MORNINGNESS-EVENINGNESS,SEX, AND THE ALTERNATIVE FIVE FACTOR MODEL OF PERSONALITY

Recent research on personality and circadian typology indicates that evening-type subjects are more extraverted, impulsive, and novelty-seeking, while morning ones tend to be more introverted, conscientious, agreeable, and emotionally stable. The purpose of this study was to examine the differences between circadian typologies on the Zuckerman's Alternative Five Factor Model of personality (AFFM), which has a strong biological basis, controlling for sex and age. A sample of 533 university students (168 men) participated in the study. Results showed that morning-type subjects had significant higher scores than evening-type and neither-type subjects in Activity, and in its subscales General Activity and Work Activity. A significant interaction between circadian typology and sex was found for Neuroticism-Anxiety: morning-type men showed higher scores than evening-type and neither-type, who had the lowest scores. Women presented the opposite pattern: neither-type obtained the highest scores, while morning-type showed the lowest. This is the first time the AFFM has been used in the context of circadian rhythms research. The results suggest that activity is the only trait related to extraversion associated with morningness, while Neuroticism-Anxiety was modulated by sex. These results might help highlight previous results on the association between morningness-eveningness and other models of personality assessment, and they offer new data that calls for further research. (Author correspondence: anna.muro@uab.cat)     

Circadian Typology and Emotional Intelligence in Healthy Adults

Several aspects related to health, such as satisfaction with life, perceived well-being, and psychopathological symptomatology have been associated with circadian typology and with emotional intelligence. Nevertheless, the relationships between circadian typology and emotional intelligence have not been explored yet. The purpose of the present study is to examine the relationships between circadian typology and emotional intelligence, taking into account the possible interactions between sex and physical exercise, and controlling for age. A sample of 1011 participants (649 women), aged between 18 and 50 yrs (26.92?±?6.53) completed the reduced Morningness-Eveningness Questionnaire (rMEQ) and the Trait Meta-Mood Scale-24 (TMMS-24). The TMMS-24 considers three dimensions of emotional intelligence: emotional attention, emotional clarity, and emotional repair. Women showed higher values for emotional attention, whereas men showed higher values for emotional repair (p?<?0.035, in both cases). Subjects who do physical exercise weekly showed higher values for emotional repair (p?=?0.001) regardless of circadian typology or sex. Circadian typology presents differences in all scores of emotional intelligence dimensions. Morning-type had lower emotional attention than evening- and neither-type; neither-type had lower emotional repair than morning-type, and lower emotional clarity than both evening- and morning-type (p?<?0.046, in all cases). Moreover, circadian typology modulated the sex differences in emotional attention, and only morning-type men showed a low emotional attention score. From the results of emotional intelligence we can conclude that morning typology may be a protective factor in terms of general health, whereas we should be aware that the neither-type may present a possible vulnerability to develop psychological problems.     

Circadian typology, age, and the alternative five-factor personality model in an adult women sample

Research on personality and circadian typology indicates evening-type women are more impulsive and novelty seeking, neither types are more anxious, and morning types tend to be more active, conscientious, and persistent. The purpose of this study is to examine the differences between circadian typologies in the light of the Zuckerman's Alternative Five-Factor Model (AFFM) of personality, which has a strong biological basis, in an adult sample of 412 women 18 to 55 yrs of age. The authors found morning-type women had significant higher scores than evening-type and neither-type women on Activity, and its subscales General Activity and Work Activity. In contrast, evening-type women scored significantly higher than morning-type women on Aggression-Hostility, Impulsive Sensation Seeking, and its subscale Sensation Seeking. In all groups, results were independent of age. These findings are in accordance with those previously obtained in female student samples and add new data on the AFFM. The need of using personality models that are biologically based in the study of circadian rhythms is discussed.     

