human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Alcohol use among college students has been associated with injunctive norms , which refer to the perceived acceptability of excessive drinking , and descriptive norms , which refer to perceptions of actual drinking . The purpose of this study was to examine the effect of a brief injunctive norms manipulation on both injunctive and descriptive norms about drinking alcohol and to explore differences in the malleability of norms across referent groups , sex , and gender role . Participants were 265 undergraduates ( 43 % male , 70 % freshmen ) who completed a web-based survey for course credit . A r and omly selected half was exposed to a page of information-based feedback about typical student injunctive norms . Relative to the control condition , the manipulation produced lower injunctive and descriptive norms related to typical students ' drinking but no change in either type of norm related to close friends . Femininity was associated with less permissive normative beliefs about the acceptability of excessive drinking whereas masculinity was associated with elevated perceptions of peer drinking , but neither sex nor gender role moderated the manipulation effect . We conclude that perceptions of peer approval of drinking are malleable with a very brief information-based manipulation The most commonly used method to test an indirect effect is to divide the estimate of the indirect effect by its st and ard error and compare the result ing z statistic with a critical value from the st and ard normal distribution . Confidence limits for the indirect effect are also typically based on critical values from the st and ard normal distribution . This article uses a simulation study to demonstrate that confidence limits are imbalanced because the distribution of the indirect effect is normal only in special cases . Two alternatives for improving the performance of confidence limits for the indirect effect are evaluated : ( a ) a method based on the distribution of the product of two normal r and om variables , and ( b ) resampling methods . In Study 1 , confidence limits based on the distribution of the product are more accurate than methods based on an assumed normal distribution but confidence limits are still imbalanced . Study 2 demonstrates that more accurate confidence limits are obtained using resampling methods , with the bias-corrected bootstrap the best method overall The current study was design ed to evaluate the efficacy of a mailed feedback and tips intervention as a universal prevention strategy for college drinking . Participants ( N = 1,488 ) were r and omly assigned to feedback or assessment -only control conditions . Results indicated that the mailed feedback intervention had a preventive effect on drinking rates overall , with participants in the feedback condition consuming less alcohol at follow-up in comparison with controls . In addition , abstainers in the feedback condition were twice as likely to remain abstinent from alcohol at follow-up in comparison with control participants ( odds ratio = 2.02 ) , and feedback participants were significantly more likely to refrain from heavy episodic drinking ( odds ratio = 1.43 ) . Neither gender nor severity of baseline drinking moderated the efficacy of the intervention in these analyses , but more conservative analyses utilizing last-observation carryforward suggested women and abstainers benefited more from this prevention approach . Protective behaviors mediated intervention efficacy , with participants who received the intervention being more likely to use strategies such as setting limits and alternating alcohol with nonalcoholic beverages . Implication s of these findings for universal prevention of  college  drinking are discussed BACKGROUND Considerable progress has been made toward the development of evidence -based treatments for a wide range of psychological disorders ; however , little is known about the mechanisms through which these treatments actually lead to clinical change . Although the use of traditional r and omized controlled treatment design s and tests of statistical mediation have significantly advanced underst and ing of psychological treatments , they are insufficient to test mechanisms of change . METHOD This article outlines the conceptual and method ological requirements for evaluating mechanisms of change , highlights the importance of such a focus , and offers specific recommendations for research aim ed at elucidating change mechanisms . RESULTS AND CONCLUSIONS Conceptualizing and conducting studies that test mechanisms of change requires substantial modifications to traditional research design s , but doing so will significantly enhance scientific underst and ing as well as the efficiency and effectiveness of clinical interventions AIMS This study tests whether enhancing alcohol risk messages with self-affirmation , the process of focusing on cherished aspects of oneself , increases intentions to reduce alcohol consumption and reduces actual alcohol consumption . It was also examined whether these effects differed by risk status as indicated by st and ard drinks consumed in an average week . METHODS Participants ( n = 121 ) were r and omly allocated to a self-affirmation or matched