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: AIMS To examine the prevalence rates and correlates of non-medical use of prescription stimulants ( Ritalin , Dexedrine or Adderall ) among US college students in terms of student and college characteristics . DESIGN A self-administered mail survey . SETTING One hundred and nineteen nationally representative 4-year colleges in the United States . PARTICIPANTS A representative sample of 10 904 r and omly selected college students in 2001 . MEASUREMENTS Self-reports of non-medical use of prescription stimulants and other substance use behaviors . FINDINGS The life-time prevalence of non-medical prescription stimulant use was 6.9 % , past year prevalence was 4.1 % and past month prevalence was 2.1 % . Past year rates of non-medical use ranged from zero to 25 % at individual colleges . Multivariate regression analyses indicated non-medical use was higher among college students who were male , white , members of fraternities and sororities and earned lower grade point averages . Rates were higher at colleges located in the north-eastern region of the US and colleges with more competitive admission st and ards . Non-medical prescription stimulant users were more likely to report use of alcohol , cigarettes , marijuana , ecstasy , cocaine and other risky behaviors . CONCLUSIONS The findings of the present study provide evidence that non-medical use of prescription stimulants is more prevalent among particular subgroups of US college students and types of colleges . The non-medical use of prescription stimulants represents a high-risk behavior that should be monitored further and intervention efforts are needed to curb this form of drug use OBJECTIVES Modafinil has recently been approved for the treatment of shift work sleep disorder , making it potentially available for shift-working emergency physicians . The authors ' objectives were to determine whether modafinil improved cognitive performance of emergency physicians following overnight shifts and to record symptoms and subjective evaluations of the effect of modafinil on the participants . METHODS This was a r and omized , double-blind , placebo-controlled crossover study that followed CONSORT guidelines . Participants were assigned to one of two study groups , with study sessions occurring at least seven weeks apart , and received either modafinil or placebo depending on their r and om allocation . Testing after night shifts included a coding task and an AX version of the Continuous Performance Task , both of which test cognitive function . Participants also completed visual analog scales for three subjective outcomes , and symptoms were elicited . RESULTS Modafinil facilitated performance on long interstimulus-interval AX trials ( F [ 1 , 23 ] = 6.65 , p = 0.1 ) and marginally reduced errors on AY trials in the Continuous Performance Task ( F [ 1 , 23 ] = 3.59 , p = 0.07 ) , suggesting facilitation of sustained attention , cognitive control , and working memory . Additionally , modafinil , compared with placebo , facilitated performance on the coding task at the first session . Subjective data from visual analog scales confirmed that modafinil increased perceived alertness during the simulated patient care sessions but worsened sleep onset when opportunities for sleep arose . CONCLUSIONS Modafinil increased certain aspects of cognitive function and subjectively improved participants ' ability to attend post-night-shift didactic sessions but made it more difficult for participants to fall asleep when opportunities for sleep arose Aims /hypothesisOur hypothesis is that reducing release of the inhibitory neurotransmitter gamma-aminobutyric acid ( GABA ) with modafinil will enhance symptomatic and hormonal responses to hypoglycaemia . Methods Nine healthy men received , in r and om order , two 100-mg doses of modafinil or placebo , followed by an insulin clamp in which plasma glucose was either reduced stepwise to 2.4 mmol/l or was sustained at euglycaemia ( four studies ) . Catecholamines , symptom scores and cognitive function were measured . Results Modafinil had no effect on the measured parameters during euglycaemia . During hypoglycaemia , autonomic symptom scores were significantly higher with modafinil ( increase at lowest plasma glucose concentration 271.3±118.9 vs 211.2±80.4/40 min , p=0.019 ) , and the heart rate response was increased ( 12,928±184 vs 6773±148 bpm/140 min , p=0.016 ) . Deterioration in performance of two cognitive tasks was reduced : Stroop colour – word test ( 613±204 vs 2375±161/65 min , p=0.009 ) and accuracy of a simple reaction task ( 11.3±1.8 vs 9.4±3.7 , p=0.039 ) . Conclusions /interpretationWe conclude that modafinil improves adrenergic sensitivity