A multivariate twin study of the genetic association between present moment attention and subjective wellbeing.

Considerable evidence supports the role of present-moment attention, a central feature of mindfulness, in subjective wellbeing maintenance and enhancement. Yet it is not clear why such a relation exists. This study examined the genetic and environmental contributions of present-moment attention to subjective wellbeing. Consistent with the "generalist genes hypothesis" and prior evidence, we hypothesized that presence and subjective wellbeing would show a substantial genetic correlation and smaller environmental correlation. Using a large epidemiological sample of healthy 16-year-old twins in the United Kingdom (N = 1136 monozygotic (MZ) and dizygotic (DZ) twin pairs), genetic overlap was found between presence and the cognitive component of subjective wellbeing (life satisfaction), and to a lesser extent, the affective component of subjective wellbeing (operationalized as happiness). The non-shared environmental overlap between these constructs was substantial. This study provides the first evidence known to us showing that present-centered attention, a primary component of mindfulness, has both genetic and environmental overlap with subjective wellbeing. The findings have implications for understanding mechanisms by which presence is associated with positive emotions and life satisfaction, and suggest, pending additional research, that mindfulness-based interventions to enhance wellbeing may be best suited to those with a genetic propensity toward mindful presence.

Phenomenological aspects of hypnotic interactions: the effect of kinship.

This study analyzes the relationship of various measures of hypnosis as a function of kinship. Subjects with varying degrees of kinship (mono- and dizygotic twins, siblings, and parent-child pairs) participated. The Stanford Hypnotic Susceptibility Scale, Form A (SHSS:A), as well as other measures-including the Dyadic Interactional Harmony (DIH) and the Phenomenology of Consciousness Inventory (PCI)-were used with both subjects and hypnosis practitioners. Findings indicated that the phenomenological experience of hypnosis is not determined genetically. The subjects apparently evaluated the session as related to the degree of kinship. MZ twins-on the basis of reactive interactional pattern-evaluate the hypnotic interaction similarly. This was not true for SHSS:A scores or the phenomenological aspects of the state (PCI). These findings were interpreted within the sociopsychobiological model of hypnosis.

The heritability of the skin conductance orienting response: a longitudinal twin study.

The orienting response is a widely used experimental paradigm that reflects the association between electrodermal activity and psychological processes. The present study examined the genetic and environmental etiology of skin conductance orienting response (SCOR) magnitude in a sample of twins assessed at ages 9-10, 11-13 and 14-16 years. Structural equation modeling at each visit showed that genetic influences explained 56%, 83%, and 48% of the total variance in SCOR at visits 1, 2, and 3, respectively, with the remaining variance explained by non-shared environmental factors. SCOR was moderately stable across ages, with phenotypic correlations between time points ranging from .35 to .45. A common genetic factor explained 36%, 45% and 49% of the variance in SCOR magnitude across development. Additional age-specific genetic effects were found at ages 9-10 and 11-13 years, explaining 18% and 35% of the variance, respectively. The genetic correlations among the three time points were high, ranging from .55 to .73, indicating a substantial continuity in genetic influences from ages 9 to 16. These findings suggest that genetic factors are important influences in SCOR magnitude during late childhood and adolescence.

The early auditory gamma-band response is heritable and a putative endophenotype of schizophrenia.

BACKGROUND: Reduced power and phase locking of the early auditory gamma-band response (EAGBR) have been reported in schizophrenia, but findings are equivocal. Further, little is known about genetic (heritability) and environmental influences on the EAGBR or its potential as an endophenotype of schizophrenia. The present study used a twin design to examine whether EAGBR power and phase locking are heritable and reduced in schizophrenic patients and their unaffected co-twins and thus putative endophenotypes of schizophrenia. METHODS: The study sample included a total of 194 individuals, consisting of 15 monozygotic [MZ] twin pairs concordant for schizophrenia, 9 MZ twin pairs discordant for schizophrenia, and 42 MZ and 31 dizygotic (DZ) control pairs. Evoked power and phase-locking factor of the EAGBR were computed on Morlet wavelet-transformed electroencephalogram responses to standard tones during an auditory oddball target detection task. Structural equation modeling was applied to estimate heritability and genetic and environmental correlations with schizophrenia for the EAGBR measures. RESULTS: Both evoked power and phase-locking phenotypes were heritable traits (power: h(2) = 0.65; phase locking: h(2) = 0.63). Impaired EAGBR measures were significantly associated with schizophrenia. Patients with schizophrenia and their unaffected identical co-twins exhibited significantly reduced EAGBR power compared with control subjects. In each phenotype, shared genetic factors were likely the source of the observed associations with schizophrenia. CONCLUSIONS: Our results support EAGBR measures as putative endophenotypes of schizophrenia, likely reflecting an ubiquitous local cortical circuit deficit.

