Biomedical subjects

Rosalind J Neuman

Publications and source records attributed to Rosalind J Neuman.

At least 19 recordsLinked to original sources

PubMed2006

Prenatal smoking exposure and dopaminergic genotypes interact to cause a severe ADHD subtype.

BACKGROUND: In utero exposure to smoking and alcohol are common risk factors that have been associated with attention-deficit/hyperactivity disorder (ADHD) in human beings and animal models. Furthermore, molecular studies have focused on the association between ADHD and DNA polymorphisms in dopamine pathway-related genes. We examined the joint effects of genetic and prenatal substance exposures on DSM-IV and population-defined subtypes of ADHD. METHODS: Logistic regression was used to assess the relationship between ADHD subtypes, DAT1 and DRD4 polymorphisms, and prenatal substance exposures in a birth-record sample of male and female twin pairs, aged 7-19 years. RESULTS: Interactions between prenatal exposure to smoking and variations in the DAT1 and DRD4 loci were observed in children with either the DSM-IV or population-defined ADHD combined subtypes. The odds of a diagnosis of DSM-IV combined subtype was 2.9 times greater in twins who had inherited the DAT1 440 allele and who were exposed, than in unexposed twins without the risk allele. The OR was 2.6 in the population-defined subtype. Odds ratios for the DRD4 seven-repeat allele were 3.0 (2.8) in the population-defined (DSM-IV) combined ADHD subtypes. The OR for exposed children with both alleles was 9.0 (95% confidence interval=2.0-41.5) for the population-defined combined subtypes. CONCLUSIONS: Results indicate that smoking during pregnancy is associated with specific subtypes of ADHD in genetically susceptible children.

Adolescent↗

PubMed2006

Validation of population-based ADHD subtypes and identification of three clinically impaired subtypes.

Statistically based classification methods have successfully refined ADHD into homogenous and heritable subtypes. External validity and impairment of these subtypes was examined using the Child Behavior Checklist (CBCL). We compared mean CBCL syndrome and competency t-scores across ADHD subtypes defined by latent class analysis in a sample of 1,346 individual twins from Missouri. The potential for comorbidity with conduct disorder (CD), oppositional defiant disorder (ODD), or major depression (MD) to increase impairment in specific ADHD subtypes was also examined. CBCL profiles confirm differences in severity, with more severe classes having increased syndrome scale and decreased competency scale CBCL scores. Clinically significant impairment was found for severe inattentive and combined subtypes and the mild combined subtype. Overall, the presence of comorbid CD, ODD, or MD did not result in increased ADHD subtype impairment. CBCL scores distinguish impairment in ADHD subtypes created through LCA. Comorbidity with CD, ODD, or MD does not significantly increase impairment among ADHD subtypes. The mild combined ADHD subtype represents a clinically significant but under-studied form of ADHD.

Adolescent↗

PubMed2006

Lifetime psychiatric comorbidity of alcohol dependence and bulimia nervosa in women.

Previous work from our group revealed two groups of women with bulimia nervosa (BN), one with, and one without alcohol dependence (AD). The current study sought to determine whether women with lifetime BN and AD (BN+AD+) were more similar to women with BN and no AD (BN+AD-) or to women with AD and no BN (BN-AD+) in terms of lifetime psychiatric comorbidity and psychological functioning. Data on BN and AD from 407 female relatives in a family study of alcoholism were used to create three mutually exclusive groups: BN+AD+ (n=30), BN+AD- (n=55), and BN-AD+ (n=322). Bivariate analyses revealed fewer differences between BN+AD+ and BN-AD+ women than between BN+AD+ and BN+AD- women. BN+AD+ women were more likely than BN+AD- women to have drug dependence, conduct disorder, and suicidality, and were more likely to have major depression, lower GAF scores, and to engage in unsafe sex than both BN+AD- and BN-AD+ women. After adjusting for other psychopathology and demographic variables, BN+AD+ women were more likely than BN+AD- women to have major depression, drug dependence, and tobacco dependence and more likely than BN-AD+ women to have major depression and obsessive-compulsive disorder. These results suggest that BN+AD+ women exhibit more severe psychopathology than either BN+AD- or BN-AD+ women and may represent a distinct subgroup within bulimia nervosa or alcohol dependence.

Adult↗

PubMed2006

A comparison of the latent class structure of cannabis problems among adult men and women who have used cannabis repeatedly.

