Needle-like structures discovered on positively charged lightning branches.

Lightning is a dangerous yet poorly understood natural phenomenon. Lightning forms a network of plasma channels propagating away from the initiation point with both positively and negatively charged ends-called positive and negative leaders1. Negative leaders propagate in discrete steps, emitting copious radio pulses in the 30-300-megahertz frequency band2-8 that can be remotely sensed and imaged with high spatial and temporal resolution9-11. Positive leaders propagate more continuously and thus emit very little high-frequency radiation12. Radio emission from positive leaders has nevertheless been mapped13-15, and exhibits a pattern that is different from that of negative leaders11-13,16,17. Furthermore, it has been inferred that positive leaders can become transiently disconnected from negative leaders9,12,16,18-20, which may lead to current pulses that both reconnect positive leaders to negative leaders11,16,17,20-22 and cause multiple cloud-to-ground lightning events1. The disconnection process is thought to be due to negative differential resistance18, but this does not explain why the disconnections form primarily on positive leaders22, or why the current in cloud-to-ground lightning never goes to zero23. Indeed, it is still not understood how positive leaders emit radio-frequency radiation or why they behave differently from negative leaders. Here we report three-dimensional radio interferometric observations of lightning over the Netherlands with unprecedented spatiotemporal resolution. We find small plasma structures-which we call 'needles'-that are the dominant source of radio emission from the positive leaders. These structures appear to drain charge from the leader, and are probably the reason why positive leaders disconnect from negative ones, and why cloud-to-ground lightning connects to the ground multiple times.

[Reconstruction of isolated orbital floor fractures with a prefabricated titanium mesh]. / Versorgung isolierter Orbitabodenfrakturen - Rekonstruktion mit präfabriziertem Titanmesh.

PURPOSE: Concerning safety and efficiency in surgery of isolated orbital floor fractures, several treatment modalities are being discussed. It is a matter of recent interest that prefabricated titanium meshes provide significant advantages. The purpose of this study was to review the usability of the MatrixORBITAL® plate. MATERIAL AND METHODS: In a prospective study we evaluated 10 patients (June 2011 to November 2013) with an isolated orbital floor fracture. All patients in the study group had undergone reconstruction with the MatrixORBITAL® plate. For purposes of analysis were recorded: age, gender, fracture category according to Jaquiéry et al. (2007), duration of surgery, complications, globe motility (Harms wall), exophthalmometry, function of the infraorbital nerve, evaluation of facial symmetry and aesthetic as well as personal contentment of the patient. A reference group received a PDS® sheet, an antral balloon or other materials. RESULTS: In the study group (2 women and 8 men aged between 26 and 83 years) all cases presented a large disruption of the orbital floor (> 2 cm2 bony defect; category II-III). Volume changes were universally associated with diplopia, but only in two cases with an entrapment of the inferior rectus muscle. The mean duration of the operation was 110 minutes (minimum 50, maximum 135 minutes). Postoperatively diplopia was decreasing in all cases. None of the patients had a significant impairment of visus and no reoperation was necessary. The analysis of functional outcomes between the groups mesh, PDS sheet and antral balloon revealed no significant differences. CONCLUSIONS: Based on this experience and due to good intraoperative handling, the authors recommend the prefabricated titanium plate in the treatment of isolated orbital wall fractures or in combination with the medial wall despite the material costs.

The spectrum concept of schizophrenia. Problems for diagnostic practice.

The spectrum concept of schizophrenia posits that a number of psychopathologic states, both psychotic and nonpsychotic, may share some genetic basis with schizophrenia, and may therefore constitute, together with schizophrenia itself, a genetic spectrum of schizophrenic disorders. While this is a valuable and promising research concept, its application to diagnostic practice could broaden the boundaries of schizophrenia to include patients with other conditions, thus rendering a larger population at risk for the untoward effects of the schizophrenia disgnosis itself. This may have already occurred in the Soviet Union, where a diagnostic system derived from a variant of the spectrum concept is used in routine diagnostic practice. The adoption of a spectrum-based diagnostic system should await further research on the boundaries of the spectrum, and more detailed descriptions of confirmed spectrum states.

Comparison of induced and independent major depressive disorders in 2,945 alcoholics.

