Why are immigrants at increased risk for psychosis? Vitamin D insufficiency, epigenetic mechanisms, or both?

European researchers have observed that schizophrenia is 3 times more frequent in immigrants than in native-born subjects. This increased risk is even higher in dark-skinned immigrants, and the second generation is more affected than the first one. Immigrant status is an important environmental risk factor not only for schizophrenia but also for other psychoses. The explanations proposed to date have been mainly related to epidemiological biases and psychological reasons, such as racism or social defeat, but no biological hypotheses have been tested so far. This article proposes two biological hypotheses related to changes in sun exposure, changes in diet, and stress associated with immigration, which would explain the increased risk for psychosis associated with immigrant status. (1) Vitamin D insufficiency has been proposed as a risk factor for schizophrenia. The main source of vitamin D is through photosynthesis by sun exposure, and dark skins need more sun exposure to maintain adequate blood levels. Vitamin D insufficiency in adulthood could explain why dark-skinned immigrants develop psychosis when moving to high latitude countries, and its insufficiency during pregnancy could explain why the observed risk is higher in the second generation. (2) The second hypothesis is that of epigenetics, with psychosis resulting from modifications in gene expression caused by changes in diet and/or stress related to immigration. The role of homocysteine and the vitamin B-complex, especially folic acid, in these changes in DNA transcription would vary according to the polymorphism of the methylenetetrahydrofolate reductase gene. The vitamin D insufficiency and epigenetics hypotheses are consistent with yet unexplained findings well known in the epidemiology of schizophrenia, such as the increased risk in the urban environment, the excess of winter births, the excess of schizophrenia births after maternal famine, and the shorter interbirth period before a schizophrenia birth. In order to test these hypotheses, epidemiological studies of psychosis and immigration should include objective measures of skin color, which is predicted to be a more important risk factor than ethnicity. They should measure vitamin D, homocysteine and vitamin B-complex status and assess the polymorphisms of the vitamin D receptors and the methylenetetrahydrofolate reductase gene. If confirmed, these hypotheses would lead to effective and inexpensive preventive measures which would markedly decrease the rates of psychosis and schizophrenia, as well as the burden and stigma of these diseases, and greatly improve the mental health of immigrants.

Anxiety but not depression is associated with elevated blood pressure in a community group of French elderly

OBJECTIVE

This study examined whether anxiety and depression were independently associated with elevated blood pressure in elderly persons.

METHOD

The study group consisted of 1389 subjects aged 59 to 71 years recruited from the electoral rolls of the city of Nantes (France). Subjects completed the Center for Epidemiologic Studies-Depression scale (CES-D) and the Spielberger Inventory scales to assess depressive symptoms and anxiety symptoms, respectively. Data were collected on sociodemographic characteristics, smoking and drinking habits, medical history, and drug use. Two measures of systolic and diastolic blood pressure were taken after a 10-minute rest. Body mass index was computed from weight and height measurements. Subjects taking antihypertensive drugs (N = 281) were excluded from the present analysis.

RESULTS

Depression and anxiety scores were significantly correlated (r = .61 in men; r = .65 in women; p<.001). In univariate analyses, anxiety scores were correlated with systolic and diastolic blood pressure in men, but not in women; blood pressure was not associated with depressive symptoms in either sex. Multivariate logistic regressions, controlling for possible confounders, showed that in both men and women, the risk of high blood pressure increased with increasing anxiety scores; odds ratios for high blood pressure were less than 1 in subjects with depressive symptomatology.

CONCLUSIONS

This study suggested that anxiety but not depression was independently associated with an increased risk for high blood pressure.

Prevalence and correlates of nocturnal desaturations in a sample of elderly people

We designed an epidemiological study to estimate the prevalence and correlates of nocturnal desaturations in a sample of elderly subjects from the general population. Sleep-related respiratory disturbances were assessed by questionnaire and MESAM IV (MADAUS electronic sleep apnoea monitor) ambulatory monitoring. An oxygen desaturation index (ODI), oxygen desaturation being defined as a decrease in SaO2 of or exceeding 4%, was then computed from these data. An oxygen desaturation index > or = 10 was observed in 27.0% of the 293 subjects studied (mean age 76.6+/-5.7 y, median=75 y, min.=69, max.=99), an oxygen desaturation index > or = 30in 4.4%. Multivariate analysis identified as correlates to an oxygen desaturation index > or = 10: male gender (OR=1.80; P=0.04), a high body mass index (BMI) in men (OR=1.20 per kg m2; P=0.0009), and advanced age in women (OR=1.09 per y; P=0.02). A positive association was found between loud snoring (OR=1.75; P=0.06) and an oxygen desaturation index > or = 10. However, there was no statistically significant relationship between an oxygen desaturation index > or = 10 and either daytime somnolence (OR=1.50; P=0.19) or trouble getting to sleep (OR=0.59; P=0.09). We found no significant relationship in our sample between oxygen desaturation index and arterial hypertension or cardiac dysrhythmia. Previous studies on younger populations have reported different results. It may well be the advanced age of our sample that explains these inconsistencies. For the elderly persons we studied our results underline the relatively high prevalence of sleep-related respiratory disturbances. However, these may be of less consequence than in younger populations.

