Patterns of self-reported depressive symptoms in relation to morningness-eveningness in inpatients with a depressive disorder

The influence of childhood trauma and chronotype on suicide attempts in Chinese emerging adults with severe depressive symptoms

BACKGROUND

Studies have investigated how adults with severe depressive symptoms are more likely to attempt suicide, and these adults often have traumatic experiences and chaotic sleep/wake rhythms. Thus, this study using Latent class analysis aimed to investigate the relationship between childhood trauma class, chronotype, and suicide attempts among emerging adults with severe depressive symptoms.

METHODS

This study was conducted among emerging adults with severe depressive symptoms covering 63 Universities in Jilin Province, China. A total of 1,225 emerging adults (mean age = 19.6 ± 1.78) constructed the final sample. In addition to measuring socio-demographic characteristics, the Childhood Trauma Questionnaire-Short Form, the Single-Item Chronotyping, and a single item for suicide attempts were used to evaluate childhood trauma, chronotype, and suicide attempts, respectively. Latent class analysis was applied to identify the classes of childhood trauma within emerging adults who had severe depressive symptoms. Hierarchical logistic regression models were run to investigate the effects of socio-demographic characteristics, chronotype, and childhood trauma class on suicide attempts.

RESULTS

Three latent classes were identified: the Low-risk for childhood trauma class, the Neglect class, and the High-risk for childhood abuse class. Those who suffered sexual, emotional, and physical abuse at the same time were divided into the High-risk for childhood abuse class, and were significantly more likely to experience suicide attempts than those in the Neglect class (OR = 1.97, 95%CI = 1.34-2.89, p < 0.001) and the Low-risk for childhood trauma class (OR = 2.28, 95% CI = 1.50-3.46, p < 0.001). In terms of chronotype, the results showed that the chaotic type was a risk factor for suicide attempts when compared with the evening type (OR = 0.46, 95%CI = 0.27-0.78, p < 0.01), the moderately active type (OR = 0.53, 95%CI = 0.31-0.89, p < 0.05), and the daytime type (OR = 0.42, 95%CI = 0.21-0.86, p < 0.05). Overall, the significant risk factors for suicide attempts included being female, living in an urban area, having experienced sexual, emotional, and physical abuse simultaneously, and having a chaotic chronotype.

CONCLUSION

Emerging adults suffering sexual, emotional, and physical abuse at the same time and identifying with chaotic chronotype showed a higher risk of attempting suicide. The findings provided a clinical reference to quickly identify those at high risk of suicide attempts among emerging adults with severe depressive symptoms.

Circadian Rhythms and Depression in Adolescents: A Comparative Analysis of First Episode and Recurrent-Episode Groups

Circadian rhythm disruptions are a hallmark feature of mood disorders. Patients experiencing acute depressive episodes report noticeable changes in their sleep-wake cycles. This research explains the association between depression and various circadian rhythm metrics, explicitly focusing on adolescents diagnosed with depressive disorders. Adolescence is a critical period marked by significant physiological and psychological changes, making it imperative to understand how mood disorders manifest during this phase. However, there have been minimal specific studies in pediatric populations to determine whether circadian rhythm changes differ between adolescents with first and multiple-recurrent depressive episodes. Our study involved a group of 61 adolescents aged between 13 and 18. We performed a cross-sectional study of a clinical population of patients presenting to a child and adolescent psychiatry clinic diagnosed with depression. Participants were asked to complete self-report evaluations using several tools: the Korean version of the Biological Rhythms Interview of Assessment in Neuropsychiatry (K-BRIAN), the Korean Translation of Composite Scale to Measure Morningness-Eveningness (KtCS), and the Seasonal Pattern Assessment Questionnaire (SPAQ). Tools such as the Children's Depression Inventory (CDI), State-Trait Anxiety Inventory (STAI), and K-Mood Disorder Questionnaire (K-MDQ) were employed for the assessment of clinical characteristics of depression. Based on the frequency of their depressive episodes, participants were bifurcated into two distinct groups: those experiencing their first episode (n = 22, mean age: 15.09 ± 1.44 years) and those with recurrent episodes (n = 39, mean age: 15.95 ± 1.26 years). At first, the two groups' data revealed no significant differences regarding mood or circadian rhythm metrics (CDI: first episode 26.18 ± 10.54 and recurrent episode 25.90 ± 10.59, STAI-S: first episode 56.91 ± 12.12 and recurrent episode 57.49 ± 11.93, STAI-T: first episode 60.36 ± 11.63 and recurrent episode 59.09 ± 12.10, SPAQ-total: first episode 6.59 ± 4.86 and recurrent episode 6.77 ± 5.23, KtCS: first episode 30.32 ± 5.83 and recurrent episode 28.13 ± 7.36). However, we observed significant correlations between circadian rhythm disruptions and depression scales (CDI with SPAQ-weight (r = 0.26), KtCS (r = -0.48), K-BRIAN-sleep (r = 0.58), K-BRIAN-activity (r = 0.64), K-BRIAN-social (r = 0.71), and K-BRIAN-eating (r = 0.40)). These correlations were especially pronounced in the recurrent episode group, suggesting that with the progression and chronicity of depression, the relationship between circadian rhythms and depression becomes more intertwined and evident. In conclusion, especially in adolescents, as the severity and chronicity of depression increase, the interplay between circadian rhythms and mood disorders becomes more pronounced, warranting further research and clinical attention.

