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Alex Gamma

Publications and source records attributed to Alex Gamma.

34 records · Page 2Linked to original sources
PubMed2005

Excessive daytime sleepiness in young adults: a 20-year prospective community study.

OBJECTIVE: Excessive daytime sleepiness (EDS) is a symptom with high clinical and public health importance because of its association with increased risk for accidents, decreased productivity, and impaired quality of life. Little information is available regarding the longitudinal course or clinical correlates of EDS. The aim of this study was to explore associations between self-reported EDS, sleep disorder symptoms, major depression, and anxiety in a longitudinal community study of young adults. METHOD: A prospective single-age community study of young adults (Zurich Cohort Study) was conducted from 1978 through 1999. Information was derived from 6 interviews administered when participants (N = 591) were ages 20, 22, 27, 29, 34, and 40 years. Trained health professionals administered a semistructured interview for health habits and psychiatric and medical conditions. The presence of either or both of 2 symptoms-accidentally falling asleep or excessive need for sleep during the day-was used to establish the presence of EDS. RESULTS: EDS was a common complaint among the study participants, with increasing prevalence with age. Cross-sectionally, EDS was associated with insomnia symptoms, nocturnal hypersomnia, anxiety disorders, somatization, and reduced quality of life. Longitudinally, impaired sleep quality, waking up too early, and anxiety were associated with later EDS. Conversely, EDS was not significantly associated with later anxiety or depressive disorders. CONCLUSIONS: Insomnia symptoms and anxiety are associated with the subsequent occurrence of EDS. Although these findings do not demonstrate causality, insomnia and anxiety disorders are prevalent and treatable conditions, and our results may have important clinical implications for the prevention and treatment of EDS. Whether the results of this study are limited to populations with elevated levels of psychopathology remains to be tested.

Adult↗
PubMed2004

The association between short sleep duration and obesity in young adults: a 13-year prospective study.

STUDY OBJECTIVES: Obesity has become a major health problem with increasing prevalence. Given the limited availability of effective treatment of weight problems, the identification of potentially modifiable risk factors may lead to preventive approaches to obesity. The objective of this study was to test the hypothesis that short sleep duration is associated with obesity and weight gain during young adulthood. DESIGN: Prospective single-age cohort study of young adults. Information was derived from 4 interviews when participants were ages 27, 29, 34, and 40 years. SETTING: Community setting. PARTICIPANTS: 496 young adults. MEASUREMENTS AND RESULTS: Trained health professionals administered a semistructured interview for psychiatric and medical conditions and health habits. This study showed an association between short sleep duration and obesity (at age 27 years, odds ratio: 7.4, 95% confidence interval: 1.3-43.1) and a negative association between sleep duration and body mass index in young adults. These associations persisted after controlling for a variety of potentially confounding variables, including family history of weight problems, levels of physical activity, and demographic variables. Associations between sleep duration and obesity diminished after age 34 years. There was a trend (P = .08) for average change rate of weight gain to be negatively associated with average change rate of sleep duration. CONCLUSIONS: Because sleep duration is a potentially modifiable risk factor, these findings might have important clinical implications for the prevention and treatment of obesity.

Adult↗
PubMed2004

Comparison of simultaneously recorded [H2(15)O]-PET and LORETA during cognitive and pharmacological activation.

The complementary strengths and weaknesses of established functional brain imaging methods (high spatial, low temporal resolution) and EEG-based techniques (low spatial, high temporal resolution) make their combined use a promising avenue for studying brain processes at a more fine-grained level. However, this strategy requires a better understanding of the relationship between hemodynamic/metabolic and neuroelectric measures of brain activity. We investigated possible correspondences between cerebral blood flow (CBF) as measured by [H2O]-PET and intracerebral electric activity computed by Low Resolution Brain Electromagnetic Tomography (LORETA) from scalp-recorded multichannel EEG in healthy human subjects during cognitive and pharmacological stimulation. The two imaging modalities were compared by descriptive, correlational, and variance analyses, the latter carried out using statistical parametric mapping (SPM99). Descriptive visual comparison showed a partial overlap between the sets of active brain regions detected by the two modalities. A number of exclusively positive correlations of neuroelectric activity with regional CBF were found across the whole EEG frequency range, including slow wave activity, the latter finding being in contrast to most previous studies conducted in patients. Analysis of variance revealed an extensive lack of statistically significant correspondences between brain activity changes as measured by PET vs. EEG-LORETA. In general, correspondences, to the extent they were found, were dependent on experimental condition, brain region, and EEG frequency.

Adult↗
PubMed2004

Obsessive-compulsive severity spectrum in the community: prevalence, comorbidity, and course.

