The Natural History of Drinking and Alcohol-Related Problems After Traumatic Brain Injury

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1 185 The Natural History of Drinking and Alcohol-Related Problems After Traumatic Brain Injury Charles H. Bombardier, PhD, Nancy R. Temkin, PhD, Joan Machamer, MA, Sureyya S. Dikmen, PhD ABSTRACT. Bombardier CH, Temkin NR, Machamer J, Dikmen SS. The natural history of drinking and alcohol-related problems after traumatic brain injury. Arch Phys Med Rehabil 2003;84: Objective: To describe changes in drinking from before traumatic brain injury (TBI) to 1 year after TBI. Design: Inception cohort with 1-year follow-up. Setting: Level I trauma center. Participants: Adults (N 197) hospitalized with a broad range of head injury severity. Interventions: Not applicable. Main Outcome Measures: Alcohol consumption and alcohol-related problems. Results: Drinking and alcohol-related problems decreased substantially from preinjury to 1 year after TBI. However, about one quarter of the sample reported heavy drinking, significant problems, or both during the first year after TBI. Preinjury alcohol use and problems were highly predictive of heavy use and problems after TBI. Conclusion: Although drinking and alcohol-related problems decreased after TBI, there appears to be an ongoing need for prevention and intervention efforts. Screening for preinjury alcohol problems can be used to identify the vast majority of persons who will develop alcohol-related problems within 1 year after injury. Key Words: Alcoholism; Brain injuries; Natural history; Rehabilitation by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation MUCH HAS BEEN WRITTEN about the prevalence of alcohol-related problems before traumatic brain injury (TBI). Considerable evidence exists that persons with TBI are frequently intoxicated at the time of injury, that they frequently have a history of more chronic alcohol problems than the general population, and that a history of alcohol problems may From the Departments of Rehabilitation Medicine (Bombardier, Machamer, Dikmen), of Neurological Surgery (Temkin, Dikmen), and of Biostatistics (Temkin), University of Washington School of Medicine, Seattle, WA. Supported by the Agency for Healthcare Research and Quality (grant no. HS05304), the National Institute of Neurological Disorders and Stroke, National Institutes of Health (grant no. NS19643), the National Center for Injury Prevention and Control and the Disabilities Prevention Program, National Center for Environmental Health (grant no. R49/CCR011714), and the National Institute on Disability and Rehabilitation Research (grant no. H133A980023). The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the granting agencies. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated. Correspondence to Charles Bombardier, PhD, Dept of Rehabilitation Medicine, Box , Harborview Medical Ctr, 325 9th Ave, Seattle, WA 98104, chb@u.washington.edu. Reprints are not available /03/ $35.00/0 doi: /apmr influence neuropsychologic and functional outcomes after TBI. 1 However, less has been written about alcohol use after TBI and even less about change in drinking from before to after TBI. The question of change in drinking behavior is particularly salient because clinicians are being asked to undertake universal screening for preinjury alcohol problems when people are hospitalized for traumatic injury, including TBI. 2-4 Screening soon after injury assumes that preinjury alcohol problems are predictive of postinjury drinking. Yet, as will be discussed later, this assumption lacks verification. There are some reasons to question the assumption that past drinking behavior is a good predictor of future drinking behavior. For example, some evidence suggests that drinking problems may not continue after TBI. 5 It has also been reported 6 that a significant percentage (20%) of persons who were drinking heavily after TBI reported a history of only light drinking or abstinence before TBI. The epidemiologic literature on alcoholism in the general population has shown that considerable spontaneous change occurs in problem drinking from year to year. 7 Moreover, changes in the course of alcoholism are usually not attributable to treatment. 