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The aim of this study was to examine whether the presence of risk alleles of the norepinephrine transporter gene (SLC6A2) polymorphisms is associated with differences in regional cerebral blood flow (rCBF) measured by 99mTc-HMPAO single photon emission computerized tomography in a Korean sample of ADHD.
Methods
The present study included 24 children with ADHD (9.5±2.4 years), consisting of 20 boys and 4 girls, aged 6-16 years. We investigated the G1287A and -3081(A/T) polymorphisms of the SLC6A2. The rCBF was compared between the ADHD subjects with and without risk alleles at the G1287A polymorphism and at the -3081(A/T) polymorphism. Image analyses were performed with voxelwise t-statistics using SPM2.
Results
1) The ADHD subjects with the A allele (risk allele) at the G1287A polymorphism showed reduced perfusion in the left middle frontal gyrus, left inferior parietal lobule, precuneus, right superior frontal gyrus, and right superior parietal lobule as compared with ADHD subjects without the A allele (p< 0.001).
2) The ADHD subjects with the A allele at the G1287A polymorphism showed increased perfusion in the right middle frontal gyrus, right middle temporal gyrus, right superior temporal gyrus, right fusiform gyrus, right precentral gyrus, and right anterior lobe of cerebellum as compared with ADHD subjects without the A allele (p< 0.001).
3) No significant perfusion differences were found between ADHD subjects with and without the T allele (risk allele) at the -3081(A/T) polymorphism.
Conclusion
Our findings suggest that the SLC6A2 G1287A polymorphism might exert differential effects on rCBF in children with ADHD.
There are two major forms of long-term depression (LTD) of synaptic transmission in the central nervous system, which require activation of either N-methyl-D-aspartate receptors (NMDARs) or metabotropic glutamate receptors (mGluRs). In synapses in the perirhinal cortex we have directly compared the Ca2+ signalling mechanisms involved in NMDAR-LTD and mGluR-LTD. Whilst both forms of LTD involve Ca2+ release from intracellular stores the Ca2+ sensors involved are different; NMDAR-LTD involves calmodulin, whilst mGluR-LTD involves the neuronal Ca2+ sensor (NCS) protein NCS-1. In addition, there is a specific requirement for IP3 and PKC as well as protein interacting with C-kinase (PICK-1) in mGluR-LTD. NCS-1 binds directly to PICK1, via its BAR domain, in a Ca2+-dependent manner. Furthermore, the NCS-1-PICK1 association is stimulated by activation of mGluRs, but not NMDARs, and introduction of a PICK1 BAR domain fusion protein specifically blocks mGluR-LTD. Thus, NCS-1 is a component of a novel mechanism involved in mGluR-LTD.
Somatization is a common symptom of depression. Somatization is also related to sleep problem including insomnia.Depression is the one of the most common cuase of insomnia. Therefore, it would be needed to investigate the interaction between depression, insomnia and somatization.
Objectives
To investigate the independent effects of major depressive disorder (MDD) and insomnia on somatization.
Aims
To compare somatization of primary insomnia, MDD with insomnia, MDD without insomnia, and normal controls.
Methods
A total of 181 participants without serious medical problem were recruited. Subjects were divided into 4 groups based on the SCID-IV and ICD-10 insomnia criteria:
1) normal controls,
2) primary insomnia,
3) MDD without insomnia, and
4) MDD with insomnia.
The somatization subscores of the SCL-90-R were completed by participants.
Results
There were significant between-group differences in somatization (F=25.30, p< 0.001). MDD with insomnia showed higher somatization compared to normal controls (p< 0.001), primary insomnia (p=0.01), or MDD without insomnia (p< 0.001). Primary insomnia had higher somatization than normal controls (p< 0.01), while there was no significant difference between MDD without insomnia and normal controls. Presence of insomnia predicted higher somatization (beta=0.44, p< 0.001), while there was only non-significant association between MDD and somatization (beta=0.14, p=0.08).
Conclusions
In the current study, insomnia was associated with somatization independently from major depression. Subjects with primary insomnia showed higher somatization. Within MDD patients, presence of insomnia was related to higher somatization. Our finding suggests that insomnia may partly mediate the relationship between depression and somatization.
There have been many changes in the treatment of bipolar disorder.
Objective
It is necessary to develop guidelines that can more aptly respond to cultural issues and specifics in different countries.