OBJECTIVE: Depressive episodes among alcohol-dependent men and women are heterogeneous in causation and clinical course. This study tested three hypotheses regarding the rates and clinical characteristics of two potential subtypes of these affective states: those that appear to be substance-induced mood disorders and those that are independent major depressive episodes. METHOD: Semistructured, detailed interviews were administered to 2,945 alcohol-dependent subjects as part of the Collaborative Study on the Genetics of Alcoholism. With the use of a time line method for determining the type of mood disorder among probands, relatives, and comparison subjects, individuals with histories of the two types of mood disorders were compared. RESULTS: Major depressive episodes with an onset before the development of alcohol dependence or during a subsequent long abstinence period (i.e., independent depressions) were observed in 15.2% of the alcoholics, while 26.4% reported at least one substance-induced depressive episode. According to a logistic regression analysis, the subjects with independent (as compared to substance-induced) major depressive episodes were more likely to be married, Caucasian, and female, to have had experience with fewer drugs and less treatment for alcoholism, to have attempted suicide, and, on the basis of personal interviews with family members, to have a close relative with a major mood disorder. CONCLUSIONS: These results support the contention that it is possible to differentiate between what appear to be substance-induced and independent depressive episodes in alcoholics. Such differentiation might be important for establishing prognosis and optimal treatment.

Developmental sequence from disruptive behavior diagnosis to adolescent alcohol dependence.

OBJECTIVE: The authors sought to clinically describe the relationship of disruptive behavior disorders with both alcohol dependence and the use of a variety of substances. METHOD: The Child Semi-Structured Assessment for the Genetics of Alcoholism was used to collect data on 54 adolescents with a diagnosis of alcohol dependence. The frequency and age at onset of the disruptive behavior disorder diagnoses were examined as well as age at first use of alcohol, tobacco, marijuana, and other street drugs. RESULTS: Nearly three-quarters of the alcohol-dependent adolescents had at least one disruptive behavior disorder diagnosis. Attention deficit hyperactivity disorder (ADHD) typically occurred first, followed by conduct disorder. Substance use began with alcohol or tobacco, followed by marijuana and then other street drugs. Alcohol dependence began significantly later than the onset of either ADHD or conduct disorder and significantly later than the first use of tobacco. CONCLUSIONS: Disruptive behavior diagnoses, particularly conduct disorder, typically precede the initiation of use of a variety of substances that, in turn, precede the diagnosis of alcohol dependence in adolescents.

Familiality and heritability of subtypes of attention deficit hyperactivity disorder in a population sample of adolescent female twins.

OBJECTIVE: Attention deficit hyperactivity disorder (ADHD) is a highly heritable but clinically heterogeneous syndrome. The study examined the familiality and heritability of ADHD subtypes as defined by DSM-IV and by latent-class analysis in a population sample of adolescent female twins. METHOD: To determine which elements of ADHD cluster together, latent-class analysis was applied to data obtained from parents on the 18 DSM-IV ADHD symptoms in 4,036 female twins age 13-23 years in a population sample identified from the registry of all births in Missouri for the years 1968-1996. Relative risk and odds ratios were used to assess within-subtype and between-subtype familiality and heritability of both DSM-IV and latent-class ADHD subtypes. RESULTS: Latent-class analysis was most compatible with the existence of three mild and three severe classes of ADHD symptoms in the general population. The three severe classes showed moderate overlap with DSM-IV ADHD subtypes. The primarily inattentive and combined subtypes of DSM-IV ADHD co-clustered within families. The primarily hyperactive/impulsive DSM-IV subtype and the individual latent-class analysis subtypes did not co-cluster. Subtypes defined by both approaches were highly heritable. CONCLUSIONS: Unlike DSM-IV subtypes of ADHD, latent-class ADHD subtypes appear to be independently transmitted in families. These classes may be more appropriate targets for molecular genetic studies of ADHD.

Evidence for a locus on chromosome 1 that influences vulnerability to alcoholism and affective disorder.