8 Ultimately, if preinjury drinking is a good predictor of postinjury drinking, then efforts to identify the individuals who had preinjury problems and to conduct secondary prevention may be quite useful. If, however, preinjury drinking is not that predictive of postinjury drinking, then secondary prevention efforts would be of less value and other intervention models should be developed. Kreutzer et al 9 were among the first to describe a tendency toward reduced drinking after TBI. They recruited 87 brain injury clinic outpatients an average of 48 months postinjury. According to their retrospective data, the number of moderate to heavy drinkers seemed to decline by two thirds from before to after TBI. The number of persons with self-identified alcohol problems declined by one third after TBI. Twenty-five percent of the subject sample was reportedly abstinent preinjury, whereas 72% were abstinent postinjury. Twenty-seven percent drank alcohol both pre- and post-tbi. Only 1.2% began drinking, and 4.8% reported developing drinking problems for the first time after TBI. Another study 10 analyzed data from 73 people followed longitudinally (1 3y after TBI) and 322 persons with crosssectional data from the Traumatic Brain Injury Model Systems database. Of all persons with TBI, 55% to 56% were abstinent from alcohol 1 to 3 years after TBI. Consumption varied but tended to increase over years 1 to 3. Moderate to heavy drinking was reported by 22% to 29% of the sample 1 to 3 years after TBI. Of persons who were moderate to heavy drinkers at 1 year postinjury, 56% to 69% continued moderate to heavy drinking at 2 to 3 years post-tbi. That study suggested moderate stability in drinking after TBI but did not include data on preinjury alcohol use. Therefore, the change in drinking from preinjury to postinjury could not be evaluated. Dikmen et al 11 described drinking and alcohol problems before and after TBI in a large consecutive sample of hospitalized patients. In that sample, 45% endorsed 2 or more

2 186 DRINKING AND TRAUMATIC BRAIN INJURY, Bombardier alcohol-related problems on the (preinjury) lifetime version of the Short Michigan Alcoholism Screening Test (SMAST). In contrast, about 25% reported experiencing 2 or more alcoholrelated problems during both the year before and the year after TBI. In terms of alcohol consumption, about 40% reported drinking none or less than 1 drink weekly before injury, whereas over 60% reported drinking none or less than 1 drink weekly 1 year after injury. Predictors of greater decreases in drinking after TBI were more severe TBI (as defined by initial Glasgow Coma Scale [GCS] score) and higher blood alcohol level (BAL) at the time of injury. Although the study described secular changes in drinking, it did not address the relation between preinjury and postinjury drinking or problems. A study by Hibbard et al 5 provided data on the relation between substance abuse before and after TBI. The investigators conducted structured clinical interviews to examine rates of pre- and postinjury psychiatric disorders in a communityresiding sample of 100 persons who were an average of 7 years post-tbi. Based on retrospective reports, 40% of the sample was diagnosed as having had a substance disorder before injury according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition. 12 In contrast, 28% of the sample met criteria for having had a substance abuse disorder since TBI. Interestingly, 80% of those judged to have had a preinjury substance abuse disorder did not have a substance abuse disorder any time after injury, and 71% of those with a substance abuse disorder after injury were not judged to have had such a diagnosis any time before TBI. This study suggests the possibility that TBI frequently triggers substance abuse and associated problems in previously unaffected persons. It also suggests that TBI results in recovery from substance abuse problems for many of those who had preinjury problems in this area. In the present study, we hoped to add to the existing literature by examining the course of drinking and alcohol-related problems longitudinally as a function of preinjury drinking and alcohol problems. To accomplish this, we analyzed the same drinking data reported on by Dikmen et al. 11 We predicted that persons with greater preinjury alcohol use and more lifetime alcohol-related problems would be at higher risk of heavy drinking and alcohol problems after TBI, compared with those who were not heavy or problem drinkers before TBI. Similarly, we predicted that heavy alcohol use or alcohol-related problems after TBI would be rare among persons who did not drink heavily or have significant problems before TBI. METHODS Procedures The study was reviewed and approved by the institutional review board of the University of Washington. Subjects who met study inclusion criteria were approached by research personnel and informed about the purpose of the project, procedures involved, and the voluntary nature