Aims
The Korean Medication Algorithm for Bipolar Disorder (KMAP-BP) was firstly published in 2002, with updates in 2006 and 2010. This third update reviewed the experts' consensus of opinion on the pharmacological treatments of bipolar disorder.
Methods
The newly revised questionnaire composed of 55 key questions about clinical situations including 223 sub-items was sent to the experts.
Results
Combination of mood stabilizer (MS) and atypical antipsychotic (AAP) was the first-line treatment option in acute mania. For the management of severe psychotic bipolar depression, combination of MS and AAP, combination of AAP and LTG, combination of MS, AAP and AD or LTG, combination of AAP and AD, and combination of AAP, AD and LTG was the first-line treatments. Combination of MS and AAP was the treatment of choice for management of mixed features. Combination of MS and AAP, MS or AAP monotherapy was the first-line options for management of maintenance phase after manic episode. For maintenance treatment after bipolar I depression, combination of MS and AAP, combination of MS and LTG, combination of AAP and LTG, MS or LTG monotherapy, and combination of MS, AAP and LTG were the first-line options.
Conclusion
Despite the limitations of expert consensus guideline, KMAP-BP 2014 may reflect the current patterns of clinical practice and recent researches.
This cross-sectional study was aimed to investigate the factors associated with bipolar disorder in pregnant female, including sociodemographic parameters, social support, social conflict, suicidal idea and sleep.
Methods
A total of 84 pregnant female were recruited. They filled out self-completing questionnaires on sociodemographic factors, obstetric history, depressive symptoms and bipolarity. Depressive symptoms were assessed using the Korean version of the Edinburgh Postnatal Depression Scale (EPDS). Bipolarity was assessed using the Korean version of the Mood Disorder Questionnaire (K-MDQ).
Results
Nineteen participants (22.6%) had positive K-MDQ scores, suggesting the present of bipolarity. Positive EPDS group had twenty subjects (25%) who had depressive symptoms. The diathesis of bipolar disorder was associated with marital dissatisfaction, social conflict, depression and sleep. The multiple logistic regression analysis revealed that the only poor sleep was a risk of bipolarity.
Conclusions
Pregnant female with bipolarity were more depressed and sleep problems than those without bipolarity. The results showed that the most important factor of influencing bipolarity was sleep.
This study aimed to explore thedifference in emotional recognition of musical auditory stimulation and artfulvisual stimulation between helathy people and patients with schizophrenia.
Method
20 songs and 20 paintings thatcontained sad or cheerful emotions were presented to 123 patients withschizophrenia and 224 healthy people as control group. The subjects were askedto tell about their emotions that they had felt from each musical auditorystimulation and artful visual stimulation. To measure such emotions, the Emotional Empathy Scale was used. The level of psychopathology in patientsgroup were evaluated with the Positive and Negative Syndrome Scale and the Formal Thought Disorder Rating Scale.
Result
The correct answer rate to musical auditoryand artful visual stimulation of the patient group was significantly lower than that of thecontrol group. Thepatient group showed lower emotional empathic ability compared to the controlgroup. In the patient group, the correct answer rate to musical and artfulstimulation showed a negative correlation with score with Formal ThoughtDisorder Rating Scale.
Conclusion
Patients with schizophrenia have difficulties inprecise emotional recognition to auditory and visual stimulations, and this isassociated with lowered empathic ability and thinking disorder of patients withschizophrenia. If an psychosocial rehabilitation program or psychotherapy isimplemented to patients with schizophrenia, it is deemed to be necessary to make a mediation to improve the emotional recognition and expression ability of patients with schizophrenia.
This study was aimed to discover the correlation between those getting tattoos and their psychopathology relating to their delinquent behavior and emotional problems.
Methods
Date for this study was collected from 19-year-old men who were receiving a physical examination for conscription at the Korea Military Manpower Administration. 400 data sheets were collected among them. All of sjubjects were evaluated on the following measures: sociodemographic variants, Juvernile delinquency scale, State-trait anger expression inventory, Beck depression inventory, State-triat anxiety inventory, and Positive affect and negative affect schedule.
Results
In comparison with those without tattooes, those with a tattoo scored higher in the scales that were related to delinquency, anger, depression, and negateive emotion. Furthermore, there were positive correlations between the number of tattoos and the scores for the Juvenile delinquent tendency and behavior scale as well as on the State-triat anxiety scale.
