• Traumatic Brain Injury and Schizophrenia in Members of Schizophrenia and Bipolar Disorder Pedigrees

      Malaspina, Dolores; Goetz, Raymond R.; Friedman, Jill Harkavy; Kaufmann, Charles A.; Faraone, Stephen V.; Tsuang, Ming; Cloninger, C. Robert; Nurnberger, John I.; Blehar, Mary C. (American Psychiatric Association Publishing, 2001-03)
      Objective: Schizophrenia following a traumatic brain injury could be a phenocopy of genetic schizophrenia or the consequence of a gene-environment interaction. Alternatively, traumatic brain injury and schizophrenia could be spuriously associated if those who are predisposed to develop schizophrenia have greater amounts of trauma for other reasons. The authors investigated the relationship between traumatic brain injury and psychiatric diagnoses in a large group of subjects from families with at least two biologically related first-degree relatives with schizophrenia, schizoaffective disorder, or bipolar disorder. Method: The Diagnostic Interview for Genetic Studies was used to determine history of traumatic brain injury and diagnosis for 1,275 members of multiplex bipolar disorder pedigrees and 565 members of multiplex schizophrenia pedigrees. Results: Rates of traumatic brain injury were significantly higher for those with a diagnosis of schizophrenia, bipolar disorder, and depression than for those with no mental illness. However, multivariate analysis of within-pedigree data showed that mental illness was related to traumatic brain injury only in the schizophrenia pedigrees. Independent of diagnoses, family members of those with schizophrenia were more likely to have had traumatic brain injury than were members of the bipolar disorder pedigrees. The members of the schizophrenia pedigrees also failed to show the gender difference for traumatic brain injury (more common in men than in women) that was expected and was present in the bipolar disorder pedigrees. Subjects with a schizophrenia diagnosis who were members of the bipolar disorder pedigrees (and thus had less genetic vulnerability to schizophrenia) were less likely to have had traumatic brain injury (4.5%) than were subjects with schizophrenia who were members of the schizophrenia pedigrees (and who had greater genetic vulnerability to schizophrenia) (19.6%). Conclusions: Members of the schizophrenia pedigrees, even those without a schizophrenia diagnosis, had greater exposure to traumatic brain injury compared to members of the bipolar disorder pedigrees. Within the schizophrenia pedigrees, traumatic brain injury was associated with a greater risk of schizophrenia, consistent with synergistic effects between genetic vulnerability for schizophrenia and traumatic brain injury. Posttraumatic-braininjury schizophrenia in multiplex schizophrenia pedigrees does not appear to be a phenocopy of the genetic disorder.
    • Impact of Tic Disorders on ADHD Outcome Across the Life Cycle: Findings From a Large Group of Adults With and Without ADHD

      Spencer, Thomas J.; Biederman, Joseph; Faraone, Stephen V.; Mick, Eric; Coffey, Barbara; Geller, Daniel; Kagan, Jake; Bearman, Sarah Kate; Wilens, Timothy (American Psychiatric Association Publishing, 2001-04)
      Objective: The impact of tic disorders on the outcome of attention deficit hyperactivity disorder (ADHD) remains a subject of high scientific and clinical interest. To evaluate the impact of comorbid ADHD and tic disorders from a lifespan perspective, the authors systematically examined data from adults with and without ADHD. Method: They comprehensively evaluated 312 consecutively referred adults with ADHD and 252 comparison subjects without ADHD. Tic disorders were characterized along with a wide range of neuropsychiatric correlates, including other comorbid disorders as well as indexes of function in the domains of school, cognition, and interpersonal functioning. Results: A significantly greater proportion of adults with ADHD (12%) than those without ADHD (4%) had tic disorders. Tic disorders followed a mostly remitting course and had little impact on functional capacities. In addition, tic disorders were not associated with stimulant use. Conclusions: These findings in adults with ADHD confirm and extend previous findings in young subjects with ADHD, documenting that although individuals with ADHD are at greater risk for tic disorders, the presence of tic disorders has a limited impact on ADHD outcome.
    • Meta-Analysis of the Association Between the 7-Repeat Allele of the Dopamine D4Receptor Gene and Attention Deficit Hyperactivity Disorder