control condition before viewing emotive graphic alcohol warning posters in a question naire-based study . RESULTS There were significant increases in intentions to reduce alcohol consumption in self-affirmed participants , and these effects were stronger in participants with higher behavioural risk . Intentions in turn significantly predicted a reduction in self-reported alcohol consumption . CONCLUSIONS These findings support the use of self-affirmation to enhance alcohol awareness campaigns , particularly in individuals with high behavioural risk Both heavy drinking and related risky sexual behavior among college students are common and are often associated with a number of negative consequences . A previously reported r and omized controlled trial showed that a brief personalized normative feedback ( PNF ) intervention reduced the alcohol consumption and alcohol-related risky sexual behavior of heavy drinking , sexually active college students ( Lewis et al. , 2014 ) . For the present study , we examined what activities students were engaged in when viewing the feedback , as well as who they were with and where they were when receiving the intervention . Furthermore , we conducted supplemental analyses with perceived attentiveness as a hypothesized predictor of change using the same sample ( N = 480 ) . Findings indicated that most students were engaged in activities when viewing the feedback and that most students viewed the feedback alone and at home . Furthermore , results revealed PNF to be most effective in reducing drinks per week among participants who reported greater attention . Clinical implication s and suggestions for additional research examining how attentiveness can be increased during Web-based interventions are discussed OBJECTIVE Despite long-st and ing social psychological research supporting the influence of injunctive norms ( i.e. , what is commonly approved or disapproved ) on behavior , support for this influence on health behaviors is limited . We examined the utility of correcting misperceptions of injunctive norms for improving sun protection and whether changes in attitudes mediated the injunctive norm-intention relationship . METHOD At baseline 263 community residing primarily White women , aged 37 to 77 years , reported their beliefs about sun protection and tanning and their perceptions of " typical women 's " approval of sun protection versus tanning . Women underestimated approval of sun protection and overestimated approval of tanning . In a r and omized trial , 189 of these women received either information about sun protection or information plus personalized normative feedback ( PNF ) . PNF compared each woman 's own perceptions of typical women 's approval of tanning and sun protection with actual normative values , both measured at baseline . PNF communicated that most women approve of others who sun protect . RESULTS PNF led to more positive sun protection injunctive norms , attitudes , and intentions at immediate posttest and more positive intentions and self-reported behavior at 4-week follow-up . Baseline discrepancy between a woman 's beliefs and actual normative values related negatively to changes in sun protection in the control condition but positively in the PNF condition . As hypothesized , changes in attitudes partially mediated the influence of PNF on changes in intentions . CONCLUSIONS The present research demonstrates the utility of correcting injunctive norm misperceptions for promoting healthy behaviors . That attitudes changed in response to PNF and mediated the norm-intention relationship suggests a method for influencing attitudes that may limit reactance AIMS To test whether an expectancy challenge ( EC ) changes implicit and explicit alcohol-related cognitions and binge drinking in young heavy drinkers . This is important for theoretical and practical reasons : the EC presents a critical test for the hypothesized mediational role of alcohol cognitions and the EC has been presented as a promising intervention to counter alcohol problems in heavy drinking youth . SETTING , PARTICIPANTS AND INTERVENTION : Ninety-two heavy drinking college and university students ( half women ) were assigned r and omly to the EC or control condition ( a sham alcohol experiment in the same bar-laboratory ) . MEASUREMENTS Explicit alcohol cognitions and alcohol use were assessed with paper- and -pencil measures . Alcohol use was assessed prior to the experiment and during a 1-month follow-up . Implicit alcohol-related cognitions were assessed with two versions of the  Implicit Association Test  ( IAT ) , adapted to assess implicit valence and arousal associations with alcohol . FINDINGS AND CONCLUSIONS The EC result ed in decreased explicit positive arousal expectancies in men and women alike . There was some evidence for a differential reduction in implicit arousal associations , but findings depended on the version of the IAT and on the scoring-algorithm used . In men ( but not in women ) there was a short-lived differential reduction in prospect i ve alcohol use ( significant in week 3 of the follow-up ) , and this reduction was partially mediated by the decrease in explicit positive arousal expectancies . These findings suggest that an EC successfully changes explicit alcohol