Biomedical subjects

P A Silva

Publications and source records attributed to P A Silva.

At least 19 recordsLinked to original sources

PubMed2001

Failure to overcome 'innate' fear: a developmental test of the non-associative model of fear acquisition.

The non-associative, Darwinian theory of fear acquisition proposes that some individuals fail to overcome biologically-relevant fears (e.g. height) because they (1) do not have sufficient safe exposure to the relevant stimuli early in life or (2) are poor habituators who have difficulty 'learning not to fear'. These two hypotheses were tested in a longitudinal birth cohort study. Study 1 found evidence for reduced exposure to height stimuli in childhood for individuals with a fear of heights compared to study members without fear. Study 2 found evidence for higher levels of stress reactivity (a proxy for habituation) in childhood and adolescence among 18-year-old height phobics compared to study members with dental phobia and those with no fear. The results were discussed in relation to recent findings suggesting that some evolutionary-relevant fears may appear in the absence of traumatic 'learning' experiences. The merits of adding a fourth, non-associative pathway to Rachman's [Rachman, S. (1977)]. The conditioning theory of fear acquisition: a critical examination. Behaviour Research and Therapy, 15, 375-387) three pathways model of fear acquisition were briefly considered.

Adolescent↗

PubMed2001

Child-rearing antecedents of intergenerational relations in young adulthood: a prospective study.

Data gathered from mothers on parenting and family climate when almost 1,000 children in the Dunedin, New Zealand, longitudinal study were 3, 5, 7, 9, 13, and 15 years of age were used to predict intergenerational relations between young adult children (age 26) and their middle-aged parents. Analyses focused on distinct developmental epochs revealed greater prediction from the middle-childhood and early-adolescent periods than from the early-childhood years: most indicated that more supportive family environments and child-rearing experiences in the family of origin forecasted more positive and less negative parent-child relationships (in terms of contact, closeness, conflict, reciprocal assistance) in young adulthood, though associations were modest in magnitude. Some evidence indicated that (modestly) deleterious effects on intergenerational relations of experiencing relatively unsupportive child-rearing environments in 1 but not 2 (of 3) developmental periods studied could be offset by relatively supportive family environments in the remaining developmental periods.

Adolescent↗

PubMed2001

Behaviour and developmental effects of otitis media with effusion into the teens.

OBJECTIVE: To examine whether behavioural or cognitive sequelae of otitis media with effusion (OME) continue into late childhood and the early teens (11-18 years). SETTING: Data from a large multipurpose birth cohort study: the Dunedin multidisciplinary health and development study. PARTICIPANTS: Around 1000 children from the study. The main independent variable of interest was otological status of the child up to age 9. MAIN OUTCOME MEASURES: Parent and teacher rated behaviour problems, including antisocial, neurotic, hyperactive, and inattentive behaviours, and tests of academic achievement including intelligence quotient (IQ), reading, and spelling were available in a high proportion of the cohort at ages 11 to 18 years. RESULTS: After adjustments for covariates such as socioeconomic status, hyperactive and inattentive behaviour problems were evident as late as 15 years, and lower IQ associated with OME remained significant to 13 years. The largest effects were observed for deficits in reading ability between 11 and 18 years. CONCLUSIONS: No previous study considering behaviour problems as an outcome has followed children long enough to determine whether some of the early sequelae of OME are still present in the early to late teens. Some developmental sequelae of OME, particularly deficits in reading ability, can persist into late childhood and the early teens.

Acoustic Impedance Tests↗

PubMed2000

Mental disorders and violence in a total birth cohort: results from the Dunedin Study.

BACKGROUND: We report on mental disorders and violence for a birth cohort of young adults, regardless of their contact with the health or justice systems. METHODS: We studied 961 young adults who constituted 94% of a total-city birth cohort in New Zealand, April 1, 1972, through March 31, 1973. Past-year prevalence of mental disorders was measured using standardized DSM-III-R interviews. Past-year violence was measured using self-reports of criminal offending and a search of official conviction records. We also tested whether substance use before the violent offense, adolescent excessive perceptions of threat, and a juvenile history of conduct disorder accounted for the link between mental disorders and violence. RESULTS: Individuals meeting diagnostic criteria for alcohol dependence, marijuana dependence, and schizophrenia-spectrum disorder were 1.9 (95% confidence interval [CI], 1.0-3.5), 3.8 (95% CI, 2.2-6.8), and 2.5 (95% CI, 1.1-5.7) times, respectively, more likely than control subjects to be violent. Persons with at least 1 of these 3 disorders constituted one fifth of the sample, but they accounted for half of the sample's violent crimes (10% of violence risk was uniquely attributable to schizophrenia-spectrum disorder). Among alcohol-dependent individuals, violence was best explained by substance use before the offense; among marijuana-dependent individuals, by a juvenile history of conduct disorder; and among individuals with schizophrenia-spectrum disorder, by excessive perceptions of threat and a history of conduct disorder. CONCLUSIONS: In the age group committing most violent incidents, individuals with mental disorders account for a considerable amount of violence in the community. Different mental disorders are linked to violence via different core explanations, suggesting multiple-targeted prevention strategies.