      Faraone, Stephen V.; Doyle, Alysa E.; Mick, Eric; Biederman, Joseph (American Psychiatric Association Publishing, 2001-07)
      Objective: Family, twin, and adoption studies show attention deficit hyperactivity disorder (ADHD) to have a substantial genetic component. Although several studies have shown an association between ADHD and the 7-repeat allele of the dopamine D4 receptor gene (DRD4), several studies have not. Thus, the status of the ADHD-DRD4 association is uncertain. Method: Meta-analysis was applied to case-control and family-based studies of the association between ADHD and DRD4 to assess the joint evidence for the association, the influence of individual studies, and evidence for publication bias. Results: For both the case-control and family-based studies, the authors found 1) support for the association between ADHD and DRD4, 2) no evidence that this association was accounted for by any one study, and 3) no evidence for publication bias. Conclusions: Although the association between ADHD and DRD4 is small, these results suggest that it is real. Further studies are needed to clarify what variant of DRD4 (or some nearby gene) accounts for this association.
    • Lack of Association Between Parental Alcohol or Drug Addiction and Behavioral Inhibition in Children

      Biederman, Joseph; Hirshfeld-Becker, Dina R.; Rosenbaum, Jerrold F.; Perenick, Sarah G.; Wood, Julia; Faraone, Stephen V. (American Psychiatric Association Publishing, 2001-10)
      Objective: “Behavioral inhibition to the unfamiliar” has been proposed as a precursor to anxiety. A recent study proposed that it may also be a precursor to alcoholism. The authors sought to replicate the latter finding through a secondary analysis of data from a large study of young children (age 2–6 years)—offspring of parents with panic and depressive disorders—who had been assessed for behavioral inhibition through laboratory-based observations. Method: The offspring were stratified on the basis of presence or absence of parental lifetime history of DSM-III-R alcohol dependence (N=115 versus N=166, respectively) or drug dependence (N=78 versus N=203). The rates of behavioral inhibition were then compared between groups. Results: Despite adequate power to detect associations, neither parental alcohol dependence nor drug dependence was associated with a higher risk for behavioral inhibition in the offspring. Conclusions: These results are not consistent with the hypothesis linking behavioral inhibition to addictions
    • Further Evidence of Association Between Behavioral Inhibition and Social Anxiety in Children

      Biederman, Joseph; Hirshfeld-Becker, Dina R.; Rosenbaum, Jerrold F.; Hérot, Christine; Friedman, Deborah; Snidman, Nancy; Kagan, Jerome; Faraone, Stephen V. (American Psychiatric Association Publishing, 2001-10)
      Objective: The authors sought to examine psychopathological correlates of behavioral inhibition in young offspring of parents with panic disorder and/or major depression. Method: Behavioral inhibition, determined by using standard laboratory observations, was assessed in four groups of children (age 2–6 years): 129 children of parents with both panic disorder and major depression, 22 children of parents with panic disorder alone, 49 children of parents with major depression alone, and 84 comparison children of parents with neither panic disorder nor major depression. Psychopathology in children ≥5 years was compared between children with behavioral inhibition (N=64) and without (N=152). Results: Social anxiety disorder (social phobia or avoidant disorder) was significantly more likely to be found in the children with behavioral inhibition (17%) than in those without (5%). Noninhibited children were significantly more likely than inhibited children to have disruptive behavior disorders (20% versus 6%, respectively) and had higher scores on the attention problems scale of the Child Behavior Checklist (mean=52.1 versus 50.8). Conclusions: This study adds to the growing literature suggesting an association between behavioral inhibition and social anxiety disorder and an inverse relationship between inhibition and disruptive behavior disorders.
    • Separating Attention Deficit Hyperactivity Disorder and Learning Disabilities in Girls: A Familial Risk Analysis

      Doyle, Alysa E.; Faraone, Stephen V.; DuPre, Emily P.; Biederman, Joseph (American Psychiatric Association Publishing, 2001-10)
      Objective: Familial risk analysis was used to clarify the relationship in girls between attention deficit hyperactivity disorder (ADHD) and learning disabilities in either mathematics or reading. Method: The authors assessed the presence of ADHD and learning disabilities in 679 first-degree relatives of three groups of index children: girls with ADHD and a comorbid learning disability, girls with ADHD but no learning disabilities, and a comparison group of girls without ADHD. Results: The risk for ADHD was similarly higher in families of ADHD probands with and without learning disabilities; both groups had significantly higher rates of ADHD than did families of the comparison girls. In contrast, only among relatives of ADHD probands with a learning disability was there a higher risk for learning disabilities. A strong (although statistically nonsignificant) difference emerged that suggested at least some degree of cosegregation of ADHD and learning disabilities in family members. There was no evidence of nonrandom mating between spouses with ADHD and learning disabilities. Conclusions: These results extend previously reported findings regarding the relationship of ADHD and learning disabilities to female subjects and raise the possibility that, in girls, the relationship between ADHD and learning disabilities is due to shared familial risk factors.
    • Influence of Gender on Attention Deficit Hyperactivity Disorder in Children Referred to a Psychiatric Clinic