cognitions and that this may have short-lived beneficial effects in heavy drinking young men OBJECTIVE The current study examined the efficacy of mailed personalized normative feedback ( PNF ) as a brief alcohol intervention for at-risk college drinkers , and investigated discrepancy as a possible mediator of the intervention effect . METHOD Participants consisted of 100 at-risk college drinkers who completed an alcohol-use assessment at baseline , 6-week posttest and 6-month follow-up . Measures included number of drinks consumed per heaviest drinking week , frequency of heavy-drinking episodes , peak blood alcohol concentration and number of alcohol-related problems , all for the last month . Participants were r and omly assigned to either a mailed brief intervention ( MBI ; n = 49 ) or attention-control ( C ; n = 51 ) group . The MBI group received mailed PNF that was based on baseline responses to the drinking measures ; the C group received a psychoeducational brochure about alcohol . RESULTS Mixed-model , repeated measures ANOVAs were used to examine the effects of time , group and gender on discrepancy and the drinking variables . Following the intervention , the MBI group reported significantly higher perceived discrepancy between self and others ' drinking than the C group . The MBI group reported consuming significantly fewer drinks per heaviest drinking week and engaging in heavy episodic drinking less frequently than the C group at the 6-week posttest ; however , these differences were no longer evident at the 6-month follow-up . Hierarchical regression analyses did not provide evidence for the hypothesized mediating effect of discrepancy . CONCLUSIONS Mailed PNF may be a cost- and time-efficient means of developing discrepancy and temporarily reducing heavy alcohol consumption among at-risk college drinkers In this study , the authors developed and evaluated a single-session experiential expectancy challenge ( EC ) intervention , seeking to reduce alcohol use by changing key positive expectancies among moderate to heavy drinking male and female college students . Participants ( N=217 ) were r and omly assigned to attend a 90- to 120-min EC session , CD-ROM alcohol education , or assessment only . Participants were assessed at pretest , posttest , and 1-month follow-up . Exposure to the EC intervention led to significant decreases in alcohol expectancies and subsequent alcohol consumption in both genders at follow-up . No significant changes were evident in either control condition . This study is the first to effectively decrease expectancies and drinking in college students  with a single-session EC intervention . Further , although several studies have demonstrated the utility of the intervention with men , it is the first to do so with women . This study represents a critical step in the process of translating an innovative , theory-based intervention into a more practical format that makes it more accessible to those who seek effective drinking-reduction strategies for college campuses Brief interventions for college heavy drinkers have shown promise in reducing drinking and alcohol-related negative consequences . However , intervention duration , content , method of delivery , and follow-up length vary across studies . It therefore remains unclear whether intervention length significantly influences the interventions ' efficacy . The present study is a r and omized clinical trial systematic ally evaluating the efficacy of two brief interventions aim ed at reducing alcohol use and alcohol-related negative consequences among college student drinkers . Treatment mediators were also evaluated . Participants ( N=278 ) were , on average , 20.1 years old ( SD=2.4 ) , mostly Caucasian ( 87 % ) and female ( 71 % ) . They were r and omly assigned to a 10-minute brief intervention , a 50-minute brief intervention , or an attention-control group . Both active interventions were provided by clinical graduate students trained in Brief Alcohol Screening and Intervention for College Students ( BASICS ) . As hypothesized , participants in both active conditions significantly reduced their alcohol consumption , as compared to the control group participants F(2,264)=9.84 , p=.00 , η(2)=.07 . There were no significant differences in alcohol-related negative consequences F(2,264)=3.08 , p=.06 , η(2)=.02 . The hypothesized mediators , alcohol drinking norms and coping behavioral strategies , explained significant variance in intervention efficacy , but neither self-efficacy nor alcohol expectancies were significant mediators . Given the preliminary nature of our investigation , more research is warranted to determine parameters of the critical mechanisms of change within brief alcohol interventions with college student drinkers A r and omized controlled trial , using parent-based intervention ( PBI ) was design ed to reduce the incidence of alcohol-involved sexual victimization among first-year college students . The PBI , adapted from Turrisi et al. ( 2001 ) , was design ed to increase alcohol-specific and general communication between mother and daughter . Female graduating high school seniors and their mothers were recruited from the community and r and omly assigned to one of four conditions : Alcohol PBI ( 
    Output:
    
