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Biomedical subjects

R Poulton

Publications and source records attributed to R Poulton.

At least 37 records · Page 2Linked 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

Psychological disorders and dental anxiety in a young adult population.

OBJECTIVES: It has been suggested that some individuals who are fearful or anxious about dental treatment have a constitutional vulnerability to anxiety disorders as evidenced by the presence of multiple fears, generalized anxiety or panic disorders. This paper compares the prevalence of psychological disorders among dentally anxious and non-anxious groups drawn from the general population. METHODS: Data were obtained as part of a birth cohort study when study members were aged 18 years. They were assessed using the Dental Anxiety Scale (DAS) and the Diagnostic Interview Schedule (DIS). The disorders diagnosed by the DIS were major depressive episode, dysthymia, generalized anxiety disorder, panic disorder, agoraphobia, social phobia, simple phobia, obsessive compulsive disorder, conduct disorder, cannabis and alcohol dependence. RESULTS: Overall, 12.5% of study members had DAS scores of 13 or more and were considered to be dentally anxious. Those who were dentally anxious were more likely than the non-anxious to be diagnosed with one or more psychological disorders (55.0% vs. 42.3%). However, those with DAS scores of 13 or 14 (moderately dentally anxious) were broadly similar to the non-anxious in terms of their psychological profile. This excess prevalence of psychological disorder was largely accounted for by high rates of disorder among those with DAS scores of 15 or more (highly dentally anxious). The highly anxious were more likely than the non-anxious to have a diagnosis of conduct disorder, agoraphobia, social phobia, simple phobia or alcohol dependence. Odds ratios ranged from 2.8 to 5.0 after controlling for the effects of gender. The data also suggested that dentally anxious individuals with psychological disorders were more likely to maintain their anxiety over time. CONCLUSIONS: In this population of young adults, high rates of psychological disorder were characteristic of those with high levels of dental anxiety. Psychological disorder was related to the maintenance of dental anxiety over time.

Adolescent↗
PubMed2001

Paths to panic disorder/agoraphobia: an exploratory analysis from age 3 to 21 in an unselected birth cohort.

OBJECTIVE: To evaluate childhood temperamental traits and early illness experiences in the etiology of adult panic disorder with agoraphobia. METHOD: Evaluated temperamental and illness experience factors, at ages 3 through 18, as predictors of panic and agoraphobia at ages 18 or 21 in an unselected sample (N = 992). Analyses were conducted with classification trees. RESULTS: Experience with respiratory ill health predicted panic/agoraphobia relative to other anxiety disorders and healthy controls. Also, temperamental emotional reactivity at age 3 predicted panic/agoraphobia in males but did not predict other anxiety disorders, compared with healthy controls. Furthermore, temperament and ill health interacted with gender. CONCLUSIONS: Results are discussed in terms of cognitive theories of fear of physical symptoms and biological models of respiratory disturbance for panic/agoraphobia.

Adolescent↗
PubMed2001

The irritable bowel syndrome and psychiatric disorders in the community: is there a link?

OBJECTIVE: Psychiatric morbidity is high among patients who present to referral centers with irritable bowel syndrome (IBS). However, few studies have investigated the relationship between psychiatric disturbance and IBS in community samples. We hypothesized that psychiatric disorders are linked to IBS in the general community, but this is influenced by the criteria used to establish a diagnosis of IBS. METHODS: The data were collected from a birth cohort born in Dunedin (New Zealand) between April 1972 and March 1973. This cohort consisted of 1037 members (52% male), who were assessed at ages 3, 5, 7, 9, 11, 13, 15, 18, 21, and 26 yr. GI symptoms were recorded at age 26 yr, using an abbreviated version of the Bowel Symptom Questionnaire; psychiatric history was obtained at ages 18 and 21 yr, using a modified version of the Diagnostic Interview Schedule. RESULTS: The prevalence of IBS was 12.7% according to the Manning criteria and 4.3% according to the Rome II criteria. The IBS was not significantly related to a diagnostic history for psychiatric illness overall, nor to a history of anxiety disorders, depressive disorders, and substance dependence. These results were independent of the IBS criteria used; there was no association between psychiatric history and IBS when IBS was defined according to the Manning criteria (p = 0.11 to 0.98) or the Rome criteria (p = 0.18 to 0.92): Rome and Manning criteria subjects did not significantly differ from each other in terms of psychiatric history (p = 0.16 to 0.89). CONCLUSION: In a cohort of young adults with IBS from New Zealand, IBS appears to not be related to psychiatric disorders.