of study participation. Participants were recruited within days of injury and evaluated initially at 1 month after TBI. Follow-up assessments were performed at 1 year after TBI. At each time point, trained examiners conducted structured interviews to obtain pertinent data from subjects. The procedures used and data obtained were part of a larger study of neuropsychologic and psychosocial recovery after TBI. 13 Subjects Subjects were drawn from consecutively admitted patients with acute TBI hospitalized at Harborview Medical Center, a level I trauma center in Seattle, WA. Patient selection criteria included (1) loss of consciousness of any duration, posttraumatic amnesia lasting at least 1 hour, or other objective evidence of brain trauma; (2) survival of at least 1 month postinjury; (3) age 15 years or older at the time of their injury; (4) speaking English well enough to complete the assessments; and (5) willingness to participate in a longitudinal outcome study. There was no upper age limit. Preexisting conditions were not a cause for exclusion in this study. Of the 285 patients who met our inclusion criteria, 197 (69%) participated in the initial assessment phase of the study at 1 month postinjury. The modal reasons for not participating in the initial evaluation were refusal to participate (n 30) or our inability to schedule assessments (n 38). The main analyses were based on 174 cases (88%) of the initial inception cohort with complete 1-year follow-up data. Subjects ranged in age from 15 to 85 years (mean, 30y) and averaged 12 years of education. The sample was 73% male. Measures Alcohol consumption: quantity and frequency. Subjects alcohol consumption was measured in terms of quantity and frequency by asking the number of alcoholic beverages consumed at a typical sitting and the number of sittings in a typical week. At the time of the initial evaluation, subjects were asked about their alcohol consumption before injury. At the 1-year evaluation, subjects were asked about their alcohol consumption since their injury. were not differentiated into beer, wine, or distilled liquor, because the purpose of the inquiry was only to obtain an approximate self-report of drinking behavior. Quantity responses were coded as (1) none or less than 1 drink per sitting, (2) 1 2 drinks per sitting, (3) 3 4 drinks per sitting, (4) 5 6 drinks per sitting, (5) 7 9 drinks per sitting, and (6) 10 or more drinks per sitting. Frequency was coded as (1) none or less than 1 time per week, (2) 1 2 times per week, (3) 3 4 times per week, (4) 5 6 times per week, (5) 7 9 times per week, and (6) 10 or more times per week. Alcohol consumption was summarized by combining quantity and frequency responses into 4 drinking categories: abstinent, light, moderate, and heavy drinking (table 1). These categories were constructed to be roughly equivalent to the classic quantity-frequency index created by Cahalan et al in Drinking 5 or more drinks per occasion was considered heavy drinking regardless of drinking frequency. This definition was based on evidence that drinking 5 or more drinks per occasion is considered excessive and is associated with risk of adverse health outcomes such as traumatic injury. 15 We defined drinking as little as 1 to 2 drinks per occasion 7 to 9 times per week as heavy drinking because 7 drinks per week corresponds to the 80th percentile for Americans generally and the 70th percentile for American men. Lifetime alcohol-related problems. The SMAST 16 is a 13- item list of common signs and symptoms of alcoholism. In it, subjects indicate whether they have ever experienced each symptom of problem drinking before their injury and since the injury. Examples of items include: Does any member of your family (wife, husband, parents) ever worry or complain about your drinking? Have you ever gotten into trouble at work because of drinking? Item scores are equally weighted and summed to form a total score. The SMAST is used because it is brief and has demonstrated reliability and validity in several