agent
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Alcohol use among college students has been associated with injunctive norms , which refer to the perceived acceptability of excessive drinking , and descriptive norms , which refer to perceptions of actual drinking . The purpose of this study was to examine the effect of a brief injunctive norms manipulation on both injunctive and descriptive norms about drinking alcohol and to explore differences in the malleability of norms across referent groups , sex , and gender role . Participants were 265 undergraduates ( 43 % male , 70 % freshmen ) who completed a web-based survey for course credit . A r and omly selected half was exposed to a page of information-based feedback about typical student injunctive norms . Relative to the control condition , the manipulation produced lower injunctive and descriptive norms related to typical students ' drinking but no change in either type of norm related to close friends . Femininity was associated with less permissive normative beliefs about the acceptability of excessive drinking whereas masculinity was associated with elevated perceptions of peer drinking , but neither sex nor gender role moderated the manipulation effect . We conclude that perceptions of peer approval of drinking are malleable with a very brief information-based manipulation The most commonly used method to test an indirect effect is to divide the estimate of the indirect effect by its st and ard error and compare the result ing z statistic with a critical value from the st and ard normal distribution . Confidence limits for the indirect effect are also typically based on critical values from the st and ard normal distribution . This article uses a simulation study to demonstrate that confidence limits are imbalanced because the distribution of the indirect effect is normal only in special cases . Two alternatives for improving the performance of confidence limits for the indirect effect are evaluated : ( a ) a method based on the distribution of the product of two normal r and om variables , and ( b ) resampling methods . In Study 1 , confidence limits based on the distribution of the product are more accurate than methods based on an assumed normal distribution but confidence limits are still imbalanced . Study 2 demonstrates that more accurate confidence limits are obtained using resampling methods , with the bias-corrected bootstrap the best method overall The current study was design ed to evaluate the efficacy of a mailed feedback and tips intervention as a universal prevention strategy for college drinking . Participants ( N = 1,488 ) were r and omly assigned to feedback or assessment -only control conditions . Results indicated that the mailed feedback intervention had a preventive effect on drinking rates overall , with participants in the feedback condition consuming less alcohol at follow-up in comparison with controls . In addition , abstainers in the feedback condition were twice as likely to remain abstinent from alcohol at follow-up in comparison with control participants ( odds ratio = 2.02 ) , and feedback participants were significantly more likely to refrain from heavy episodic drinking ( odds ratio = 1.43 ) . Neither gender nor severity of baseline drinking moderated the efficacy of the intervention in these analyses , but more conservative analyses utilizing last-observation carryforward suggested women and abstainers benefited more from this prevention approach . Protective behaviors mediated intervention efficacy , with participants who received the intervention being more likely to use strategies such as setting limits and alternating alcohol with nonalcoholic beverages . Implication s of these findings for universal prevention of  college  drinking are discussed BACKGROUND Considerable progress has been made toward the development of evidence -based treatments for a wide range of psychological disorders ; however , little is known about the mechanisms through which these treatments actually lead to clinical change . Although the use of traditional r and omized controlled treatment design s and tests of statistical mediation have significantly advanced underst and ing of psychological treatments , they are insufficient to test mechanisms of change . METHOD This article outlines the conceptual and method ological requirements for evaluating mechanisms of change , highlights the importance of such a focus , and offers specific recommendations for research aim ed at elucidating change mechanisms . RESULTS AND CONCLUSIONS Conceptualizing and conducting studies that test mechanisms of change requires substantial modifications to traditional research design s , but doing so will significantly enhance scientific underst and ing as well as the efficiency and effectiveness of clinical interventions AIMS This study tests whether enhancing alcohol risk messages with self-affirmation , the process of focusing on cherished aspects of oneself , increases intentions to reduce alcohol consumption and reduces actual alcohol consumption . It was also examined whether these effects differed by risk status as indicated by st and ard drinks consumed in an average week . METHODS Participants ( n = 121 ) were r and omly allocated to a self-affirmation or