and some aspects of cognitive function at hypoglycaemia , possibly by reducing neuronal central GABA concentrations Common complaints among shift workers are sleep disruptions and increased sleepiness while working , which may contribute to shift workers being more susceptible to diminished performance and work-related accidents . The purpose of this double-blind , within-participant study was to examine the effects of the alerting agent modafinil on cognitive/psychomotor performance , mood , and measures of sleep during simulated shift work . In all , 11 participants completed this 23-day residential laboratory study . They received a single oral modafinil dose ( 0 , 200 , 400 mg ) 1 h after waking for three consecutive days under two shift conditions : day shift and night shift . Shifts alternated three times during the study , and shift conditions were separated by an ‘ off ’ day . When participants received placebo , cognitive performance and subjective ratings of mood were disrupted during the night shift , relative to the day shift . Objective and subjective measures of sleep were also disrupted , but to a lesser extent . Modafinil reversed disruptions in cognitive performance and mood during the night shift . While modafinil produced few effects on sleep measures during the night shift , the largest dose produced several sleep alterations during the day shift . These data demonstrate that abrupt shift changes produced cognitive performance impairments and mood disruptions during night shift work . Therapeutic doses of modafinil attenuated night-shift-associated disruptions , but the larger dose produced some sleep impairments when administered during day-shift work The rate of onset of a drug 's effect is an important determinant of its abuse potential . This experiment examined the acute behavioral effects of orally administered sustained-release methylpheni date ( SR ; 20 - 40 mg ) , immediate-release methylpheni date ( IR ; 20 - 40 mg ) , and placebo in 10 healthy volunteers .  Drug effects were assessed before drug administration and periodically afterwards for 6 hr using drug-effect question naires and performance measures that are sensitive to the acute effects of stimulants . The IR formulation produced stimulant-like drug effects ( e.g. , increased ratings of " good effects " ) that generally varied as a function of dose and time . The SR formulation produced only transient effects on these measures . These findings are consistent with previous research on the influence of rate of onset using other drugs and suggest that the abuse potential of IR methylpheni date may be greater than that of SR methylpheni date So that reinforcing and subjective effects of methylpheni date as a function of dose and level of sleepiness could be evaluated , 21 volunteers received methylpheni date ( 5 , 10 , or 20 mg ) or placebo on 2 sampling days . After 4 and 8 hr time in bed ( TIB ) , they chose their preferred capsule on 5 days . Methylpheni date was chosen more frequently after 4 hr TIB ( 60 % ) than it was after 8 hr TIB ( 33 % ) . The strongest preference ( 68 % ) was seen in the 10-mg group . At 10 and 20 mg , stimulant-like subjective effects were reported . The 10-mg group was more adversely affected by the restricted bedtime and showed more pronounced drug effects with methylpheni date . These results indicate that sleepiness modulates the reinforcing and subjective effects of methylpheni date The indirect catecholamine agonist methylpheni date ( Ritalin ) is the drug treatment of choice in attention deficit/hyperactivity disorder ( AD/HD ) , one of the most common behavioral disorders of childhood ( DSM-IV ) , although symptoms may persist into adulthood . Methylpheni date can enhance cognitive performance in adults and children diagnosed with AD/HD ( Kempton et al. , 1999 ; Riordan et al. , 1999 ) and also in normal human volunteers on tasks sensitive to frontal lobe damage , including aspects of spatial working memory ( SWM ) performance ( Elliott et al. , 1997 ) . The present study investigated changes in regional cerebral blood flow ( rCBF ) induced by methylpheni date during performance of a self-ordered SWM task to define the neuroanatomical loci of the beneficial effect of the drug . The results show that the methylpheni date -induced improvements in working memory performance occur with task-related reductions in rCBF in the dorsolateral prefrontal cortex and posterior parietal cortex . The beneficial effects of methylpheni date on working memory were greatest in the subjects with lower baseline working memory capacity . This is to our knowledge the first demonstration of a localization of a drug-induced improvement in SWM performance in humans and has relevance for