Characteristics of psychological time in patients with depression and potential intervention strategies

Psychological time reveals information about an individual's psychological state and psychopathological traits and, thus, has become a new perspective through which the occurrence and development of depression can be examined. Psychological time includes time perception, time perspective, circadian rhythms, and passage of time. Patients with depression are characterized by inaccurate time interval estimation, habitual negative thoughts about the past and future, evening-type circadian rhythms, and slow passage of time. Habitual negative thoughts about the past and future and evening-type circadian rhythms influence the formation of depression, and poor time interval estimation and slow passage of time may result from depression. Further study is needed accurately exploring psychological time and influencing factors in patients with depression, and prospective cohort studies could further clarify this complex relationship. In addition, the study of psychological time has important implications for developing effective interventions to reduce depression.

The relationship between morningness-eveningness and mood symptoms and quality of life in euthymic state of mood disorders: Results from a prospective observational cohort study

BACKGROUND

The clinical importance of morningness-eveningness, especially in mood disorders, is prevailing. The differential relation of chronotype with diagnoses of early-onset mood disorders, mood symptoms, anxiety, and quality of life was evaluated.

METHODS

Early-onset mood disorder patients [n = 419; 146 major depressive disorder (MDD); 123 bipolar I disorder (BDI); 150 bipolar II disorder (BDII)] from the Mood Disorder Cohort Research Consortium were assessed for chronotype using the composite scale for morningness (CSM) and its association with clinical variables obtained during the clinician-verified euthymic state.

RESULTS

The mean total CSM of BDI was significantly higher than MDD and BDII (p < 0.001). In all types of mood disorders, higher total CSM was associated with lower Quick inventory of depressive symptomatology (p < 0.005) and higher WHO quality of life (p < 0.005). Such negative correlations between the total CSM and Montgomery-Asberg depression rating were significant in MDD and BDI (p < 0.05) and marginally significant in BDII (p = 0.077). CSM was a significant contributor to quality of life in BDI (p < 0.001) and BDII (p = 0.011), but it was not for MDD.

LIMITATIONS

The defined 'euthymic state' that may not fully reflect the remission of episode; limited generalizability due to clinical characteristic of early-onset mood disorder; the disparity between diurnal preference measured by the CSM and chronotype; possible effects of the last mood episode polarity and medication; and, lack of control group.

CONCLUSION

Less eveningness was associated with less severe depressive symptoms and better quality of life. This suggests that morningness may reduce residual depressive symptoms and recover function of patients.

Evening chronotype as a bipolar feature among patients with major depressive disorder: the results of a pilot factor analysis

Objectives:

The bipolar spectrum concept has resulted in a paradigm shift that has affected both the diagnosis and therapy of mood disorders, with bipolarity becoming an indicator of treatment resistance in depression. Evening circadian preference has also been linked to affective disorders. The aim of our study was to confirm the relationship between the severity of depressive symptoms, bipolar features, chronotype, and sleep quality among patients with major depressive disorder.

Methods:

A group of 55 individuals who were recruited from a mental health outpatient clinic completed the following psychometric tools: a Chronotype Questionnaire comprising morningness-eveningness (ME) and subjective amplitude of the rhythm (AM) scales, the Hypomania Checklist 32 (HCL-32), the Beck Depression Inventory (BDI) and the Pittsburgh Sleep Quality Index (PSQI).