matched control condition before viewing emotive graphic alcohol warning posters in a question naire-based study . RESULTS There were significant increases in intentions to reduce alcohol consumption in self-affirmed participants , and these effects were stronger in participants with higher behavioural risk . Intentions in turn significantly predicted a reduction in self-reported alcohol consumption . CONCLUSIONS These findings support the use of self-affirmation to enhance alcohol awareness campaigns , particularly in individuals with high behavioural risk Both heavy drinking and related risky sexual behavior among college students are common and are often associated with a number of negative consequences . A previously reported r and omized controlled trial showed that a brief personalized normative feedback ( PNF ) intervention reduced the alcohol consumption and alcohol-related risky sexual behavior of heavy drinking , sexually active college students ( Lewis et al. , 2014 ) . For the present study , we examined what activities students were engaged in when viewing the feedback , as well as who they were with and where they were when receiving the intervention . Furthermore , we conducted supplemental analyses with perceived attentiveness as a hypothesized predictor of change using the same sample ( N = 480 ) . Findings indicated that most students were engaged in activities when viewing the feedback and that most students viewed the feedback alone and at home . Furthermore , results revealed PNF to be most effective in reducing drinks per week among participants who reported greater attention . Clinical implication s and suggestions for additional research examining how attentiveness can be increased during Web-based interventions are discussed OBJECTIVE Despite long-st and ing social psychological research supporting the influence of injunctive norms ( i.e. , what is commonly approved or disapproved ) on behavior , support for this influence on health behaviors is limited . We examined the utility of correcting misperceptions of injunctive norms for improving sun protection and whether changes in attitudes mediated the injunctive norm-intention relationship . METHOD At baseline 263 community residing primarily White women , aged 37 to 77 years , reported their beliefs about sun protection and tanning and their perceptions of " typical women 's " approval of sun protection versus tanning . Women underestimated approval of sun protection and overestimated approval of tanning . In a r and omized trial , 189 of these women received either information about sun protection or information plus personalized normative feedback ( PNF ) . PNF compared each woman 's own perceptions of typical women 's approval of tanning and sun protection with actual normative values , both measured at baseline . PNF communicated that most women approve of others who sun protect . RESULTS PNF led to more positive sun protection injunctive norms , attitudes , and intentions at immediate posttest and more positive intentions and self-reported behavior at 4-week follow-up . Baseline discrepancy between a woman 's beliefs and actual normative values related negatively to changes in sun protection in the control condition but positively in the PNF condition . As hypothesized , changes in attitudes partially mediated the influence of PNF on changes in intentions . CONCLUSIONS The present research demonstrates the utility of correcting injunctive norm misperceptions for promoting healthy behaviors . That attitudes changed in response to PNF and mediated the norm-intention relationship suggests a method for influencing attitudes that may limit reactance AIMS To test whether an expectancy challenge ( EC ) changes implicit and explicit alcohol-related cognitions and binge drinking in young heavy drinkers . This is important for theoretical and practical reasons : the EC presents a critical test for the hypothesized mediational role of alcohol cognitions and the EC has been presented as a promising intervention to counter alcohol problems in heavy drinking youth . SETTING , PARTICIPANTS AND INTERVENTION : Ninety-two heavy drinking college and university students ( half women ) were assigned r and omly to the EC or control condition ( a sham alcohol experiment in the same bar-laboratory ) . MEASUREMENTS Explicit alcohol cognitions and alcohol use were assessed with paper- and -pencil measures . Alcohol use was assessed prior to the experiment and during a 1-month follow-up . Implicit alcohol-related cognitions were assessed with two versions of the  Implicit Association Test  ( IAT ) , adapted to assess implicit valence and arousal associations with alcohol . FINDINGS AND CONCLUSIONS The EC result ed in decreased explicit positive arousal expectancies in men and women alike . There was some evidence for a differential reduction in implicit arousal associations , but findings depended on the version of the IAT and on the scoring-algorithm used . In men ( but not in women ) there was a short-lived differential reduction in prospect i ve alcohol use ( significant in week 3 of the follow-up ) , and this reduction was partially mediated by the decrease in explicit positive arousal expectancies . These findings suggest that an EC successfully changes explicit alcohol