OBJECTIVES: To describe lifetime prevalence rates, course and comorbidity of obsessive-compulsive disorder (OCD), obsessive-compulsive syndromes (OCS) and OC-symptoms (OC-sx) up to age 41. METHODS: In the Zurich community cohort study 591 subjects were selected after screening at the age of 19 and studied prospectively by 6 interviews from 20 to 40; they represent 1599 subjects of the normal population. The diagnoses of OCD met DSM-IV criteria. Course was assessed by graphic illustrations and prospective data. RESULTS: The lifetime prevalence rate was 3.5 % for OCD (males 1.7%, females 5.4 %) and 8.7 % for OCS (males 9.9%, females 7.5 %). The onset of OC-sx was 18 years (median); and in 70% before age 20. OCD was treated in one third of cases, OCS in 6.1%. The course of symptoms was chronic in 60%,but OCD and OCS showed in most cases considerable improvements over time. OCD reduced quality of life mostly in the subject's psychological wellbeing and at work but to a considerable extent also in other social roles. Comorbidity was prominent with bipolar disorder, panic disorder and social phobia and also significant with bulimia, binge eating, generalized anxiety disorder and suicide attempts; there was no association with substance abuse/dependence. CONCLUSION: OCD and OCD are manifestations of a wide spectrum of severity with high prevalence and strong clinical validity. The long-term course is better than generally assumed.

Adult↗
PubMed2004

Is bipolar I disorder heterogeneous?

OBJECTIVES: The question whether bipolar I disorder should be subdivided into a preponderantly manic group (M) with no depression or only mild depression (Md) and a nuclear manic-depressive group (MD) has been rarely studied although the problem was raised more than 50 years ago. This paper seeks to elucidate this question by contributing further data. METHODS: 406 patients with mood disorders hospitalised at some time during the period 1959-1963 were followed-up every five years until 1985; mortality data were collected up to 1997. Data on episodes, outcome, suicides and attempted suicides, alcohol and substance abuse/dependence and long-term medication, as well as on personality (melancholic and manic type) were collected. Major mood disorders were subclassified according to their hospitalisation for depression (D) and/or mania (M). RESULTS: 30 manic patients (M/Md), 130 bipolar I (MD), 60 bipolar II patients (Dm) and 186 major depressive patients (D) were compared. The manic group differed from the bipolar I group in several variables: better school achievement, milder course of the illness (fewer recurrences), significantly less suicidality and a trend to less chronicity and more recovery. Manic patients required less long-term medication than bipolars and they differed in personality types from bipolars, the personality of manic patients being more often of the manic rather than the melancholic type, they were also more aggressive than bipolars. The family history data showed that the overall morbidity risk of first degree relatives of manic patients was significantly lower than that of bipolar patients. CONCLUSIONS: In accord with several other studies our data point to the existence of a more manic (M/Md) group of bipolar subjects. The diagnosis predicts a better course, lower suicidality and fewer and different treatment needs than does nuclear bipolar I (MD) disorder. The M/Md groups, as clinically interesting subgroups of the mood spectrum, should become a target of further research.

Adult↗
PubMed2003

Recurrence of bipolar disorders and major depression. A life-long perspective.

OBJECTIVE: It is not known whether the risk of recurrence declines with time in bipolar disorders and in major depression. This study describes the life-long recurrence risk of bipolar I, bipolar II and major depressive disorders. METHOD: 160 bipolar-I, 60 bipolar-II and 186 depressive patients hospitalised between 1959 and 1963 were followed up every five years from 1965 to 1985. The course prior to the index hospitalisation was assessed in retrospect. The recurrence risk was computed by the multiplicative intensity model (Aalen et al. 1980). RESULTS: The cumulative intensity curves for the transition from states of remission to new episodes remained linear over 30 to 40 years after onset, indicating a constant risk of recurrence over the life-span up to the age of 70 or more. The recurrence risk of bipolar disorders (0.40 episodes per year) was about twice that of depression (0.20 episodes per year); BP-II disorders had only a slightly higher recurrence risk than BP-I disorders. There were no significant gender differences in the course of either bipolar or depressive disorders. CONCLUSION: If long-term trials confirm its efficacy, these results support lifelong prophylactic treatment of severe types of mood disorders.

Adult↗
PubMed2003

Toward a re-definition of subthreshold bipolarity: epidemiology and proposed criteria for bipolar-II, minor bipolar disorders and hypomania.