Circadian Typology,Age, and the Alternative Five-Factor Personality Model in an Adult Women Sample

Research on personality and circadian typology indicates evening-type women are more impulsive and novelty seeking, neither types are more anxious, and morning types tend to be more active, conscientious, and persistent. The purpose of this study is to examine the differences between circadian typologies in the light of the Zuckerman's Alternative Five-Factor Model (AFFM) of personality, which has a strong biological basis, in an adult sample of 412 women 18 to 55 yrs of age. The authors found morning-type women had significant higher scores than evening-type and neither-type women on Activity, and its subscales General Activity and Work Activity. In contrast, evening-type women scored significantly higher than morning-type women on Aggression-Hostility, Impulsive Sensation Seeking, and its subscale Sensation Seeking. In all groups, results were independent of age. These findings are in accordance with those previously obtained in female student samples and add new data on the AFFM. The need of using personality models that are biologically based in the study of circadian rhythms is discussed. (Author correspondence: anna.muro@uab.cat)     

CIRCADIAN TYPOLOGY AND TEMPERAMENT AND CHARACTER PERSONALITY DIMENSIONS

The purpose of the present study is to explore the relationships between circadian typology and Cloninger’s model of the seven dimensions of personality, taking into account the possible sex interactions. This model considers four temperament dimensions (viz., HA, harm avoidance; NS, novelty seeking; RD, reward dependence; and PS, persistence) and three character dimensions (viz., SD, self-directedness; C, cooperativeness; and ST, self-transcendence). A sample of 862 university students (500 women), between 18 and 30 (21.94?±?2.64) yrs of age completed the short versions of the Temperament and Character Inventory (TCI-56) and the reduced Morningness-Eveningness Questionnaire (rMEQ). Women showed higher values for HA, RD, and C, while men showed higher values for NS. Evening-type subjects had higher NS but lower HA, PS, and SD scores. Moreover, circadian typology modulated the sex differences in HA and NS, and only evening-type men showed a lower HA score and higher NS score. Circadian typology is related to Cloninger’s model of Temperament and Character personality dimensions. Future studies should further examine possible implications, regarding both the vulnerability of developing psychopathological disorders and the prognosis of response to different treatments. (Author correspondence: aadan@ub.edu)     

Gender differences in morningness-eveningness preference

Morningness-eveningness preference (morning-, intermediate-, evening-type) or circadian typology is the individual difference that most clearly explains the variations in the rhythmic expression of biological or behavioral patterns. The aim of this study was to analyze gender difference in morningness-eveningness preference using the Horne and Ostberg questionnaire in the largest university student population selected so far (N = 2135), with an age range 18-30 yr. Morningness-eveningness questionnaire (MEQ) score distribution closely correlated to the normal curve (range 17-78, mean = 48.25; SD = 10.11), with 338 (15.84%) morning-types, 1273 (59.62%) intermediate-types, and 524 (24.54%) evening-types. The men and women differed significantly in their mean scores (p < 0.0001) and distribution per circadian typology (p < 0.00001), with the men presenting a more pronounced eveningness preference. Three factors were identified by factor analysis: time of greatest efficiency (I), sleep time/sleep phase (II), awakening time/sleep inertia (III). The MEQ items sensitive to gender differences were essentially those included in factor I and factor II. The results are discussed in relation to recent models of circadian regulation of the sleep-wake cycle.     

Chronotype differences in suicidal behavior and impulsivity among suicide attempters

Morning- and evening-type individuals differ on a number of psychological and biological variables. There has been increasing interest in the relationship between chronotype and personality traits. The aim of this study was to investigate the relationship between impulsivity and chronotype in suicide attempters. Eighty-nine suicide attempters were included in the study, and systematic information on suicide attempts was recorded. The Morningness-Eveningness Questionnaire was applied to determine chronotype, and attempter impulsivity was measured by the total score of the Barratt Impulsiveness Scale. Significant differences between chronotype and impulsivity scores were found. Evening-type subjects reported significantly higher impulsivity scores than both neither- and morning-types. A significant association between chronotype and type of suicide attempt was detected. The largest proportion of violent suicide attempters were evening-type subjects. Violent suicide attempters also reported significantly higher impulsivity scores than nonviolent attempters. Previous studies have pointed out possible relations between eveningness and impulsivity. Current findings suggest that eveningness may be a risk factor for violent suicide attempts by increasing impulsivity.     

