***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: BACKGROUND Cognitive dysfunction persists in the euthymic phase of bipolar disorder and may provide a marker of underlying neuropathology and disease vulnerability . This study aim ed to replicate a deficit in sustained attention in euthymic bipolar patients and investigate sustained attention in first-degree relatives of bipolar prob and s and in remitted patients with major depressive disorder . METHODS The rapid visual information processing ( RVIP ) task was used to measure sustained attention in 15 euthymic patients with bipolar disorder and 15 control subjects in experiment 1 and in 27 first-degree relatives of bipolar prob and s , 15 remitted patients with major depressive disorder , and 46 control subjects in experiment 2 . RESULTS Sustained attention deficit was confirmed in the euthymic bipolar patients in experiment 1 , but the deficit was not statistically significant in remitted major depressed patients or in the relatives of bipolar prob and s. CONCLUSIONS A deficit of sustained attention is not present in patients with recurrent major depression tested during remission nor is it discriminable in the first-degree relatives of bipolar prob and s. Thus , the confirmed abnormality in euthymic bipolar patients may be acquired as a consequence of bipolar illness . However , future studies of relatives will require larger sample sizes to exclude or utilize small genetic effects BACKGROUND White-matter hyperintensities are commonly found on magnetic resonance imaging ( MRI ) of elderly people with or without dementia . Studies of the relation between severity of white-matter hyperintensities and cognitive impairment have had conflicting results . We undertook a longitudinal study of age-related decline in intellectual function and MRI at age 80 years . METHODS From a cohort of 698 people born in 1914 and living in seven municipalities in Denmark , 68 healthy non-demented individuals had been tested with the Wechsler adult intelligence scale ( WAIS ) at ages 50 , 60 , and 70 , and they agreed to further WAIS testing at age 80 , and cerebral MRI at age 80 - 82 ( mean age 82.3 years ) . We scored separately the numbers of periventricular and deep white-matter hyperintensities . FINDINGS Scores for periventricular hyperintensities in this sample included all possible degrees of severity , but no participant scored more than 75 % of maximum for deep white-matter hyperintensities . Neither type was related to the WAIS IQs of the 80-year assessment , but both were significantly associated with decline in performance IQ from age 50 to age 80 years ( bivariate correlation coefficients 0.32 , p=0.0087 , and 0.28 , p=0.0227 , respectively ) . An analysis based on two WAIS subtests showed that the association between white-matter hyperintensities and cognitive impairment was significant only for cognitive decline in the decade 70 - 80 years . INTERPRETATION Both periventricular and deep white-matter hyperintensities are related to decline in intelligence but , in healthy octogenarians , the cumulative effect of these features alone explains only a small part of the large differences among individuals in age-related decline in intelligence . Interpretation of the presence and severity of white-matter hyperintensities in a diagnostic context must be done cautiously BACKGROUND Neuropsychological deficits have been reported in patients with major depressive disorder ( MDD ) during an acute episode of MDD . Little is known whether these abnormalities persist when patients are remitted . The purpose of the present study was to describe the neuropsychological functioning of fully remitted , unmedicated patients with a history of MDD by focusing on tasks related to prefrontal cortex functioning . METHODS Twenty-eight young to middle-aged , unmedicated , fully remitted patients with MDD were compared to 23 healthy control subjects on tasks from the Cambridge Automated Neuropsychological Test Battery ( CANTAB ) and the California Verbal Learning Test ( CVLT ) . RESULTS Patients with remitted MDD relative to controls were impaired on tasks of rapid visual information processing ( RVIP ) , psychomotor performance and spatial working memory ( SWM ) . After correction for residual depressive symptoms , deficits in sustained attention remained significant . LIMITATIONS CANTAB tasks are not equated for difficulty , and difficulty differences between the CANTAB tasks and the CVLT are not known . CONCLUSIONS These findings suggest deficits in sustained attention as vulnerability marker for MDD . The functional importance of this finding and the neuronal networks involved remain to be eluci date CONTEXT It has been suggested that lithium may have neuroprotective abilities , but it is not clear whether lithium reduces the risk of dementia . OBJECTIVE To investigate whether continued treatment with lithium reduces the risk of dementia in a nationwide study . DESIGN An observational cohort study with linkage of registers of all patients prescribed lithium and diagnosed as having dementia in Denmark from January 1 , 1995 , through December 31 , 2005 . SETTING We identified all patients treated with lithium in Denmark within community psychiatry , private specialist , and general practice s and a r and om sample of 30 % of the general population . Subjects A total of 16,238 persons who purchased lithium at least once and 1,487,177 persons from the general population who did not purchase lithium .  