Conclusion
Those with tattoos had experienced anger, anxiety, and depression more strongly in comparison with those without tattoos. These reults recommended that tattooed males should be evaluated more on their regrading psychopathology compared to those without tattoos.
: Human impulsivity is a complex multidimensional construct encompassing cognitive, emotional, and behavioral aspects. Previous animal studies have suggested that striatal dopamine receptors play a critical role in impulsivity. in this study, we investigated the relationship between self-reported cognitive impulsiveness and dopamine D2/3 receptor availability in striatal subdivisions in healthy subjects using high-resolution positron emission tomography (PET) with [11C]raclopride.
Methods:
Twenty-one participants completed 3-Tesla magnetic resonance imaging and high-resolution PET scans with [11C]raclopride. The trait of impulsiveness was measured using the Barratt Impulsiveness Scale (BIS-11). Partial correlation analysis was performed between BIS-11 scores and D2/3 receptor availability in striatal subregions, controlling for the confounding effects of temperament characteristics that are conceptually or empirically related to dopamine, which were measured by the Temperament and Character Inventory.
Results:
The analysis revealed that the non-planning (p = 0.004) and attentional (p = 0.007) impulsiveness subscale scores on the BIS-11 had significant positive correlations with D2/3 receptor availability in the pre-commissural dorsal caudate. There was a tendency toward positive correlation between non-planning impulsiveness score and D2/3 receptor availability in the post-commissural caudate.
Conclusions:
These results suggest that cognitive subtrait of impulsivity is associated with D2/3 receptor availability in the associative striatum that plays a critical role in cognitive processes involving attention to detail, judgment of alternative outcomes, and inhibitory control.
The aim of this study was to monitor changes of prescription trends for bipolar disorder in inpatient settings in one university hospital.
Methods
A retrospective chart review was performed and data of 188 cases (2009–2012) and 118 cases (1998–2001) with a diagnosis of bipolar disorder were collected. Data on demographic variables, duration of hospitalization, kinds of psychotropic medications and the patterns of prescription over each four-year period were analyzed.
Results
The proportion of patients with manic episode was decreased, whereas those of mixed and depressive episodes were increased. The use of lithium was decreased with the increased use of valproate. Increased use of lamotrigine in depressive episode was prominent. The use of combination treatment with mood stabilizers and antipsychotics was almost same level in both periods. The use of typical antipsychotics was significantly decreased and that of atypical antipsychotics was increased. Especially, the use of quetiapine showed great increase. In bipolar depression, the use of antidepressant was increased.
Conclusions
Data showed that quetiapine monotherapy had favorable effect on acute manic symptoms and well tolerated. Also this result suggests that quetiapine monotherapy may improve the self-perceived quality of sleep without any daytime impairment following sleep in acute manic patients.
Despite the advance in pharmacotherapy for posttraumatic stress disorder (PTSD), poor treatment adherence to pharmacotherapy for PTSD is a critical issue.
Objectives
We intended to evaluate the predictors of premature discontinuation of psychiatric outpatient treatment after discharge for noncombat-related PTSD.
Aims
This study aimed to examine the sociodemographic and disease-related variables associated with the premature discontinuation of psychiatric outpatient treatment after discharge among patients with non-combat-related posttraumatic stress disorder.
Methods
We retrospectively reviewed the medical records of patients who were discharged with a diagnosis of posttraumatic stress disorder.
Results
Fifty-five percent of subjects prematurely discontinued outpatient treatment within 6 months of discharge. Comparing sociodemographic variables between the 6-month non-follow-up group and 6-month follow-up group, there were no variables that differed between the two groups. However, comparing disease-related variables, the 6-month follow-up group showed a longer hospitalization duration and higher Global Assessment of Function score at discharge. The logistic regression analysis showed that a shorter duration of hospitalization predicted premature discontinuation of outpatient treatment within 6 months of discharge.
Conclusions
The duration of psychiatric hospitalization for posttraumatic stress disorder appeared to influence the premature discontinuation of outpatient treatment after discharge.
This study examined the prescribing patterns for medications to treat bipolar disorder in outpatient-based psychiatric practice focusing on atypical antipsychotics.