Economic decision-making in morning/evening-type people as a function of time of day

Decision-making is affected by psychological factors like emotional state or cognitive control, which may also vary with circadian rhythmicity. Here, we tested the influence of chronotype (32 morning-type versus 32 evening-type) and time of day (9 a.m. versus 5 p.m.) on interpersonal decision-making as measured by the Ultimatum Game. Participants had to accept or reject different economic offers proposed by a virtual participant. Acceptance involved distribution of gains as proposed, whereas rejection resulted in no gain for either player. The results of the game showed a deviation from rational performance, as participants usually rejected the unfair offers. This behaviour was similar for both chronotype groups, and in both times of day. This result may reflect the robustness of decision-making strategies across standard circadian phases under ecological conditions. Furthermore, morning-types invested more time than evening-types to respond to high-uncertainty offers. This more cautious decision-making style of morning-types fits with our finding of higher proactive control as compared to evening-types when performing the AX-Continuous Performance Task. In line with the literature on personality traits, our results suggest that morning-types behave with more conscientiousness and less risk-taking than evening-type individuals.     

Chronotype Differences in Suicidal Behavior and Impulsivity Among Suicide Attempters

Morning- and evening-type individuals differ on a number of psychological and biological variables. There has been increasing interest in the relationship between chronotype and personality traits. The aim of this study was to investigate the relationship between impulsivity and chronotype in suicide attempters. Eighty-nine suicide attempters were included in the study, and systematic information on suicide attempts was recorded. The Morningness-Eveningness Questionnaire was applied to determine chronotype, and attempter impulsivity was measured by the total score of the Barratt Impulsiveness Scale. Significant differences between chronotype and impulsivity scores were found. Evening-type subjects reported significantly higher impulsivity scores than both neither- and morning-types. A significant association between chronotype and type of suicide attempt was detected. The largest proportion of violent suicide attempters were evening-type subjects. Violent suicide attempters also reported significantly higher impulsivity scores than nonviolent attempters. Previous studies have pointed out possible relations between eveningness and impulsivity. Current findings suggest that eveningness may be a risk factor for violent suicide attempts by increasing impulsivity. (Author correspondence: dryavuzselvi@yahoo.com)     

Mindfulness and self-compassion along the chronotype: a cross-sectional study

It is well established in the literature that morning-type individuals present better health indicators than evening-types. Mindfulness is considered an adaptive self-regulation skill associated with well-being and physical and mental health. However, there is scarce studies that relate chronotype and mindfulness. Thus, in this research, our aim was to study the relationship between chronotype and mindfulness-related variables. For this purpose, a sample composed of 483 participants from the community was recruited through an online survey and invited to fill out the Five Facet Mindfulness Questionnaire, the Self-Compassion Scale, and the Composite Morningness Scale. Regarding mindfulness measure, the results indicated that morning-types presented higher levels of “acting with awareness” than intermediate and evening-types. Additionally, as to self-compassion measure, morning-types presented higher levels of “mindfulness” and “overall self-compassion” than intermediate and evening-types. The remaining associations examined were not statistically significant. In sum, the morning-types showed higher scores in some of the mindfulness and self-compassion scales which seem to suggest that this morningness tendency may function as protective factor concerning eventual disorders´ development. Nonetheless, more systematic studies are needed to better understand this association and subsequently foster changes for psychological intervention.     