Results:

Factor analysis identified two latent components, accounting cumulatively for 58% of variables: depressive symptoms (BDI and PSQI) and bipolarity (ME, AM, and HCL-32). After rotation, ME loading in the first factor increased the result to a significant level. The correlation between the two components was very low.

Conclusions:

Evening chronotype appears to be a bipolarity-related marker, with this relationship being independent of its link to depressive symptoms and sleep quality. Eveningness and high circadian rhythm amplitude may offer promise as diagnostic, prognostic, and therapeutic predictors.

Diurnal preference and depressive symptomatology: a meta-analysis

Eveningness, a preference for later sleep and rise times, has been associated with a number of negative outcomes in terms of both physical and mental health. A large body of evidence links eveningness to Major Depressive Disorder (MDD). However, to date, evidence quantifying this association is limited. The current meta-analysis included 43 effect sizes from a total 27,996 participants. Using a random-effects model it was demonstrated that eveningness is associated with a small effect size (Fisher's Z = - 2.4, 95% CI [- 0.27. - 0.21], p < 0.001). Substantial heterogeneity between studies was observed, with meta-regression analyses demonstrating a significant effect of mean age on the association between diurnal preference and depression. There was also evidence of potential publication bias as assessed by visual inspection of funnel plots and Egger's test. The association between diurnal preference and depression is small in magnitude and heterogenous. A better understanding of the mechanistic underpinnings linking diurnal preference to depression and suitably powered prospective studies that allow causal inference are required.

The association between chronotype and suicidality among students of the medicine and psychology faculties - the mediating role of general mental health indices

The aim of the present study was to evaluate whether anxiety and insomnia symptoms, somatic symptoms, and social dysfunction mediate the link between chronotype and suicidality, as depressive symptoms are known to do, among students of the faculties of Medicine and Psychology. Data from a total of 289 students were eligible for the analysis. The students completed the Suicide Behaviors Questionnaire - Revised, Composite Scale of Morningness, General Health Questionnaire. Single-predictor linear regression models were created to predict suicidality, with a subsequent mediation analysis. A preference toward eveningness was associated with an increase in suicidality Somatic symptoms, anxiety/insomnia, and depressive symptoms fully mediated the relationship between chronotype and suicidality. Depressive symptoms were found to present the strongest effect size of mediation. Social dysfunction was associated with both eveningness and suicidality, but did not play a mediating role. There might be a need to evaluate nonpsychotic mental health indices other than depressive symptoms when assessing the link between suicidality and chronotype among students of the faculties of Medicine and Psychology.

Differential Co-Occurring Patterns Between Depressive Symptomatology and Sleep-Wake-Related Disturbances in Mood Disorders

PURPOSE

This study aimed to elucidate the various co-occurring patterns of depressive symptomatology and sleep-wake-related disturbances (SWRDs) in patients with mood disorders.

PATIENTS AND METHODS

Individuals in non-acute states of major depressive disorder or bipolar disorder were recruited. The Beck Depression Inventory II (BDI-II) was utilized to evaluate depressive symptoms. BDI-II items were classified into three domains: cognitive, affective, and somatic. Between-domain differences with various SWRDs were examined. Latent class analysis was used to empirically classify participants using BDI-II items as indicator variables. Co-occurring patterns between domains of BDI-II items and SWRDs were re-examined in each subgroup to elucidate inter-individual differences.

RESULTS

In total, 657 participants were enrolled. Of participants, 66.8% were female, and 52.4% were diagnosed with major depressive disorder. Each BDI-II domain exhibited different co-occurring patterns. The somatic domain was most likely to co-occur with various SWRDs. Three subgroups were derived from latent class analysis and were designated as poor sleep quality and high insomnia (n=150), poor sleep quality and moderate insomnia (n=248), and poor sleep quality and low insomnia (n=159). The group with more severe insomnia presented with more severe depressive and anxiety symptoms. The three subgroups further differed in co-occurring patterns. From the low insomnia to high insomnia group, the associations with various SWRDs appeared in the sequence of somatic, affective, and cognitive domains.

CONCLUSION

Co-occurring patterns between domains of depressive symptomatology with various SWRDs differ and may vary among individuals.

