***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 Cloninger 's theory of personality , including 4 temperament dimensions and 3 character dimensions , is one of the most noteworthy theories in recent years . Several studies have explored temperament dimensions as a predictor of response to antidepressant treatments in major depression , but these have provided inconsistent results . The present study explored temperament as well as character dimensions , as measured by the  Temperament and Character Inventory ( TCI ) , as possible predictors of response to maprotiline , the most-widely prescribed antidepressant in Japan . METHODS 86 consecutive patients with major depression underwent a 16-week open  trial of maprotiline . They filled out the TCI at baseline , and were followed up at weeks 8 and 16 by using the  Hamilton Rating Scale for Depression . RESULTS Hierarchial logistic regression analyses demonstrated that response to maprotiline was significantly predicted by the cooperativeness score at the 8-week outcome assessment , and by the self-directedness score at the 16-week outcome assessment , after controlling the possible effects of clinical variables on the response . There was no evidence that either temperament dimensions or their 2-way interactions significantly predicted the response . LIMITATIONS Large replication studies with other antidepressants are needed for generalizing the results in this study . CONCLUSIONS The results in this study regarding temperament dimensions seem consistent with findings in previous studies , which are , as a whole , inconsistent with each other . It is suggested that character dimensions ( particularly cooperativeness and self-directedness ) , rather than temperament dimensions , may be important predictors of response to antidepressants . Antidepressants may differ in the personality configurations that predict optimal responses We attempted to prospect ively examine the effects of personality traits in 68 acutely depressed patients treated with desipramine over 4 - 5 weeks to assess whether the presence or absence of these traits played a role in response to antidepressant treatment . Overall the 39 responders had statistically significantly lower cluster III personality trait scores than non-responders , and a trend toward lower cluster I and cluster II scores . We then followed the 39 desipramine responders for up to 6 months on the dose to which they responded in accordance with st and ard clinical practice . Overall 23 of the 39 sustained their initial improvement , with eight relapsing and eight dropping out between 5 weeks and 6 months . When comparing these three groups with the 29 initial non-responders , those who sustained the 6-month response had statistically significantly lower cluster II , cluster III , and total personality scores than initial responders who relapsed , initial responders who dropped out and did not complete 6 months of treatment , and initial non-responders Clinical predictors of drug response in major depression have been weak and inconsistent . Eighty-four patients suffering from a current major depressive episode completed a 6-week double-blind trial of either clomipramine or desipramine . Temperament , as measured by the Tridimensional Personality Question naire , accounted for 35 % of the variance in treatment outcome , compared with less than 5 % predicted by clinical variables . In the more severely depressed patients , temperament predicted nearly 50 % of the variance in treatment outcome , which is the first time that such a substantial predictor of drug response has been identified . Within depressed women , temperament also predicted response to different antidepressant drugs .  The potential importance of temperament , and the need for replication of these findings is discussed CONTEXT There is extensive evidence implicating dysfunctions in stress responses and adaptation to stress in the pathophysiological mechanism of major depressive disorder ( MDD ) in humans . Endogenous opioid neurotransmission activating mu-opioid receptors is involved in stress and emotion regulatory processes and has been further implicated in MDD . OBJECTIVE To examine the involvement of mu-opioid neurotransmission in the regulation of affective states in volunteers with MDD and its relationship with clinical response to antidepressant treatment . DESIGN Measures of mu-opioid receptor availability in vivo ( binding potential [ BP ] ) were obtained with positron emission tomography and the mu-opioid receptor selective radiotracer carbon 11-labeled carfentanil during a neutral state . Changes in BP during a sustained sadness challenge were obtained by comparing it with the neutral state , reflecting changes in endogenous opioid neurotransmission during the experience of that emotion . SETTING Clinics and neuroimaging facilities at a university medical center . PARTICIPANTS Fourteen healthy female volunteers and 14 individually matched patient volunteers diagnosed with MDD were recruited via advertisement and through outpatient clinics . INTERVENTIONS Sustained neutral and sadness states , r and omized and counterbalanced