Sleep quality,chronotype and social jetlag differentially associate with symptoms of attention deficit hyperactivity disorder in adults

Attention deficit hyperactivity disorder (ADHD) is a common neurobehavioural disorder which has been associated with sleep and circadian rhythm disturbances. Numerous studies have linked evening circadian typology with traits and behaviours associated with the disorder, although a precise reason for this relationship has not been clarified. The current study examines ADHD symptoms, impulsivity, cognitive failures, sleep quality and chronotype in a cohort of healthy young adults (N = 396). Results show significant, small magnitude associations between mid-point of sleep on free days, social jetlag (SJL) and ADHD symptoms and impulsivity, although not with cognitive failures. Similarly, sleep quality is also associated with ADHD symptoms and impulsivity. Group-wise approaches show that higher SJL is associated with significantly more ADHD symptoms and impulsivity, and later mid-sleep on free days is also associated with more ADHD symptoms. Stepwise multiple linear regression reveals that, when controlling for age and sex, SJL but not mid-sleep on free days is a significant predictor of ADHD symptoms and impulsivity. These results indicate that SJL may be an important factor to consider when exploring circadian rhythm associations with ADHD symptoms.     

Relationships Among Circadian Typology,Psychological Symptoms,and Sensation Seeking

Recently, attention has been focused on the relationship among circadian typology, psychiatric symptoms, and personality traits. This study analyzes the influence of circadian typology on psychological distress, and the sensation-seeking personality trait. Five hundred seventeen college students (173 males), aged 17 to 30, answered the Composite Scale of Morningness (CSM), the General Health Questionnaire 28-item version (GHQ-28), and the Sensation Seeking Scale-V (SSS-V). The evening-type subjects in our sample scored higher than the neither- and morning- type in the GHQ-28 total score, as well as in the four subscales that composed it (Psychosomatic Symptoms, Anxiety and Insomnia, Social Dysfunction, and Severe Depression) (p?<?0.02 in all cases). The evening-type subjects also had a larger proportion of psychiatric cases than the other two circadian typologies (p?<?0.0001 in all cases). Moreover, the evening-type subjects obtained higher scores in the SSS-V total score and in the subscales of Disinhibition and Boredom Susceptibility (p?<?0.001 in all cases). A positive correlation was observed between the GHQ-28 and the SSS-V total scores in the total sample, but only for the evening-type group (r?=?0.217; p?<?0.027). In the evening group, several relations were also found between the subscales of the GHQ-28 and the subscales of the SSS-V (r?>?0.206; p?<?0.036). All these data point to a relationship between evening-type subjects and the level of psychological distress and the sensation-seeking personality trait. They also suggest that eveningness could be related to developing psychological distress and personality traits that could, in turn, be related to developing other problems, such as drug consumption.     

Do different circadian typology measures modulate their relationship with personality? A test using the Alternative Five Factor Model

The relationship between personality and circadian typology shows some inconsistent results and it has been hypothesized that the model used to measure personality might have a moderating effect on this relationship. However, it has never been explored if this inconsistency was dependent on the questionnaire used to measure differences in circadian rhythms as well. We explored this issue in a sample of 564 university students (32% men; 19–40 years) using the Zuckerman–Kuhlman Personality Questionnaire, which is based on an evolutionary-biological approach, in combination with the Composite Scale of Morningness (CSM) and the reduced Morningness–Eveningness Questionnaire (rMEQ). Both questionnaires detected differences between circadian typologies in Sociability (highest in evening types; ET) and Impulsive Sensation-Seeking scales (highest in ET), while the CSM also detected differences in Activity (lowest in ET) and Aggression-Hostility (highest in ET). Further, both questionnaires detected differences between circadian typologies in the subscales General Activity (morning types [MT] higher than ET), Impulsivity (ET highest) and Sensation-Seeking (highest in ET). Differences between circadian typologies/groups in the subscales Parties (highest in ET) and Isolation Intolerance (lowest in MT) were only detected by the rMEQ. The CSM clearly separated evening types from neither and morning types while the rMEQ showed that neither types are not intermediate but closer to evening types in General Activity and Isolation Intolerance, and closer to morning types in Impulsive Sensation-Seeking, Parties, Impulsivity and Sensation Seeking. The obtained results indicate that the relationship between circadian typology and personality may be dependent on the instrument used to assess circadian typology. This fact may help to explain some of the conflicting data available on the relationship between these two concepts.     