      Biederman, Joseph; Mick, Eric; Faraone, Stephen V.; Braaten, Ellen; Doyle, Alysa; Spencer, Thomas; Wilens, Timothy E.; Frazier, Elizabeth; Johnson, Mary Ann (American Psychiatric Association Publishing, 2002-01)
      Objective: The substantial discrepancy in the male-to-female ratio between clinic-referred (10 to 1) and community (3 to 1) samples of children with attention deficit hyperactivity disorder (ADHD) suggests that gender differences may be operant in the phenotypic expression of ADHD. In this study the authors systematically examined the impact of gender on the clinical features of ADHD in a group of children referred to a clinic. Method: The study included 140 boys and 140 girls with ADHD and 120 boys and 122 girls without ADHD as comparison subjects. All subjects were systematically assessed with structured diagnostic interviews and neuropsychological batteries for subtypes of ADHD as well as emotional, school, intellectual, interpersonal, and family functioning. Results: Girls with ADHD were more likely than boys to have the predominantly inattentive type of ADHD, less likely to have a learning disability, and less likely to manifest problems in school or in their spare time. In addition, girls with ADHD were at less risk for comorbid major depression, conduct disorder, and oppositional defiant disorder than boys with ADHD. A statistically significant gender-by-ADHD interaction was identified for comorbid substance use disorders as well. Conclusions: The lower likelihood for girls to manifest psychiatric, cognitive, and functional impairment than boys could result in gender-based referral bias unfavorable to girls with ADHD
    • Linkage of chromosome 13q32 to schizophrenia in a large veterans affairs cooperative study sample

      Faraone, Stephen V.; Skol, Andrew D.; Tsuang, Debby W.; Bingham, Stephen; Young, Keith A.; Prabhudesai, Sarita; Haverstock, Susan L.; Mena, Felicitas; Menon, Aerath Sri Kumar; Bisset, Darren; et al. (Wiley, 2002-07-29)
      Several prior reports have suggested that chromosomal region 13q32 may harbor a schizophrenia susceptibility gene. In an attempt to replicate this finding, we assessed linkage between chromosome 13 markers and schizophrenia in 166 families, each with two or more affected members. The families, assembled from multiple centers by the Department of Veterans Affairs Cooperative Studies Program, included 392 sampled affected subjects and 216 affected sib pairs. By DSM-III-R criteria, 360 subjects (91.8%) had a diagnosis of schizophrenia and 32 (8.2%) were classified as schizoaffective disorder, depressed. The families had mixed ethnic backgrounds. The majority were northern European-American families (n = 62, 37%), but a substantial proportion were African-American kindreds (n = 60, 36%). Chromosome 13 markers, spaced at intervals of approximately 10 cM over the entire chromosome and 2-5 cM for the 13q32 region were genotyped and the data analyzed using semi-parametric affected only linkage analysis. For the combined sample (with race broadly defined and schizophrenia narrowly defined) the maximum LOD score was 1.43 (Z-score of 2.57; P = 0.01) at 79.0 cM between markers D13S1241 (76.3 cM) and D13S159 (79.5 cM). Both ethnic groups showed a peak in this region. The peak is within 3 cM of the peak reported by Brzustowicz et al.
    • Evidence for the multigenic inheritance of schizophrenia