OBJECTIVE: Depression (major depression or depressive syndrome) is more prevalent in alcoholic than in nonalcoholic subjects in families with multiple members with alcoholism studied as part of the Collaborative Study on the Genetics of Alcoholism (National Institute on Alcohol Abuse and Alcoholism). First-degree relatives of probands with comorbid alcoholism and depression have a higher prevalence of both disorders than relatives of probands with alcoholism alone, and both groups have a higher prevalence than the relatives of comparison subjects selected without regard to psychopathology. Data from the collaborative study were used to test three phenotypes (comorbid alcoholism and depression, alcoholism or depression, and depression) for genetic linkage. METHOD: Genome-wide sibling-pair linkage analyses were performed with the phenotypes comorbid alcoholism and depression, alcoholism or depression, and depression (major depression or depressive syndrome). Analyses were performed in two data sets (initial and replication data sets) from subject groups ascertained with identical criteria, as well as in the combined data set. RESULTS: Peak lod scores on chromosome 1 (near 120 centimorgan) for the alcoholism or depression phenotype were 5.12, 1.52, and 4.66 in the initial, replication, and combined data sets, respectively. The corresponding lod scores on chromosome 2 were 2.79, 0.20, and 3.26; on chromosome 6, they were 3.39, 0.00, and 0.92; and on chromosome 16, they were 3.13, 0.00, and 2.06. Lod scores on chromosome 2 for the comorbid alcoholism and depression phenotype in the three data sets were 0.00, 4.12, and 2.16, respectively. CONCLUSIONS: The results suggest that a gene or genes on chromosome 1 may predispose some individuals to alcoholism and others to depression (which may be alcohol induced). Loci on other chromosomes may also be of interest.

No association of the dopamine transporter gene 3' VNTR polymorphism with ADHD subtypes in a population sample of twins.

Dopamine pathway genes have been the subject of a variety of studies testing the association of candidate genes and liability for attention-deficit hyperactivity disorder (ADHD). Due to the known effects of stimulant medications such as methylphenidate on the dopamine transporter, a variety of case control and family-based transmission distortion genetic studies of ADHD have focused on DAT1 polymorphisms. The most widely reported positive finding has been with a variable number of tandem repeats (VNTR) polymorphism of unknown function in the 3' untranslated region of the DAT1 gene. In this report, we test for association of alleles of this polymorphism with ADHD using population-derived samples of twins. We use the transmission disequilibrium test and ADHD subtypes defined by both DSM-IV and latent class criteria. We fail to demonstrate any significant association or trend for association of any of the VNTR alleles with any of the variously defined ADHD subtypes.

Lack of association of dopamine D4 receptor gene polymorphisms with ADHD subtypes in a population sample of twins.

Attention-deficit hyperactivity disorder (ADHD) is a common, highly heritable syndrome of childhood characterized by problems with inattention, hyperactivity, and impulsivity. A variety of case control and family-based transmission distortion genetic studies of ADHD have focused on the possible involvement of polymorphisms of the DRD4 receptor gene. The majority of studies have examined the association of variously defined ADHD with an exon 3 polymorphism containing a variable number of imperfect 48 base pair repeats. Recently, McCracken et al. [2000: Mol Psych 5:531-536] reported an association of the DSM-IV primarily inattentive ADHD subtype with a 5' 120 base pair repeat polymorphism in the DRD4 gene. In this report, we test for the possible association of these two polymorphisms with population-derived samples of DSM-IV ADHD subtypes. Furthermore, we extend previous studies by testing for associations with ADHD subtypes derived from latent-class analysis of interview responses. In contrast to most, but not all, previous studies, we failed to demonstrate any significant association of the exon 3 7-repeat allele with ADHD. Nor did we replicate the association of the 5'120 base pair repeat polymorphism. We do find a significant association of the exon 3 3-repeat allele with a novel talkative/impulsive latent-class-defined subtype of ADHD.

Diagnostic interview for children and adolescents (DICA)

OBJECTIVE: To describe the evolution of the Diagnostic Interview for Children and Adolescents (DICA) as well as the goals of the instrument and the issues surrounding its use. METHOD: Administration procedures, psychometric properties, and comparisons with other measures are reviewed. RESULTS: The DICA, once considered a structured interview, can now be used in a semistructured format. It displays good reliability and works well with younger children. CONCLUSION: The DICA is a useful measure for both research and clinical settings, and it provides a reliable tool for assessing psychiatric information in children and adolescents.

Prevalence of affective disorder in the child and adolescent offspring of a single kindred: a pilot study.