Are all evening-types doomed? Latent class analyses of perceived morningness–eveningness,sleep and psychosocial functioning among emerging adults

An overwhelming amount of research has indicated that evening-types report more negative psychosocial functioning as well as more negative sleep characteristics (e.g. more sleep problems) relative to morning-types. Researchers also find a strong, consistent link between poor sleep characteristics and negative psychosocial functioning. These studies, however, have been based on a variable-centred approach, and thus were not able to assess possible individual differences within morning-types and evening-types with respect to their sleep characteristics prior to assessing differences in psychosocial functioning. Thus, it is not clear whether it is morningness–eveningness per se or sleep characteristics that explain the differences in psychosocial functioning found between morning-types and evening-types. The purpose of the present two-year longitudinal study was to employ a person-centred approach to determine whether there are subgroups within morning-types and evening-types based on 10-sleep characteristics (e.g. sleep problems and sleep duration). Then subgroups were compared on three indices of psychosocial functioning (i.e. academics, intrapersonal adjustment and alcohol consumption), both concurrently, as well as one year later. Participants were 780 (72.2% female; M?=?19.0 years, SD?=?0.90) emerging adults at a mid-sized university in Southern Ontario, who were either morning-types or evening-types. A latent class analysis (LCA) conducted for morning-types yielded two subgroups, classified as having good sleep characteristics (i.e. morning-good) and poor sleep characteristics (i.e. morning-poor). Results of a second LCA conducted for evening-types yielded three subgroups, classified as having good (i.e. evening-good), moderate (i.e. evening-moderate) and poor (i.e. evening-poor) sleep characteristics. Results comparing subgroups across the 10-sleep characteristics indicated that morning-good and evening-good individuals reported very similar scores, and both were characterized by the least sleep problems and longest sleep duration relative to the other subgroups. In terms of the three psychosocial functioning indices we found that academic achievement generally did not differ across the five subgroups (i.e. morning-good, morning-poor, evening-good, evening-moderate and evening-poor). With respect to intrapersonal adjustment, morning-good and evening-good subgroups reported significantly better intrapersonal adjustment relative to the other subgroups across time. Interestingly, evening-type subgroups generally reported higher alcohol consumption than morning-type subgroups. Overall, these results suggest that intrapersonal adjustment in particular appears to be associated more with differences in sleep characteristics (i.e. sleep problems and duration), than with morningness–eveningness per se, while the opposite is generally true for alcohol consumption. Lifestyle and personality factors likely also play a critical role. Importantly, our study is the first to identify a subgroup of evening-types who report good sleep characteristics and similar levels of intrapersonal adjustment and academic achievement to that of the majority of morning-types.     

Eveningness associates with smoking and sleep problems among pregnant women

Sleep problems during pregnancy impair maternal health and increase the risk for adverse pregnancy outcome. The circadian preference toward eveningness has been associated with sleep problems in previous studies. Here, we studied whether evening-type women had more sleep problems during their pregnancy, as compared with other chronotypes, in a sample consisting of 1653 pregnant women from the Finnish CHILD-SLEEP Birth Cohort. Chronotype was assessed with a shortened version of the morningness–eveningness questionnaire. Pregnant evening-type women reported more sleep problems, including troubles of falling asleep (OR = 3.4, p < 0.0001), poor sleep quality (OR = 2.9, p < 0.01) and daily tiredness (OR = 3.2, p < 0.0001) than the morning-type women, even after controlling for sleep duration and sleep deprivation. They had higher scores on Epworth Sleepiness Scale (p < 0.05), Basic Nordic Sleep Questionnaire (p < 0.0001) and Global Seasonality Score (p < 0.01) and were also more often smokers, also during pregnancy (p < 0.001) and reported poorer general health (p < 0.001) than the morning-type women. They also reported having had more sleep problems during their childhood (OR = 1.5, p < 0.05) and adolescence (OR = 2.0, p < 0.001) than the morning-type women. Our results indicate that eveningness is associated with more sleep problems and unhealthy life habits during pregnancy.     

