Vigilance described by the time-on-task effect in EEG activity during a cued Go/NoGo task.

Vigilance refers to the ability to maintain attention and to remain alert to stimuli in prolonged and monotonous tasks. Vigilance decrement describes the decline in performance in the course of such sustained attention tasks. Time-related alterations in attention have been found to be associated with changes in EEG. We investigated these time-on-task effects on the basis of changes in the conventional EEG spectral bands with the aim of finding a compound measure of vigilance. 148 healthy adults performed a cued Go/NoGo task that lasted approximately 21 min. Behavioural performance was examined by comparing the number of errors in the first and last quarters of the task using paired t-test. EEG data were epoched per trial, and time-on-task effects were modelled by using multiple linear regression, with frequency spectra band power values as independent variables and trial number as the dependent variable. Behavioural performance decreased in terms of omission errors only. Performance of the models, expressed by predicted R-squared, was between 0.10 and 0.27, depending on the particular task condition. The time-on-task EEG spectral changes were characterized by broad changes in the alpha and frontal changes in the beta and gamma bands. We were able to identify a set of EEG spectral features that predict time-on-task. Our output is considered to be a measure of vigilance, reflecting the allocation of mental resources for the maintenance of attention.

Behavioral and Neurophysiological Markers of ADHD in Children, Adolescents, and Adults: A Large-Scale Clinical Study.

This study aimed to re-evaluate the possible differences between attention-deficit/hyperactivity disorder (ADHD) subjects and healthy controls in the context of a standard Go/NoGo task (visual continuous performance test [VCPT]), frequently used to measure executive functions. In contrast to many previous studies, our sample comprises children, adolescents, and adults. We analyzed data from 447 ADHD patients and 227 healthy controls. By applying multivariate linear regression analyses, we controlled the group differences between ADHD patients and controls for age and sex. As dependent variables we used behavioral (number of omission and commission errors, reaction time, and reaction time variability) and neurophysiological measures (event-related potentials [ERPs]). In summary, we successfully replicated the deviations of ADHD subjects from healthy controls. The differences are small to moderate when expressed as effect size measures (number of omission errors: d = 0.60, reaction time variability: d = 0.56, contingent negative variation (CNV) and P3 amplitudes: -0.35 < d < -0.47, ERP latencies: 0.21 < d < 0.29). Further analyses revealed no substantial differences between ADHD subtypes (combined, inattentive, and hyperactive/impulsive presentation), subgroups according to high- and low-symptomatic burden or methylphenidate intake for their daily routine. We successfully replicated known differences between ADHD subjects and controls for the behavioral and neurophysiological variables. However, the small-to-moderate effect sizes limit their utility as biomarkers in the diagnostic procedure. The incongruence of self-reported symptomatic burden and clinical diagnosis emphasizes the challenges of the present clinical diagnosis with low reliability, which partially accounts for the low degree of discrimination between ADHD subjects and controls.

Evaluating the reliability of hair analysis in monitoring the compliance of ADHD patients under treatment with Lisdexamphetamine.

Considering the high clinical and forensic relevance of pharmaco-adherence during lisdexamphetamine (LDX) treatment for attention-deficit/hyperactivity disorder (ADHD), the aim here was to evaluate hair analysis as a tool for monitoring compliance in patients currently undergoing long term treatment with LDX, by detecting possible interruptions of medication intake or changes in dosage. For this purpose, a total of 24 patients from an outpatient clinic for ADHD were recruited. Hair and urine samples were taken after three consecutive therapy sessions over a 7-month period and analyzed for amphetamine (AMP) enantiomers and other drugs, using chiral and achiral liquid chromatography-tandem mass spectrometry (LC-MS/MS). Participants also provided information on the condition of their hair, the consumption of illegal psychotropic substances and the regularity of taking LDX. Two participants withdrew from the study early. Urine analyses were positive for D-AMP in all urine samples and therapy sessions, except in two patients who did not take LDX on a daily basis. D-AMP was detected in all hair samples; however, no correlation was found between prescribed dose/day and D-AMP concentrations in proximal hair segments. Qualitative interpretation of hair analysis showed that 18 of the 22 study completers were compliant concerning the intake of LDX without additional consumption of illegal D,L-AMP. Analysis of urine taken during the therapy sessions showed no correlation between D-AMP concentrations and prescribed dosage, with or without normalization for creatinine. In conclusion, chiral LC-MS/MS hair analysis might represent a non-invasive way to confirm LDX use within the approximate period covered by the hair segment tested, but it does not allow for quantitative therapeutic drug monitoring because of interindividual variability of concentrations in hair. Drug concentrations in hair at different stages of long-term treatment should thus be interpreted with caution by clinicians and forensic experts alike when making assessments of treatment adherence.