3 DRINKING AND TRAUMATIC BRAIN INJURY, Bombardier 187 Table 1: Definitions of Abstinent, Light, Moderate, and Heavy Drinking Categories None or 1 Drink Quantity of Alcohol Consumed per Drinking Occasion Frequency of alcohol consumption Do not drink or drink 1/wk Abstinent Light Moderate Heavy Heavy Heavy 1 2 times/wk Abstinent Light Moderate Heavy Heavy Heavy 3 4 times/wk Abstinent Moderate Moderate Heavy Heavy Heavy 5 6 times/wk Abstinent Moderate Heavy Heavy Heavy Heavy 7 9 times/wk Abstinent Heavy Heavy Heavy Heavy Heavy 10 times/wk Abstinent Heavy Heavy Heavy Heavy Heavy populations. 2 We used the traditional cutoff of 3 or more to indicate a clinically significant history of alcohol problems. 16 RESULTS Alcohol Consumption Before and After TBI Table 2 summarizes the data on drinking categories before and 1 year after TBI. Comparing pre- to postinjury drinking categories reveals a clear trend toward decreased drinking in most categories. The modal drinker preinjury, representing 40.8% of the sample, was in the heavy drinking category. That is, they drank at least 1 to 2 drinks 7 to 9 times per week or at least 5 to 6 drinks per occasion regardless of drinking frequency. One year after TBI, the modal person (35.6%) reportedly abstained from alcohol. The number of abstainers increased by 158% (from 24 to 62), whereas the number of heavy drinkers decreased by 59% (71 to 29). Generally, less change in drinking was observed among persons who drank in the light and moderate drinking categories before injury. In contrast, very few individuals changed toward greater alcohol use from pre- to postinjury. Only 1 of 24 persons (4%) who were abstainers before their TBI became moderate or heavy drinkers by 1 year after TBI. Eight of 37 light drinkers (22%) became moderate to heavy drinkers after TBI. Taken together, the data document mostly healthy changes in drinking habits from pre- to postinjury. As we would hope, many of the most significant changes in drinking are among those at higher levels of consumption before TBI. On the other hand, the data document substantial ongoing drinking within the first year after TBI, a period when alcohol use is believed to interfere potentially with neurologic recovery. 17 There is little evidence in these data to suggest that TBI triggers increased drinking among persons who did not drink before their injury. Alcohol Problems Before and After TBI Next we examined the relation between pre- and postinjury alcohol-related problems (fig 1). Before TBI, 113 (63.5%) of all subjects reported a normal range of alcohol-related problems (ie, scored 2 on the SMAST). Among this group, only 4 (3.5%) developed significant alcohol-related problems by 1 year after TBI. Of the 65 (36.5%) who scored in the alcoholic range ( 3) on the SMAST before injury, 25 (38.5%) reported a continuation of significant alcohol-related problems during the year after their injury. The remaining 40 (61.5%) no longer scored in the alcoholic range on the SMAST, suggesting that their alcohol problems were in full or partial remission. If we use zero alcohol-related problems on the SMAST as the criterion for remission, 30.8% of those with significant preinjury alcohol problems were in remission throughout the first year post-tbi. The chances of reporting significant alcohol-related problems (SMAST score 3) 1 year after injury is related to the magnitude of preinjury alcohol-related problems (see fig 1). As this figure implies, the presence or absence of preinjury alcohol problems is highly predictive of postinjury alcohol problems ( , P.001). In fact, the relative risk that a person with a history of alcohol problems will continue to have significant alcohol problems after TBI is 10.9 times greater than the probability that a person without preinjury alcohol problems will develop significant alcohol problems. Changes in Alcohol Use and Problems Single measures of outcome consumption or problems, for example have been criticized for leading to divergent or even contradictory conclusions about outcome. 18 Alternatively, composite measures can summarize diverse alcohol-related behaviors in a way that one hopes clarifies global outcomes. Progress has been made recently in the area of describing and Pre-TBI Quantity-Frequency Category Table 2: Preinjury Versus Postinjury Alcohol Consumption Abstainer Light Quantity-Frequency Category 1 Year Post-TBI Moderate Abstainer 16 (9.2) 7 (4.0) 1 (0.6) 0 24 (13.8) Light 16 (9.2) 13 (7.5) 7 (4.0) 1 (0.6) 37 (21.3) Moderate 11 (6.3) 7 (4.0) 15 (8.6) 9 (5.2) 42 (24.1) Heavy 19 (10.9) 13 (7.5) 20 (11.5) 19 (10.9) 71 (40.8) Totals 62 (35.6) 40 (23.0) 43 (24.7) 29 (16.7) 174 NOTE. See table 1 for definitions of drinking categories. Heavy Totals N (%)

