Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sex difference”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources
PubMed2002

Null sex differences in general intelligence: evidence from the WAIS-III.

There is an increasing number of studies claiming that the sex differences in general intelligence are "real." The empirical evidence is based on the summation of the standardized sex differences in several cognitive batteries. However, the scientific construct of general ability rests on the correlations among test scores, rather than on their summation. The latter (ability in general) is an arbitrary variable, not a scientific construct. General ability is not a function of any particular cognitive test, but a source of variance evidenced by the correlation between several diverse tests, each of which reflects general ability (g) to some extent, but also group factors and test specificity. Because there are important educational, economic, and social consequences of a group difference in general ability, it is especially germane to evaluate the possibility of an average sex difference in its proxy measures, such as IQ. The Spanish standardization of the WAIS-III is analyzed in the present study. The sample was made up of 703 females and 666 males, aged 15-94, drawn as a representative sample of the population in terms of educational level and geographical location. Although a male advantage of 3.6 IQ points is observed, the difference is in "ability in general," not in "general ability" (g). Given that the main ingredient of the strong association between IQ and a broad range of social correlates is g, and given that there is no sex difference in g, then the average IQ sex-difference favoring males must be attributed to specific group factors and test specificity.

Adult↗
PubMed2002

Sex differences in analgesic responses: evidence from experimental pain models.

BACKGROUND AND OBJECTIVE: Sex-related influences on the experience of pain have received considerable empirical attention. Women are at greater risk for several forms of clinical pain and exhibit greater perceptual responses to experimental pain. In recent years, investigators have turned their attention to the influence of sex-related factors on analgesic responses. The purpose of this review is to examine the literature on sex differences in analgesic responses, emphasizing findings from experimental studies. METHODS: First, important methodological issues in laboratory pain research are presented, and sex differences in responses to experimentally-induced pain are briefly addressed. Next, previous data from non-human animal research and human experimental and clinical research related to sex differences in analgesia are discussed. Also, preliminary results are presented from an ongoing study in our laboratory examining analgesic responses in women and men. RESULTS AND CONCLUSIONS: Both previous research and preliminary findings from our laboratory suggests that opioids produce greater analgesic responses in women than men. Potential mechanisms underlying sex differences in analgesia are proposed, and important directions for future research are suggested.

Analgesics↗
PubMed1987

Sex differences in neuroticism: a quantitative synthesis of published research.

The personality trait of neuroticism is thought to be an important risk factor for depression. To ascertain the possible role of neuroticism in producing sex differences in depression, a meta-analysis was carried out on published studies reporting sex- and age-specific norms for neuroticism inventories. A general sex difference was found, with females having higher scores. However, the sex difference was greater in young and middle-aged adults than in children or the very elderly. This age trend in sex differences for neuroticism is similar in form to that previously reported for depression, except that the sex difference for depression completely disappeared in the very young and very old, but the sex difference in neuroticism did not.

Depressive Disorder↗
PubMed1998

Sex difference in the size of the neural song control regions in a dueting songbird with similar song repertoire size of males and females.

Previous studies have suggested a causal relation between sex differences in behavior such as singing and sex differences in the size of brain areas such as the forebrain song control areas of songbirds. In the present study we show that the size of the forebrain vocal control areas nucleus hyperstriatalis ventrale pars caudale (HVC) and nucleus robustus archistriatalis (RA) and its neuron numbers are about twice as large in males as in females of the African dueting bush shrike Laniarius funebris. However, song types are of similar complexity (number of elements per song type, physical properties of elements) in both sexes, and repertoire size does not differ between males and females. Furthermore, in captivity male and female shrikes are able to learn the same song types. This demonstrates for the shrike that sex differences in the size of vocal control areas and in its neuron numbers do not predict the type of sex-typical vocal behavior. This result is supported by a statistical comparison of the sex differences in HVC size, RA size, and song repertoire size of all songbird species studied to date. Sex differences in species in which only the males sing are indeed larger than in species in which the females also sing; in songbird species with singing females, however, the sex differences in HVC and RA volume appear to be independent of the vocal repertoire size of females. The songbird model therefore does not support the notion that sex differences in area size and neuron number explain sex differences in a behavior that occurs in both sexes. Furthermore, in the shrike, neuron soma size is similar in males and females in the song motonucleus hypoglossus pars tracheosyringealis (nXIIts) and in the premotor nucleus RA, but is sexually dimorphic in the higher vocal center HVC. Thus, male and female shrikes produce songs of similar complexity with different neuron phenotypes.