EEG/ERP-based biomarker/neuroalgorithms in adults with ADHD: Development, reliability, and application in clinical practice.

Objectives: The electrophysiological characteristics of attention-deficit/hyperactivity disorder (ADHD) and recent machine-learning methods promise easy-to-use approaches that can complement existing diagnostic tools when sufficiently large samples are used. Neuroalgorithms are models of multidimensional brain networks by means of which ADHD patient data can be separated from healthy control data.Methods: Spontaneous electroencephalographic and event-related potential (ERP) data were collected three times over the course of 2 years from a multicentre sample of adults comprising 181 patients with ADHD and 147 healthy controls. Spectral power and ERP amplitude and latency measures were used as input data for a semi-automatic machine-learning framework.Results: ADHD patients and healthy controls could be classified with a sensitivity ranging from 75% to 83% and specificity values of 71% to 77%. In the analysis of the repeated measurements, sensitivity values of the selected logistic regression model remained high (72% and 76%), while specificity values slightly decreased over time (64% and 67%).Conclusions: Implementation of the system in clinical practice requires facilities to track affected networks, as well as expertise in neuropathophysiology. Therefore, the use of neuroalgorithms can enhance the diagnostic process by making it less subjective and more reliable and linking it to the underlying pathology.

Skills and compensation strategies in adult ADHD - A qualitative study.

OBJECTIVE: The primary objectives of this study were to investigate how adult patients with ADHD coped with their symptoms prior to diagnosis and treatment, what skills and compensation strategies they had developed and what their self-perceptions of these strategies were. METHODS: We used a qualitative approach to analyze interviews with 32 outpatients of a specialty care unit at a university hospital. RESULTS: Patients reported frequent use of diverse compensatory strategies with varying degrees of effectiveness. These were classified into five categories (organizational, motoric, attentional, social, psychopharmacological). In certain circumstances, ADHD symptoms were even perceived as useful. CONCLUSION: Before diagnosis and treatment, patients with ADHD may develop a variety of skills to cope with their symptoms. Several of these skills are perceived as helpful. Knowledge of self-generated coping strategies may help better understand patients and their histories and thus facilitate patient cooperation. Moreover, knowing ways in which such patients cope with their symptoms may help elucidate reasons for late or under-diagnosing of the disorder.

Attitudes Toward Stimulant Treatment of Offspring of Adult Patients with Attention-Deficit/Hyperactivity Disorder.

AIM: The objective of this study was to investigate how adult patients with attention-deficit/hyperactivity disorder viewed the testing and use of stimulants in their children. METHODS: Using a qualitative approach, we interviewed 32 outpatients from a special care unit of a university hospital. RESULTS: Emerging themes centered around concerns about the right age to test children and opinions about stimulant treatment ranging from unreserved agreement to reluctance, as well as the need for a shared decision with the child. CONCLUSIONS: Our results suggest that better psychoeducational programs are needed, especially for adults with attention-deficit/hyperactivity disorder, in which long-term consequences of the disorder, areas of impairment, and possible treatment effects in their children are explained and concerns about unknown side effects and the right time to test and treat are addressed.

Adult attention-deficit/hyperactivity disorder and nicotine withdrawal: a qualitative study of patient perceptions.

BACKGROUND: Nicotine use has been reported to ameliorate symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD). Furthermore, adults with ADHD have a relatively high prevalence of cigarette smoking and greater difficulty abstaining from smoking. Overall, though, there is scant literature investigating the beliefs, perceptions and experiences of smokers with ADHD regarding smoking cessation and withdrawal. METHODS: Our participants (n = 20) fulfilling criteria for ADHD and a past or current dependence from nicotine were recruited from the in- and outpatient clinic of the Zurich University Psychiatric Hospital and the Psychiatric Services Aargau (Switzerland). We conducted in-depth interviews to explore their motivations to quit, past experiences with and expectations about quitting using a purposeful sampling plan. The sample was selected to provide diversity in relation to level of nicotine dependence, participation in a smoking-cessation program, gender, age, martial status and social class. Mayring's qualitative content analysis approach was used to evaluate findings. RESULTS: Adult smokers with ADHD had made several attempts to quit, experienced intense withdrawal symptoms, and relapsed early and often. They also often perceived a worsening of ADHD symptoms with nicotine abstinence. We identified three motives to quit smoking: 1) health concerns, 2) the feeling of being addicted, and 3) social factors. Most participants favored a smoking cessation program specifically designed for individuals with ADHD because they thought ADHD complicated their nicotine withdrawal and that an ADHD-specific smoking cessation program should address specific symptoms of this disorder. CONCLUSIONS: Since treatment initiation and adherence associate closely with perception, we hope these findings will result in better cessation interventions for the vulnerable subgroup of smokers with ADHD.