cognitions and that this may have short-lived beneficial effects in heavy drinking young men OBJECTIVE The current study examined the efficacy of mailed personalized normative feedback ( PNF ) as a brief alcohol intervention for at-risk college drinkers , and investigated discrepancy as a possible mediator of the intervention effect . METHOD Participants consisted of 100 at-risk college drinkers who completed an alcohol-use assessment at baseline , 6-week posttest and 6-month follow-up . Measures included number of drinks consumed per heaviest drinking week , frequency of heavy-drinking episodes , peak blood alcohol concentration and number of alcohol-related problems , all for the last month . Participants were r and omly assigned to either a mailed brief intervention ( MBI ; n = 49 ) or attention-control ( C ; n = 51 ) group . The MBI group received mailed PNF that was based on baseline responses to the drinking measures ; the C group received a psychoeducational brochure about alcohol . RESULTS Mixed-model , repeated measures ANOVAs were used to examine the effects of time , group and gender on discrepancy and the drinking variables . Following the intervention , the MBI group reported significantly higher perceived discrepancy between self and others ' drinking than the C group . The MBI group reported consuming significantly fewer drinks per heaviest drinking week and engaging in heavy episodic drinking less frequently than the C group at the 6-week posttest ; however , these differences were no longer evident at the 6-month follow-up . Hierarchical regression analyses did not provide evidence for the hypothesized mediating effect of discrepancy . CONCLUSIONS Mailed PNF may be a cost- and time-efficient means of developing discrepancy and temporarily reducing heavy alcohol consumption among at-risk college drinkers In this study , the authors developed and evaluated a single-session experiential expectancy challenge ( EC ) intervention , seeking to reduce alcohol use by changing key positive expectancies among moderate to heavy drinking male and female college students . Participants ( N=217 ) were r and omly assigned to attend a 90- to 120-min EC session , CD-ROM alcohol education , or assessment only . Participants were assessed at pretest , posttest , and 1-month follow-up . Exposure to the EC intervention led to significant decreases in alcohol expectancies and subsequent alcohol consumption in both genders at follow-up . No significant changes were evident in either control condition . This study is the first to effectively decrease expectancies and drinking in college students  with a single-session EC intervention . Further , although several studies have demonstrated the utility of the intervention with men , it is the first to do so with women . This study represents a critical step in the process of translating an innovative , theory-based intervention into a more practical format that makes it more accessible to those who seek effective drinking-reduction strategies for college campuses Brief interventions for college heavy drinkers have shown promise in reducing drinking and alcohol-related negative consequences . However , intervention duration , content , method of delivery , and follow-up length vary across studies . It therefore remains unclear whether intervention length significantly influences the interventions ' efficacy . The present study is a r and omized clinical trial systematic ally evaluating the efficacy of two brief interventions aim ed at reducing alcohol use and alcohol-related negative consequences among college student drinkers . Treatment mediators were also evaluated . Participants ( N=278 ) were , on average , 20.1 years old ( SD=2.4 ) , mostly Caucasian ( 87 % ) and female ( 71 % ) . They were r and omly assigned to a 10-minute brief intervention , a 50-minute brief intervention , or an attention-control group . Both active interventions were provided by clinical graduate students trained in Brief Alcohol Screening and Intervention for College Students ( BASICS ) . As hypothesized , participants in both active conditions significantly reduced their alcohol consumption , as compared to the control group participants F(2,264)=9.84 , p=.00 , η(2)=.07 . There were no significant differences in alcohol-related negative consequences F(2,264)=3.08 , p=.06 , η(2)=.02 . The hypothesized mediators , alcohol drinking norms and coping behavioral strategies , explained significant variance in intervention efficacy , but neither self-efficacy nor alcohol expectancies were significant mediators . Given the preliminary nature of our investigation , more research is warranted to determine parameters of the critical mechanisms of change within brief alcohol interventions with college student drinkers A r and omized controlled trial , using parent-based intervention ( PBI ) was design ed to reduce the incidence of alcohol-involved sexual victimization among first-year college students . The PBI , adapted from Turrisi et al. ( 2001 ) , was design ed to increase alcohol-specific and general communication between mother and daughter . Female graduating high school seniors and their mothers were recruited from the community and r and omly assigned to one of four conditions : Alcohol PBI ( 
    Output:
    