      Freedman, Robert; Leonard, Sherry; Olincy, Ann; Kaufmann, Charles A.; Malaspina, Dolores; Cloninger, C. Robert; Svrakic, Dragan; Faraone, Stephen V.; Tsuang, Ming T. (Wiley, 2002-08-21)
      Schizophrenia is assumed to have complex inheritance because of its high prevalence and sporadic familial transmission. Findings of linkage on different chromosomes in various studies corroborate this assumption. It is not known whether these ®endings represent heterogeneous inheritance, in which various ethnic groups inherit illness through different major gene effects, or multigenic inheritance, in which affected individuals inherit several common genetic abnormalities. This study therefore examined inheritance of schizophrenia at different genetic loci in a nationally collected European American and African American sample. Seventy-seven families were previously genotyped at 458 markers for the NIMH Schizophrenia Genetics Initiative. Initial genetic analysis tested a dominant model, with schizophrenia and schizoaffective disorder, depressed type, as the affected phenotype. The families showed one genome-wide significant linkage (Z ¼ 3.97) at chromosome 15q14, which maps within 1 cM of a previous linkage at the a7-nicotinic receptor gene. Chromosome 10p13 showed suggestive linkage (Z ¼ 2.40). Six others (6q21, 9q32, 13q32, 15q24, 17p12, 20q13) were positive, with few differences between the two ethnic groups. The probability of each family transmitting schizophrenia through two genes is greater than expected from the combination of the independent segregation of each gene. Two trait-locus linkage analysis supports a model in which genetic alleles associated with schizophrenia are relatively common in the general population and affected individuals inherit risk for illness through at least two different loci.
    • Differential Effect of Environmental Adversity by Gender: Rutter’s Index of Adversity in a Group of Boys and Girls With and Without ADHD

      Biederman, Joseph; Faraone, Stephen V.; Monuteaux, Michael C. (American Psychiatric Association Publishing, 2002-09)
      Objective: This study examined the effect of gender in mediating the association between environmental adversity and the risk of attention deficit hyperactivity disorder (ADHD) and associated impairments. Method: The authors studied 280 ADHD and 242 healthy comparison probands of both genders who were between the ages of 6 and 17 years. They tested the association between Rutter’s indicators of adversity (including family conflict, social class, family size, maternal psychopathology, and paternal criminality) and ADHD, comorbidity, and functioning. Results: Greater levels of environmental adversity were associated with a greater risk for ADHD and other comorbidity in both genders in a dose-dependent fashion. However, learning disability and global functioning were modified by gender, with more detrimental effects observed in boys than in girls. Low social class, maternal psychopathology, and family conflict were significantly associated with psychopathology and functional impairment in the probands, with control for gender, parental ADHD, proband ADHD status, and maternal smoking during pregnancy. Conclusions: Psychosocial adversity in general and low social class, maternal psychopathology, and family conflict in particular increased the risk for ADHD and associated morbidity independently of gender and other risk factors, but gender modified the risk for adverse cognitive and interpersonal outcomes; boys were more vulnerable to the disorder than girls. Because of the difficulties in separating the effects of genetics from environment, these results must be interpreted as provisional until confirmation from twin and adoption studies.
    • Treatment of nonpsychotic relatives of patients with schizophrenia: Six case studies

      Tsuang, Ming T.; Stone, William S.; Tarbox, Sarah I.; Faraone, Stephen V. (Wiley, 2002-11-27)
      There is growing support for the notion that the genetic liability for schizophrenia could be manifested in brain dysfunction, even without the full manifestations of schizophrenia [Meehl, 1962, 1989; Seidman, 1997; Faraone et al., 2001]. This liability is characterized clinically by neurologic, neurobiological, psychiatric, neuropsychological, and psychosocial impairments in nonpsychotic, first-degree relatives of people with schizophrenia and includes eye tracking dysfunction [Levy et al., 1994], allusive thinking [Catts et al., 1993], neurologic signs [Erlenmeyer-Kimling et al., 1982], biochemical abnormalities [Callicott et al., 1998], char acteristic auditory evoked potentials [Friedman and Squires-Wheeler, 1994], neuroimaging assessed brain abnormalities [Seidman et al., 1997], and neuropsycho logical impairment [Kremen et al., 1994]. Paul Meehl introduced the term ‘‘schizotaxia’’ in 1962 to describe the genetic predisposition to schizophrenia [Meehl, 1962], and we have modified the concept to take account of subsequent research [Faraone et al., 2000]. The concept of schizotaxia raises at least three fundamental issues: 1) What is the conceptual basis of schizotaxia? 2) Is it a valid syndrome? and 3) perhaps most importantly from the point of view of the eventual prevention of schizo phrenia, is it treatable? In this paper, we review the model of schizotaxia by focusing first on its nature and extent. We then describe preliminary research criteria for its diagnosis in nonpsychotic relatives of schizo phrenic patients, followed by a presentation of our initial attempts to treat schizotaxia. Finally, prospects for the future focus on the need to validate the proposed syndrome further and on the clinical implications of treating schizotaxia.
    • Family-based and case-control association studies of catechol-O-methyltransferase in attention deficit hyperactivity disorder suggest genetic sexual dimorphism