Adult attention-deficit/hyperactivity disorder: Associations between subtype and lifetime substance use - a clinical study.

ADHD is the one of the most prevalent childhood disorders and has been associated with impairments persisting into adulthood. Specifically, childhood ADHD is an independent clinical risk factor for the development of later substance use disorders (SUD). Moreover, adults who meet diagnostic criteria for ADHD have shown high rates of comorbid SUDs. Few studies, however, have reported on the relationship between ADHD subtypes and SUD in adult samples. The purpose of this study was to characterize a clinical sample of adults with ADHD and to identify possible associations between ADHD subtypes, lifetime substance use, and if ADHD subtypes may be preferentially associated with specific substances of abuse. We recruited 413 adult ADHD patients, performed an evaluation of their ADHD and conducted an interview on their use of psychotropic substances. Complete data was obtained for 349 patients. Lifetime substance abuse or dependence was 26% and occasional use was 57% in this sample. The inattentive subtype was significantly less likely to abuse or be dependent on cocaine than the combined subtype. Our findings underscore the high rate of comorbidity between substance use and ADHD in adults. The more frequent abuse/dependence of cocaine by adult patients with hyperactive-impulsive symptoms should be kept in mind when treating this patient group.

Temperamental differences between bipolar disorder, borderline personality disorder, and attention deficit/hyperactivity disorder: some implications for their diagnostic validity.

BACKGROUND: The relationship between borderline personality disorder (BPD), bipolar disorder (BD), and attention deficit/hyperactivity disorder (ADHD) requires further elucidation. METHODS: Seventy-four adult psychiatric in- and out-patients, each of them having received one of these diagnoses on clinical assessment, were interviewed and compared in terms of diagnostic overlap, age and sex distribution, comorbid substance, anxiety and eating disorders, and affective temperament. RESULTS: Diagnostic overlap within the three disorders was 54%. Comorbidity patterns and gender ratio did not differ. The disorders showed very similar levels of cyclothymia. LIMITATIONS: Sample size was small and only a limited number of validators were tested. CONCLUSIONS: The similar extent of cyclothymic temperament suggests mood lability as a common denominator of BPD, BD, and ADHD.

Adult attention-deficit/hyperactivity disorder and nicotine use: a qualitative study of patient perceptions.

BACKGROUND: Adult Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with high rates of comorbid substance use disorders, and cigarette smoking has a particularly high prevalence in this population. However, there is an ongoing debate as to whether this tobacco use is an attempt at "self-medication" or due to behavioral disinhibition. There is a surprising lack of qualitative studies that investigate the subjective perceptions of adults with ADHD regarding cigarette smoking. The present study was designed to fill this gap in the literature. METHODS: We recruited twelve adult patients with ADHD and comorbid tobacco use from our ADHD consultation service, an outpatient facility of the Zurich University Psychiatric Hospital. Subjects were interviewed using qualitative methodology, and Mayring's qualitative content analysis was used to evaluate findings. RESULTS: We identified two explanatory models linking ADHD and tobacco use: smoking as an attempt at self-medication and "smoking as a social behavior". On one hand, subjects considered tobacco a therapeutic aid, reporting positive effects on "inner tension" and cognitive function, and noted possible antidepressant properties as well. On the other hand, subjects considered smoking to enhance social functioning and to have a positive impact on interpersonal relationships. The majority believed that stimulant medications offered only a transient decrease in patterns of tobacco use because their ability to reduce nicotine cravings wore off quickly. Others believed that stimulants had no effect or even reinforced cigarette use. CONCLUSIONS: Participants had different views about the link between cigarette smoking and ADHD. While the majority thought of nicotine as a sort of therapy, viewing smoking as a way to self-medicate symptoms of ADHD, motivations for nicotine use were also related to self-image, desire to belong to a peer-group, and a drive to undermine perceived social norms. Ultimately, these findings can be used by clinicians to improve treatment alliance and collaboration.