BACKGROUND: The boundaries of bipolarity have been expanding over the past decade. Using a well characterized epidemiologic cohort, in this paper our objectives were: (1). to test the diagnostic criteria of DSM-IV hypomania, (2). to develop and validate criteria for the definition of softer expressions of bipolar-II (BP-II) disorder and hypomania, (3). to demonstrate the prevalence, clinical validity and comorbidity of the entire soft bipolar spectrum. METHODS: Data on the continuum from normal to pathological mood and overactivity, collected from a 20-year prospective community cohort study of young adults, were used. Clinical validity was analysed by family history, course and clinical characteristics, including the association with depression and substance abuse. RESULTS: (1). Just as euphoria and irritability, symptoms of overactivity should be included in the stem criterion of hypomania; episode length should probably not be a criterion for defining hypomania as long as three of seven signs and symptoms are present, and a change in functioning should remain obligatory for a rigorous diagnosis. (2). Below that threshold, 'hypomanic symptoms only' associated with major or mild depression are important indicators of bipolarity. (3). A broad definition of bipolar-II disorder gives a cumulative prevalence rate of 10.9%, compared to 11.4% for broadly defined major depression. A special group of minor bipolar disorder (prevalence 9.4%) was identified, of whom 2.0% were cyclothymic; pure hypomania occurred in 3.3%. The total prevalence of the soft bipolar spectrum was 23.7%, comparable to that (24.6%) for the entire depressive spectrum (including dysthymia, minor and recurrent brief depression). LIMITATION: A national cohort with a larger number of subjects is needed to verify the numerical composition of the softest bipolar subgroups proposed herein. CONCLUSION: The diagnostic criteria of hypomania need revision. On the basis of its demonstrated clinical validity, a broader concept of soft bipolarity is proposed, of which nearly 11% constitutes the spectrum of bipolar disorders proper, and another 13% probably represent the softest expression of bipolarity intermediate between bipolar disorder and normality.

Adult↗
PubMed2003

Recurrent brief depression--past and future.

Recurrent brief depressive disorder (RBD) is a well-defined and significantly prevalent affective disorder with an increased risk of suicidal behavior and significant clinical impairment in the community and general practice. RBD is characterized by depressive episodes occurring at least once a month and lasting for only a few days. The lifetime co-occurrence of both RBD and major depressive disorder (MDD), called combined depression (CD), increases substantially the risk for suicide attempts, even more than is known for "pure" MDD. Diagnostic criteria for RBD can be found in the ICD-10 and DSM-IV and are helpful in both, research and clinical routine. Furthermore, several methodological issues are covered in this paper, which make clinical diagnostic and drug response evaluation of RBD very different from MDD. However, clinical procedures rather bear a resemblance to those used in the treatment of migraine or epilepsy. Formal differences in the course of RBD and MDD create different needs concerning the design of drug treatment studies. Absence of special methodological requirements and highly selected patient samples has probably been responsible for false negative results in double-blind, placebo-controlled treatment studies. Although several authors reported successful treatment of RBD with different compounds in about 60 patients, it is still not possible to deduce a treatment algorithm for RBD to date. Obviously, future treatment studies without the limitations of previous studies are clearly required for RBD.

Adolescent↗
PubMed2003

Diagnostic issues in bipolar disorder.

Bipolar disorder is a highly recurrent and chronic psychiatric condition that shortens life expectancy, causes functional impairment and disruption to social, work and family life. Several forms of bipolar disorder are recognised, including both bipolar I and bipolar II disorder. Bipolar I is characterised by recurrent episodes of depression and mania whereas bipolar II disorder is characterised by recurrent depression and hypomania, a milder form of mania. There has been debate concerning the definition of hypomania since at least the 1970s. The main areas of argument focus on the minimum duration of hypomania, its stem criteria and the number of symptoms required for diagnosis. Arriving at the correct definition of hypomania is a key diagnostic issue. There is increasing evidence for the existence of a broad spectrum of bipolar disorders, and data demonstrating the clinical validity of modifying some of the criteria for hypomania are reviewed here.

Bipolar Disorder↗
PubMed2002

Toward validation of atypical depression in the community: results of the Zurich cohort study.

AIMS: This paper (1) examines the validity of the atypical subtype of depression in a community-based longitudinal cohort study, (2) presents estimates of the prevalence and sex differences of DSM-IV atypical depression and a newly more broadly defined atypical syndrome in the community and (3) compares the clinical correlates and treatment patterns of those with atypical depression with other depressives. METHODS: The Zurich cohort study is comprised of 591 subjects selected from a population-based cohort of young adults representative of the canton of Zurich in Switzerland, who were screened in 1978 with the Symptom Checklist 90-R [L.R. Derogatis (1977)] and followed prospectively with five interviews between 1979 and 1993. Atypical depression was defined on a spectrum ranging from atypical major to minor to atypical depressive symptoms alone. RESULTS: The rate of DSM-IV atypical major depressive episodes in this community is 4.8% and for major atypical depression syndrome is 7.3%. Whereas there was no marked sex difference for nonatypical features, there was a significant female preponderance for DSM-IV and broadly defined atypical depressive subtypes. Systematic investigation of the diagnostic criteria for atypical depression revealed that a nonhierarchical definition of atypical depression with respect to mood reactivity yielded as valid a syndromic definition as the current hierarchy based on mood reactivity as an essential feature. Very high comorbidity (odd ratios>2.0) was found with seasonality, bipolar II, social phobia, binge eating, neurasthenia and sociopathy. LIMITATIONS: Atypical depression was not defined à priori, its criteria were derived from two sections of the Zurich interview. CONCLUSIONS: Atypical depression has high population prevalence and substantial significance in terms of clinical severity, impairment, and service use. The intriguing finding that the sex difference in depression may be attributed to atypical features of depression will need further investigation. Overall, our data indicate that the atypical subtype of depression is a valid entity based on evidence from such traditional indicators of validity as inclusion criteria and indicators of course. However, there are some problems with discriminatory validity from other disorders. Although comorbidity with these disorders may in part reflect an operational artifact of symptom overlap, further work needs to be done in distinguishing atypical depression from bipolar II.