Adolescent↗

PubMed2000

The effects of pre- and post-natal sunlight exposure on human growth: evidence from the Southern Hemisphere.

Several recent studies have reported a causal association between stature and month of birth. Perinatal exposure to sunlight has been suggested as the principal factor underlying this relationship, although the mechanisms involved remain a matter of debate. The longitudinal design of the present study allowed us to directly test the influence of perinatal sunlight exposure (and other meteorological and behavioural factors) on body size at birth and at regular intervals up to age 26. The findings confirmed that pre-natal sunlight is one of the most significant determinants of height. However, the trimester of greatest influence differs depending on the age at which study members were measured.

Birth Weight↗

PubMed1999

Water trauma and swimming experiences up to age 9 and fear of water at age 18: a longitudinal study.

A small number of retrospective studies on the etiology of specific fears have obtained findings consistent with a biological (non-associative) explanation of fear acquisition. Unfortunately, reliance on imperfect memory to recall conditioning events which occurred many years earlier limits the conclusions that can be drawn from such data. The present investigation attempts to overcome this methodological shortcoming by examining the relationship between water trauma (i.e. conditioning) and water skills (e.g. swimming) before the age of 9 and the presence of water fear and phobia at age 18 in a longitudinal birth cohort. We found no evidence of a relationship between water confidence and water trauma up to the age of 9 and fear of water at age 18. Similar findings were obtained for water phobia at age 18 with the exception that study members who were less able to immerse themselves in water with confidence at age 9 were more likely to report water phobia at age 18. Associative and non-associative explanations of these findings were discussed.

Adolescent↗

PubMed1998

Evidence for a non-associative model of the acquisition of a fear of heights.

Theories that fear results from previous traumatic experience (i.e. conditioning theories) have enjoyed widespread support for over half a century. Recent research, however, has cast doubt on the validity of these models in some specific phobias. Two studies on the etiology of height phobia have obtained findings consistent with a non-associative, evolutionary explanation of fear acquisition (Menzies and Clarke, 1993a, Behaviour Research and Therapy, 31, 355-365; Menzies and Clarke, 1995a, Behaviour Research and Therapy, 33, 795-805). Unfortunately, the retrospective nature of these studies limits the conclusions that can be drawn from these data. Like all retrospective research, these studies depend on adult subjects imperfect ability to recall conditioning events that may have occurred many years earlier. The present investigation overcomes these methodological shortcomings by examining the relationship between putative conditioning events before the age of 9 yr and the presence of height fear at ages 11 and 18 yr in a large birth cohort studied longitudinally. To our knowledge this is the first study that has prospectively examined the relationship between relevant traumatic events early in life and the onset of height fear in late adolescence. No positive relationship was found between a history of falls resulting in injury (i.e. fracture, dislocation, intracranial injury or laceration) before the age of 9 and fear of heights at age 11 or 18. Interestingly, falls resulting in injury between the ages of 5 and 9 occurred more frequently in those without a fear of heights at 18 (P < 0.01)--a finding in the opposite direction to that predicted by conditioning theory but consistent with non-associative theories of fear acquisition. In general, the results provide strong support for non-associative models of fear and are difficult to reconcile with conditioning theories.

Accidental Falls↗

PubMed1998

Dental fear with and without blood-injection fear: implications for dental health and clinical practice.

The relation between dental, blood and injection fear and oral health was examined in 936 New Zealand 18-year-olds. Of the approximately ten percent (n = 96) of the sample who reported a dental fear, 1 in 10 also reported a fear of blood and 53% a co-morbid fear of injections. Study members with dental fear alone or co-morbid dental and blood or injection fear had significantly worse oral health (i.e. greater caries experience) than a no-fear comparison group or individuals with blood-injection fear only. Further, individuals with dental and blood or injection fear had a significantly higher level of recent tooth decay than individuals with dental fear alone. Time since last dental treatment also tended to be highest in this group. Implications for dental health and practice were discussed.

Adolescent↗

PubMed1998

Assortative mating for antisocial behavior: developmental and methodological implications.