      Qian, Qiujin; Wang, Yufeng; Zhou, Rulun; Li, Jun; Wang, Bing; Glatt, Stephen; Faraone, Stephen V. (Wiley, 2003-03-04)
      Attention deficit hyperactivity disorder (ADHD) is the most common childhood-onset behavioral disorder. Boys are more often affected than girls. Family, twin, and adoption studies have supported a strong genetic basis. Some studies show that a catechol-O-methyltransferase (COMT) polymorphism affecting enzyme activity was associated with personality characteristics and diseases, such as novelty-seeking personality, substance abuse, and heroin addiction, whose features are similar to ADHD or are associated with ADHD. These findings suggest that the COMT gene may be a candidate gene for ADHD. TDT, HHRR, and case-control association studies were conducted within a sample of 202 nuclear ADHD families, 340 ADHD cases, and 226 controls in the Han Chinese population. Diagnoses and ADHD subtypes were ascertained according to DSM-IV criteria using American Clinical Diagnostic Interviewing Scales. The HHRR analysis suggested that the low enzyme-activity COMT Met allele was preferentially transmitted to ADHD boys (160 trios, χ2 = 3.858, P = 0.05, df = 1) but not girls. This association is particularly pronounced among male ADHD probands without any comorbidity (50 trios, HHRR: χ2 = 5.128, P = 0.024, df = 1; TDT: χ2 = 4.558, P = 0.033, df = 1), especially the ADHD-I subtype (32 trios, HHRR: χ2 = 5.792, P = 0.016, df = 1; TDT: χ2 = 5.333, P = 0.021, df = 1). The case-control study revealed that the Val allele was more frequent in females meeting ICD-10 or DSM-IV criteria for ADHD than in female controls (86 and 79.5%, respectively, χ2 = 4.059, P = 0.044, df = 1). Although these results suggest the COMT gene exerts some influence on the risk for ADHD in the Han Chinese population, given the potential for Type I error, these findings require replication before drawing definitive conclusions. © 2003 Wiley-Liss, Inc.
    • Electronic Text Displays: Reading Rehabilitation of Low Vision Patients with Age-Related Macular Degeneration

      Aquilante, K. (SUNY College of Optometry, 2003-03-23)
      The purpose of this study was to investigate whether reading performance, measured in words per minute, improved during an hour of within-session practice. The reading methods were three computer-generated presentations including (1) MNREAD, a modified page format, (2) RSVP, which presents one word at a time, and (3) SCROLL, where text pans from right to left across a screen. Forty-five young readers with normal vision, forty-five elder readers with normal vision, and forty-five readers with low vision due to age-related macular degeneration read by one of these methods. None of the participants had previous experience reading with MNREAD, RSVP of SCROLL. There was little evidence that within-session practice improved performance. Only 10 of 135 participants had modest reading rate gains, and there was no statistical difference between reading method or subject group for this small subset of readers.
    • Family-based association study of markers on chromosome 22 in schizophrenia using African-American, European-American, and Chinese families

      Takahashi, Sakae; Cui, Yu-hu; Kojima, Takuya; Han, Yong-hua; Zhou, Ru-lum; Kamioka, Masashi; Yu, Shun-ying; Matsuura, Masato; Matsushima, Eisuyke; Wilcox, Marsha; et al. (Wiley, 2003-06-13)
      Several studies suggest that loci at chromosome 22q11.2-q13 might be linked to susceptibility to schizophrenia. Here we performed family-based association studies on chromosome 22q using 12 DNA microsatellite markers in African-American, European-American, and Chinese pedigrees. The marker D22S683 showed significant linkage and association with schizophrenia in not only the European-American sample but also in a combined sample (European-American and Chinese samples). Notably, D22S683 is located nearby and between D22S278 and D22S283, which have shown linkage and association to schizophrenia in prior reports. However, we found no significant association for the African-American sample. In conclusion, our data provide further support for the idea that the region around D22S683 contains a susceptibility gene for schizophrenia. © 2003 Wiley-Liss, Inc.
    • CAG-Repeat length in exon 1 of KCNN3 does not influence risk for schizophrenia or bipolar disorder: A meta-analysis of association studies