Animals↗
PubMed2006

Sex differences in cognitive abilities test scores: a UK national picture.

BACKGROUND AND AIMS: There is uncertainty about the extent or even existence of sex differences in the mean and variability of reasoning test scores ( Jensen, 1998; Lynn, 1994, ; Mackintosh, 1996). This paper analyses the Cognitive Abilities Test (CAT) scores of a large and representative sample of UK pupils to determine the extent of any sex differences. SAMPLE: A nationally representative UK sample of over 320,000 school pupils aged 11-12 years was assessed on the CAT (third edition) between September 2001 and August 2003. The CAT includes separate nationally standardized tests for verbal, quantitative, and non-verbal reasoning. The size and recency of the sample is unprecedented in research on this issue. METHODS: The sheer size of the sample ensures that any sex difference will achieve statistical significance. Therefore, effect sizes (d) and variance ratios (VR) are employed to evaluate the magnitude of sex differences in mean scores and in score variability, respectively. RESULTS: The mean verbal reasoning score for girls was 2.2 standard score points higher than the mean for boys, but only 0.3 standard points in favour of girls for non-verbal reasoning (NVR), and 0.7 points in favour of boys for quantitative reasoning (QR). However, for all three tests there were substantial sex differences in the standard deviation of scores, with greater variance among boys. Boys were over represented relative to girls at both the top and the bottom extremes for all tests, with the exception of the top 10% in verbal reasoning. CONCLUSIONS: Given the small differences in means, explanations for sex differences in wider domains such examination attainment at age 16 need to look beyond conceptions of 'ability'. Boys tend to be both the lowest and the highest performers in terms of their reasoning abilities, which warns against the danger of stereotyping boys as low achievers.

Achievement↗
PubMed1998

Sex differences in escape-avoidance response in mice after acute administration of raclopride, clozapine, and SCH 23390.

Sex differences in the effects of haloperidol in the escape-avoidance response in mice have previously been found in various studies carried out in our laboratory. Males were more affected than females by the disruptive effects of this neuroleptic. The work described herein extended the study of these sex differences to raclopride, clozapine, and SCH 23390, using several doses of each drug in acute administration. The results showed dose-dependent sex differences in the deteriorating effects of these dopamine antagonists in the escape-avoidance response. Male mice were more affected by the inhibitory effects of these drugs, showing fewer escape responses and more nonresponses than females. Sex differences were found with all three of the dopamine antagonists studied, indicating, therefore, that these differences do not depend on a unique type of dopaminergic receptor. The results obtained in motor activity, measured by the number of crossings during the adaptation period and the intertrial intervals, suggest that the motor effects are not the origin of these differences. It is concluded that, besides haloperidol, other dopamine antagonists also show sex differences in their behavioral effects in escape-avoidance response in mice, with males being more affected than females by the inhibitory action of these drugs.

Animals↗
PubMed1975

Human intelligence: sex differences.

An extensive review of the literatureon sex differences in human intelligence leads to the conclusion that there is stron evidence for sex differences in processing both verbal and spatial information. The few genetic studies that there are all point toward a sex-link mode of inheritance of certain spatial abilities.

Adolescent↗
PubMed2004

Catastrophizing as a mediator of sex differences in pain: differential effects for daily pain versus laboratory-induced pain.