underst and ing the treatment of AD/HD Rationale Methylpheni date , a dopaminergic and noradrenergic reuptake inhibitor , has been shown in young , healthy adult volunteers to produce pronounced effects on working memory and sustained attention . We were interested in assessing whether similar improvements could be conferred upon elderly volunteers in order to gain a more complete underst and ing of the effects of age on monoaminergic manipulations of working memory and attention , as well as to explore the potential for pharmacological intervention in attention and executive dysfunction disorders in this age group . Objectives The main aim of the study was to characterise the dose-related effects of methylpheni date on a range of neuropsychological functions in elderly healthy volunteers . Methods Sixty healthy elderly adult male volunteers received either a single oral dose of placebo , 20 mg or 40 mg methylpheni date prior to performing a variety of tasks design ed to assess memory , attention and executive function . A r and omised double-blind , between-subjects design was used . Results Methylpheni date had significant cardiovascular and subjective effects . However , unlike in younger volunteers , no significant effects of drug on working memory ( spatial span and spatial working memory ) , response inhibition ( stop-signal ) or sustained attention ( rapid visual information processing ) were seen . Subtle effects on latency similar to those in younger volunteers were identified : both doses of methylpheni date result ed in a slowing in response time during set-shifting and decision-making . Conclusions The results of this study demonstrate that , in elderly subjects , the cognitive effects of methylpheni date are grossly attenuated and distinct from the profile previously described in younger volunteers . It is suggested that methylpheni date may not be appropriate as a pharmacological intervention in elderly patient groups , such as those reporting age-related cognitive decline Abstract Previous studies of the effects of the psychomotor stimulant , methylpheni date , have concentrated on vigilance and reaction time tasks . In this study , the effects of methylpheni date on more complex aspects of cognition were studied using tasks from the CANTAB battery and related tests which have been shown to be sensitive to frontal lobe dysfunction . Twenty-eight young healthy men participated in a counterbalanced , double-blind , placebo-controlled study of the effects of methylpheni date .  Cognitive assessment included tests of spatial working memory , planning , verbal fluency , attentional set-shifting and sustained attention .  Methylpheni date had significant effects on performance of the tests of spatial working memory and planning but not on the attentional and fluency tests . When the drug was taken on the first test session , performance on the spatial tests was enhanced by the drug compared to placebo . However , when the drug was taken second , performance accuracy was impaired whereas response latencies were decreased . These results are consistent with a hypothesis that methylpheni date influences performance in two conflicting ways ; enhancing executive aspects of spatial function on novel tasks but impairing previously established performance . This pattern of effects is discussed within the framework of dual , interacting arousal mechanisms ABSTRACT Objective : To assess the pharmacodynamics of armodafinil compared with modafinil and placebo on measures of alertness in healthy volunteers undergoing sleep loss . Research design and methods : In a double-blind , active- and placebo-controlled , parallel-group study , 107 healthy male volunteers ( aged 18–40 years ) were r and omized to receive a single oral dose of armodafinil ( 100 , 150 , 200 , or 300 mg ) , modafinil ( 200 mg ) , or placebo administered at 19:25 h. Main outcome measures : The primary outcome was the Maintenance of Wakefulness Test ( MWT ) , administered every 2 hours from 22:00–08:00 h. Secondary outcomes included the Psychomotor Vigilance Task ( PVT ) and the Karolinska Sleepiness Scale . Blood sample s for pharmacokinetic analysis were collected hourly . Adverse events were evaluated throughout the 2‐day laboratory stay and by telephone on day 9 . Results : All four doses of armodafinil , and the dose of 200 mg modafinil , 
    Output:
    
agent
Based on a systematic review and meta- analysis we show that expectations regarding the effectiveness of these drugs exceed their actual effects , as has been demonstrated in single- or double-blind r and omised controlled trials .
For methylpheni date an improvement of memory was found , but no consistent evidence for other enhancing effects was uncovered .