in order , elicited by the cued recall of an autobiographical event associated with that emotion . Following imaging procedures , patients underwent a 10-week course of treatment with 20 to 40 mg of fluoxetine hydrochloride . MAIN OUTCOME MEASURES Changes in mu-opioid receptor BP during neutral and sustained sadness states , negative and positive affect ratings , plasma cortisol and corticotropin levels , and clinical response to antidepressant administration . RESULTS The sustained sadness condition was associated with a statistically significant decrease in mu-opioid receptor BP in the left inferior temporal cortex of patients with MDD and correlated with negative affect ratings experienced during the condition . Conversely , a significant increase in mu-opioid receptor BP was observed in healthy control subjects in the rostral region of the anterior cingulate . In this region , a significant decrease in mu-opioid receptor BP during sadness was observed in patients with MDD who did not respond to antidepressant treatment . Comparisons between patients with MDD and controls showed significantly lower neutral-state mu-opioid receptor BP in patients with MDD in the posterior thalamus , correlating with corticotropin and cortisol plasma levels . Larger reductions in mu-opioid system BP during sadness were obtained in patients with MDD in the anterior insular cortex , anterior and posterior thalamus , ventral basal ganglia , amygdala , and periamygdalar cortex . The same challenge elicited larger increases in the BP measure in the control group in the anterior cingulate , ventral basal ganglia , hypothalamus , amygdala , and periamygdalar cortex . CONCLUSIONS The results demonstrate differences between women with MDD and control women in mu-opioid receptor availability during a neutral state , as well as opposite responses of this neurotransmitter system during the experimental induction of a sustained sadness state . These data demonstrate that endogenous opioid neurotransmission on mu-opioid receptors , a system implicated in stress responses and emotional regulation , is altered in patients diagnosed with MDD Six mood induction studies and a meta- analysis were conducted to test 2 models of the  extraversion-pleasant affect relation . The affect-level model suggests that extraverts should be happier than introverts in both neutral and positive mood conditions . The reactivity model posits that extraverts react particularly strongly to pleasant stimuli and that they should be happier than introverts only in positive conditions . In all studies , extraverts failed to exhibit greater emotional reactivity when pleasantness items were analyzed . When activated positive affect items were analyzed , results were mixed . The meta- analysis confirmed that there is only a slight reactivity effect overall , and this effect emerges only in activated positive affect items . Furthermore , the meta- analysis showed that the correlation in neutral conditions is strong enough to support the affect-level model Cardiac vagal tone , as indexed by abnormalities in the level and /or reactivity of respiratory sinus arrhythmia ( RSA ) , has been related to psychiatric impairment , including risk for depression . Longitudinal studies of depression have focused on RSA levels and have found mixed support for the hypothesis that low RSA levels predict a more pernicious course of depression . The current investigation focuses on the relation between RSA reactivity and the course of depression . We measured depressed persons ' RSA reactivity to sadness- , fear- , and amusement-inducing emotion films  and reassessed participants ' diagnostic status 6 months later . Depressed persons who exhibited a higher degree of vagal withdrawal to the sad film were more likely to recover from depression . Implication s for the study of RSA in depression are discussed Depressed individuals often fail to react to emotionally significant stimuli . The significance of this pattern of emotional dysregulation in depression is poorly understood . In the present study , depressed and nondepressed participants  viewed st and ardized neutral , sad , fear , and amusing films ; and experiential , behavioral , and physiological responses to each film were assessed . Compared with nondepressed controls , depressed participants reported sadness and amusement in a flattened , context -insensitive manner . Those depressed participants who reported the least reactivity to the sad film exhibited the greatest concurrent impairment . Prospect ively , the depressed participant who exhibited the least behavioral and heart rate reactivity to the amusing film were the least likely to recover from depression . Loss of the context -appropriate modulation of emotion in depression may reflect a core feature of emotion dysregulation in this disorder BACKGROUND Human affective responses appear to be regulated by limbic and paralimbic circuits . However , much less is known about the neurochemical systems engaged in this regulation . The mu-opioid neurotransmitter system is distributed in , and thought to regulate the function of , brain regions central ly implicated