4 188 DRINKING AND TRAUMATIC BRAIN INJURY, Bombardier Seventy-two percent of those with heavy drinking or problems before TBI were abstinent or drinking without significant problems at follow-up. Eighty-three percent of persons with heavy drinking and problems were in a better composite drinking category: heavy drinking or problems, 45%; normal drinking without problems, 17%; or were abstinent, 21% at 1 year after TBI. Fig 1. Percentage of subjects with significant alcohol problems after TBI as a function of preinjury alcohol problem severity. Significant alcohol problems is defined as SMAST score of >3 at 1 year post-tbi. empirically validating a composite measure of alcohol-related outcomes. 19 These authors operationalized 4 clinically relevant outcome categories: (1) abstinent, (2) moderate drinking without problems, (3) heavy drinking or problems, and (4) heavy drinking and problems. This model was adapted to describe drinking and alcohol problems together for the present sample. Abstinence and heavy drinking were defined as before, based on quantity and frequency data. Light and moderate drinking were combined under the category of moderate drinking. Having a significant drinking problem was defined as obtaining a score of 3 or more on the SMAST within the year before assessment. Our data corresponding to these composite categories are in table 3. The most frequent outcome before and after TBI from this perspective was abstinence or normal drinking, that is, light to moderate drinking and no significant problems. Normal drinking or abstinence increased from 49% preinjury to 74% at follow-up. In contrast, the frequency of heavy drinking and problems declined by over two thirds, whereas the frequency of heavy drinking or problems declined by 32%. Of those in the heavy drinking and/or problem categories before injury (n 89), 39 (44%) remained in 1 of those 2 categories 1 year after TBI. Almost 26% of the sample reported heavy drinking and/or significant alcohol-related problems at 1 year postinjury. Another way of summarizing the data is that 18 (10%) of the sample were in a worse drinking category after TBI, whereas 64 (37%) were unchanged and 92 (53%) moved into a better drinking category. No persons who were abstinent and without recent alcohol problems before injury developed either heavy drinking or problems by 1 year postinjury. Of the normal drinkers, only 6 (10%) developed heavy drinking or significant alcohol problems or both, whereas 23 (37%) became abstinent. DISCUSSION Our primary research question had to do with the course of alcohol use and problems after TBI. These data lead us to make 3 major conclusions on this point. First, drinking and alcoholrelated problems decreased considerably from preinjury to 1 year postinjury. Abstinence rates increased from 14% to 36%. The proportion of persons who did not report significant alcohol-related problems increased from 64% to 84%. The percentage that was both abstinent and reported no significant alcohol problems increased from 13% to 32%. Depending on the criteria used, rates of remission from significant alcohol problems ranged from 30.8% (based on SMAST scores) to 56% (based on the composite measure). These data must be interpreted in the context of remission rates among community-residing alcoholics in the United States. Large-scale prevalence studies show that among men between the ages of 18 and 29 years, the lifetime prevalence of alcoholism is 28%, the 1-year prevalence of alcoholism is 18%, and 36% of lifetime alcoholics are in remission during a given year. 7 That is, they have a lifetime history of significant alcohol problems but do not report any symptoms of alcoholism during the year before the survey. These data imply that the natural history of alcoholism in the general population is episodic and recurrent rather than chronic and progressive. Therefore, the changes in drinking and alcohol problems observed among persons with TBI are not unique but may reflect a naturally occurring waxing and waning of this condition found in the general population. It is difficult to determine whether remission rates are greater in the year after TBI than the base rate of remission expected among young men generally. Although this is an interesting theoretical question, a more pragmatic question is, What factors may promote abstinence or moderation in drinking in the general population with alcohol problems as well as among those recovering from TBI? Considerable research has been done on factors that lead to spontaneous remission in persons with alcohol problems. Not surprisingly, health problems frequently precede spontaneous reductions in alcohol use, 20 and people who are employed or married are more likely to make enduring changes in alcohol use after trauma. 21 There are few data on predictors of reduced drinking among persons with TBI. Prior research has indicated that greater depth of coma (lower GCS) predicted less drinking at 1-year Table 3: Composite Alcohol Outcome Categories Before and 1 Year After TBI Outcome Category 1 Year Post-TBI Pre-TBI Outcome Category Abstinent, No Problems Normal Drinking, No Problems Heavy Drinking or Problems Heavy Drinking and Problems Totals N (%) Abstinent, no problems 15 (8.6) 7 (4.0) (12.6) Normal drinking, no problems 23 (13.2) 34 (19.5) 5 (2.9) 1 (0.6) 63 (36.2) Heavy drinking or problems 9 (5.2) 25 (14.4) 8 (4.6) 5 (2.9) 47 (27.0) Heavy drinking and problems 9 (5.2) 7 (4.0) 19 (10.9) 7 (4.0) 42 (24.1) Totals 56 (32.2) 73 (42.0) 32 (18.4) 13 (7.5) 174