Physiological reactivity to infant crying: a behavioral genetic study.

In this study, we examined adults' cardiac reactivity to repeated infant cry sounds in a genetically informative design. Three episodes of cry stimuli were presented to a sample of 184 adult twin pairs. Cardiac reactivity increased with each cry episode, indicating that subjects were increasingly sensitized to repeated infant distress signals. Non-parents showed more cardiac reactivity than parents, and males displayed a larger increase in heart rate (HR) in response to repeated cry sounds than females. Multivariate genetic modeling showed that the genetic component of adults' HR while listening to infant crying was substantial. Genetic factors explained 37-51% of the variance in HR and similar genes influenced HR at baseline and HR reactivity to infant crying. The remaining variance in HR across the cry paradigm was accounted for by unique environmental influences (including measurement error). These results point to genetic and experiential effects on HR reactivity to infant crying that may contribute to the explanation of variance in sensitive and harsh parenting.

Are auditory P300 and duration MMN heritable and putative endophenotypes of psychotic bipolar disorder? A Maudsley Bipolar Twin and Family Study.

BACKGROUND: Impaired P300 auditory response has been reported in patients with psychotic bipolar disorder (BPD) and unaffected relatives of psychotic bipolar patients. Deficits in mismatch negativity (MMN), however, have not been observed in bipolar patients. To our knowledge, no family study of MMN in BPD has been reported. The current study combined the Maudsley twin and bipolar family samples using genetic model fitting analyses to: (1) assess the relationship between BPD and MMN, (2) substantiate the association between psychotic BPD and P300 variables, (3) verify the genetic overlap of BPD with P300 amplitude previously reported in the twin sample, and (4) examine the shared genetic influences between BPD and bilateral temporal scalp locations of P300 components. METHOD: A total of 301 subjects were included in this study, including 94 twin pairs, 31 bipolar families, and 39 unrelated healthy controls. Statistical analyses were based on structural equation modelling. RESULTS: Both P300 and MMN are heritable, with heritability estimates of 0.58 for MMN, 0.68-0.80 for P300 amplitude, and 0.21-0.56 for P300 latency. The bipolar patients and their relatives showed normal MMN. No significant association, either genetic or environmental, was found with BPD. BPD was significantly associated with reduced P300 amplitude and prolonged latency on midline and bilateral temporal-posterior scalp areas. Shared genetic factors were the main source of these associations. CONCLUSIONS: The results confirm that MMN is not an endophenotype for psychotic BPD whereas P300 amplitude and latency components are valid endophenotypes for psychotic BPD.

Spiritual well-being and health.

Data on empirical associations between religious variables and health outcomes are needed to clarify the complex interplay between religion and mental health. The aim of this study was to determine whether associations with health variables are primarily attributable to explicitly religious aspects of spiritual well-being (SWB) or to "existential" aspects that primarily reflect a sense of satisfaction or purpose in life. Three hundred forty-five pairs of twins from the Vietnam Era Twin Registry completed a diagnostic interview and questionnaires containing the 2-factor SWB Scale and general health items. Observed associations between SWB and health outcomes were uniquely explained by the SWB subscale of existential well-being, with much less of a unique explanatory contribution from religious well-being or "spiritual involvement." We concluded that studies of SWB and health should continue to distinguish between explicitly religious variables and others that more closely approximate the psychological construct of personal well-being.

Parent-child feedback predicts sibling contrast: using twin studies to test theories of parent-offspring interaction in infant behavior.

Several studies report apparent sibling contrast effects in analyses of twin resemblance. In the presence of genetic differences, contrast effects reduce the dizygotic (DZ) twin correlation relative to that in monozygotic (MZ) twins and produce higher DZ than MZ variance. Explanations of contrast effects are typically cast in terms of direct social interaction between twins or an artifact of the process of rating children by their parents. We outline a model for sibling imitation and contrast effects that depends on social interaction between parents and children. In addition to predicting the observed pattern of twin variances and covariances, the parental mediation of child imitation and contrast effects leads to differences in the variance of parents of MZ and DZ twins and differences between the correlations of parents with their MZ and DZ children.

Pilot study of spirituality and mental health in twins.

OBJECTIVE: The goal of this study was to investigate associations between empirically defined dimensions of spirituality, personality variables, and psychiatric disorders in Vietnam era veterans. METHOD: One hundred pairs of male twins from the Vietnam Era Twin Registry were administered the self-report Spiritual Well-Being Scale and a pilot Index of Spiritual Involvement. Correlation analyses were supplemented with regression analyses that examined the relative influence of genetic and environmental factors on aspects of spirituality. RESULTS: Existential well-being was significantly associated with seven of 11 dimensions of personality and was significantly negatively associated with alcohol abuse or dependence and with two of three clusters of personality disorder symptoms. Associations between mental health variables and religious well-being or spiritual involvement were much more limited. CONCLUSIONS: Useful distinctions can be made between major dimensions of spirituality in studies of spirituality, religious coping, and mental health.