Methods
Retrospective chart review of patients admitted to a university hospital with a primary diagnosis of bipolar disorder in a period from January 2008 to December 2012 was conducted. We reviewed Diagnostic and Statistical Manual of Mental Disorders, fourth edition diagnosis and detailed clinical information at index episode. Psychotropic medications were grouped into six categories; atypical antipsychotics, typical antipsychotics, lithium, anticonvulsants, antidepressants, and minor tranquilizers. Severity, rapid cycling type, psychiatric comorbidity and disease duration were computed focusing on atypical antipsychotics.
Results
In 344 patients who were prescribed major psychotropic medications, atypical antipsychotics were prescribed in 70.9% of subjects, anticonvulsants in 73.3%, lithium in 36.9%, antidepressants in 41.9%, and typical antipsychotics in 0.9% of subjects. About 12.5% of subjects were treated with the monotherapy. Atypical antipsychotics prescription was favored in subjects with manic and mixed episodes or severe episode. Prescribing trend is independent of rapid cycling type. Prescription of antidepressants were more frequent in subjects who were recently diagnosed as bipolar disorder or prescribed new medications or existed psychiatric comorbidity.
Conclusions
The development of bipolar disorder's psychopharmacology has been reflected in the prescription pattern of psychotropic medications in Korea. This study suggests that atypical antipsychotics have played major role in treatment of bipolar disorder.
The purpose of this study was to evaluate the occurrence of the suicidal ideation and associated factors with self-reported suicidal ideation within the last 12 months among Korean adolescents.
Methods
A total of 1533 adolescents were recruited from middle schools (age range: 13-14 years) in Korea. According to existence of suicidal ideation, they were divided 2 group – suicidal ideation group and non-suicidal ideation group, and the differences between groups in terms of various characteristics, including depression (Kovacs’ Children’s Depression Inventory), school and family factors, and health related conditions.
Results
A total of 501 (32.7%) middle school students reported suicidal ideation, and the rate of suicidal attempt was 6.9% (n=106). The associated factors of suicidal ideation were female (OR= 2.42, p<0.001), below average academic achievement (OR=1.43, p=0.007), perceived low parental support (OR=2.09, p=0.001), depression (OR=3.25, p<0.001), current alcohol use (OR=2.37, p=0.003), self reported poor health (OR=1.54, p =0.043), and school bullying (OR=1.91, p =0.005).
Conclusions
These results may have important implications for the strategies and specified intervention in preventing suicidal ideation in Korean adolescents.
We evaluated the difference in sleep skills between patients with and without need of hypnotics after sleep CBT.
Methods
Total 131 insomnia patients' sleep disturbances were assessed by visual analogue scales. Patients received 9 sessions of sleep CBT and were prescribed hypnotics for prn during 3 months. Sleep CBT was focused on the sleep hygiene and sleep stimulus-control guidelines. Sleep hygiene guidelines were Limit the time spent in bed (SH1), Get regular exercise (SH2), Avoid light at night (SH3), Avoid heavy meals or drinking (SH4), Quiet, dark, and comfortable bedroom (SH5), Avoid caffeine, alcohol, and nicotine (SH6), Relaxing bedtime routine (SH7),Llight bedtime snack (SH8), Remove the bedroom clock (SH9). Sleep stimulus-control guidelines were Go to bed only when sleepy (SSC1), Use the bed for sleeping or sex (SSC2), Get out of bed when unable to sleep (SSC3), Get up at the same time (SSC4), Avoid napping (SSC5). Each sleep skill state was evaluated by Likert scale, and they were compared between before and after CBT. Patients were divided into two groups: still need of hypnotics and no need of hypnotics after 3 months.
Results
Forty-six (35.1%) patients replied they needed not hypnotics any more, but 85 (64.9%) patients replied they still needed hypnotics after CBT. Sleep VAS (25.26±8.52 vs. 32.64±8.95, p<0.001), SH2 (3.67±0.92 vs. 2.76±1.06, p=0.030), SH7 (4.08±0.55 vs. 2.76±0.76, p<0.001) were different in two groups.
Conclusions
Among several CBT skills, regular moderate exercise in daytime and a relaxing bedtime routine seem to be key components.
The Internet is commonly used in modern society; however, Internet use may become a problematic behaviour. There is an increasing need for research on problematic Internet use (PIU) and its’ associated risk factors.
Objectives
This study aims to explore the prevalence and health correlates of problematic Internet use among South Korean adults.