BACKGROUND: Little empirical evidence exists to determine if there are alternative classification schemes for cannabis abuse and dependence beyond the definitions provided by Diagnostic and Statistical Manual (DSM) criteria. Current evidence is not conclusive regarding gender differences for cannabis use, abuse and dependence. It is not known if symptom profiles differ by gender. METHODS: Latent class analysis (LCA) was used to assess whether cannabis abuse and dependence symptom patterns suggest a severity spectrum or distinct subtypes and to test whether symptom patterns differ by gender. Data from 3312 men and 2509 women in the National Longitudinal Alcohol Epidemiologic Survey (NLAES) who had used cannabis 12 + times life-time were included in the present analyses. The comparability of the solutions for men and women was examined through likelihood ratio chi(2) tests. RESULTS: Based on the Bayesian information criterion and interpretability, a four-class solution was selected, and the classes were labeled as 'unaffected/mild hazardous use', 'hazardous use/abuse', 'abuse/moderate dependence' and 'severe abuse/dependence'. The solutions were generally suggestive of a severity spectrum. Compared to men, women were more likely to be in the 'unaffected/mild hazardous use' class and less likely to be in the 'abuse/moderate dependence' or 'severe abuse/dependence' classes. The results were generally similar for men and women. However, men had consistently and substantially higher endorsements of hazardous use than women, women in the 'abuse/moderate dependence' class had moderately higher rates for four dependence symptoms, and women in two of the classes were more likely to endorse withdrawal. CONCLUSION: Our findings generally support the severity dimension for DSM-IV cannabis abuse and dependence symptomatology for both men and women. While our results indicate that public health messages may have generic and not gender-specific content, treatment providers should focus more effort on reducing hazardous use in men and alleviating withdrawal in women.

Adolescent↗

PubMed2006

The latent class structure of ADHD is stable across informants.

Previous studies have looked at the structure of attention-deficit/hyperactivity disorder (ADHD) using latent class analysis (LCA) of Child Behavior Checklist (CBCL) or Diagnostic and Statistical Manual of Mental Disorders (DSM) symptom structure. These studies have identified distinct classes of children with inattentive, hyperactive, or combined subtypes and have used these classes to refine genetic analyses. The objective of the current report is to determine if the latent class structure of ADHD subtypes is consistent across informant using the Conners' Rating Scales (CRS). LCA was applied to CRS forms from mother, father, and teacher reports of 1837, 1329 and 1048 latency aged Dutch twins, respectively. The optimal solution for boys was a 5-class solution for mothers, a 3-class solution for fathers, and a 4-class solution for teachers. For girls, a 4-class solution for mothers and a 3-class for fathers and teachers was optimal. Children placed into a class by one informant had markedly increased odds ratio of being placed into the same or similar class by the other informants. Results from LCA using Dutch twins with the CRS show stability across informants suggesting that more stable phenotypes may be accessible for genotyping using a multi-informant approach.

Adult↗

PubMed2005

Genetic analysis of the maximum drinks phenotype.

Using data provided by the Collaborative Study on the Genetics of Alcoholism we studied the genetics of a quantitative trait: the maximum number of drinks consumed in a 24-hour period. A two-stage method was used. First, linkage analysis was performed, followed by association analysis in regions where linkage was detected. Additionally, the extent of linkage disequilibrium among single-nucleotide polymorphisms (SNP) associated with the phenotype was assessed. Linkage to chromosomes 2 and 7 was detected, and follow-up association analysis found multiple trait-associated SNPs in the chromosome 7 linkage region. Chromosome 4, which has been implicated in previous studies of the maximum drinks phenotype, did not pass our threshold for linkage evidence in stage 1, but secondary analyses of this chromosome indicated modest evidence for both linkage and association. The evidence suggests that chromosome 7 may harbor an additional locus influencing the maximum drinks consumption phenotype.

Alcohol Drinking↗

PubMed2005

Brain-derived neurotrophic factor and autoantibodies to neural antigens in sera of children with autistic spectrum disorders, Landau-Kleffner syndrome, and epilepsy.