Factors related to current and subsequent psychotropic drug use in an elderly cohort

AIMS OF THE STUDY

The purpose of this study was to estimate the prevalence of psychotropic drug use in a cohort of elderly persons and to examine factors related to current and subsequent drug use.

POPULATION

A representative cohort of non-institutionalized subjects aged 65 and over living in New Haven, Connecticut, was interviewed in 1982, and again in 1985 and 1988. Psychotropic drug use during the prior two weeks was assessed at each home interview.

RESULTS

At the baseline interview in 1982, 12.3% of the subjects reported using psychotropic drugs, half of them (6.25%) benzodiazepines. In multivariate analyses, psychotropic drug use was significantly associated with female gender and white ethnicity but not with older age. Psychotropic drug use and depressive symptomatology were strongly correlated in both genders. However, less than 5% of the subjects reporting high depressive symptomatology were using antidepressants. Psychotropic drug use was also associated with sleep problems in men and medical conditions in women. Psychotropic drug consumption increased slightly to 15.1% in 1988. Continuous use (use reported in 1982, 1985 and 1988) was found in 4.5% of the sample; it was strongly related to both depressive symptomatology and sleep problems reported at baseline. New use, beginning either in 1985 or in 1988, was observed in 12.6% of the sample; it was related to female gender, older age, and, among baseline health variables, to depressive symptomatology.

CONCLUSIONS

Prevalence of psychotropic drug use in this cohort of elderly people was lower than in other studies conducted in the U.S. The reasons for this variation are discussed. Continuous use was not higher for benzodiazepines than for other psychotropic drugs.

Breathing disorders during sleep and cognitive performance in an older community sample: the EVA Study

OBJECTIVES

To determine whether poor cognitive performance was associated with symptoms related to the sleep apnea syndrome, snoring, and breathing stoppage during sleep.

DESIGN

Cross-sectional analysis of data collected at baseline in the EVA Study, a 4-year cohort study.

SETTING

The city of Nantes in western France.

SAMPLE

A total of 1389 persons, aged 60 to 70 years, recruited from the electoral rolls of the city of Nantes.

MEASUREMENTS

Demographic characteristics and data on drug use and tobacco and alcohol consumption were collected using a standardized questionnaire. Weight and height were measured. Individuals completed a previously validated sleep questionnaire about nocturnal sleep characteristics, snoring, breathing stoppage during sleep, and day-time sleepiness. Trained psychologists administered eight neuropsychological tests: The Mini-Mental State Examination, Trail Making Test, Digit Symbol Substitution Test of the WAIS-Revised, Benton Visual Retention Test, Paced Auditory Serial-Addition Task, Auditory Verbal Learning Test, Raven Progressive Matrices, and Word Fluency Test. Depressive symptomatology was assessed by the Center for Epidemiologic Studies-Depression scale.

MAIN RESULTS

In this older sample, 49.5% of subjects reported snoring, and 10.8% reported breathing stoppage during sleep. Both respiratory disorders were associated significantly with male gender and high body mass index. In men, prevalence of snoring was increased significantly in those with alcohol consumption greater than 40 mL per day. Breathing stoppage during sleep was associated with depressive symptoms in women. Logistic regression models adjusted for age, gender, educational level, tobacco status and alcohol consumption, depressive symptomatology, and number of medications found that both snoring and breathing stoppage were associated with low scores (< or = 10th percentile) in tests requiring visual attention skills, the Trail Making Test (OR = 2.14, 95% CI = 1.24-3.69 and OR = 1.88, 95% CI = 1.04-3.39, respectively), and the Digit Symbol Substitution Test (OR = 1.80, 95% CI = 1.09-2.99 and OR = 1.58, 95% CI = .87-2.89, respectively). These relationships were significant only when either snoring or breathing stoppage was associated with daytime sleepiness.

CONCLUSIONS

This cross-sectional analysis suggested that in community-dwelling individuals 60 to 70 years of age, snoring and breathing stoppage during sleep associated with daytime sleepiness were risk factors for low cognitive performance in tests requiring visual attention skills.