Do people mate assortatively for antisocial behavior? If so, what are the implications for the development and persistence of antisocial behavior? We investigated assortative mating for antisocial behavior and its correlates in a sample of 360 couples from Dunedin, New Zealand. We found substantial assortative mating for self-reports of antisocial behavior per se and for self-reports of couple members' tendencies to associate with antisocial peers (0.54 on average). Perceptions about the likelihood of social sanctions for antisocial behavior (e.g., being caught by the authorities or losing the respect of one's family) showed moderate assortative mating (0.32 on average). However, assortative mating for personality traits related to antisocial behavior was low (0.15 on average). These findings suggest that, whereas assortative mating for many individual-difference variables (such as personality traits) is low, assortative mating for actual antisocial behaviors is substantial. We conclude that future family studies of antisocial behavior should endeavor to measure and understand the influence of assortative mating. In addition, we outline a testable behavior-genetic model for the development of antisocial behavior, in which genes and environments promoting or discouraging antisocial behavior become concentrated within families (due to assortative mating), giving rise to widely varying individual developmental trajectories that are, nevertheless, similar within families.

Adult↗

PubMed1998

Development of depression from preadolescence to young adulthood: emerging gender differences in a 10-year longitudinal study.

The authors investigated the emergence of gender differences in clinical depression and the overall development of depression from preadolescence to young adulthood among members of a complete birth cohort using a prospective longitudinal approach with structured diagnostic interviews administered 5 times over the course of 10 years. Small gender differences in depression (females greater than males) first began to emerge between the ages of 13 and 15. However, the greatest increase in this gender difference occurred between ages 15 and 18. Depression rates and accompanying gender differences for a university student subsample were no different than for a nonuniversity subsample. There was no gender difference for depression recurrence or for depression symptom severity. The peak increase in both overall rates of depression and new cases of depression occurred between the ages of 15 and 18. Results suggest that middle-to-late adolescence (ages 15-18) may be a critical time for studying vulnerability to depression because of the higher depression rates and the greater risk for depression onset and dramatic increase in gender differences in depression during this period.

Adolescent↗

PubMed1998

The structure and stability of common mental disorders (DSM-III-R): a longitudinal-epidemiological study.

The latent structure and stability of 10 common mental disorders were examined in a birth cohort at ages 18 and 21. A 2-factor model, in which some disorders were presumed to reflect internalizing problems and others were presumed to reflect externalizing problems, provided a more optimal fit to the data than either a 1- or a 4-factor model. To a significant extent, persons in the sample retained their relative positions on the latent factors across the 3-year period from age 18 to age 21. Results offer potential clarification of the meaning of comorbidity in psychopathology research by suggesting that comorbidity may results from common mental disorders being reliable, covariant indicators of stable, underlying "core psychopathological processes."

Adolescent↗

PubMed1998

Comorbid mental disorders: implications for treatment and sample selection.

Disorders from the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) were assessed in a birth cohort of 961 young adults. Comorbid cases exceeded single-disordered cases in chronic history of mental illness, use of treatments, physical health problems, functional interference in daily life, and impaired adaptation across domains such as work, education, health, and social-support networks. Single-disorder cases were also more impaired than nondisordered cases, but comorbid cases were the most severely impaired. Our findings suggest that (a) samples that underrepresent comorbidity (pure single-disorder cases or student samples) will underestimate effect sizes for relations between a disorder and its correlates, whereas samples that overrepresent comorbidity (clinical or adjudicated samples) will overestimate effect sizes, (b) comorbidity is accompanied by complications that challenge treatment planning, compliance, and coordination of service delivery, and (c) comorbidity is associated with physical, educational, and economic problems that make it a broad societal concern.

Adult↗

PubMed1998

Developmental antecedents of partner abuse: a prospective-longitudinal study.

Prospective measures of risk factors for partner abuse were obtained from a large birth cohort in 4 domains: socioeconomic resources, family relations, educational achievements, and problem behaviors. Partner abuse outcomes were measured at age 21. Results showed that antecedents of abuse included risk factors from all 4 domains. Risk factors were similar for men and women. Some age 3 antecedents were significant, but the strongest correlations were from age 15. In multivariate analyses, the most consistent predictor was the presence of early problem behaviors. In a cross-validation tests, abuse was moderately predictable by the same antecedents, whether the outcome measure was self-report or reports from partners of sample members. Findings suggest that theories of partner abuse should account for developmental influences from multiple life domains and that primary prevention of partner abuse should begin in adolescence.

Adolescent↗

PubMed1998

Adult physical health outcomes of adolescent girls with conduct disorder, depression, and anxiety.