Sex differences in the experience of pain have been widely reported, with females generally reporting more frequent clinical pain and demonstrating greater pain sensitivity. However, the mechanisms underpinning such differences, while subject to intense speculation, are not well-characterized. Catastrophizing is a cognitive and affective process that relates strongly to enhanced reports of pain and that varies as a function of sex. It is thus a prime candidate to explain sex differences; indeed, several prior studies offer evidence that controlling for catastrophizing eliminates the gap between men and women in reported pain. We recruited 198 healthy young adults (115 female) who took part in laboratory studies of pain responses, including thermal pain, cold pain, and ischemic pain, and who also completed questionnaires assessing catastrophizing, mood, and day-to-day painful symptoms (e.g. headache, backache). Women reported greater levels of catastrophizing, more recent painful symptoms, and demonstrated lower pain thresholds and tolerances for noxious heat and cold relative to men. Mediational analyses suggested that after controlling for negative mood, catastrophizing mediated the sex difference in recent daily pain but did not mediate the much larger sex differences in pain threshold and tolerance. These findings highlight the role of catastrophizing in shaping pain responses, as well as illuminating potentially important differences between experimental pain assessment and the clinical experience of pain.

Adaptation, Psychological↗
PubMed2001

Sex differences in the prevalence of human birth defects: a population-based study.

BACKGROUND: Sex differences in the prevalence of several human birth defects have often been reported in the literature, but the extent of sex differences for most birth defects is unknown. To determine the full extent of sex differences in birth defects in a population, we examined population-based data from the Metropolitan Atlanta Congenital Defects Program (MACDP). METHODS: MACDP records were analyzed for 1968 through 1995. We determined the sex-specific prevalence of all major birth defects, using the total number of live births by sex during these years as the denominator. For each specific defect, we calculated a relative risk with regard to sex on the basis of the ratio of prevalence among males to prevalence among females. Male-female relative risks were also determined for total major birth defects and for several broad categories of defects. RESULTS: The overall prevalence of major defects at birth was 3.9% among males and 2.8% among females. All but two of the major categories of birth defects (nervous system defects and endocrine system defects) had a higher prevalence among males. Defects of the sex organs were eight and one-half times more prevalent among males and accounted for about half of the increased risk of birth defects among males relative to females. Urinary tract defects were 62% more prevalent among males, and gastrointestinal tract defects were 55% more prevalent among males. Among specific defect types, twofold or greater differences in prevalence by sex were common. CONCLUSIONS: Our data indicate that sex differences in the prevalence of specific human birth defects are common, and male infants are at greater risk for birth defects than female infants. Several mechanisms have been proposed to account for these differences.

Congenital Abnormalities↗
PubMed1991

Sex differences in suicidal behaviour of referred adolescents.

Reports of suicidal behaviour from four countries using the same measures were higher for girls than for boys, and higher in self-reports than in parent reports for both referred and normal adolescents. In a sample of 480 referred adolescents, patterns of 'low' and 'high' suicidal scores were different when age, sex and diagnosis were considered. The probability of high scores for girls showed only a marginal increase with age, while there was a striking rise for boys. An affective diagnosis doubled the probability of high scores for both boys and girls, while it had no effect on low scores. Psychosocial stressors also increased the probability of high suicidal scores, particularly in adolescents with an affective disorder. Sex differences in suicidal behaviour were marked in the low-scoring groups.

Adolescent↗
PubMed1994

Ontogeny of sex differences among newly-generated neurons of the juvenile avian brain.

In zebra finches, only males sing and brain regions controlling song exhibit sex differences in neuron number that stem from actions of estrogen during a critical developmental period. In certain song nuclei, these dimorphisms emerge long after neurogenesis and migration are complete, and estrogen promotes masculinization by preventing the death of well-differentiated neurons. But in another region, the higher vocal center (HVC), cellular mechanisms underlying sex differences in neuron number are not so well understood. In the HVC, neurogenesis continues throughout the post-hatch period of sexual differentiation, and sex differences arise during this time because neuron number increases in males but not females. We used [3H]thymidine autoradiography to establish when sex differences in neuron number first develop among a small group of HVC neuronal cohorts. We report that HVC neurons labeled by [3H]thymidine on days 15 and 16 after hatching are sexually dimorphic in number within 10 days of their birth, even before all cells in this cohort complete their migration and/or differentiation. This suggests that the cellular mechanisms contributing to sex differences in neuron number in the HVC may differ from those in other sexually dimorphic neural regions of the vertebrate nervous system. In addition, we found that although many thymidine-labeled HVC neurons ultimately project to the robust nucleus of the archistriatum (RA), a sexually dimorphic target, sex differences in their number develop before this efferent projection is established. These results have important implications regarding the site(s) of hormone action, since they suggest that sexual differentiation acts on certain HVC neurons before they establish their efferent projections, and perhaps even before they arrive within the HVC.