Circadian Functioning and Quality of Life in Substance Use Disorder Patients With and Without Comorbid Major Depressive Disorder

Aim: Although a relationship between circadian disruption and development of several psychiatric disorders, such as major depressive disorder (MDD) and substance use disorder (SUD), has been observed, knowledge on this area is scarce yet. Therefore, this study aims to analyze the circadian functioning and quality of life (QOL) in SUD patients with and without comorbid MDD, two highly prevalent clinical entities with difficult therapeutic management. Methods: One hundred sixty-three male patients under treatment, 81 with SUD and 82 with SUD comorbid major depressive disorder (SUD + MDD), were evaluated. For the circadian functioning assessment, we calculated Social Jet Lag (SJL) and used the reduced Morningness-Eveningness Questionnaire (rMEQ) and the Pittsburgh Sleep Quality Index (PSQI). QOL was measured using the shortened version of the World Health Organization's Quality of Life Questionnaire (WHOQOL-BREF). We collected sociodemographic and clinical variables to evaluate their possible influence on the circadian functioning. Intergroup differences among the variables were examined by different analyses of covariance (ANCOVA and MANCOVA). The possible relationships of quantitative clinical variables with rMEQ, PSQI, and WHOQOL-BREF were explored using bivariate correlation analysis. Results: Lower SJL appears in the SUD + MDD group compared with SUD. The intermediate-type was more prevalent in the SUD group, while a higher percentage of morning-type patients was found in the SUD + MDD. Sleep quality (including latency and daytime dysfunction) was worse for SUD + MDD patients than for SUD even after controlling age and age of SUD onset variables. Last, QOL was poorer in patients with SUD + MDD and, for them, psychological health had a negative relationship with SJL and severity of depression. Conclusions: Our data support and extend previous findings indicating that SUD + MDD is associated with worse clinical characteristics, more sleep problems, and poorer QOL than SUD patients. These results underline the importance of a precise assessment of these measurements in future studies conducted in SUD patients with/without MDD comorbidity that could be considered from a therapeutic point of view.

Chronotypes and affective disorders: A clock for mood?

Affective disorders are often accompanied by circadian rhythm disruption and the major symptoms of mental illness occur in a rhythmic manner. Chronotype, also known as circadian preference for rest or activity, is believed to exert a substantial influence on mental health. Here, we review the connection between chronotypes and affective disorders, and discuss the potential underlying mechanisms between these two phenomena.

Time of Day Matters: An Exploratory Assessment of Chronotype in a Forensic Psychiatric Hospital

A growing body of evidence links the late chronotype to mental illness, aggression, and aversive personality traits. However, much of what we know about these associations is based on healthy cohorts, and it is unclear how individuals with high levels of aggression, including forensic psychiatric populations, but not offenders, are affected. The present study aimed to measure chronotype in a forensic psychiatric inpatient population, evaluate the impact of diagnosis, and identify any interactive relationships between chronotype, diagnosis, aggression, and dark triad traits. Subjects completed the reduced Morningness-Eveningness Questionnaire (rMEQ), Munich ChronoType Questionnaire (MCTQ), Pittsburgh Sleep Quality Index (PSQI), Buss Perry Aggression Questionnaire-Short Form (BPAQ-SF), and Short Dark Triad Questionnaire (SD3). We sampled 55 forensic psychiatric patients (52 males) between the ages of 23 and 73 years (mean ± SD: 39.6 ± 14.3 years). Among the patients sampled, 25% were evening types and 36% were morning types. Eveningness was greater in patients with a personality disorder; however, no chronotype differences were found for psychosis patients. Patients without psychosis had a positive association between anger and eveningness, as well as between hostility and eveningness. For subjects with a substance use disorder, morningness was positively associated with narcissism. Conversely, an association between eveningness and greater narcissism was identified in patients who did not have a substance use disorder. These findings suggest that, compared to the general population, evening types are more prevalent in forensic psychiatric populations, with the strongest preference among patients diagnosed with a personality disorder. No differences in chronotype were identified for psychosis patients, which may be related to anti-psychotic medication dosing. Given the sex distribution of the sample, these findings may be more relevant to male populations.