Sensory and sensorimotor gating in adult attention-deficit/hyperactivity disorder (ADHD).

Even though there is an impaired perceptual capacity in attention-deficit/hyperactivity disorder (ADHD) patients, psychophysiological alterations, such as impaired gating as indexed by prepulse inhibition (PPI) or suppression of P50 auditory event-related potentials, have not been found in patients with ADHD. Hence, potential relationships of psychophysiological measures of gating to psychopathology and cognitive performance remain unclear. The present study investigates two distinct operational measures of gating as well as cognitive performance within adult ADHD patients in order to assess the relationship of these measures to psychopathology. PPI, P50 suppression, cognitive performance, and psychopathologic symptoms were assessed in 26 ADHD patients and 26 healthy control subjects. ADHD patients compared to healthy control subjects exhibited impaired P50 suppression, performed worse in cognitive tasks, and reported more psychopathological symptoms, but were normal in the test of PPI. Thus, P50 gating deficits are not specific to schizophrenia-spectrum disorders. These findings highlight the differences between P50 gating and PPI as measures of the gating construct. In keeping with the lack of correlations between these two putative operational measures of gating seen in both humans and animals, adult ADHD patients exhibit deficient P50 suppression and poor cognitive performance, despite exhibiting normal levels of PPI.

High dose methylphenidate treatment in adult attention deficit hyperactivity disorder: a case report.

INTRODUCTION: Stimulant medication improves hyperactivity, inattention, and impulsivity in both pediatric and adult populations with Attention Deficit Hyperactivity Disorder (ADHD). However, data regarding the optimal dosage in adults is still limited. CASE PRESENTATION: We report the case of a 38-year-old Caucasian patient who was diagnosed with Attention Deficit Hyperactivity Disorder when he was nine years old. He then received up to 10 mg methylphenidate (Ritalin®) and 20 mg sustained-release methylphenidate (Ritalin SR®) daily. When he was 13, his medication was changed to desipramine (Norpramin®), and both Ritalin® and Ritalin SR® were discontinued; and at age 18, when he developed obsessive-compulsive symptoms, his medication was changed to clomipramine (Anafranil®) 75 mg daily. Still suffering from inattention and hyperactivity, the patient began college when he was 19, but did not receive stimulant medication until three years later, when Ritalin® 60 mg daily was re-established. During the 14 months that followed, he began to use Ritalin® excessively, both orally and rectally, in dosages from 4800-6000 mg daily. Four years ago, he was referred to our outpatient service, where his Attention Deficit Hyperactivity Disorder was re-evaluated. At that point, the patient's daily Ritalin® dosage was reduced to 200 mg daily orally, but he still experienced pronounced symptoms of, Attention Deficit Hyperactivity Disorder so this dosage was raised again. The patient's plasma levels consistently remained between 60-187 nmol/l-within the recommended range-and signs of his obsessive-compulsive symptoms diminished with fluoxetine 40 mg daily. Finally, on a dosage of 378 mg extended-release methylphenidate (Concerta®), his symptoms of Attention Deficit Hyperactivity Disorder have improved dramatically and no further use of methylphenidate has been recorded during the 24 months preceding this report. CONCLUSIONS: Symptoms of Attention Deficit Hyperactivity Disorder (ADHD) in this adult patient, who also manifested a co-occurring obsessive compulsive disorder, dramatically improved only after application of a higher-than-normal dose of methylphenidate. We therefore suggest that clinicians consider these findings in relation to their adherence to current therapeutic guidelines.

A new rating scale for adult ADHD based on the Symptom Checklist 90 (SCL-90-R).

Attention deficit hyperactivity disorder (ADHD) in adults is increasingly recognized as a clinically important syndrome. The aim of this study was to evaluate the psychometric performance of a new scale for adult ADHD based on the widely used Symptom Checklist 90 Revised (SCL-90-R). Scale performance was assessed in a clinical study including 100 ADHD patients and 65 opiate-dependent patient controls, and in the Zurich study, an epidemiological age cohort followed over 30 years of adult life. Assessments included a ROC analysis of sensitivity and specificity, internal consistency, test-retest reliability, external validity and measurement invariance over nine testing occasions. The new scale showed a sensitivity and specificity of 75 and 54%, respectively, internal consistency over 0.8 (McDonald's omega, Cronbach's alpha), one-year test-retest reliabilities over 0.7, statistically significant and substantial correlations with two other validated self-rating scales of adult ADHD (R = 0.5 and 0.66, respectively), and an acceptable degree of longitudinal stability (i.e., measurement invariance). The proposed scale must be further evaluated, but these preliminary results indicate it could be a useful rating instrument for adult ADHD in situations where SCL-90-R data, but no specific ADHD assessment, are available, such as in retrospective data analysis or in prospective studies with limited methodical resources.