Prospective time estimation over a night without sleep

The aim of the present study was to investigate the time of night effect on prospective time estimation efficiency. Fifty-four participants took part in six consecutive experimental sessions from 10:00 p.m. to 8:00 a.m. at intervals of 2 h, during which they had to carry out two kinds of tasks (simple reaction time and prospective time estimation), give an evaluation of their subjective alertness, and record body temperature. In agreement with previous data on body temperature, subjective alertness and performance in simple reaction time showed a significant decrease during the night, while performance in prospective time estimation did not change over the night. Taking into account circadian typology we found that morning-types tended to produce significantly shorter time intervals and less time estimation accuracy than evening-types. With reference to recent cognitive timing models and data derived from free-running conditions, it is hypothesised that internal pace-makers pulse at different rates between the extreme chronotypes.     

Diurnal changes of ERP response to sound stimuli of varying frequency in morning-type and evening-type subjects

In order to study the cognitive function rhythm related to the auditory frequency system for people who prefer to be active in the morning and at night, we conducted an experiment during morning (09:00), evening (17:00) and late-night (01:00) periods. On the basis of a morningness/eveningness questionnaire, six moderately morning-type subjects (M-types) and seven evening-type subjects (E-types) were selected. Diurnal variation of event-related potential (ERP) were assessed under low-frequency (250/500 Hz) and high-frequency (1000/2000 Hz) condition using an oddball task. M-types were tested during the morning (09:00) and evening (17:00) periods, and E-types were tested during the evening (17:00) and midnight (01:00) periods. Subjects were asked to press a button when the target stimulus was detected. We found that the P300 amplitude at 09:00 was significantly greater than that at 17:00 for M-types, was significantly greater at 17:00 than that at 01:00 for E-types. A significant difference of P300 latency and P300 amplitude was observed at 17:00 between M-types and E-types. The P300 amplitude obtained after a low-frequency stimulus was significantly greater than that after a high-frequency stimulus at 09:00 for M-types, and at 01:00 for E-types. These results revealed that stimulus frequency had effects on the diurnal changes of human cognitive function, and circadian typology had a direct effect on the diurnal change of human cognitive function. This study has extended the previous findings of auditory P300 studies on diurnal variations in terms of circadian typology and stimulus parameter.     

Social cognition under stress: Differential effects of stress-induced cortisol elevations in healthy young men and women

Humans as social beings often have to perform complex social cognitive tasks while under stress (e.g., during a social conflict). Previous research has established that the brain regions responsible for social cognitive tasks are target regions for stress hormones. However, little experimental research has been done testing the acute effects of stress on social cognition. Here, we investigated whether stress exposure and the ensuing glucocorticoid (i.e., cortisol) elevations affect social cognition. Thirty-two men and 32 women were exposed to either a psychosocial stress or a non-stressful control test before assessing their social cognition using the Reading the Mind in the Eyes Test (RMET) and the Movie for the Assessment of Social Cognition (MASC). Results showed differential effects of stress-induced cortisol responses among men and women for the MASC, but not the RMET. Among men, high cortisol responders displayed elevated MASC scores compared with low cortisol responders. Moreover, for stressed men a positive association between the magnitude of the cortisol responses to the stressor and MASC scores emerged. Among women, enhanced MASC scores were found for low cortisol responders relative to high cortisol responders and non-stressed controls. A strong negative association between cortisol reactivity and MASC scores was found among women. These results imply sex specific effects of glucocorticoids on social cognition and partially support the idea of sex differences in biobehavioral stress responses, with men engaging in fight-or-flight responses while women may react to stress with tending and befriending behavior.