Methods
We recruited the participants aged between 18 and 84 years old among the online panel of an online research service. The sample size of the survey was 500. Of these 500 participants, 51.4% (n = 257) were men and 48.6% (n = 243) were women. A participant was classified as a problematic Internet use (PIU) if his/her total score of Young's Internet Addiction Scale (YIA) was above 50. Stress Response Index (SRI), Fagerstrom test for nicotine dependence, lifetime average caffeine consumption, and sociodemographic query form were used in the collection of data. The t test and chi-square test were used for data analysis.
Results
One hundred ninety-seven (39.4%) of the participants was classified into the PIU group. There was no difference of gender and education between PIU and normal users. However, PIU group was younger (mean 39.5 years) than normal users (mean 45.8 years). PIU group was more likely to have high levels of perceived stress, nicotine dependence, and drink more often caffeinated beverages (P < 0.05).
Conclusions
These data indicate that problematic Internet use is associated with perceived stress level, nicotine and caffeine use in South Korean Internet users. More research is needed to better understand the relationship between Internet use and mental health issues.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
This research aimed to identify the effects of depressive mood of female high school students on dysmenorrhea and sleep quality.
Methods
This research was conducted for 2 months from September 2015 to October 2015. A total of 3 types of self-reported questionnaire were adopted for the research. Control group was separated by Zung Self-rating Depression Scale (ZSDS). Each group adopted a self-made questionnaire for research on menstruation and Pittsburgh Sleep Quality Index (PSQI) for research on sleep. Chi2 test and AVOVA analysis through SPSS-21 were used as statistics methods.
Results
Analysis was made on 72 female students who submitted clear answers to the questionnaire. There were 34 students from normal mood group and 38 from depressive mood group. Depressive group presented meaningful results on regularity, pain severity, and drug treatment history of menstruation. Particularly, depressive group had 51.4% among subjects having severe menstrual pain of grade 3 by VMS (verbal multidimensional scoring system), way higher than 27.6% among subjects in the normal group. PSQI for sleep showed a meaningful result that 20.8% of those in the normal group were diagnosed with sleep disorder compared to 86.8% for the depressive group. A meaningful difference was seen in sleep latency, sleep duration, sleep disturbance, use of sleep medication, daytime functional disturbance among 7 items of PSQI.
Conclusion
This research showed that female high school students with depressive mood had high frequency and severity in dysmenorrhea and sleep quality disturbance.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
This research examined gender variations in depressive mood for high school students affected by emotional upset and how such depressive mood affect their sleep quality.
Methods
Research was conducted from September 2015 to October 2015. Both males and females were divided into normal group and depressive group by Zung Self-rating Depression Scale (ZSDS). Each group adopted the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality.
Results
Analysis was made on a total of 155 students, which were 83 male students and 72 female. The average ZSDS for all high school students was 43.38 and the average PSQI was 5.39. The number of male students in the normal and depressive group who were diagnosed with sleep disorder were 2 (3.8%) and 9 (29.0%), respectively (P < 0.05). But the number of female students in the normal and depressive group who were diagnosed with sleep disorder were 11 (32.4%) and 33 (86.8%), respectively (P < 0.05). Both males and females shared a meaningful result over sleep latency, sleep disturbance, use of sleep medication, and daytime functional disturbance among 7 items of PSQI for sleep quality, and female students had a significantly meaningful result over sleep duration, habitual sleep effects (P < 0.05).