Adult↗
PubMed2002

A new bipolar spectrum concept: a brief review.

Research on the broad bipolar spectrum is dependent on the definition of hypomania. We recently proposed a new, softer syndromal definition with clinical validity. This broadens the diagnosis of bipolar II (BP-II) disorder at the expense of major depressive disorder (MDD). There is evidence for a third group of suspected BP-II manifesting major depression plus hypomanic symptoms. The two bipolar-II groups together are as prevalent as MDD. A new concept of minor bipolar disorder embracing dysthymia, minor and recurrent brief depression with hypomanic syndromes and symptoms is discussed. Some methodological pitfalls of research on drug-induced hypomania as an element of the bipolar spectrum are also summarized.

Bipolar Disorder↗
PubMedDate not supplied

Prevalence of mental disorders in the Zurich Cohort Study: a twenty year prospective study.

BACKGROUND: In order to minimise retrospective recall in developing estimates of the prevalence of mental disorders in the general population, we conducted a prospective study of a cohort of youth from Zurich, Switzerland. METHOD: A 20 year prospective study of a community-based cohort aged 19-20 from Zurich Switzerland. The sample was enriched by subjects scoring high on the Symptom Checklist 90 R (Derogatis, 1977). A semi-structured diagnostic interview was administered by clinically experienced psychologists and psychiatrists. The six interviews from 1979 to 1999 assessed diagnoses and sub-threshold manifestations of major diagnostic categories (with the exception of schizophrenia) for the past twelve months, depending on the current DSM versions (DSM-III, DSM-III R, DSM-IV). Additional information on symptoms and treatment were collected for the years between the interviews. The reported prevalence rates are weighted for stratified sampling and cumulate the one-year rates of the six interviews. RESULTS: The cumulative weighted prevalence rates for any psychiatric disorder were 48.6% excluding, and 57.7% including tobacco dependence. In addition 29.2% and 21.8%, respectively manifested sub-diagnostic syndromes. Overall there were no significant gender differences. The corresponding treatment prevalence rates were 22.4% and 31.1%, respectively for the diagnostic subjects and 6.9% and 6.1%, respectively for the sub-diagnostic groups. The total treatment prevalence rate was 37.2% of the population (males 30.0%, females 44.1%). CONCLUSIONS: Our findings reveal that psychiatric disorders are quite common in the general population. When the spectra of mental disorders are considered, nearly three quarters of the general population will have manifested at least one of the mental disorders across their lifetime. LIMITATIONS: The data are based on a relatively small sample; a single age cohort, and the study was conducted in Zurich, Switzerland. These study features may diminish the generalisability of the findings.

Adult↗
PubMedDate not supplied

Acute psychological and neurophysiological effects of MDMA in humans.

Since the mid 1990s, MDMA has been increasingly used as a recreational drug called "Ecstasy" by young people in Europe and the United States. However, despite the widespread recreational use of Ecstasy, systematic data on the psychological and neurobiological effects of MDMA have been scant. To further our understanding of the mechanism of action of MDMA, the authors conducted several studies in healthy human volunteers in an effort to characterize the psychological, cognitive and behavioral effects of MDMA in healthy human volunteers. Prospective placebo-controlled within-subject study designs and standardized psychometric ratings and neuropsychological tests were used to assess the acute, short-term and prolonged effects of the drug. To elucidate the role of various neurotransmitter and receptor systems involved in the action of MDMA in humans, the blocking effects of specific receptor antagonists on MDMA-induced psychological alterations and measures of sensory information processing were studied. To identify the functional neuroanatomy involved in the action of MDMA, Positron Emission Tomography (PET) was used. The present contribution summarizes the acute effect of MDMA on psychological and cognitive measures, information processing, and regional brain activity in healthy human volunteers.

Humans↗