Evening preference and poor sleep independently affect attentional-executive functions in patients with depression

Cognitive impairments are well documented in major depressive disorder (MDD), however, they cannot be fully explained by depressive symptom severity. We investigated how diurnal preference and sleep quality affect cognitive function in MDD. In 34 inpatients with current MDD and 29 healthy controls (HC), we obtained diurnal preference (Morningness-Eveningness Questionnaire, MEQ) and subjective sleep quality (Pittsburgh Sleep Quality Index, PSQI). Further, current mood and neuropsychological performance (Trail Making Test, TMT, part A and B) were assessed in the evening and in the following morning. Patients with MDD performed worse than HC on the TMT-B (particularly requiring executive function), but not on the TMT-A (assessing foremost visuomotor processing speed). In general, participants with evening preference (MEQ-score median split) performed poorer on the TMT than participants with morning preference. Subgroup analyses within MDD confirmed the negative effect of evening preference on the TMT. In addition, patients with severely impaired sleep quality (PSQI > 10) performed cognitively worse than patients with normal to moderately impaired sleep quality (PSQI ≤ 10). The results were largely independent of current mood state. Our findings suggest that evening preference and severely impaired sleep quality independently contribute to cognitive impairment in MDD.

Eveningness is associated with greater subjective cognitive impairment in individuals with self-reported symptoms of unipolar depression

BACKGROUND

Eveningness is associated with depression diagnosis and increased depressive symptom severity. Time-of-day preference has been linked with differences in cognitive function in the general population, with cognitive difficulties being a major factor in psychosocial impairment in depression. We therefore investigated the impact of time-of-day preference and self-reported depressed state on subjective cognitive function.

METHODS

Participants over the age of 18 with a self-reported history of depression completed an online questionnaire. They provided demographic and mental health information, and completed self-report scales assessing depression symptoms, time-of-day preference, and cognition. Participants were classified as "currently" or "previously depressed" based on self-reported symptoms, and as having a morning, neither, or evening time-of-day preference.

RESULTS

A total of 804 participants reporting a history of unipolar depression were included. Currently-depressed participants reported more cognitive difficulties in all areas measured. Evening types reported more complex attentional and retrospective memory difficulties than neither types, and reported more executive and prospective memory difficulties than both neither and morning types. There was an additive effect of mood state and time-of-day preference, with self-reported depressed evening types reporting the most cognitive problems.

LIMITATIONS

Depression history, time-of-day preference, and cognitive function were assessed using unsupervised self-report measures. Time-of-day preference does not necessarily reflect the physiological circadian system.

CONCLUSIONS

Both depressed state and evening preference were individually associated with subjective cognitive complaints in people with a self-reported history of unipolar depression. The additive effect of poor mood and eveningness is important given the high prevalence of eveningness in depression. Assessment of time-of-day preference could help to identify those susceptible to cognitive symptoms, and inform treatment.

Eveningness Is Associated With Greater Depressive Symptoms in Type 2 Diabetes Patients: A Study in Two Different Ethnic Cohorts

BACKGROUND

Eveningness is associated with greater depressive symptoms in the general population. Depression and type 2 diabetes (T2D) commonly coexist. We aimed to explore the association between morningness-eveningness and depressive symptoms in T2D patients in the United States and in Thailand.

PARTICIPANTS

T2D patients (n = 182) from an endocrinology clinic in Chicago, Illinois, and six hospitals in Thailand (n = 251) were enrolled.

METHODS

Diabetes history was collected. Depressive symptoms were assessed by the Center for Epidemiologic Studies Depression scale (CES-D). The Chicago cohort completed the Morningness-Eveningness Questionnaire (MEQ) and the Thai cohort completed the Composite Scale of Morningness (CSM). Sleep quality was assessed using the Pittsburg Sleep Quality Index (PSQI).

RESULTS

The mean (SD) CES-D score was 13.7 (9.1) in Chicago and 11.9 (6.4) in Thailand. In Chicago participants, after adjusting for age, sex, ethnicity, hemoglobin A1c, insulin use, and PSQI score, greater eveningness (lower MEQ scores) was associated with higher CESD scores (B = -0.117, p = 0.048). In Thai participants, after adjusting for age, sex, and PSQI score, eveningness (lower CSM score) was associated with higher CES-D score (B = -0.147, p = 0.016). In both cohorts, however, eveningness was not independently associated with the likelihood of being in the at-risk range for clinical depression (CES-D ≥ 16).

CONCLUSIONS

Eveningness is independently associated with greater depressive symptoms in T2D in two different ethnic cohorts. The results support the association between individual differences in circadian rhythms and psychological functioning in T2D.

The relationship between morningness-eveningness and resilience in mood disorder patients

BACKGROUND

There is some evidence that resilience is related to mental illness. Patients with a mood disorder have a tendency to show eveningness, and they tend to be less resilient. However, no study has investigated the association between resilience and morningness-eveningness in patients with a mood disorder. The aim of this study was to explore whether morningness-eveningness is related to resilience in patients with a mood disorder.