Modafinil on the other h and , was found to improve attention for well-rested individuals , while maintaining wakefulness , memory and executive functions to a significantly higher degree in sleep deprived individuals than did a placebo .
However , repeated doses of modafinil were unable to prevent deterioration of cognitive performance over a longer period of sleep deprivation though maintaining wakefulness and possibly even inducing overconfidence in a person 's own cognitive performance
***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: AIMS To examine the prevalence rates and correlates of non-medical use of prescription stimulants ( Ritalin , Dexedrine or Adderall ) among US college students in terms of student and college characteristics . DESIGN A self-administered mail survey . SETTING One hundred and nineteen nationally representative 4-year colleges in the United States . PARTICIPANTS A representative sample of 10 904 r and omly selected college students in 2001 . MEASUREMENTS Self-reports of non-medical use of prescription stimulants and other substance use behaviors . FINDINGS The life-time prevalence of non-medical prescription stimulant use was 6.9 % , past year prevalence was 4.1 % and past month prevalence was 2.1 % . Past year rates of non-medical use ranged from zero to 25 % at individual colleges . Multivariate regression analyses indicated non-medical use was higher among college students who were male , white , members of fraternities and sororities and earned lower grade point averages . Rates were higher at colleges located in the north-eastern region of the US and colleges with more competitive admission st and ards . Non-medical prescription stimulant users were more likely to report use of alcohol , cigarettes , marijuana , ecstasy , cocaine and other risky behaviors . CONCLUSIONS The findings of the present study provide evidence that non-medical use of prescription stimulants is more prevalent among particular subgroups of US college students and types of colleges . The non-medical use of prescription stimulants represents a high-risk behavior that should be monitored further and intervention efforts are needed to curb this form of drug use OBJECTIVES Modafinil has recently been approved for the treatment of shift work sleep disorder , making it potentially available for shift-working emergency physicians . The authors ' objectives were to determine whether modafinil improved cognitive performance of emergency physicians following overnight shifts and to record symptoms and subjective evaluations of the effect of modafinil on the participants . METHODS This was a r and omized , double-blind , placebo-controlled crossover study that followed CONSORT guidelines . Participants were assigned to one of two study groups , with study sessions occurring at least seven weeks apart , and received either modafinil or placebo depending on their r and om allocation . Testing after night shifts included a coding task and an AX version of the Continuous Performance Task , both of which test cognitive function . Participants also completed visual analog scales for three subjective outcomes , and symptoms were elicited . RESULTS Modafinil facilitated performance on long interstimulus-interval AX trials ( F [ 1 , 23 ] = 6.65 , p = 0.1 ) and marginally reduced errors on AY trials in the Continuous Performance Task ( F [ 1 , 23 ] = 3.59 , p = 0.07 ) , suggesting facilitation of sustained attention , cognitive control , and working memory . Additionally , modafinil , compared with placebo , facilitated performance on the coding task at the first session . Subjective data from visual analog scales confirmed that modafinil increased perceived alertness during the simulated patient care sessions but worsened sleep onset when opportunities for sleep arose . CONCLUSIONS Modafinil increased certain aspects of cognitive function and subjectively improved participants ' ability to attend post-night-shift didactic sessions but made it more difficult for participants to fall asleep when opportunities for sleep arose Aims /hypothesisOur hypothesis is that reducing release of the inhibitory neurotransmitter gamma-aminobutyric acid ( GABA ) with modafinil will enhance symptomatic and hormonal responses to hypoglycaemia . Methods Nine healthy men received , in r and om order , two 100-mg doses of modafinil or placebo , followed by an insulin clamp in which plasma glucose was either reduced stepwise to 2.4 mmol/l or was sustained at euglycaemia ( four studies ) . Catecholamines , symptom scores and cognitive function were measured . Results Modafinil had no effect on the measured parameters during euglycaemia . During hypoglycaemia , autonomic symptom scores were significantly higher with modafinil ( increase at lowest plasma