5 DRINKING AND TRAUMATIC BRAIN INJURY, Bombardier 189 follow-up. 11 Therefore, factors such as closer supervision and less access to alcohol may account for some of the observed decrease in alcohol use and problems. Higher BAL on hospital admission also predicted greater decreases in alcohol use from preinjury to 1 year postinjury. 11 Because BAL and alcohol consumption tend to correlate positively, the BAL s predictive power may reflect that persons with high BAL drink more before injury and thus have more room to decrease. On the other hand, higher BAL also has a positive correlation with self-reported readiness to change alcohol use after TBI. 22 People with alcohol-related TBI may reduce their consumption because of increased awareness of the negative consequences of drinking, spontaneous self-change efforts, and seeking help from substance abuse treatment programs. The reason for the tendency to decrease drinking after TBI merits further study to potentially extend or build on this natural recovery process. The second main conclusion is that 1 year after TBI, a subset of survivors are characterized by heavy drinking and alcoholrelated problems. On the composite measure, about one quarter of the sample reported heavy drinking, significant alcohol problems, or both within 1 year after TBI. Although it is difficult to compare across different studies, this finding is consistent with the 22% to 29% of moderate to heavy drinkers 1 to 3 years post-tbi found by Kreutzer et al 10 as well as the 28% of persons meeting criteria for substance abuse or dependence reported by Hibbard et al. 5 The third conclusion is that preinjury alcohol use and problems are highly predictive of heavy use and alcohol problems after TBI. In the present study, only 7% of those who were abstinent or who reported normal drinking before their injury began moderate or heavy drinking or developed significant alcohol problems in the year after their TBI. Persons who reported a history of significant alcohol-related problems on the SMAST were about 10 times more likely to have significant alcohol problems at 1 year postinjury compared with those who scored in the normal range on the SMAST. These results are consistent with previous research that has found that few people develop alcohol use problems for the first time after TBI. 9 These results also support the use of universal alcohol screening measures to identify persons at risk for heavy alcohol use and alcohol problems after TBI. Clinical Implications Other implications about relapse and secondary prevention efforts can also be drawn from these data. At 1 month after TBI, drinking is significantly lower than before injury and 1 year after injury. 11 It also appears that the majority of cases that relapse into problem drinking do so within the first year postinjury because the overall rates of heavy drinking found at 1 year postinjury are closely comparable to the proportion of heavy drinking found at 2, 3, and 7 years after TBI Similarly, beyond 1 year postinjury the overall rates of persons with significant alcohol problems remain fairly steady. 10 Therefore, the first year postinjury, when the majority of relapses occur, may be a critical time to conduct secondary prevention programs. The window of opportunity seems to be soon after injury, perhaps within the first month when drinking is at the lowest point. 11 Because high-risk persons can be identified, we recommend that relapse prevention efforts focus on these individuals before they resume drinking. We hypothesize that preventing relapse into heavy drinking during this period can alter the longer-term course of drinking in this population. If at-risk persons can be motivated to abstain, learn alternative coping strategies, and obtain social support not to drink during this first year after TBI, perhaps they can cope with TBI without resorting to alcohol abuse. Effective secondary prevention programs may require several stages. During acute rehabilitation, at-risk persons can be identified, and strategies can be used to educate and motivate such persons to abstain from alcohol and to seek appropriate help during their first year after TBI. 23 During