METHODS

We recruited 224 patients with major depressive disorder (MDD), 77 with bipolar disorder (BD), and 958 control participants. Morningness-eveningness and resilience were evaluated using the Composite Scale of Morningness (CS) and the Connor-Davidson Resilience Scale (CD-RISC), respectively.

RESULTS

The CD-RISC scores were significantly lower in patients with MDD, followed by those with BD, than those of the control group. The CD-RISC score was positively correlated with the CS score in patients with MDD and BD. Multiple linear regression analyses revealed that the CS score was significantly associated with the CD-RISC score after controlling for the possible influence of age, gender, length of education, economic status, onset age, and suicide attempt history in the MDD group. However, the association did not reach statistical significance in patients with BD.

CONCLUSIONS

Higher resilience was positively correlated with morningness in patients with MDD or BD. In multiple regression analysis, a significant linear relationship was observed between resilience and morningness only in patients with MDD. The biological mechanism underlying the relationship between morningness-eveningness and resilience should be explored.

History of suicide attempt and right superior temporal gyrus volume in youth with treatment-resistant major depressive disorder

BACKGROUND

Growing evidence suggests an endophenotype for suicidality, including brain morphometric features, could provide an improved platform for suicide risk assessment. Reduced right superior temporal gyrus (rSTG) volumes have been implicated in suicidality across psychiatric disorders. Treatment-resistant depression (TRD) has unique neurobiology and adolescents with TRD are at increased suicide risk. Here, we investigated whether reduced rSTG volume was present in adolescents with TRD and history of suicide attempt.

METHODS

45 adolescents - 14 with history of suicide attempt and TRD, 14 without a suicide attempt history and TRD, and 17 healthy controls - underwent magnetic resonance imaging and reconstructed rSTG volumes were compared. Depressive and anxious symptoms were assessed with Hamilton depression and anxiety rating scales, and differences between attempters and non-attempters were explored.

RESULTS

Adolescents with TRD and history of suicide attempt showed reduced rSTG volume compared to healthy controls. Exploratory analyses revealed greater diurnal variation in depressive symptoms in the suicide attempt group compared to non-attempters.

LIMITATIONS

Sample size and temporal separation between suicide attempt date and data collection limits interpretation of findings.

CONCLUSIONS

Reduced rSTG volume may serve as a marker of suicide attempt in adolescence and specific symptom features may have a role in suicide risk assessment. Presently, risk assessment is limited by patient self-report and clinical judgement. A biological model of suicidality will be key to improve risk assessment and could lead to novel treatment approaches. Our findings extend previous results and contribute to our neurobiological understanding of suicidality.

Chronotype and Mental Health: Recent Advances

PURPOSE OF REVIEW

Evening chronotype is increasingly recognized as a correlate of, and perhaps a contributor to, mental illness. The current review evaluates recent evidence for the association between chronotype and mental illness and putative mechanisms underlying the association, while highlighting methodological advances and areas of research that are relatively under-examined in the literature.

RECENT FINDINGS

While evening chronotype is most consistently associated with severity of mood disorder symptoms, emerging evidence implicates evening chronotype as a transdiagnostic correlate of substance use severity, anxiety symptoms, attentional difficulties, and maladaptive behaviors such as aggression. Longitudinal studies point to the possibility that evening chronotype precedes problematic substance use, depression, and anxiety. Neural processes related to reward and affective regulation may underlie associations between evening chronotype and illness. The literature on chronotype and mental illness has evolved to (1) include associations with a broader range of psychiatric symptom profiles; (2) explore underlying mechanisms; and (3) expand on earlier research using objective measures and more sophisticated study designs. In addition to further mechanistic research, additional work is needed to examine the stability and key subcomponents of the chronotype construct, as well as more attention to pediatric and special populations. This research is needed to clarify the chronotype-mental health relationship, and to identify how, when, and what aspects of chronotype can be targeted via therapeutic interventions.