Conclusion
This research showed that sleep quality of all high school students was not too bad but it can be problematic for those with depressive mood. Especially, female students were diagnosed with sleep disorder more than male students.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
Heat shock proteins (HSPs) consist of highly preserved stress proteins that are expressed in response to stress. Two studies were carried out to investigate whether HSP genes in hair follicles from beef calves can be suggested as indicators of heat stress (HS). In study 1, hair follicles were harvested from three male Hanwoo calves (aged 172.2 ± 7.20 days) on six dates over the period of 10 April to 9 August 2017. These days provided varying temperature–humidity indices (THIs). In study 2, 16 Hanwoo male calves (aged 169.6 ± 4.60 days, with a BW of 136.9 ± 6.23 kg) were maintained (4 calves per experiment) in environmentally controlled chambers. A completely randomized design with a 2 × 4 factorial arrangement involving two periods (thermoneutral: TN; HS) and four THI treatment groups (threshold: THI = 68 to 70; mild: THI = 74 to 76; moderate THI = 81 to 83; severe: THI = 88 to 90). The calves in the different group were subjected to ambient temperature (22°C) for 7 days (TN) and subsequently to the temperature and humidity corresponding to the target THI level for 21 days (HS). Every three days (at 1400 h) during both the TN and HS periods, the heart rate (HR) and rectal temperature (RT) of each individual were measured, and hair follicles were subsequently collected from the tails of each individual. In study 1, the high variation (P < 0.0001) in THI indicated that the external environment influenced the HS to different extents. The expression levels of the HSP70 and HSP90 genes at the high-THI level were higher (P = 0.0120, P = 0.0002) than those at the low-THI level. In study 2, no differences in the THI (P = 0.2638), HR (P = 0.2181) or RT (P = 0.3846) were found among the groups during the TN period, whereas differences in these indices (P < 0.0001, P < 0.0001 and P < 0.0001, respectively) were observed during the HS period. The expression levels of the HSP70 (P = 0.0010, moderate; P = 0.0065, severe) and HSP90 (P = 0.0040, severe) genes were increased after rapid exposure to heat-stress conditions (moderate and severe levels). We conclude that HSP gene expression in hair follicles provides precise and accurate data for evaluating HS and can be considered a novel indicator of HS in Hanwoo calves maintained in both external and climatic chambers.
To investigate the association between parity and the risk of incident dementia in women.
Methods
We pooled baseline and follow-up data for community-dwelling women aged 60 or older from six population-based, prospective cohort studies from four European and two Asian countries. We investigated the association between parity and incident dementia using Cox proportional hazards regression models adjusted for age, educational level, hypertension, diabetes mellitus and cohort, with additional analysis by dementia subtype (Alzheimer dementia (AD) and non-Alzheimer dementia (NAD)).
Results
Of 9756 women dementia-free at baseline, 7010 completed one or more follow-up assessments. The mean follow-up duration was 5.4 ± 3.1 years and dementia developed in 550 participants. The number of parities was associated with the risk of incident dementia (hazard ratio (HR) = 1.07, 95% confidence interval (CI) = 1.02–1.13). Grand multiparity (five or more parities) increased the risk of dementia by 30% compared to 1–4 parities (HR = 1.30, 95% CI = 1.02–1.67). The risk of NAD increased by 12% for every parity (HR = 1.12, 95% CI = 1.02–1.23) and by 60% for grand multiparity (HR = 1.60, 95% CI = 1.00–2.55), but the risk of AD was not significantly associated with parity.
Conclusions
Grand multiparity is a significant risk factor for dementia in women. This may have particularly important implications for women in low and middle-income countries where the fertility rate and prevalence of grand multiparity are high.
We aimed to investigate the heterogeneity of seasonal suicide patterns among multiple geographically, demographically and socioeconomically diverse populations.
Methods
Weekly time-series data of suicide counts for 354 communities in 12 countries during 1986–2016 were analysed. Two-stage analysis was performed. In the first stage, a generalised linear model, including cyclic splines, was used to estimate seasonal patterns of suicide for each community. In the second stage, the community-specific seasonal patterns were combined for each country using meta-regression. In addition, the community-specific seasonal patterns were regressed onto community-level socioeconomic, demographic and environmental indicators using meta-regression.
Results
We observed seasonal patterns in suicide, with the counts peaking in spring and declining to a trough in winter in most of the countries. However, the shape of seasonal patterns varied among countries from bimodal to unimodal seasonality. The amplitude of seasonal patterns (i.e. the peak/trough relative risk) also varied from 1.47 (95% confidence interval [CI]: 1.33–1.62) to 1.05 (95% CI: 1.01–1.1) among 12 countries. The subgroup difference in the seasonal pattern also varied over countries. In some countries, larger amplitude was shown for females and for the elderly population (≥65 years of age) than for males and for younger people, respectively. The subperiod difference also varied; some countries showed increasing seasonality while others showed a decrease or little change. Finally, the amplitude was larger for communities with colder climates, higher proportions of elderly people and lower unemployment rates (p-values < 0.05).
Conclusions
Despite the common features of a spring peak and a winter trough, seasonal suicide patterns were largely heterogeneous in shape, amplitude, subgroup differences and temporal changes among different populations, as influenced by climate, demographic and socioeconomic conditions. Our findings may help elucidate the underlying mechanisms of seasonal suicide patterns and aid in improving the design of population-specific suicide prevention programmes based on these patterns.