Adolescent↗
PubMed2001

Psychological disorder, conditioning experiences, and the onset of dental anxiety in early adulthood.

Most studies examining the origins of dental fear and anxiety have relied on cross-sectional data. These are subject to several problems, such as recall and uncertainty concerning temporal relationships. This paper uses longitudinal data from the Dunedin Multidisciplinary Health and Development Study to assess risk factors for the development of dental anxiety in persons between the ages of 18 and 26 years. It was hypothesized that psychological factors would be as important as conditioning experiences in the genesis of dental anxiety over this period. The eight-year incidence of dental anxiety was 16.5%. Five variables entered models predicting onset: multiple fears, symptoms of substance dependence, previous experience of invasive dental treatment, dental visiting pattern, and the extraction of one or more teeth. Separate analyses for those avoiding and those using dental services resulted in different explanatory models. These results indicated that both psychological and conditioning variables contributed to the development of dental anxiety in this population of young adults.

Adolescent↗
PubMed2001

IL-1 genotype and adult periodontitis among young New Zealanders.

Several recent studies have investigated the association between interleukin-1 genotype and periodontitis in clinical samples, where generalizability is an issue. The aim of this study was to investigate the association between adult periodontitis and IL-1 genotype in a population-based sample of 26-year-olds. Based on probing depth (PD) measurements, participants were divided into three disease groups: "Severe" (1+ teeth with 5+mm PD; N = 25), "Moderate" (2+ teeth with 4+mm PD; N = 36), and "Controls" (the remainder; N = 800). The "periodontitis-associated genotype" (PAG; Kornman et al., 1997) was present in 20.0% of the "Severe" group and in 34.8% of "Controls", whereas the IL-1A(+4845) [1,1]/IL-1B(+3953) [2,2] genotype was present in 12.0% and 0.9%, respectively. After controlling for sex, smoking status, and plaque levels, we found that those with IL-1B(+3953) [1,1]/IL-1A(+4845) [2,2] had 12.3 times the odds of being in the "Severe" group. Analysis of these data suggests that the IL-1A(+4845) [1,1]/IL-1B(+3953) [2,2] genotype is associated with periodontal disease in this young population. Future periodontal data collections as this cohort ages are required to confirm the predictive value of that genotype.

Adult↗
PubMed2001

Onset of and patterns of change in dental anxiety in adolescence and early adulthood: a birth cohort study.

OBJECTIVE: To assess the onset of and patterns of change in dental anxiety during adolescence and early adulthood. DESIGN: A birth cohort study of 1,037 individuals born in Queen Mary Hospital, Dunedin, New Zealand between 1 April 1972 and 31 March 1973. Data were collected from these individuals at birth, every two years between the ages of 3 and 15 and at 18, 21 and 26 years. STUDY MEMBERS: Data on dental anxiety were obtained at the 15, 18 and 26-year assessments from 678 study members. OUTCOMES: Dental anxiety was assessed using the Dental Anxiety Scale. Study members with a score of 13 or over were classified as being dentally anxious. RESULTS: The prevalence of dental anxiety increased from 10.6% at age 15 years to 13.3% at 18 years and 21.1% at 26 years. Of the 31.2% who were anxious at one or more data collection periods, approximately one third were anxious by the age of 15, one third became anxious between 16 and 18 years and one third between 18 and 26 years. High rates of remission were observed. Of 72 study members who were dentally anxious at 15 years, 22% were persistent cases, anxious at all three data collection points; 24% were recurrent cases, anxious at 26 but not anxious at 18 years; and 54% were remitted cases, no longer anxious at 26 years. There were no gender differences in the onset and course of dental anxiety over the developmental periods observed. CONCLUSIONS: The period of observation was one of instability with respect to anxiety about dental treatment. Early adulthood in particular appeared to be a life stage during which this population was vulnerable to the onset of dental anxiety. This may be related to dental disease and treatment factors, or changing psychological states during significant life transitions.