Associations of depression and seasonality with morning-evening preference: Comparison of contributions of its morning and evening components

Despite predominance of positive findings on associations of morning-evening preference with seasonality and depression, it remains to be clarified whether morning and evening components of this preference equally contribute to these associations and whether these associations persist after accounting for confounding variables. Data on retrospectively reported seasonal changes in well-being, mood, and behaviors were collected from 2398 residents of West Siberia, South and North Yakutia, Chukotka, Alaska, and Turkmenistan. Other self-reports included mental and physical health, sleep duration, and adaptabilities of the sleep-wake cycle. Depression was found to be linked to morning rather than evening component of morning-evening preference, i.e., morning lateness. Morning lateness was also linked to retrospectively reported degree of seasonal changes rather than to severity of problems associated with such changes. Variation in morning-evening preference explained not more than 2% and 4% of the total variation in depression and seasonality, respectively. The associations became even weaker but remained significant after accounting for other differences between respondents, such as their gender, age, physical health, and adaptability of their sleep-wake cycle. These results have practical relevance for understanding of the roles playing by morning earliness and insensitivity to seasonal changes in the environment to protection against different mood disorders.

State- and trait-like variation in morning and evening components of morningness-eveningness in winter depression

PURPOSE

Evening preference (eveningness) can be a risk factor for depression and a shift toward morning preference (morningness) can occur in response to treatment. A study of winter depression provides possibility to longitudinally evaluate state- and trait-like variation in morningness-eveningness during treatment in winter and remission in summer.

MATERIAL AND METHODS

Female patients with winter depression and controls without a psychiatric history (n = 54 and 32 with mean age ± standard deviation of 34.4 ± 11.0 and 35.7 ± 9.5 years, respectively) were treated with two-hour bright light for a week during winter period. Some of them (n = 40 and 19, respectively) were then restudied in summer. Measures obtained during the winter period from patients before and after treatment were compared to those obtained from controls and from the same patients in the summer period. Among compared measures, there were self-assessments of state- and trait-like differences in morning and evening components of morningness-eveningness.

RESULTS

The groups of depressed patients and controls differed in self-assessments of morning but not evening component of morningness-eveningness. The difference in state-like variation in morning component became non-significant after treatment and in summer. On the other hand, trait-like variation in this component demonstrated adequate test-retest (winter-summer) reliability, i.e. a shift toward trait-like eveningness persisted in patients in the summer.

CONCLUSIONS

The observed normalization of state-like variation in morning component of morning-evening preference can be mainly explained by the disappearance of such depressive symptoms as lack of energy, social withdrawal, loss of interest in once enjoyable activities, etc.

Associations between chronotypes and psychological vulnerability factors of depression

Chronotypes have been associated with psychopathology. The eveningness chronotype has been consistently linked with depressed states or depressive disorder, but the underlying mechanism remains unclear. Prior studies have shown associations between chronotype and personality traits that are linked to depression (e.g. neuroticism), but other psychological vulnerability factors have not been previously investigated in relation to chronotypes. The aim of this study was to examine the association between chronotypes, depression and psychological risk factors of depression (namely, cognitive reactivity and worry), in a large cohort of depressed patients and healthy individuals. We used data from the Netherlands Study of Depression and Anxiety (n = 1654), which includes 1227 clinically diagnosed individuals with a lifetime diagnosis of depression and 427 healthy controls. We assessed cognitive reactivity (Leiden Index of Depression Sensitivity-Revised) and trait worry (Penn State Worry Questionnaire). We controlled for sociodemographic factors as well as for insomnia and neuroticism. We found that the evening type is associated with higher cognitive reactivity scores, especially with increased rumination. Cognitive reactivity also mediated the relationship between chronotype and depression status, even when controlling for neuroticism and insomnia. Trait worry was not associated with chronotype. Our findings show that depressogenic cognitions are more prevalent in evening types and perhaps mediate the association between chronotype and depression. Further prospective research is needed to determine the timeline of the association. Nevertheless, results imply that targeting depressogenic cognitive processes, perhaps in combination with chronotherapeutic treatments, may be particularly useful in evening types.

CLOCK gene variants associated with the discrepancy between subjective and objective severity in bipolar depression

BACKGROUND

The discrepancy between subjective and objective severity of depressive syndromes has been proposed as a predictor of treatment outcome and suicidal risk in depression, and is associated with depressive cognitive distortions. A recent study reported that evening-type depressed patients showed higher depressive cognitions than morning-type patients. Therefore, it can be hypothesized that genetic factors affecting evening preference, such as carrying of the CLOCK rs1801260*C allele, may influence the discrepancy.