Animals↗
PubMed1998

The development of sex differences in cardiovascular disease mortality: a historical perspective.

OBJECTIVES: Little is known about why males have higher cardiovascular disease (CVD) mortality rates than do females. An important factor that has hampered efforts in this regard is the lack of clarity about whether male excess mortality from CVD has existed throughout history. To answer this question, an investigation was conducted of trends in CVD mortality differences between the sexes from the time when data first became available until the present, including the full range of age groups. METHODS: Mortality statistics for CVD in England and Wales from 1861 through 1992 and in the United States from 1900 through 1991 were used. RESULTS: Three stages in the relationship between male and female CVD mortality were found: (1) An early stage of equal male and female mortality, (2) a stage of the appearance of sex differences in mortality, and (3) a stage with consistently present male excess mortality. CONCLUSION: Male excess mortality from CVD has not always been present in the historical record. Further research is needed to elucidate the causes of this excess mortality.

Cardiovascular Diseases↗
PubMed1978

Sex differences in hepatic sulfation of taurolithocholate in the rat.

Metabolism of the bile salts by formation of sulfate esters is catalyzed by bile salt sulfotransferase, an enzyme isolated from rat liver and kidney. The activity of bile salt sulfotransferase was measured in liver and kidney of male and female rats and in oophorectomized rats with or without estrogen replacement. In vitro sulfotransferase activity was correlated with in vivo sulfation by measuring the percentage of an infused dose (0.03 micron per 100 g per min) of taurolithocholate, which was excreted in bile as the sulfate. The activity of sulfotransferase in liver was higher in females (26.3 +/- 3.0 pmoles per mg of protein per min) than in males (9.6 +/- 3.9) and was lower (12.1 +/- 3.8) after oophorectomy. The decrease in activity was prevented by replacement of estrogen. Renal sulfotransferase activity did not differ between the sexes and was unaffected by oophorectomy. Hepatic sulfotransferase activity measured in vitro correlated with in vivo sulfation of taurolithocholate. This study shows definite sex differences in hepatic bile salt sulfotransferase activity, which in females is affected by the presence of estrogen. The correlation between in vitro sulfotransferase activity and in vivo bile salt sulfation suggests that bile salt sulfotransferase is responsible for bile salt sulfation in vivo.

Animals↗
PubMed1999

Dose dependency of sex differences in the effects of repeated haloperidol administration in avoidance conditioning in mice.

Sex differences in the effects of haloperidol in active avoidance conditioning in mice have previously been found in various studies carried out in our laboratory. Males were more affected than females by the disruptive effects of this neuroleptic. The work described here broadens the study of these sex differences to higher doses of haloperidol (0.1 and 0.2 mg/kg) using a repeated administration schedule (5 days). The results did not show sex differences in the deteriorating effects of this dopamine antagonist in the escape-avoidance response, but a tendency in the number of nonresponses was observed in the same direction as former results: male animals were more sensitive than females to the inhibitory effect of the low dose of haloperidol. It is concluded that the appearance of sex differences in the effects of haloperidol on active avoidance conditioning is a dose-dependent phenomenon.

Animals↗
PubMed2003

Sex differences in the pituitary-adrenal response following acute antidepressant treatment in sheep.