Factors related to sleep apnea syndrome in sleep clinic patients

We examined 129 patients recruited from two sleep clinics to study the sleep apnea syndrome (SAS), defined by the apnea-hypopnea index (AHI) > or = 10. Information was registered from a self-administered questionnaire, basal physical measurements, and polysomnography. In 68 subjects recorded for two consecutive nights, a high correlation was found between first- and second-night AHIs (r = 0.89). Habitual loud snoring and breathing arrests during sleep were associated with AHI > or = 10. A model including these two variables, sex, age, and body mass index was created in order to predict AHI > or = 10 and with which it was possible to successfully classify almost three of four patients. Among subjective sleep questionnaire items, only daytime sleepiness was related to drops of transcutaneous oxygen tension. These discrepancies in the observed relationship between sleep parameters and subjective sleep items reduce the questionnaire value in epidemiologic settings where it aimed to detect SAS, as defined solely by the AHI value.

Factors associated with low cognitive performance in general practice

In the preparatory phase of a randomised controlled trial data were collected to assess the magnitude of changes on cognitive functions in 1628 volunteers (age range 45-75 years) that were recruited from general practitioners' patient population. Subjects were administered a short neuropsychological battery of tests including three paper-and-pencil tests, which assessed immediate recall, delayed memory, and attention. Being on antihypertensive medication was associated with low results for all three tests in every age group, and in all strata according to blood pressure levels. Psychotropic drug use was correlated with low results for all three tests. Differences between psychotropic drug users and nonusers increased with age. Antihypertensive treatment and psychotropic drug use seem to be important to consider in longitudinal studies of cognitive decline in aging.

[Sleep disorders in psychiatric diseases. Epidemiological aspects]

Very few epidemiological surveys have specifically studied relationships between sleep disturbances and psychiatric diseases. In this review, we preferred to use the classification proposed in 1979 by the Association of Sleep Disorders Centers. It includes four main categories: insomnias, excessive sleepiness, troubles of the wake/sleep schedule and parasomnias. Evaluating psychiatric disorders among general populations is easier owing to DSM III and DSM III-R criteria, but there are not equivalent criteria in evaluating sleep disorders. It is almost impossible to realize polysomnographic recordings in large samples, therefore sleep disorders are to be detected by questionnaires. It has been shown that there is a good correlation between self-reports and polysomnographic recordings among clinical and general samples. The prevalence of insomnia, defined as difficulties of initiating and maintaining sleep, is estimated between 9 and 31%. It is higher among women, elderly people, separated and divorced subjects, and low educational levels' groups. It has to be noticed that polysomnographic records of some subjective insomniacs are not different from those of good sleepers, sleep latency excepted. These subjective (and not objective) insomniacs have high scores in anxiety scale, depression scale, or psychologic distress. Insomnia is more frequently noted amongst subjects with psychiatric diagnoses, especially major depressive disorders and anxiety disorders. Depressive disorders are present in 21-40% of insomniacs versus 0-1% of non-insomniacs, and anxiety disorders in 13-24% of insomniacs versus 3-10% of non-insomniacs. In depressive disorders, sleep alterations are frequently noted: they are difficulties of initiating and maintaining sleep, decreasing proportion of slow-wave sleep, decreasing time of REM (rapid eye movement) sleep and REM sleep latency, and increasing density of REM sleep. Of these modifications, the last two ones seem to be specific for depression. The relationships between sleep, aging and depression are more complex than previously noted. For example, differences between depressed and non-depressed subjects depend on the age of the population. The prevalence of hypersomnia is lower than the insomnia's. It varies between 2 and 4%. It is more frequently noted among young people, and never married subjects. Two specific aetiologies must be looked for: sleep apnea syndrome and narcolepsy. These diagnoses are respectively found in 45% and 24% of hypersomniacs examined in American Sleep Centers. Hypersomnias are objectived by the Multiple Sleep Latency Test, which measures the physiologic sleep tendency.(ABSTRACT TRUNCATED AT 400 WORDS)

[Sleep apnea syndrome: psychiatric aspects]

The prognosis of sleep apnea syndrome (SAS) is dominated by cardiovascular complications. However, this disease is concerned with psychiatric field through specific clinical patterns. Nocturnal respiratory arrests are responsible for hypoxic and hypercapnic events including sleep fragmentation, reduction of slow wave sleep and rapid eye movement sleep. Alertness disturbances and sleep disorders are the most common functional complaints. Memory and cognitive disorders, personality changes and anxiodepressive syndromes may occur but are often neglected due to the increase of frequency with age together with the frequency of SAS; clinicians should consequently be aware of the fact that such troubles may be related to sleep respiratory disorders. In this case polysomnography should be performed before prescribing hypnotics, tranquilizers or sedative antidepressants.