OBJECTIVE: To examine the young adult physical health outcomes of adolescent girls with behavior problems. METHOD: Girls with conduct disorder, girls with depression, girls with anxiety, and healthy girls (N = 459) who had been evaluated at age 15 years were followed up at age 21, when general physical health, substance dependence, and reproductive health were assessed. RESULTS: After control for potentially confounding variables including prior health, adolescent conduct disorder predicted more medical problems, poorer self-reported overall health, lower body mass index, alcohol and/or marijuana dependence, tobacco dependence, daily smoking, more lifetime sexual partners, sexually transmitted disease, and early pregnancy. Adolescent depression predicted only adult tobacco dependence and more medical problems; adolescent anxiety predicted more medical problems. CONCLUSIONS: The robust link between female adolescent conduct disorder and poor physical health in adulthood suggests that intervention with girls who have conduct disorder may be a strategy for preventing subsequent health problems.

Adolescent↗

PubMed1998

Dental caries and changes in dental anxiety in late adolescence.

Little is known about changes in dental anxiety with ageing and their association with changes in oral health. This study examined the relationship between changes in dental caries experience and dental anxiety from 15 to 18 years of age among adolescent participants in the Dunedin Multidisciplinary Health and Development Study. Dental anxiety was estimated using the Corah Dental Anxiety Scale (DAS), and individuals with a DAS score of 13+ were identified as being dentally anxious. Dental examinations were performed on 649 individuals at ages 15 and 18, and a DMFS score was computed for each. Caries prevalence among those who were dentally anxious at both 15 and 18 years was significantly higher than for those who were not at either age. Regression analysis revealed that dental anxiety predicted caries incidence between ages 15 and 18 years. Dental anxiety is likely to be a significant predictor of dental caries experience, and may be a risk factor for dental caries incidence.

Adolescent↗

PubMed1998

Comorbidity between abuse of an adult and DSM-III-R mental disorders: evidence from an epidemiological study.

OBJECTIVE: The purpose of this study was to report the prevalence, risk, and implications of comorbidity between partner violence and psychiatric disorders. METHOD: Data were obtained from a representative birth cohort of 941 young adults through use of the Conflict Tactics Scales and Diagnostic Interview Schedule. RESULTS: Half of those involved in partner violence had a psychiatric disorder; one-third of those with a psychiatric disorder were involved in partner violence. Individuals involved in severe partner violence had elevated rates of a wide spectrum of disorders. CONCLUSIONS: The findings support the importance of mental health clinicians screening for partner violence and treating victims and perpetrators before injury occurs.

Adult↗

PubMed1997

Prevalence and correlates of cannabis use and dependence in young New Zealanders.

AIMS: To determine change in patterns of cannabis use in New Zealand in an unselected birth cohort and investigate the relationship between level of cannabis use, violent behaviour and employment history. METHOD: Prospective longitudinal design using members of the Dunedin Multidisciplinary Health and Development Study at ages 15, 18 and 21 years. RESULTS: Rates of cannabis use increased from 15% (n = 144) at age 15 years to more than half of the sample seen at age 21 years (n = 497; 52.4%). DSM-III-R defined cannabis dependence assessed at age 18 and 21 years increased from 6.6% (n = 61) to 9.6% (n = 91). Males were more likely to use and be dependent on cannabis than females. Early use substantially increased the risk for the development of cannabis dependence in young adulthood. Cross-sectional analysis at age 21 found levels of cannabis use and dependence to be higher among the unemployed and those with a history of violent behaviour. CONCLUSIONS: Prevalence rates of cannabis use in young New Zealanders were found to be higher than previously reported. A history of unemployment or of violent behaviour was associated with more frequent cannabis use at age 21. Males were more likely than females to use cannabis frequently and to meet DSM-III-R criteria for dependence at age 21. It is suggested that drug education campaigns should specifically target young males.

Adolescent↗

PubMed1997

Antecedents of adult interpersonal functioning: effects of individual differences in age 3 temperament.

We examined whether temperamental differences at age 3 are linked to interpersonal functioning in young adulthood. In a sample of over 900 children, we identified 5 distinct groups of children based on behavioral observations: Well-adjusted, undercontrolled, reserved, confident, and inhibited. At age 21, we assessed the children's interpersonal functioning in 4 social contexts: in the social network, at home, in romantic relationships, and at work. We found three patterns of relations: (a) Well-adjusted, reserved, and confident children defined a heterogeneous range of normative adult interpersonal behavior, (b) inhibited children had lower levels of social support but normative adjustment in romantic relationships and at work, and (c) undercontrolled children had lower levels of adjustment and greater interpersonal conflict across adult social contexts.

Adolescent↗