Chronotype differences in suicidal behavior and impulsivity among suicide attempters.
ABSTRACT 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.
SourceAvailable from: Konrad S. Jankowski[Show abstract] [Hide abstract]
ABSTRACT: Morningness–eveningness describes individual preferences for activity at specified times of the day. The present research aimed to test whether sun time entrains humans and whether this effect is observable in sleep–wake timing, in the timing of social rhythm and in morningness preference. Furthermore, we tested whether different reference points (activity expressed in standard time or in sun time, morningness preference scores) provide concordant results about differences in chronotype according to longitude. University students were tested in two locations (Warsaw, Poland; Heidelberg, Germany) positioned within the same time zone but differing according to longitude, thus daylight appeared earlier in the east (Warsaw) than in the west (Heidelberg). Sampling was scheduled to obtain similar photoperiods and other environmental factors in two locations. Measures consisted of times of day when various activities occurred (e.g. going to bed, waking up, going outdoors) in the seven days prior to data collection, morningness preference, and depressiveness. Varsovians and Heidelbergers did not differ in morningness preference and depressiveness, but Varsovians, compared to Heidelbergers, undertook a number of activities (e.g. wake up, get up, having breakfast, first contact with another person and going outdoors) at an earlier clock time (21–38 min earlier, depending on activity), did not differ in starting and finishing classes/work, and were later in eating lunch and dinner. However, all the activities of Varsovians (except for going outdoors) were positioned later according to sun time reference. Thus, residents from east as compared to those from the west had similar morningness preference, were more morning positioned in many aspects according to standard time, but were later according to sun time. Results indicated university students entrained to sun time to some extent, and morning activities more coupled to sun time.Time & Society 06/2014; 23(2):258-276. DOI:10.1177/0961463X14535911 · 0.46 Impact Factor
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ABSTRACT: Background Suicidal behavior has been reported to be associated with seasonality and chronotype. However, no study has reported the suicidality according to chronotype and seasonality in patients with major depressive disorder (MDD). This study evaluated the relationship of suicidality and biological rhythm in patients with MDD. Methods A total of 120 patients with MDD participated. We evaluated their seasonal patterns, chronotypes (morningness, wake up early and are at their best during the first part of the day; eveningness, feel best and most alert during late hours), suicidal ideations, and other clinical variables including symptom severity. Results Patients with seasonality showed significantly higher suicidal ideation than patients without seasonality. Compared to morning-type participants, the evening-type participants showed higher suicidality. Suicidal ideation was positively correlated with eveningness tendencies and hypomanic personality traits. Limitations First, we did not analyze the causal relationship between biological rhythm and suicidality. Secondly, suicidal ideation does not in most cases reflect an actual attempt. Lastly, we did not categorize seasonal pattern into summer or winter type. Conclusions Our findings suggest that biological rhythm is significantly associated with suicidal ideation in patients with MDD.Journal of Affective Disorders 10/2014; 168:294–297. DOI:10.1016/j.jad.2014.07.001 · 3.71 Impact Factor
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ABSTRACT: Several studies documented that lower scores on the Morningness-Eveningness Questionnaire (MEQ) are associated with a higher global seasonality of mood (GSS). As for the Modern Man artificial lighting predominantly extends evening activity and exposure to light, and as evening bright light phase is known to delay circadian rhythms, this chronic exposure could potentially lead to both lower Morningness as well as higher GSS. The aim of the study was to investigate if the MEQ-GSS relationship holds in the Old Order Amish of Lancaster County, PA, a population that does not use network electrical light. 489 Old Order Amish adults (47.6% women), with average (SD) age of 49.7 (14.2) years, completed both the Seasonal Pattern Assessment Questionnaire (SPAQ) for the assessment of GSS, and MEQ. Associations between GSS scores and MEQ scores were analyzed using linear models, accounting for age, gender and relatedness by including the relationship matrix in the model as a random effect. GSS was inversely associated with MEQ scores (p=0.006, adjusted). include a potential recall bias associated with self-report questionnaires and no actual light exposure measurements. We confirmed the previously reported inverse association between MEQ scores and lower seasonality of mood, for the first time in a population that does not use home network electrical lighting. This result suggests that the association is not a byproduct of exposure to network electric light, and calls for additional research to investigate mechanisms by which Morningness is negatively associated with seasonality. Published by Elsevier B.V.Journal of Affective Disorders 11/2014; 174C:209-214. DOI:10.1016/j.jad.2014.11.039 · 3.71 Impact Factor