postacute rehabilitation at-risk persons could be referred to learn specific relapse prevention strategies 24 or could receive prearranged booster sessions to shore up motivation to remain abstinent before relapse occurs. It may also be useful to engage interested persons in self-help programs such as Alcoholics Anonymous (AA). Whatever secondary prevention program is planned, drinking should be monitored routinely among at-risk persons to identify relapse as early as possible. Those who relapse could be referred for a more thorough assessment, brief interventions, or treatment. Brief motivational interventions can be repeated at that point with the goal of having the person reconsider the personal costs and benefits of drinking in light of their overall recovery and rehabilitation goals. Referrals can be made to combined brain injury and substance abuse treatment programs where they are available. 6 When specialized treatment programs are not available, clinicians should not hesitate to refer patients to traditional treatment programs or AA because some evidence suggests that obtaining any kind of help is associated with greater reductions in drinking at 1 year after injury. 11 Finally, for persons unable or unwilling to engage in substance abuse programs, there is an empirically validated treatment that intervenes exclusively through the family or concerned others in the person s life. Controlled research has shown that community reinforcement therapy with concerned others is better than other approaches at significantly improving the chances that the target person will enter treatment and reduce alcohol use before treatment. 25 Other benefits of this therapy approach include reduced emotional distress in the concerned other. Some rehabilitation programs may not wish to identify highrisk persons. In such cases, relapse prevention strategies may be woven, explicitly or implicitly, into generic psychosocial treatments for TBI survivors. Core relapse prevention strategies such as learning to identify and to cope differently with stressful situations, emotional distress, interpersonal conflict, and boredom is relevant to persons recovering from TBI whether or not they are at risk for returning to alcohol abuse. An advantage of this approach is that persons recovering from TBI who are at-risk drinkers report little interest in formal alcohol treatment or AA. 26 Such persons may be more willing to participate in generic outpatient treatment that includes strategies relevant to relapse prevention than in programs identified as dealing with substance abuse. Limitations and Future Directions The present study s primary data are limited to relatively brief self-report measures of alcohol use and alcohol-related problems. Our confidence in these self-report data would be strengthened by having collateral information from others or objective data as a validity check. On the other hand, it is reasonable to consider self-reported alcohol-related data to be as reliable and valid as self-report data on other behaviors. Sander et al 27 found a high degree of agreement, typically greater than 90%, between self- and collateral reports of alcohol use among persons with TBI. More general reviews of this issue in the substance abuse literature conclude that persons with alcohol problems generally provide reliable and valid reports if interviewed in clinical settings, when they are alcohol

6 190 DRINKING AND TRAUMATIC BRAIN INJURY, Bombardier free, and when they are given reassurances of confidentiality. Each of these conditions was met in the present study. At least 2 factors limit the representativeness of the sample and may have led to inaccurate estimates of the magnitude of alcohol abuse and of return to drinking. First, approximately 30% of eligible patients were not able to be assessed. The major reasons for not gathering data on these persons were the patient s refusal to participate at the outset of the study, our inability to contact the subject and inability to schedule and conduct the initial evaluation, and the patient having a brain injury so severe that the he/she could not adequately participate. If alcohol abuse is overrepresented in such subjects, our results would underestimate alcohol problems. Next, 89 (45%) of the sample consisted of persons with more severe TBI who also participated in a seizure prevention study and were told by a study nurse that they should not drink alcohol. This may have had a moderating effect on drinking. The extent to which this advice may have influenced drinking is unknown and cannot be disentangled from the confounding variable of brain injury severity. The results are also limited by the absence of formal diagnostic measures of alcohol abuse or dependence. Although we used well-accepted brief measures of alcohol use and alcoholrelated problems, these data are not comprehensive enough to permit us to make alcohol-related diagnoses. The advantages of using diagnostic measures in future research would include being able to compare rates of diagnoses with large epidemiologic studies such as the National Health Interview Survey. 