Main Outcome Measure Diagnosis of dementia or Alzheimer disease during inpatient or outpatient hospital care . RESULTS Persons who purchased lithium at least once had an increased rate of dementia compared with persons not exposed to lithium ( relative risk , 1.47 ; 95 % confidence interval , 1.22 - 1.76 ) . For persons who continued to take lithium , the rate of dementia decreased to the same level as the rate for the general population . The rate of dementia decreased early after the consumption of lithium tablets corresponding to 1 prescription ( typically 100 tablets ) and stayed at a low level , although with a slight increase according to the number of subsequent prescriptions . The association between the number of prescriptions for lithium and dementia was unique and different from the association between the number of prescriptions for anticonvulsants and dementia . All findings were replicated in subanalyses with Alzheimer disease as the outcome . CONCLUSIONS Continued lithium treatment was associated with reduction of the rate of dementia to the same level as that for the general population . Method ological reasons for this finding can not be excluded , owing to the nonr and omized nature of data BACKGROUND A review of studies of cognition in the euthymic phase of unipolar and bipolar affective disorder reveals diverging results . METHODS The study was design ed as a controlled cohort study , with the Danish psychiatric case register of admissions used to identify patients and the Danish civil register to identify controls . Patients who were hospitalized between 19 and 25 years ago with an affective diagnosis and who at interviews fulfilled criteria for a primary affective unipolar or bipolar disorder , according to ICD-10 , were compared with age- and gender-matched controls . Interviews and assessment of the cognitive function  were made in the euthymic phase of the disorder . In all , 118 unipolar patients , 28 bipolar patients and 58 controls were included . Analyses were adjusted for differences in the level of education and for sub clinical depressive and anxiety symptoms . RESULTS Patients with recurrent episodes were significantly more impaired than patients with a single episode and more impaired than controls . Also , within patients the number of prior episodes seemed to be associated with cognitive outcome . There was no difference in the severity of the dysfunction between unipolar and bipolar patients . CONCLUSIONS Cognitive impairment in out- patients with unipolar and bipolar disorder appears to be associated with the number of affective episodes OBJECTIVE To investigate whether treatment with lithium in patients with mania or bipolar disorder is associated with a decreased rate of subsequent dementia . METHODS Linkage of register data on prescribed lithium in all patients discharged from psychiatric health care service with a diagnosis of mania or bipolar disorder and subsequent diagnoses of dementia in Denmark during a period from 1995 to 2005 . RESULTS A total of 4,856 patients with a diagnosis of a manic or mixed episode or bipolar disorder at their first psychiatric contact were included in the study . Among these patients , 2,449 were exposed to lithium ( 50.4 % ) , 1,781 to anticonvulsants ( 36.7 % ) , 4,280 to antidepressants ( 88.1 % ) , and 3,901 to antipsychotics ( 80.3 % ) during the study period . A total of 216 patients received a diagnosis of dementia during follow-up ( 103.6/10,000 person-years ) . During the period following the second prescription of lithium , the rate of dementia was decreased compared to the period following the first prescription . In contrast , the rates of dementia during multiple prescription periods with anticonvulsants , antidepressants , or antipsychotics , respectively , were not significantly decreased compared to the rate of dementia during the period with one prescription of these drugs . CONCLUSIONS Continued treatment with lithium was associated with a reduced rate of dementia in patients with bipolar disorder in contrast to continued treatment with anticonvulsants , antidepressants , or antipsychotics . Method ological reasons for these findings can not be excluded due to the nonr and omized nature of the data 
    Output:
    
Cognitive dysfunction seems to be present in individuals suffering from unipolar disorder in the remitted state .
Furthermore , there is a need to identify the cognitive difficulties in individuals suffering from unipolar disorder in relation to psychosocial function , quality of life and risk of recurrence and to assess the effect of treatment intervention on cognitive function