glucose concentration 271.3±118.9 vs 211.2±80.4/40 min , p=0.019 ) , and the heart rate response was increased ( 12,928±184 vs 6773±148 bpm/140 min , p=0.016 ) . Deterioration in performance of two cognitive tasks was reduced : Stroop colour – word test ( 613±204 vs 2375±161/65 min , p=0.009 ) and accuracy of a simple reaction task ( 11.3±1.8 vs 9.4±3.7 , p=0.039 ) . Conclusions /interpretationWe conclude that modafinil improves adrenergic sensitivity and some aspects of cognitive function at hypoglycaemia , possibly by reducing neuronal central GABA concentrations Common complaints among shift workers are sleep disruptions and increased sleepiness while working , which may contribute to shift workers being more susceptible to diminished performance and work-related accidents . The purpose of this double-blind , within-participant study was to examine the effects of the alerting agent modafinil on cognitive/psychomotor performance , mood , and measures of sleep during simulated shift work . In all , 11 participants completed this 23-day residential laboratory study . They received a single oral modafinil dose ( 0 , 200 , 400 mg ) 1 h after waking for three consecutive days under two shift conditions : day shift and night shift . Shifts alternated three times during the study , and shift conditions were separated by an ‘ off ’ day . When participants received placebo , cognitive performance and subjective ratings of mood were disrupted during the night shift , relative to the day shift . Objective and subjective measures of sleep were also disrupted , but to a lesser extent . Modafinil reversed disruptions in cognitive performance and mood during the night shift . While modafinil produced few effects on sleep measures during the night shift , the largest dose produced several sleep alterations during the day shift . These data demonstrate that abrupt shift changes produced cognitive performance impairments and mood disruptions during night shift work . Therapeutic doses of modafinil attenuated night-shift-associated disruptions , but the larger dose produced some sleep impairments when administered during day-shift work The rate of onset of a drug 's effect is an important determinant of its abuse potential . This experiment examined the acute behavioral effects of orally administered sustained-release methylpheni date ( SR ; 20 - 40 mg ) , immediate-release methylpheni date ( IR ; 20 - 40 mg ) , and placebo in 10 healthy volunteers .  Drug effects were assessed before drug administration and periodically afterwards for 6 hr using drug-effect question naires and performance measures that are sensitive to the acute effects of stimulants . The IR formulation produced stimulant-like drug effects ( e.g. , increased ratings of " good effects " ) that generally varied as a function of dose and time . The SR formulation produced only transient effects on these measures . These findings are consistent with previous research on the influence of rate of onset using other drugs and suggest that the abuse potential of IR methylpheni date may be greater than that of SR methylpheni date So that reinforcing and subjective effects of methylpheni date as a function of dose and level of sleepiness could be evaluated , 21 volunteers received methylpheni date ( 5 , 10 , or 20 mg ) or placebo on 2 sampling days . After 4 and 8 hr time in bed ( TIB ) , they chose their preferred capsule on 5 days . Methylpheni date was chosen more frequently after 4 hr TIB ( 60 % ) than it was after 8 hr TIB ( 33 % ) . The strongest preference ( 68 % ) was seen in the 10-mg group . At 10 and 20 mg , stimulant-like subjective effects were reported . The 10-mg group was more adversely affected by the restricted bedtime and showed more pronounced drug effects with methylpheni date . These results indicate that sleepiness modulates the reinforcing and subjective effects of methylpheni date The indirect catecholamine agonist methylpheni date ( Ritalin ) is the drug treatment of choice in attention deficit/hyperactivity disorder ( AD/HD ) , one of the most common behavioral disorders of childhood ( DSM-IV ) , although symptoms may persist into adulthood . Methylpheni date can enhance cognitive performance in adults and children diagnosed with AD/HD ( Kempton et al. , 1999 ; Riordan et al. , 1999 ) and also in normal human volunteers on tasks sensitive to frontal lobe damage , including aspects of spatial working memory ( SWM ) performance ( Elliott et al. , 1997 ) . The present study investigated changes in regional cerebral blood flow ( rCBF ) induced by methylpheni date during performance of a self-ordered SWM task to define the neuroanatomical loci of the beneficial effect of the drug . The results show that the methylpheni date -induced improvements in working memory