Adolescent↗
PubMed2000

Users of unconventional practitioners: a profile of 26 year old New Zealanders.

AIMS: To profile 26 year old New Zealand users of unconventional practitioners. METHODS: 977 members of the Dunedin Multidisciplinary Health and Development Study participating in the age-26 assessment (1998-1999) answered questions about twelve-month service use, education, income, recent medical history, current health status and avoidance of medical situations. RESULTS: 10% had used an unconventional practitioner in the previous twelve months. The majority (88%) had also used a conventional practitioner. Those using both types of practitioner were heavy users of health services (twelve visits/year). Compared to those who used conventional practitioners exclusively, they had significantly higher incomes and were more likely to report a serious injury, a current disability, a history of back problems, role limitations due to physical health problems, and more bodily pain (all p < 0.01). CONCLUSIONS: 26 year old New Zealand users of unconventional practitioners have a similar profile to their counterparts in other developed countries. It appears that their health needs are not fully met by conventional services, emphasising the need for more research into the aetiology and treatment of ailments (e.g. back pain) for which unconventional practitioners are commonly sought. The Medical Council of New Zealand guidelines on unconventional medicine are discussed in light of these findings.

Adult↗
PubMed2000

Nutritional supplement use among 26-year-olds.

AIMS: To estimate the prevalence of use of nutritional supplements among young adults, to examine the source of those supplements and to investigate sex differences in usage. METHODS: Participants in the age-26 years assessments of the Dunedin Multidisciplinary Health and Development Study were asked to bring containers for any medication (including supplements) taken in the previous two weeks. Medication data (including prescription source) were recorded and analysed for 978 of 980 Study members. RESULTS: The prevalence of supplement use was 16.6%; 20.4% among females and 13.3% for males (p<0.01). Multivitamin preparations were the most widely consumed, followed by water-soluble vitamin supplements (such as folate and vitamin C). Folate use was higher among females and was taken by 35.7% of pregnant females. Most supplements were self-prescribed, although a doctor had prescribed over one-third of the mineral supplements. Most supplements had been taken for weeks or months, rather than years. CONCLUSIONS: Nutritional supplement usage among young adults is reasonably common, and involves a wide range of preparations. The extent of use among younger people suggests a need for regulation of their manufacture, sale and usage, and research to examine their efficacy.

Adult↗
PubMed2000

Children's self-reported psychotic symptoms and adult schizophreniform disorder: a 15-year longitudinal study.

BACKGROUND: Childhood risk factors for the development of adult schizophrenia have proved to have only modest and nonspecific effects, and most seem unrelated to the adult phenotype. We report the first direct examination of the longitudinal relationship between psychotic symptoms in childhood and adulthood. METHODS: We analyzed prospective data from a birth cohort (N = 761), in which children were asked about delusional beliefs and hallucinatory experiences at age 11 years, and then followed up to age 26 years. Structured diagnostic interviews were employed at both ages and self-report of schizophreniform symptoms was augmented by other data sources at age 26 years. RESULTS: Self-reported psychotic symptoms at age 11 years predicted a very high risk of a schizophreniform diagnosis at age 26 years (odds ratio, 16.4; 95% confidence interval, 3.9-67.8). In terms of attributable risk, 42% of the age-26 schizophreniform cases in the cohort had reported 1 or more psychotic symptoms at age 11 years. Age-11 psychotic symptoms did not predict mania or depression at age 26 years, suggesting specificity of prediction to schizophreniform disorder. The link between child and adult psychotic symptoms was not simply the result of general childhood psychopathology. CONCLUSION: These findings provide the first evidence for continuity of psychotic symptoms from childhood to adulthood.