Bone mineral density in young women on methadone substitution.

Little is known about bone mineral density (BMD) in patients with heroin addiction and subsequent methadone substitution. The goal of this study was to compare bone mass density of young HIV-negative women on long-term methadone treatment to a local group of young healthy women. Eleven women (aged 20-29) with previous heroin dependence and current methadone substitution (20-140 mg, median 60, daily) for 1.5-9 (median 3) years were compared to 30 healthy women (aged 20-28). Participants were examined with dual-energy X-ray absorptiometry of the lumbar spine (L2-L4), of the total proximal hip area, and of the femoral neck. Patients and controls had neither current nor lifetime underweight condition, had comparable ages at menarche, and did not differ significantly in current body mass index (21.9 ± 4.0, respectively, 20.5 ± 1.5 kg/m(2)) in spite of a largely unhealthy lifestyle (cigarette, alcohol, and cocaine consumption in patients). Patients' total-hip parameters were marginally lower than those of controls (BMD P = 0.054, T score P = 0.049), whereas the femoral neck and lumbar spine parameters did not differ significantly between the two groups. Long-term methadone substitution in HIV-negative women seems to slightly affect bone mass density.

Prevalence, course, and comorbidity of insomnia and depression in young adults.

STUDY OBJECTIVES: (1) To describe the prevalence and prospective course of insomnia in a representative young-adult sample and (2) to describe the cross-sectional and longitudinal associations between insomnia and depression. DESIGN: Longitudinal cohort study. SETTING: Community of Zurich, Switzerland. PARTICIPANTS: Representative stratified population sample. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: The Zurich Study prospectively assessed psychiatric, physical, and sleep symptoms in a community sample of young adults (n=591) with 6 interviews spanning 20 years. We distinguished 4 duration-based subtypes of insomnia: 1-month insomnia associated with significant distress, 2- to 3-week insomnia, recurrent brief insomnia, and occasional brief insomnia. The annual prevalence of 1-month insomnia increased gradually over time, with a cumulative prevalence rate of 20% and a greater than 2-fold risk among women. In 40% of subjects, insomnia developed into more chronic forms over time. Insomnia either with or without comorbid depression was highly stable over time. Insomnia lasting 2 weeks or longer predicted major depressive episodes and major depressive disorder at subsequent interviews; 17% to 50% of subjects with insomnia lasting 2 weeks or longer developed a major depressive episode in a later interview. "Pure" insomnia and "pure" depression were not longitudinally related to each other, whereas insomnia comorbid with depression was longitudinally related to both. CONCLUSIONS: This longitudinal study confirms the persistent nature of insomnia and the increased risk of subsequent depression among individuals with insomnia. The data support a spectrum of insomnia (defined by duration and frequency) comorbid with, rather than secondary to, depression.

The barriers to smoking cessation in Swiss methadone and buprenorphine-maintained patients.

BACKGROUND: Smoking rates in methadone-maintained patients are almost three times higher than in the general population and remain elevated and stable. Due to the various negative health effects of smoking, nicotine dependence contributes to the high mortality in this patient group. The purpose of the current study was to investigate Swiss methadone and buprenorphine-maintained patients' willingness to stop smoking and to clarify further smoking cessation procedures. METHODS: Substance abuse history, nicotine dependence, and readiness to stop smoking were assessed in a sample of 103 opiate-dependent patients in the metropolitan area of Zurich, Switzerland. Patients were asked to document their smoking patterns and readiness to quit. RESULTS: Only a small number of patients were willing to quit smoking cigarettes (10.7%) and, even though bupropione or nicotine replacement therapy was included in the fixed daily treatment care, only one patient received nicotine replacement therapy for smoking cessation. A diagnosis of depression in patients' clinical records was associated with readiness to stop smoking. No significant associations were found between readiness to quit smoking and age, methadone treatment characteristics, and presence of co-dependencies. CONCLUSION: The current prescription level of best medicine for nicotine dependence in Swiss methadone and buprenorphine-maintained patients is far from adequate. Possible explanations and treatment-relevant implications are discussed.

Reduction in the suicide rate during Advent--a time series analysis.