RATIONALE: Depression is more prevalent in women than in men, and therapeutic responses may also differ between the sexes. In addition, abnormal regulation of the hypothalamic-pituitary-adrenal (HPA) axis is more common in depressed women. OBJECTIVES: To further examine these phenomena, the present study was designed to investigate whether sex differences exist in the HPA axis responses of male and female sheep following acute antidepressant administration. METHODS: Two commonly prescribed antidepressants, imipramine (a tricyclic antidepressant, TCA; 2.0 and 5.0 mg/kg) and sertraline (a selective serotonin reuptake inhibitor, SSRI; 0.5, 2.0 and 5.0 mg/kg) were administered to gonadectomized male and female sheep via acute subcutaneous injection. Treatment order was randomized. Jugular blood was sampled for the measurement of prolactin, adrenocorticotropin (ACTH), and cortisol by radioimmunoassay. RESULTS: Treatment with sertraline resulted in a comparable increase in prolactin secretion in male and female sheep. However, sertraline stimulated ACTH and cortisol secretion in females but not in males, a sexually dimorphic effect that was independent of circulating sex steroids. Treatment with imipramine had no effect on prolactin, ACTH or cortisol levels in male or female sheep. CONCLUSIONS: These data suggest that the HPA axes of females are more sensitive to the stimulatory effects of serotonin following acute treatment with the SSRI, sertraline.

Adrenocorticotropic Hormone↗
PubMed2004

Sex differences in emotional reactivity to daily life stress in psychosis.

BACKGROUND: The expression of schizophrenia has been reported to differ between the sexes. The current study investigates whether these sex differences in clinical expression are reflected in one underlying mechanism that may be causally related to psychosis, namely increases in stress sensitivity in daily life. METHOD: Forty-two participants (22 men, 20 women) with Research Diagnostic Criteria-defined psychotic disorder in a state of clinical remission were studied with the Experience Sampling Method (a structured diary technique assessing current context and mood in daily life) to assess (1) appraised subjective stress related to daily events and activities and (2) emotional reactivity conceptualized as changes in both negative affect and positive affect in relation to the subjective stress. Data were collected from January 1997 to May 1999. RESULTS: Multilevel regression analyses revealed that women reported a significantly (p < .05) increased emotional reactivity to daily life stress compared with men, reflected in both an increase in negative affect and a decrease in positive affect. CONCLUSION: These results suggest that gender differences may not be limited to the characteristics of psychosis but may also be reflected in underlying etiologic mechanisms. Furthermore, these results might strengthen the hypothesis that women are more susceptible than men to a schizoaffective expression of schizophrenia.

Adult↗
PubMed1993

Sex differences in intensity of emotional experience: a social role interpretation.

According to gender role theory, women's greater emotional intensity than men's stems from normative expectations for sex differences that arise as a result of men's and women's social roles. In the 1st experiment, endorsement of normative expectations for sex differences was associated with sex differences in Ss' own emotions: To the extent that they endorsed stereotypical differences between men and women, female Ss reported personally experiencing emotions of greater intensity and male Ss reported experiencing emotions of lesser intensity. The 2nd study manipulated expectations for responsiveness while Ss viewed a series of emotion-inducing slides. When instructions rendered normative expectations comparable for men and women, no sex differences were obtained in emotion self-reports. Furthermore, women evidenced more extreme electromyograph physiological responding than men, suggesting general sex differences in emotion that are not limited to self-report.

Attitude↗
PubMed1986

Sex differences in adolescent psychopathology.

The patterns of sex differences in psychiatric morbidity are reviewed and hypothesis for the empirical study formulated. Psychiatric treatment and registration for social problems are thoroughly examined in a prospective longitudinal study of a representative birth cohort of 6,482 adolescents. Mental health and psychiatric symptomatology are also checked by a questionnaire. The data obtained are analysed for males and females separately. The results clearly show that there are major sex differences in the pattern of psychopathology in adolescence. These differences are complex and seem related to sex role expectations among parents, adolescents and mental health professionals, and to social factors and the changes experienced in life. The results give some guidelines for the future development of psychiatric care for adolescents.

Adolescent↗