Adolescent↗
PubMed2000

Dishabituation processes in height fear and dental fear: an indirect test of the non-associative model of fear acquisition.

The fear dishabituation hypothesis described in the non-associative model of fear acquisition was tested in a longitudinal birth cohort study. Results were consistent with height fear and phobia dishabituation. That is, 're-emergence' of a fear of heights occurred between age 11 and 18 years among individuals who reported higher levels of non-specific stress at age 15. Interestingly, there was no evidence for dental fear dishabituation--a finding consistent with the non-associative model of fear acquisition. Strengths and weaknesses of the study were considered and the results discussed in relation to laboratory-based findings on (dis)habituation.

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↗
PubMed2000

Incidence of dental anxiety in young adults in relation to dental treatment experience.

OBJECTIVES: To document the incidence of dental anxiety among individuals aged 18 years at baseline and 26 years at follow-up, and to determine if dental treatment experience continues to play a significant etiological role with respect to the onset of dental anxiety in young adults. METHODS: Dental anxiety scale (DAS; Corah, 1969) scores at ages 15, 18 and 26 were obtained for Study members in the Dunedin Multidisciplinary Health and Development Study. Dental examinations were conducted, and sociodemographic and dental service-use data were collected using a self-report questionnaire. Using a case definition of a DAS score of 13 or more, age 18-26 incident cases were identified and their dental treatment experience and service-use characteristics compared with the remainder. RESULTS: DAS scores at 18 and 26 were available for 792 (80.8%) of the 980 26-year-old Study members. An increase in dental anxiety prevalence was observed over the eight-year period, with an annualized incidence of 2.1%. Fewer incident cases had visited a dentist in the previous eight years, and there were no differences between incident cases and others in their eight-year DFS, FS or tooth-loss increments. A subgroup of "recurrent" cases was identified who were dentally anxious at 15 and 26 but not at 18, and their eight-year incidence of tooth loss due to caries was substantially higher than non-cases. CONCLUSIONS: Aversive conditioning experiences appear to be unrelated to the adult onset of dental anxiety, and it may be that particular temperamental or psychological traits are associated with the condition.

Adolescent↗
PubMed2000

The respiratory effects of cannabis dependence in young adults.

AIM: To evaluate the relationship between cannabis dependence and respiratory symptoms and lung function in young adults, while controlling for the effects of tobacco smoking. SETTING AND PARTICIPANTS: Nine hundred and forty-three young adults from a birth cohort of 1037 subjects born in Dunedin, New Zealand in 1972/1973 were studied at age 21. MEASUREMENTS: Standardized respiratory symptom questionnaires were administered. Spirometry and methacholine challenge tests were undertaken. Cannabis dependence was determined using DSM-III-R criteria. Descriptive analyses and comparisons between cannabis-dependent, tobacco-smoking and non-smoking groups were undertaken. Adjusted odds ratios for respiratory symptoms, lung function and airway hyper-responsiveness (PC20) were measured. FINDINGS: Ninety-one subjects (9.7%) were cannabis-dependent and 264 (28.1%) were current tobacco smokers. After controlling for tobacco use, respiratory symptoms associated with cannabis dependence included: wheezing apart from colds, exercise-induced shortness of breath, nocturnal wakening with chest tightness and early morning sputum production. These were increased by 61%, 65%, 72% (all p < 0.05) and 144% (p < 0.01) respectively, compared to non-tobacco smokers. The frequency of respiratory symptoms in cannabis-dependent subjects was similar to tobacco smokers of 1-10 cigarettes/day. The proportion of cannabis-dependent study members with an FEV1/FVC ratio of < 80% was 36% compared to 20% for non-smokers (p = 0.04). These outcomes occurred independently of co-existing bronchial asthma. CONCLUSION: Significant respiratory symptoms and changes in spirometry occur in cannabis-dependent individuals at age 21 years, even although the cannabis smoking history is of relatively short duration.