Research has shown that there are different seasonal effects in suicide. The aim of this study is to demonstrate that the decrease in suicide rate at the end of the year is extended over the last weeks of the year and represents a specific type of seasonal effect. Suicide data were extracted from individual records of the Swiss mortality statistics, 1969-2003. The data were aggregated to daily frequencies of suicide across the year. Specifically, the period October-February was examined using time-series analysis, i.e., the Box-Jenkins approach with intervention models. The time series models require a step function to account for the gradual drop in suicide frequencies in December. The decrease in suicide frequencies includes the whole Advent and is accentuated at Christmas. After the New Year, there is a sharp recovery in men's suicide rate but not in women's. The reduction in the suicide rate during the last weeks of the year exceeds the well-recognised effect of reduced rates on major public holidays. It involves valuable challenges for suicide prevention such as timing of campaigns and enhancement of social networks.

Is depression a risk factor for heart complaints? Longitudinal aspects in the Zurich study.

BACKGROUND: The objective of this longitudinal study was to assess the association between major depression and heart complaints in a population of young and healthy adults. METHODS: Starting at the age 20/21, participants of the Zurich Study underwent 6 structured, psychological interviews during a span of 20 years. We evaluated longitudinal data from 277 persons who participated in all 6 interviews including questions about heart complaints. RESULTS: Over 20 years, heart complaints were reported by two thirds of participants, and the frequency of depression was 11.4%. At the age of 40/ 41, heart complaints were significantly associated with earlier heart complaints and major depression, both more often in women. Recurrent brief depression showed a tendency, but neither minor depression nor depressive symptoms were predictive for later heart complaints. CONCLUSIONS: This study suggests that major depression is a predictor for heart complaints at the age of 40 and that the severity of depressive disorder in younger age has an effect on subsequent heart complaints. Follow-up data will help to elucidate whether these subjective heart complaints show any correlation with a later coronary heart disease.

The use of complementary and alternative medicine in the general population: results from a longitudinal community study.

BACKGROUND: Many patients with psychological or physical problems are interested in non-medical approaches. The reasons for the growing popularity of complementary and alternative medicine (CAM) are not well understood considering that evidence of the effectiveness of conventional therapies is greater than ever before. We have examined data from the Zurich Study to determine trends and predictors of CAM use in Switzerland. METHOD: The Zurich Study is a longitudinal community study that was started in 1979 with a sample of 591 participants born in 1958 and 1959. In 1999, the last of six interview waves with face-to-face interviews was conducted. CAM use was analyzed with data from interviews in 1993 and 1999. Polytomous logistic regression analysis focused on the personal, demographic and sociocultural background of CAM users. RESULTS: CAM use in the last 12 months was reported by 21.9% of the participants in 1993 and by 29.5% in 1999. CAM use among those exhibiting either physical or psychological problems was in the ratio of two to one. There was a trend from alternative variants of CAM (homeopathy) to complementary ones (massage, osteopathy, acupuncture). The vast majority of CAM use was in addition to conventional therapies. Predictors of CAM use were, among others, attribution of physical complaints to stress and other psychological variables, very low education level in parents, and lacking political interest. CONCLUSIONS: Besides the sociocultural background, characteristics such as the psychological attribution style play an important role in CAM use. CAM use in Switzerland is mainly of a complementary rather than an alternative nature.

Seasonal associations between weather conditions and suicide--evidence against a classic hypothesis.

Psychiatrists, epidemiologists, and sociologists have debated the existence of an association between weather conditions and suicide seasonality since the preliminary statistical investigations in the 19th century. Provided that the effect of weather conditions on suicide operates via a dose-response-like mechanism, time-series (Box-Jenkins) analysis permits an indirect test of the hypothesis that temperature or other weather variables promote higher suicide frequencies in late spring and early summer months. The authors modeled monthly data on suicide and climatic conditions (i.e., temperature, sunshine, and precipitation data) in Switzerland. Cross-correlations between the filtered (prewhitened) residual series were calculated for the period 1881-2000, for consecutive 30-year periods, for different suicide methods, and--with regard to the seasonality hypothesis--for series relying on moving 1- and 3-month frames. Positive cross-correlations emerged between suicide and temperature data for the whole time series, as well as in all consecutive 30-year periods. However, cross-correlations of data series based on moving frames showed a minor peak in associations for summer frames and a major peak in associations for winter frames, the latter reflecting suicides performed mainly outdoors (being run over by a train and jumping from high places). The results represent a novel minor effect in seasonality of suicide, which is hardly compatible with the hypothesized role of temperature in suicide seasonality.