28 Data on the proportion of persons meeting criteria for alcohol abuse versus alcohol dependence would also probably inform prevention and treatment planning. If, as we would assume, persons with alcohol dependence are in the minority, that would provide further support for the use of brief interventions in this population. It would also be interesting to determine whether rates of spontaneous recovery or time to first relapse varied as a function of diagnosis. Another limiter is that the data describe drinking outcomes only at 1 year post-tbi. Longitudinal data from representative samples are needed over shorter and longer time periods to better describe the course and consequences of alcohol use and problems after TBI. Major unanswered questions about the course of alcohol use after TBI include more carefully describing the timing of relapse within the first year. In the general alcoholism treatment literature, the majority of relapses occur within the first 3 to 6 months after treatment. 29 This may also represent the period of highest relapse after TBI. More precise information on the timing of relapse might help focus the time during which ongoing prevention efforts are needed. On the other hand, longer-term studies could more fully address the possibility that there is an ongoing trend toward increased alcohol consumption beyond 1 year after TBI. 10 An important question left unanswered is what are the triggers for relapse after TBI: the study of risk factors for relapse and, subsequently, factors for relapse prevention has contributed significantly to the treatment of substance abuse problems more generally. 24 Relapse after TBI may be linked to unique factors such as posttraumatic headache, distressing cognitive impairment, inability to work, large amounts of unstructured time, boredom, and permissive societal attitudes toward substance abuse in persons with disabilities. Knowledge of common relapse triggers in this population could help guide relapse prevention and treatment efforts. Finally, more research is needed on persons who seem to recover from their alcohol problems after TBI. How long does this period of recovery last? What factors predict who will recover and who will relapse? What role does treatment play versus natural recovery? Spontaneous recovery from alcohol problems must be taken into account when planning treatment studies. Secondary prevention studies must include adequate controls and must show that treatment provides greater improvement than the spontaneous improvement directly attributable to TBI. CONCLUSION The natural history of drinking 1 year after TBI seems to involve 3 patterns. The largest proportion of people who drank heavily or had alcohol problems before injury enter a period of moderation or remission after TBI. Almost half of those with a history of heavy drinking and/or significant problems resume a pattern of drinking heavily and/or have significant alcoholrelated problems after TBI. A small percentage of people without preinjury alcohol problems begin drinking heavily or develop problems in the wake of TBI. Overall, about one quarter of persons with TBI report heavy drinking and/or problems 1 year after TBI. Simple screening measures can be used to identify persons at high risk for having alcohol problems after TBI. Research is needed to better understand remission and relapse processes. Improved understanding of these processes may be used to develop ways to promote natural recovery and prevent relapse. Acknowledgments: We thank Dennis Donovan for his help designing the alcohol-related assessment for this project. References 1. Dikmen S, Donovan D, Loberg T, Machmer J, Temkin N. Alcohol use and its effects on neuropsychological outcome in head injury. Neuropsychology 1993;7: Bombardier C, Kilmer J, Ehde D. Screening for alcoholism among persons with recent traumatic brain injury. Rehabil Psychol 1997; 42: Dikmen S, Machmer J, Donovan D, Winn R, Temkin N. Alcohol use before and after traumatic head injury. Ann Emerg Med 1995;26: Gentilello L, Donovan D, Dunn C, Rivara F. 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