BACKGROUND: Brain derived neurotrophic factor (BDNF) elevation in newborn sera predicts intellectual/social developmental abnormalities. Other autoantibodies (AAs) to endothelial cells (ECs) and myelin basic protein (MBP) are also elevated in some children. We tested relationships between BDNF, BDNF AAs, and other AAs in children with these disorders. METHODS: BDNF levels and IgG/IgM autoantibodies to BDNF, ECs, MBP, and histones were measured in children with autism, childhood disintegrative disorder (CDD), pervasive developmental delay-not otherwise specified (PDD-nos), acquired epilepsy, Landau-Kleffner syndrome (LKS); healthy children (HC), and children with non-neurological illnesses (NNI). RESULTS: Mean BDNF levels were elevated in children with autism and CDD, (p < or = 0.0002) compared to HC or NNI. Mean IgG and IgM BDNF AAs were elevated in children with autism, CDD and epilepsy (p < or = 0.0005) compared to HC but not to NNI. Mean IgM AA EC titers detected by immunocytochemistry were higher in autism, PDD-NOS, epilepsy, and LKS (p < or = 0.005) compared to HC and NNI. While mean ELISA IgG EC AAs were higher in autism and PPD-NOS (p < 0.005) compared to HC but not NNI, ELISA IgM EC AAs were higher in children with autism, CDD, PDD-NOS, and epilepsy compared to both HC and NNI (p < 0.0005). Mean anti-MBP IgG and IgM titers were higher in all study groups (p < 0.005) except for LKS compared to both HC and NNI. CONCLUSION: Children with developmental disorders and epilepsy have higher AAs to several neural antigens compared to controls. The presence of both BDNF AAs and elevated BDNF levels in some children with autism and CDD suggests a previously unrecognized interaction between the immune system and BDNF.

Antibodies, Antinuclear↗

PubMed2005

Are there subgroups of bulimia nervosa based on comorbid psychiatric disorders?

OBJECTIVE: The current study sought to determine whether there are subtypes of bulimia nervosa (BN) differentiated by comorbid psychiatric disorders. METHOD: Data on comorbid psychiatric diagnoses in female relatives of probands and controls in the Collaborative Study of the Genetics of Alcoholism (COGA) who met criteria for BN (as outlined in the 3rd Rev. ed. of the Diagnostic and Statistical Manual of Mental Disorders) were analyzed using latent class analysis. Resulting latent classes were compared on a variety of variables related to impulsive behaviors and psychological functioning. RESULTS: The best-fitting solution, a two-class model, yielded one class (72%) characterized by substance dependence, depression, antisocial personality disorder (ASPD), and anxiety disorders, and another characterized by depression. The highly comorbid class had more suicidality, more daily smokers, sought help for emotional problems, and had lower Global Assessment of Functioning (GAF) scores compared with those in the comorbid depression only class. DISCUSSION: Latent class findings suggest the existence of two classes of BN differentiated by substance dependence, impulsive behaviors, and poorer psychological functioning.

Adult↗

PubMed2005

A systematic evaluation of ADHD and comorbid psychopathology in a population-based twin sample.

OBJECTIVE: Clinical and population samples demonstrate that attention-deficit/hyperactivity disorder (ADHD) occurs with other disorders. Comorbid disorder clustering within ADHD subtypes is not well studied. METHOD: Latent class analysis (LCA) examined the co-occurrence of DSM-IV ADHD, oppositional defiant disorder (ODD), conduct disorder (CD), and depression symptoms in a population twin sample. The authors fit separate models for ADHD and comorbid disorder symptoms. Twin concordance ratios (monozygotic versus dizygotic) were compared examining genetic influence on class membership. RESULTS: LCA of ADHD symptoms resulted in seven classes including inattentive, combined, and hyperactive subtypes in 1,616 subjects. The few ADHD symptoms (53.4%) and severe inattentive (12.3%) classes were most frequent. LCA of ODD, CD, and depression symptoms in 1,587 subjects revealed five classes including ODD (19.4%), depression (14.5%), and two composite classes: ODD/CD (6.9%) and ODD/CD/depression (7.2%). Internalizing and externalizing comorbid disorders were present across all ADHD subtypes. Odds ratios (ORs) for twin concordance indicate genetic influence on severe inattentive (OR = 4.18; 95% confidence interval [CI], 1.52-11.53) and combined (OR = 5.25; 95% CI, 1.32-20.78) ADHD classes and ODD (OR = 1.49; 95% CI, 0.70-3.17), ODD/CD (OR = 3.32; 95% CI, 0.57-19.28), and ODD/CD/depression (OR = 1.20; 95% CI, 0.30-4.77) classes. CONCLUSIONS: Internalizing and externalizing disorders did not cluster differentially within ADHD subtypes. LCA may provide a more precise characterization of comorbidity with ADHD.