Adolescent↗
PubMed2000

A longitudinal study of cannabis use and mental health from adolescence to early adulthood.

AIMS: To examine the longitudinal association between cannabis use and mental health. DESIGN: Information concerning cannabis use and mental health from 15 to 21 years was available for a large sample of individuals as part of a longitudinal study from childhood to adulthood. PARTICIPANTS: Participants were enrolled in the Dunedin Multidisciplinary Health and Development Study, a research programme on the health, development and behaviour of a large group of New Zealanders born between 1 April 1972 and 31 March 1973. MEASUREMENTS: Cannabis use and identification of mental disorder was based upon self-report as part of a general assessment of mental health using a standard diagnostic interview. Daily smoking and alcohol use at age 15 were assessed by self-report. Indices of family socio-economic status, family climate and parent-child interaction were formed using information gathered from parent report and behavioural observations over early childhood. Childhood behaviour problems were assessed by parent and teacher report. Attachment to parents was assessed in adolescence. FINDINGS: Cross-sectional associations between cannabis use and mental disorder were significant at all three ages. Both outcome variables shared similar pathways of low socio-economic status and history of behaviour problems in childhood, and low parental attachment in adolescence. Mental disorder at age 15 led to a small but significantly elevated risk of cannabis use at age 18; by contrast, cannabis use at age 18 elevated the risk of mental disorder at age 21. The latter association reflected the extent to which cannabis dependence and other externalizing disorders at age 21 were predicted by earlier level of involvement with cannabis. CONCLUSIONS: The findings suggest that the primary causal direction leads from mental disorder to cannabis use among adolescents and the reverse in early adulthood. Both alcohol use and cigarette smoking had independent associations with later mental health disorder.

Adolescent↗
PubMed1999

Twins and maternal smoking: ordeals for the fetal origins hypothesis? A cohort study.

OBJECTIVE: To assess the direct and indirect effects of being a twin, maternal smoking, birth weight, and mother's height on blood pressure at ages 9 and 18 years. DESIGN: Longitudinal study. SUBJECTS: Cohort born in 1972-3. SETTING: Dunedin, New Zealand. MAIN OUTCOME MEASURE: Blood pressure at ages 9 and 18 years. RESULTS: Compared with singletons, twins had a systolic blood pressure 4.55 (95% confidence interval 1.57 to 7.52) mm Hg lower at age 9 after adjustment for direct and indirect effects of sex, maternal smoking, mother's height, socioeconomic status, and birth weight, as well as concurrent height and body mass index. Blood pressure in children whose mothers had smoked during pregnancy was 1.54 (0.46 to 2.62) mm Hg higher than in those whose mothers did not. The total effect of birth weight on systolic blood pressure at age 9 was -0.78 (-1.76 to 0.20) mm Hg and that for mother's height was 0.10 (0.06 to 0.14) mm Hg. Similar results were obtained for systolic blood pressure at age 18. The total effect of twins, maternal smoking, and birth weight on diastolic blood pressure was not significant at either age. CONCLUSIONS: Twins had lower birth weight and lower systolic blood pressure at ages 9 and 18 than singletons. This finding challenges the fetal origins hypothesis. The effect of maternal smoking was consistent with the fetal origin hypothesis in that the infants of smokers were smaller and had higher blood pressure at both ages. This may be explained by pharmacological rather than nutritional effects. The total effect of birth weight on systolic blood pressure, after its indirect effect working through concurrent measures of height and body mass index was taken into account, was small.

Adolescent↗
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↗