surveyed 772 undergraduates regarding their experiences with blackouts.  The occurrence of a blackout was operationally defined as a positive response to the question, "Have you ever awoken after a night of drinking not able to remember things that you did or places that you went?"  Approximately ½ (51%) of those who had ever consumed alcohol reported experiencing at least one blackout at some point in their lives, and 40% experienced one in the year before the survey.  Among those who drank in the two weeks before the survey, nearly 1/10 (9.4%) experienced a blackout during this time period. 
       Students later learned that they participated in a wide range of salient events for which they had no recollection.  Such activities included vandalism, unprotected intercourse, driving an automobile, spending money, and others.  The slide below lists the percentages of students indicating that they participated in these and other activities at least once during a blackout.  The percentages are based on the number of students who have had at least one blackout (355), not the entire sample of 772 subjects.

       During the two weeks preceding the survey, equivalent percentages of males and females experienced blackouts, despite the fact that males drank significantly more often and more heavily than females.  This outcome suggests that females, a group infrequently studied in the blackout literature, are at greater risk than males for experiencing blackouts, likely due to well-known differences in body weight, proportion of body fat, etc.  There is also some evidence that females are more susceptible than males to milder forms of alcohol-induced memory impairments even when given comparable doses of alcohol (Mumenthaler et al., 1999).  Ryback (1971) suggested that mild memory impairments and blackouts represent two points on a continuum separated primarily by level of intoxication, rather than being qualitatively different types of memory impairments.  Thus, the greater susceptibility of females to mild memory impairments might be predictive of greater susceptibility to blackouts.
        While the available evidence clearly indicates that blackouts occur among college students, very little is known regarding the exact nature of these impairments among younger drinkers.  As discussed above, our understanding of blackouts has been crafted largely from observations and interviews with middle-aged male alcoholics, many of whom were hospitalized.  This group clearly does not represent the typical drinker in the US, raising questions regarding the generalizability of their experiences to the experiences of those in other groups.  For instance, based on his interviews with male alcoholics, Goodwin concluded that blackouts can be divided into fragmentary and en bloc forms, and that memory loss of the fragmentary type can often be recovered with cueing or the simple passage of time.  The duration of blackouts observed by Goodwin et al ranged from nine hours to three days in alcoholics drinking in a laboratory setting.  It is largely unknown whether blackouts that occur among college students tend to fall into the en bloc or fragmentary categories, or how long the impairments tend to last.  The literature is replete with wild accounts of events that transpire during blackouts among alcoholics, included traveling long distances of several days or even selling real estate (Goodwin, 1995).  Little is known about the events that transpire during blackouts in college students.  Further, it remains unknown how students find out about the events that transpired, how they felt about it, whether the experiences altered their drinking, etc.
        A recent study White and colleagues (2004 in press) sheds light on some of the gaps in information regarding blackouts among young drinkers.  The researchers interviewed 50 undergraduate students, all of whom had experienced at least one blackout, to gather more information about the factors related to blackouts. As in the previous study, students reported engaging in a range of risky behaviors during blackouts, including sexual activity with both acquaintances and strangers, vandalism, getting into arguments and fights, and others. During the night of their most recent blackout, most students drank either liquor alone or in combination with beer. Only 1 student out of 50 reported that their most recent blackout occurred after drinking beer alone. On average, students estimated that they consumed roughly 11.5 drinks before the onset of the blackout. Males reported drinking significantly more than females, but they did so over a significantly longer period of time. As a result, estimated peak BACs during the night of the last blackout were similar for males (0.30%) and females (0.35%). Fragmentary blackouts occurred far more often than en bloc blackouts, with four out of five students indicating that they eventually recalled bits and pieces of the events. Roughly half of all students (52%) indicated that their first full memory after the onset of the blackout was of waking up in the morning, often in an unfamiliar location. Many students, more females (59%) than males (25%), were frightened by their last blackout and changed their drinking habits as a result.
        A very interesting study by Hartzler and Fromme (2003) also provides valuable and much needed information about blackouts among young drinkers.  The authors interviewed 136 volunteers (mean age roughly 23 years) to gain insight into their experiences with alcohol-induced memory deficits.  As in the study by White and colleagues, fragmentary blackouts were far more common than those of the en bloc variety.
        Blackouts tend to occur after rapid consumption of large amounts of alcohol.  At these levels of intoxication, it is quite likely that a variety of other cognitive functions, beyond memory, are severely impaired.  At doses far lower than those necessary to produce blackouts, alcohol impairs judgment, decision-making, impulse control and host of other functions.  Colloquially, people often refer to this constellation of effects as reduced inhibitions.  In other words, while drinking, people often do things that they might not normally do, and take risks that they might not normally take.  There are certainly multiple mechanisms underlying these effects.  Fromme et al. (1997) observed that intoxicated subjects underestimate the true likelihood that negative consequences will follow risky behaviors.  Because fear of consequences typically serves to reduce risky behavior, this effect could essentially take the brakes off, leading an individual to believe that they will not be impacted negatively by their actions while intoxicated.  During a blackout, it is entirely possible for individuals to engage in a wide array of risky behaviors and awaken the next day with no memory of these actions.  As Jennison and Johnson (1994) state, "...blackout experiences, especially those of the en bloc variety, are impressive, ranging from driving cars long distances, engaging in conversation at parties in an outwardly normal state, to criminal acts such as robbery, assault, and even murder" (p. 26).
       Individuals who experience blackouts often wake up unaware of where they are, how they arrived there, or what they did the night before.  For this reason, it is perhaps not surprising that individuals are often frightened by the occurrence of blackouts.  Based upon his interviews with alcoholics, Goodwin (1977) stated,  "Realization of having had such a blackout is often accompanied by a feeling of dread or apprehension. Younger drinkers seem to react to blackouts with similar apprehension.  White and colleagues (in press) reported that half (25/50) of the college students they interviewed, more females than males, were frightened by their most recent blackout experience.  As discussed above, it is not uncommon for younger drinkers to learn that, during a blackout, they were in arguments or fights, vandalized property, had intercourse, or engaged in other activities that might be uncharacteristic of them.  Understandably, such realizations can compound the feelings of fear or disbelief that often follow blackouts.  Below is an excerpt from a recent report on college drinking from the NIAAA.  The statement provides an unfortunate example of the complexity of alcohol-induced blackouts and the uncertainty that can follow.

       As discussed in a previous section, a recent episode of MTV's The Real World offered a rare glimpse into the actions of a young, college-aged drinker in the midst of a blackout.  The Real World is a reality show in which a group of teenagers and young adults are chosen to live together in a house for a few months and have their lives videotaped.  The events are then distilled down into half hour weekly episodes.   The February 4, 2004, episode focused on an en bloc blackout experienced by one of the female roommates.  After a night of drinking at a bar with her roommates, she awoke with no memory of the events of the preceding night.  The MTV cameras documented that she engaged in a wide range of activities, including heavy flirtation with one of her male roommates, which she initiated and pursued.  The following day, she called her serious boyfriend back home and explained to him that she had no memory of what she did the night before, but that she might have cheated on him.  Click play below to watch the MTV preview for this episode, which presents the key elements of the story.

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