Adolescent↗

PubMed2005

Collaborative analysis of DRD4 and DAT genotypes in population-defined ADHD subtypes.

BACKGROUND: It has been proposed that some of the variability in reporting of associations between attention deficit hyperactivity disorder (ADHD) and candidate genes may result from mixing of genetically heterogeneous forms of ADHD using DSM-IV criteria. The goal of the current study is to test whether population-based ADHD subtypes defined by latent class analysis help resolve issues of variable findings across individual gene association studies. METHODS: Three studies which had previously reported no associations between polymorphisms of the DRD4 and DAT genes and DSM-IV defined ADHD were reanalyzed using population-based and DSM-IV defined ADHD subtypes. RESULTS: Across studies no significant associations were found for either DRD4 or DAT polymorphisms using DSM-IV ADHD subtypes. In contrast, a significant association was found between the combined data set for the 440 base pair 3' DAT VNTR polymorphism and population-defined severe combined ADHD (OR=1.25, p=.01). A marginally significant association was also found between the 7 repeat DRD4 allele and population-defined severe combined ADHD. CONCLUSION: Use of alternative population-based defined ADHD subtypes may help resolve some of the variable results presented for candidate gene association studies in ADHD.

Adolescent↗

PubMed2005

Estimation of prevalence of DSM-IV and latent class-defined ADHD subtypes in a population-based sample of child and adolescent twins.

The goal of this study is to determine the prevalence and age of onset of Diagnostic and Statistical Manual of Mental Disorders and latent class-derived attention deficit/hyperactivity disorder (ADHD) subtypes in a population-based twin sample of boys and girls. Missouri birth records identified families with a twin pair 7 to 18 years of age. Telephone screening interviews for ADHD symptoms were completed for 5007 families. Diagnostic assessments were administered to 564 families with at least one twin meeting screening criteria, plus 183 control families. Prevalence and age of onset for both ADHD nosologies were calculated by sex and zygosity from parent report data. The prevalence of any DSM-IV ADHD was 6.2% overall, 7.4% in boys and 3.9% in girls. The inattentive subtype was most common in boys; the combined subtype was most common in girls. The mean age of onset of symptoms in children with any DSM-IV ADHD was 3.5 years, with no significant differences between boys and girls. Prevalences of latent class defined ADHD subtypes also varied by sex with the severe inattentive and combined classes more common in boys than girls. The age of onset of symptoms did not differ between boys and girls but were higher than in the DSM-IV subtypes. Findings in this twin sample showed that clinically significant ADHD, defined by either DSM-IV or latent class criterion, has an early age of onset and is more common in boys than girls. As clinical samples are most commonly composed of male combined subtypes, the inattentive subtype of both sexes in the general population is an under-treated segment of the general population.

Adolescent↗

PubMed2005

Comorbidity between ADHD and symptoms of bipolar disorder in a community sample of children and adolescents.

The prevalence and frequency of comorbidity of possible bipolar disorder was examined with attention-deficit hyperactivity disorder (ADHD) in a nonreferred population of twins. Children and adolescents aged 7 to 18 years with a history of manic symptoms were identified from a population-based twin sample obtained from state birth records (n = 1610). The sample was enriched for ADHD; however, there was also a random control sample (n = 466), which allowed a look at the population prevalence of the disorder. Juveniles with threshold or below threshold manic episodes were further assessed for comorbidity with Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) and population-defined ADHD subtypes (from latent class analysis) using Fisher's exact test. Nine juveniles who exhibited DSM-IV manic (n = 1), hypomanic (n = 2) or below threshold episodes (n = 6) were identified. The population prevalence of broadly defined mania in the random sample was 0.2%. The possible manic episodes showed significant comorbidity with population-defined severe combined and talkative ADHD subtypes. It can be concluded that there is a significant association of bipolar symptoms with two population-defined subtypes of ADHD. Episodes of possible bipolar disorders as defined by DSM-IV are uncommon in this nonreferred sample. Children and adolescents with ADHD appear to be only modestly at increased risk for bipolar disorders.

Adolescent↗

PubMed2005

Limitations of DSM-IV operationalizations of alcohol abuse and dependence in a sample of Australian twins.