      Glatt, Stephen J.; Faraone, Stephen V.; Tsuang, Ming T. (Wiley, 2003-07-30)
      Schizophrenia and bipolar disorder both showsomeevidence for genetic anticipation. In addition, significant expansion of anonymous CAG repeats throughout the genome has been detected in both of these disorders. The gene KCNN3, which codes for a small/ intermediate conductance, calcium-regulated potassium channel, contains a highly polymorphic CAG-repeat array in exon 1. Initial evidence for association of both schizophrenia and bipolar disorder with increased CAG-repeat length of KCNN3 has not been consistently replicated. In the present study, we performed several metaanalyses to evaluate the pooled evidence for association with CAG-repeat length of KCNN3 derived from case-control and family-based studies of both disorders. Each group of studies was analyzed under two models, including a test for direct association with repeat length, and a test for association with dichotomized repeat-length groups. No evidence for a linear relationship between disease risk and repeat length was observed, as all pooled odds ratios approximated 1.0. Results of dichotomized allelegroup analyses were more variable, especially for schizophrenia, where case-control studies found a significant association with longer repeats but family-based studies implicated shorter alleles. The results of these meta-analyses demonstrate that the risks for both schizophrenia and bipolar disorder are largely, if not entirely, independent of CAG-repeat length in exon 1 of KCNN3. This study cannot exclude the possibility that some aspect of this polymorphism, such as repeat-length disparity in heterozygotes, influences risk for these disorders. Further, it remains unknown if this polymorphism, or one in linkage disequilibrium with it, contributes to some distinct feature of the disorder, such as symptom severity or anticipation.
    • Heterogeneity and the genetics of bipolar disorder

      Faraone, Stephen V.; Tsuang, Ming T. (Wiley, 2003-10-30)
    • Lack of Association Between Behavioral Inhibition and Psychosocial Adversity Factors in Children at Risk for Anxiety Disorders

      Hirshfeld-Becker, Dina R.; Biederman, Joseph; Faraone, Stephen V.; Segool, Natasha; Buchwald, Jennifer; Rosenbaum, Jerrold F. (American Psychiatric Association Publishing, 2004-03)
      Objective: In a previous controlled study of offspring at risk for anxiety disorders, the authors found that parental panic disorder with comorbid major depression was associated with child behavioral inhibition, the temperamental tendency to be quiet and restrained in unfamiliar situations. To explore whether this association was mediated by environmental factors, the authors examined associations between psychosocial adversity variables and behavioral inhibition in this group of children. Method: Subjects included 200 offspring of parents with panic disorder and/or major depression and 84 comparison children of parents without mood or anxiety disorders. Behavioral inhibition was assessed through laboratory observations. The associations between behavioral inhibition and the following psychosocial factors were examined: socioeconomic status; an index of adversity factors found in previous studies to be additively associated with child psychopathology; family intactness, conflict, expressiveness, and cohesiveness; exposure to parental psychopathology; sibship size; birth order; and gender. Results: The results showed no associations between behavioral inhibition and any of the psychosocial factors in the study group as a whole, despite adequate power to detect medium effect sizes. Among low-risk comparison children only, some definitions of behavioral inhibition were associated with low socioeconomic status, low family cohesion, and female gender. Conclusions: The results suggest that the psychosocial adversity factors examined in this study do not explain the previous finding that offspring of parents with panic disorder are at high risk for behavioral inhibition.
    • A Twin Study of Sexual Behavior in Men

      Lyons, Michael J.; Koenen, Karestan C.; Buchting, Francisco; Meyer, Joanne M.; Eaves, Lindon; Toomey, Rosemary; Eisen, Seth A.; Goldberg, Jack; Faraone, Stephen V.; Ban, Rachel J.; et al. (Springer Science and Business Media LLC, 2004-04)
      The role of genetic and environmental influences on age of initiation of first sexual relations and engaging in sexual activity with multiple partners (10 or more partners in 1 year) was investigated in male twins (N = 6, 744) from the Vietnam Era Twin Registry. Individual differences in both types of sexual behaviors were heritable, but only age of onset of sexual relations was significantly influenced by the environment shared by the twins. There was a moderate negative correlation between age of initiation of sexual relations and the multiple partners variable; initiating sexual relations earlier was associated with a higher probability of having multiple partners. The additive genetic influence on age of initiation also influenced the multiple partners variable. The substantial unique environmental influences on each variable were uncorrelated with each other. The data suggest that the observed association between age of initiation of sexual relations and having multiple partners is due to genetic influences common to both behaviors.
    • Information Design and Technology

      Ossowski, Candice (2004-05-01)
      This case study analyzes the effects of transforming a static HTML-based website into a dynamic database-driven one. As part of the study, a small computer company’s static website was redesigned, making it dynamic and database-driven. The theory of Human-Centered Design is applied to a real-world situation and the nine human-centered characteristics are analyzed as they relate to static and dynamic websites