Twins dispute memory ownership: a new false memory phenomenon.

In three experiments, we examined a new memory phenomenon: disputed memories, in which people dispute ownership of a memory. For example, in one disputed memory each of two twins recollected being sent home from school for wearing too short a skirt, although only one of them was actually sent home. In Experiment 1, 20 sets of same-sex adult twins were asked to produce a memory for each of 45 words, and most twins spontaneously produced at least one disputed memory. In Experiment 2,20 different sets of same-sex adult twins rated disputed memories as higher in recollective experience, imagery, and emotional reliving than nondisputed memories. In Experiment 3, siblings who were close in age as well as same-sex friends were also found to have disputed memories, but less often than twins.

Heavy consumption of cigarettes, alcohol and coffee in male twins.

OBJECTIVE: To determine the relative contribution of environmental and genetic influences on the joint distribution of heavy smoking, heavy alcohol use and heavy coffee drinking. METHOD: Multivariate structural equation modeling in a large cohort of male twins (N = 2,220 monozygotic and 2,373 dizygotic twin pairs; mean age = 62.1 years) from the National Academy of Sciences-National Research Council's World War II Twin Registry. RESULTS: The best-fitting model identified two independent (i.e., uncorrelated) sets of genetic and environmental latent factors, with one set underlying joint heavy smoking and heavy alcohol use and the other set underlying joint heavy smoking and heavy coffee drinking (chi 2 = 14,13,22 df, p > .80). Heavy alcohol use and heavy coffee drinking were uncorrelated in this sample. While common genetic factors accounted for 35% to 78% of the total genetic variance in heavy substance use, a substantial amount of genetic variance remained specific to each of the three substances. CONCLUSIONS: Several hypotheses involving genetic and environmental factors are presented to account for the independent clustering of heavy smoking and heavy alcohol use and of heavy smoking and heavy coffee drinking.

The consumption of tobacco, alcohol, and coffee in Caucasian male twins: a multivariate genetic analysis.

Despite the fact that epidemiologic studies demonstrate a consistent covariation between the use of tobacco, alcohol, and coffee, most previous behavioral genetic-studies have determined the contribution of genetic and environmental influences as if the consumption of these substances occurred independently of each other. In this study, we used multivariate structural equation modeling to determine the genetic and environmental overlap in the observed correlations between tobacco smoking and alcohol and coffee drinking in 173 monozygotic and 183 dizygotic male twin pairs (M age = 59 years; range = 52-66 years) who participated in a follow-up cardiovascular examination of the National Heart, Lung, and Blood Institute's Twin Study. Consistent with hypothesized psychoneurogenetic predispositions for the joint use of these substances, the most parsimonious model fitting these data identified a common genetic latent factor underlying the observed associations between smoking, alcohol, and coffee use in this cohort. This factor, herein called polysubstance use, underscores the role of genetic influence on the clustering of these behaviors in the same individual.

[Relation of the individual specificity of emotional autoregulation controlled by EEG feedback to the influence of a genetic factor as revealed by a twin study]. / Zavisimost' individual'noi spetsifiki protsessov émotsional'noi samoreguliatsii pod kontrolem obratnoi sviazi po EEG ot vliianiia geneticheskogo faktora, otdifferentsirovannogo bliznetsovym metodom.

On the model of biofeedback connection by the given parameters of the EEG alpha-rhythm the dynamics of bioelectrical and vegetative characteristics and correlative connections between them were compared in the pairs of mono- and dizygotic twins. More likeness in the dynamics of the studied parameters was found in the pairs of genetically identical monozygotic twins. There was a maximum increase of the objective similarity characteristics in the moment of activity realization, judging by the change of alpha-rhythm parameters. The obtained results testify to genetic determination of individual specific styles in organization of complex integrative processes of the higher nervous activity.

[Human inheritability of hypnotizability]. / Nasleduemost' gipnabel'nosti u cheloveka.

The study of hypnotizability of 1392 individuals proved the known statistical regularity in the men distribution on their hypnotizability degree. It is found that about 80% of subjects are characterized by the entering into the first stage of hypnoidal state, and about 25% of subjects--into the second and third stages. The research of hypnotizability of 60 pairs of twins revealed 78.3% of concordance on this feature, which proves the hypothesis about hereditable nature of hypnotizability. We have established the percent of hypnotizability of twins with common living to be higher than an appropriate value of twins with separate living. According to modern data the probable hereditary mechanism of hypnotizability is sex controlled by an autosomal gene with incomplete penetrance.