Alcohol abuse and dependence are among the most common psychiatric conditions identified in epidemiological surveys of the general population. The aim of this article is to examine the psychometric properties of Diagnostic and Statistical Manual of Mental Disorders, (4th ed.; DSM-IV; American Psychiatric Association, 1994) criteria for alcohol abuse and dependence using latent class analysis (LCA). Six thousand two hundred and sixty-five young Australian twins (median age 30 years) were interviewed by telephone between 1996 and 2000 using a modified version of the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA). DSM-IV symptoms of alcohol abuse and dependence were collected by structured diagnostic interview and analyzed using methods of LCA. LCA revealed a 4-class solution for women that classified individuals according to the severity of their alcohol-related problems: no/few problems (66.5%), heavy drinking (23.9%), moderate dependence (7.6%) and severe dependence (2.0%). Among men the preferred solution included 5 classes corresponding to no/few problems (46.4%), heavy drinking (34.3%), moderate dependence (12.2%), severe dependence (3.0%) and abuse (4.0%). Evidence of a male-specific class of alcohol-related problems corresponding to abuse partially supports the DSM conceptualization of alcohol use disorders but suggests that this conceptualization--and measurement--may need to be refined for women. Identification of a male-specific abuse class also has important implications for interventions and treatment as these individuals experienced significant alcohol-related problems and comprised approximately 21% of all men classified with an alcohol use disorder.

Adult↗

PubMed2004

Familial clustering of latent class and DSM-IV defined attention-deficit/hyperactivity disorder (ADHD) subtypes.

BACKGROUND: Findings from family and twin-based studies of Attention Deficit/Hyperactivity Disorder (ADHD) have indicated that inattentive and combined subtypes cluster together among sibling pairs who both express ADHD symptoms. The current report examines the familial clustering of ADHD subtypes, defined according to latent class and DSM-IV criteria, in a general population sample of 2,848 Australian twins, 1,013 of their non-twin siblings and 4,036 female twins from Missouri, USA. Significant clustering of DSM-IV inattentive and combined subtypes, and significant clustering of the same latent classes among siblings was predicted. METHOD: Logistic regression was used to assess 1) the clustering of same and different subtype combinations among twin and twin-sibling pairs and 2) whether genetic influences contribute significantly to the observed patterns of subtype combinations among siblings. RESULTS: With the exception of the DSM-IV hyperactive-impulsive subtype and the severe hyperactive-impulsive latent class, all other sibling DSM-IV and latent class ADHD subtypes consistently exhibited significant same-subtype clustering with MZ probands, DZ probands and their siblings in both samples. Furthermore, a significant genetic influence contributing to subtype concordance was detected for every DSM-IV subtype excluding hyperactive-impulsive, and for all eight latent classes. While some instances of significant different-subtype clustering among siblings was observed across both classification systems and samples, the particular subtype combinations involved were largely inconsistent across samples and no significant genetic influences contributing towards these discordant subtype combinations were detected. CONCLUSIONS: For both DSM-IV and latent class subtypes, the overall pattern of findings in both samples indicated significant familial clustering of same-subtype combinations and significant genetic influences contributing to these patterns of subtype concordance, despite important sample differences. These findings further extend previous work and are most consistent with the presence of multiple independent forms of ADHD.

Adolescent↗

PubMed2003

Genetic analysis of maximum cigarette-use phenotypes.

BACKGROUND: Using the Framingham Heart Study data set provided for Genetic Analysis Workshop 13, we defined the cigarette-use phenotype M for smokers to be the maximum number of cigarettes-per-day (MAXCIG) reported over the longitudinal course of the study. Adjustments were made for the significant covariates of gender and year of birth, and sib-pair based linkage analysis was performed. RESULTS: The primary analyses, in which individuals with MAXCIG = 0 were considered to have missing phenotype, resulted in modest linkage evidence, with LOD scores over 1 on chromosomes 5, 9, 13, 14, and 22. CONCLUSIONS: While the results reported here do not indicate definitive evidence for linkage to specific chromosomal regions, future studies may find it useful to include direct assessments of maximum and quantitative cigarette use. In defining and analyzing quantitative or "maximum use" phenotypes, the choice of how to handle individuals with MAXCIG = 0, or alternatively, individuals who are substance-naive, is a crucial one for genetic studies of nicotine and other substance use. In this study, the linkage results vary greatly depending on whether or not these "unexposed" individuals are included in the analyses.