METHOD

We tested this hypothesis in 132 patients affected by a major depressive episode in the course of bipolar disorder. The severity of depression was evaluated using self-rated (Beck Depression Inventory: BDI) and observer-rated (Hamilton Depression Rating Scale: HDRS) measures. The BDI-HDRS discrepancy score was calculated and the effects of the rs1801260 polymorphism on this score and on depressive cognitive distortions, as measured on the Cognitions Questionnaire, were examined.

RESULTS

The rs1801260*C carriers showed higher BDI-HDRS discrepancy scores than T/T homozygotes. Mediation analysis using bootstrapping procedures revealed that the dimension of depressive cognition "hopelessness" fully mediates the association between the rs1801260 polymorphism and the BDI-HDRS discrepancy.

LIMITATIONS

Many gene polymorphisms other than CLOCK rs1801260 may also influence the BDI-HDRS discrepancy and depressive cognitive distortions.

CONCLUSION

Our current results suggest that factors affecting the biological clock can influence the "non-clock" psychopathological features of mood disorders.

Sleep Duration of Inpatients With a Depressive Disorder: Associations With Age, Subjective Sleep Quality, and Cognitive Complaints

Sleep complaints and sleep disturbances are common in depression; however, the association of sleep duration and subjective sleep quality has been rarely investigated. Thus, subjective sleep quality and sleep duration were analyzed in depressed inpatients. Questionnaire data comprising clinical and sleep-related questions were sampled over a one-year period from adult inpatients with depressive syndromes. Sleep duration and items related to sleep quality were analyzed by means of group comparisons (sleep duration categories) and correlation analyses. Data of 154 patients (age 58.2±17.0 years, 63.6% women) were analyzed. Mean sleep duration was 7.2±2.1 h (16.9% of patients were below and 7.1% above age-specific recommendations), 25-40% of patients reported almost always daytime sleepiness, non-restorative sleep, attention deficits, or memory complaints with significant correlations between all variables (P<0.05). Sleep duration and sleep quality indicators showed significant curvilinear associations (quadratic contrast, P<0.05); i.e. extremely low and high sleep durations were associated with unfavorable sleep quality and subjective cognitive impairment. Non-recommended low or high sleep durations occur in a substantial proportion of patients with depression, and both were associated with poor sleep quality and subjectively impaired cognitive functions. Clinicians should be aware of these relationships. During hospitalization, a more individualized sleep-wake schedule should be applied.

The association between chronotype and perceived academic stress to depression in medical students

Depression is a multifactorial illness that is highly prevalent among medical students (MS). Chronotypes, which reflect circadian preference in humans, as well as academic stress have been associated with depression in different populations. However, it is not known how chronotype and stress might alone or in combination, associate with depression in MS. Thus, we aimed to evaluate the association between stress, chronotype and depression in MS. In a cross-sectional study, we evaluated a total of 1068 medical students from a public Medical School in Mexico City. The Patient Health Questionnaire-9 (PHQ-9) was used to evaluate depressive symptom severity and the presence of a current depressive episode with a cutoff score of 10 or higher. The Morning-Evening Questionnaire (MEQ) was used to establish chronotype and the Academic Stress Inventory was used to measure perceived academic stress (PAS). We observed that depressive symptom severity was higher in non-morning chronotypes and moderate/severe PAS groups. A factorial ANOVA showed an association between PAS groups and depressive symptom severity. Linear regression showed an association between depressive symptom severity and variables such as PAS scores (p = 0.001), family history of depression (p = 0.001), gender (p = 0.001) and academic year (p = 0.029). Logistic regression analysis showed that evening chronotype (OR: 2.3, 95% CI: 1.2-4.3, p = 0.01) and severe PAS (OR: 4.4, 95% CI: 2.8-7.0, p = 0.0001) were associated with depression. Further, MS with the combination of severe PAS and morning (OR: 5.9, 95% CI: 1.6-22.2, p = 0.01), intermediate (OR: 7.5, 95% CI: 2.3-24.4, p = 0.001) or evening (OR: 10.6, 95% CI: 2.8-40.0, p = 0.001) chronotypes showed a greater association with depression than any PAS or chronotype group alone. Being female, perceiving restricted or limited economic resources, having severe scores of academic stress, and evening chronotype were associated with an increased probability to suffer a current depressive episode. Collectively, these results show that chronotype and PAS are factors associated with depression in MS, and when combined promote this association. Our results might aid in early identification of MS susceptible to depression. Future research could focus on the implementation of simple, low cost preventive strategies, such as chronotype-oriented academic schedules.