in affective processing . OBJECTIVE To examine the involvement of mu-opioid neurotransmission in the regulation of affective states in healthy human volunteers . DESIGN Measures of mu-opioid receptor availability in vivo were obtained with positron emission tomography and the mu-opioid receptor selective radiotracer [11C]carfentanil during a neutral state and during a sustained sadness state . Subtraction analyses of the binding potential maps were then performed within subjects , between conditions , on a voxel-by-voxel basis . SETTING Imaging center at a university medical center . PARTICIPANTS Fourteen healthy female volunteers . Intervention Sustained neutral and sadness states , r and omized and counterbalanced in order , elicited by the cued recall of an autobiographical event associated with that emotion . MAIN OUTCOME MEASURES Changes in mu-opioid receptor availability and negative and positive affect ratings between conditions . Increases or reductions in the in vivo receptor measure reflect deactivation or activation of neurotransmitter release , respectively . RESULTS The sustained sadness condition was associated with a statistically significant deactivation in mu-opioid neurotransmission in the rostral anterior cingulate , ventral pallidum , amygdala , and inferior temporal cortex . This deactivation was reflected by increases in mu-opioid receptor availability in vivo . The deactivation of mu-opioid neurotransmission in the rostral anterior cingulate , ventral pallidum , and amygdala was correlated with the increases in negative affect ratings and the reductions in positive affect ratings during the sustained sadness state . CONCLUSIONS These data demonstrate dynamic changes in mu-opioid neurotransmission in response to an experimentally induced negative affective state . The direction and localization of these responses confirms the role of the mu-opioid receptor system in the physiological regulation of affective experiences in humans Predictive variables of response to imipramine and to phenelzine at 6 weeks and 6 months were studied in 116 patients suffering from major depression with melancholia ( DSM-III ) . Several sociodemographic , clinical , and biological variables were studied . For imipramine-treated patients , high social support predicted a better response at 6 weeks , while development of hypomania during follow-up was associated with a better response at 6 weeks ; absence of life events during the 6-month follow-up and initial non-suppression of dexamethasone predicted a better outcome at 6 months . For phenelzine-treated patients , development of hypomania during follow-up was associated with a better outcome at 6 months and absence of life events prior to the onset of the episode was associated with a worse outcome at 6 months Objective : The objective of this study was to test the association of positive affect as measured by the Center for Epidemiologic Studies Depression Scale ( CES‐D ) with risk of AIDS mortality , controlling for the other CES‐D subscales and laboratory measures of disease progression . Methods : Data come from the San Francisco Men 's Health Study , a prospect i ve study of a household probability sample of single men in San Francisco . The subjects were 407 men who were HIV+ at study baseline . Results : In time‐dependent Cox proportional hazards models , the positive affect subscale of the CES‐D was significantly associated with lower risk of AIDS mortality ( RR = 0.89 , CI = 0.84‐0.95 ) . When risk estimates were adjusted for time‐dependent covariates of CD4 , serum & bgr;2‐microglobulin , P24 antigen , antiretroviral use , and the other subscales of the CES‐D , positive affect remained significantly predictive of lower risk of AIDS mortality ( RR = 0.90 , CI = 0.85‐0.97 ) . When the CES‐D subscale predictors were lagged by 12 , 24 , and 36 months in order to address the possibility that positive affect was simply a marker for better health , positive affect remained significantly predictive lagged by 12 months and marginally predictive lagged by 24 months . Conclusions : Positive affect seems to be the “ active ingredient ” in the association of scores on the CES‐D depressive mood scale and mortality in this sample of HIV+ men . Future work should exp and the traditional negative‐affect‐only focus to encompass the significant role that positive affect plays in living with HIV OBJECTIVE The authors investigated patient characteristics predictive of treatment response in the National Institute of Mental Health ( NIMH ) Treatment of Depression Collaborative Research Program . METHOD Two hundred thirty-nine out patients with major depressive disorder according to the Research Diagnostic Criteria entered a 16-week multicenter clinical trial and 
    Output:
    
RESULTS Lower levels of PE predicted poorer MDD course with some consistency .
Paradoxically , both lower levels of state NE and higher levels of trait NE predicted poorer MDD course .
The relationships between emotionality and MDD course generally held even after initial depression symptom severity was taken into account .
Emotion shows promise as a predictor of MDD course .