Adult Children↗

PubMed2003

Reliability and stability of a semistructured DSM-IV interview designed for family studies.

OBJECTIVE: To determine the interrater reliability and stability of diagnoses, and to compare the results of in-person versus telephone administration of the Missouri Assessment of Genetics Interview for Children (the MAGIC), a new, semistructured, glossary-based diagnostic interview for children and adolescents. METHOD: The interview was developed for a large-scale epidemiological family genetics study. For reliability measures, parent report on offspring, child self-report, and adolescent self-report interviews were independently scored by two different raters on a population-based sample of respondents. The stability of diagnoses was assessed by comparing repeat interviews of parents, children, and adolescents, separated on average by 13 months. Frequencies of parent and adolescent report of disorders were determined for telephone and in-person interviews. RESULTS: High interrater reliabilities were achieved for individual DSM-IV symptoms and diagnoses and for individual characteristics of diagnostic domains, including number, clustering, duration, and impairment of symptoms. The stability of diagnoses was also high for parents and adolescents. No significant differences in the prevalence of attention-deficit/hyperactivity disorder and major depressive disorder were found for interviews administered in person or by telephone. CONCLUSIONS: The MAGIC demonstrates high interrater reliability and stability for DSM-IV symptoms and diagnoses.

Adolescent↗

PubMed2003

Age and birth cohort effects on rates of alcohol dependence.

BACKGROUND: Epidemiological studies of traits such as alcohol dependence and depression have often found lifetime rates in younger individuals exceeding those found in older individuals. This suggests additional influences of birth cohort or period effects so that individuals in later-born cohorts have an increased lifetime risk. METHODS: Data from the Collaborative Study on the Genetics of Alcoholism were used to investigate secular trends for alcoholism and related conditions and to examine risk predictors while taking the cohort effect into account. We used data on 4099 interviewed parents and siblings of alcohol-dependent subjects and 1054 members of control families. We used survival analysis techniques and the Cox proportional hazards regression model to estimate the relative risk for demographic covariates. We used the relative sample to predict risk in the sibling of the proband and family history information to determine whether there was a bias when deceased individuals were excluded from analysis. RESULTS: In the control sample, we observed a 1.8% lifetime rate of DSM-III-R alcohol dependence in women born before 1940, as contrasted to a 13% rate in women born after 1960, and a 15% lifetime rate in men born before 1940, contrasted with a 28% rate in men born after 1960. As expected, lifetime rates in relatives were increased when compared with controls. Highly significant risk ratios (RR) were observed for gender (RR, 2.3), cohort of birth (RR, 1.5 over a decade), daily smoking (RR, 2.0), heavy smoking (RR, 3.0), and comorbid diagnoses of antisocial personality (RR, 2.2) and depression (RR, 1.6). Analysis of the family history data indicated higher rates of alcohol dependence in relatives who were deceased compared to those who were living. CONCLUSIONS: Marked cohort differences were observed and may reflect real changes over time, or artifacts of memory recall, differential mortality, or public awareness. The analysis of all relatives (living or deceased) indicates that associated mortality may, in part, explain the secular trends seen when analyses are restricted to living, personally interviewed individuals.

Adolescent↗

PubMed2003

Reliability and stability of mothers' reports about their pregnancies with twins.

The objective of this study was to determine if mothers' retrospective reports about events in their pregnancies with twins are reliable and stable. Six hundred and twenty-four mothers completed psychiatric interviews about their twins. These interviews also contained questions about the mothers' pregnancies, the perinatal period, and the child's early development. The mothers reported first on one twin and then on the other with interviews spaced from 3 days to 2 weeks apart. Thus mothers reported on the same pregnancy twice. Of these mothers, 47 were re-interviewed 6 to 18 months later by raters blind to the results of the initial interview. The twin design allowed us to compare the short-term reliability of the 624 mothers' reports of the same pregnancy. The re-interview of the 47 mothers enabled us to compare the stability of reports over a longer time period. Agreement between the reports was measured with the kappa statistic. Kappas were good to excellent for the short-term reports of pregnancy for each twin for the 624 mothers. Kappas were equally high for the 47 mothers that were re-interviewed 6 to 18 months later. Mothers show good reliability and stability of reporting about events during pregnancy.

Female↗