performance occur with task-related reductions in rCBF in the dorsolateral prefrontal cortex and posterior parietal cortex . The beneficial effects of methylpheni date on working memory were greatest in the subjects with lower baseline working memory capacity . This is to our knowledge the first demonstration of a localization of a drug-induced improvement in SWM performance in humans and has relevance for underst and ing the treatment of AD/HD Rationale Methylpheni date , a dopaminergic and noradrenergic reuptake inhibitor , has been shown in young , healthy adult volunteers to produce pronounced effects on working memory and sustained attention . We were interested in assessing whether similar improvements could be conferred upon elderly volunteers in order to gain a more complete underst and ing of the effects of age on monoaminergic manipulations of working memory and attention , as well as to explore the potential for pharmacological intervention in attention and executive dysfunction disorders in this age group . Objectives The main aim of the study was to characterise the dose-related effects of methylpheni date on a range of neuropsychological functions in elderly healthy volunteers . Methods Sixty healthy elderly adult male volunteers received either a single oral dose of placebo , 20 mg or 40 mg methylpheni date prior to performing a variety of tasks design ed to assess memory , attention and executive function . A r and omised double-blind , between-subjects design was used . Results Methylpheni date had significant cardiovascular and subjective effects . However , unlike in younger volunteers , no significant effects of drug on working memory ( spatial span and spatial working memory ) , response inhibition ( stop-signal ) or sustained attention ( rapid visual information processing ) were seen . Subtle effects on latency similar to those in younger volunteers were identified : both doses of methylpheni date result ed in a slowing in response time during set-shifting and decision-making . Conclusions The results of this study demonstrate that , in elderly subjects , the cognitive effects of methylpheni date are grossly attenuated and distinct from the profile previously described in younger volunteers . It is suggested that methylpheni date may not be appropriate as a pharmacological intervention in elderly patient groups , such as those reporting age-related cognitive decline Abstract Previous studies of the effects of the psychomotor stimulant , methylpheni date , have concentrated on vigilance and reaction time tasks . In this study , the effects of methylpheni date on more complex aspects of cognition were studied using tasks from the CANTAB battery and related tests which have been shown to be sensitive to frontal lobe dysfunction . Twenty-eight young healthy men participated in a counterbalanced , double-blind , placebo-controlled study of the effects of methylpheni date .  Cognitive assessment included tests of spatial working memory , planning , verbal fluency , attentional set-shifting and sustained attention .  Methylpheni date had significant effects on performance of the tests of spatial working memory and planning but not on the attentional and fluency tests . When the drug was taken on the first test session , performance on the spatial tests was enhanced by the drug compared to placebo . However , when the drug was taken second , performance accuracy was impaired whereas response latencies were decreased . These results are consistent with a hypothesis that methylpheni date influences performance in two conflicting ways ; enhancing executive aspects of spatial function on novel tasks but impairing previously established performance . This pattern of effects is discussed within the framework of dual , interacting arousal mechanisms ABSTRACT Objective : To assess the pharmacodynamics of armodafinil compared with modafinil and placebo on measures of alertness in healthy volunteers undergoing sleep loss . Research design and methods : In a double-blind , active- and placebo-controlled , parallel-group study , 107 healthy male volunteers ( aged 18–40 years ) were r and omized to receive a single oral dose of armodafinil ( 100 , 150 , 200 , or 300 mg ) , modafinil ( 200 mg ) , or placebo administered at 19:25 h. Main outcome measures : The primary outcome was the Maintenance of Wakefulness Test ( MWT ) , administered every 2 hours from 22:00–08:00 h. Secondary outcomes included the Psychomotor Vigilance Task ( PVT ) and the Karolinska Sleepiness Scale . Blood sample s for pharmacokinetic analysis were collected hourly . Adverse events were evaluated throughout the 2‐day laboratory stay and by telephone on day 9 . Results : All four doses of armodafinil , and the dose of 200 mg modafinil , 
    Output:
    