OBJECTIVE: The study determined the prevalence of psychiatric disorders among the child and adolescent offspring of an extended family identified through a proband with bipolar affective disorder. METHODS: All of the not mentally retarded offspring (ages 6 to 17 years) of a single extended bipolar affective disorder pedigree were studied. Data regarding psychiatric diagnoses, intelligence, school achievement, temperament, and family functioning were collected using structured and standardized instruments. RESULTS: When the child and adolescent offspring were stratified by degree of genetic relationship to an adult with an affective disorder, there were no differences in demographic variables, IQ, school achievement, or most temperamental and family characteristics. In contrast, there were increases in the rates of affective disorders and disruptive behavior disorders in the offspring that correlated with the degree of genetic relationship to an affected adult. CONCLUSIONS: The risk of developing an early onset affective disorder is correlated with the degree of genetic relatedness to affected adults in this single, extended family. This pilot study demonstrates that the inclusion of extended relatives in high-risk studies can enhance the discrimination of genetic and environmental contributions to the development of affective disorders.

Psychopathology in children of alcoholics.

OBJECTIVE: To assess psychopathology in 125 and 158 children who are offspring of alcoholic and control parents. METHOD: Parents and children were interviewed by means of structured interviews. Parents were interviewed about themselves and about their children. Teacher reports were obtained. A total of 158 young people ages 6 to 18 years were in the study, although some of the analyses use only 125. RESULTS: Children of alcoholic parents showed higher rates of oppositional and conduct disorders but not attention deficit disorder. Children of alcoholic parents did not have significantly higher rates of depression, but they may be at risk for anxiety. These children also showed increased incidence of alcohol and other substance use but not abuse or dependence as defined by DSM-III. Few differences were detected with respect to self-esteem and achievement tests among the groups. There were no differences in the rates of psychopathology between offspring of alcoholic versus antisocial parents. CONCLUSION: These data indicate that children of alcoholics exhibit high rates of psychopathology and may be at risk specifically for oppositional and conduct disorders but not for depression. There are few differences between alcoholics and controls with respect to self-esteem and achievement tests.

Relationship of child psychopathology to parental alcoholism and antisocial personality disorder.

OBJECTIVE: To evaluate the contributions of familial factors, including parental diagnoses of alcoholism and/or antisocial personality disorder (ASPD), to the risk of developing various child psychiatric diagnoses. METHOD: Four hundred sixty-three children and their biological parents were interviewed with adult and child versions of the Semi-Structured Assessment for the Genetics of Alcoholism. Demographic and psychiatric data were compared across 3 groups of children on the basis of the presence of parental alcoholism and ASPD (no other parental diagnoses were examined). Generalized estimating equations analyses allowed the inclusion of multiple children from each family in the analyses. RESULTS: Among offspring, parental alcoholism was associated with increased risks for attention-deficit hyperactivity disorder, conduct disorder (CD), and overanxious disorder. Parental alcoholism plus ASPD was associated with increased risk for oppositional defiant disorder. Dysfunctional parenting style was associated with increased risks for CD, alcohol abuse, and marijuana abuse. Low family socioeconomic status was associated with increased risk for CD. CONCLUSIONS: Parental diagnoses of alcoholism and ASPD were associated with increased risks for a variety of childhood psychiatric disorders, and dysfunctional parenting style was associated with the diagnoses of CD, alcohol abuse, and marijuana abuse.

Psychiatric diagnoses in the child and adolescent members of extended families identified through adult bipolar affective disorder probands.

OBJECTIVE: To investigate the type and distribution of psychiatric disorders in the child and adolescent members of extended pedigrees identified through bipolar probands. METHOD: The child and adolescent offspring (24 male, 26 female, aged 6 to 17 years) and the adult parents (60) of 14 bipolar pedigrees ascertained for the National Institutes of Mental Health Genetics Initiative Study of Bipolar Affective Disorder were personally assessed using structured psychiatric interviews. A parent was also interviewed about each child or adolescent offspring. RESULTS: Twelve of the 50 interviewed offspring received a lifetime DSM-III-R diagnosis of an affective disorder. This included six cases of bipolar disorder, five cases of major depressive disorder, and one case of dysthymia. Eight of the offspring who received an affective disorder diagnosis also qualified for an anxiety disorder (four), a disruptive behavior disorder (two), or both (two). Offspring who had a parent with an affective disorder had a 5.1-fold higher risk for receiving an affective disorder diagnosis than did offspring with healthy parents. CONCLUSIONS: In a consecutive series of families identified through a proband with bipolar disorder, there were significant increases in the prevalence of affective disorder diagnoses in the child and adolescent offspring. The distribution of illness in offspring was compatible with the presence of important genetic factors which contribute to early-onset affective illness.

Latent class and factor analysis of DSM-IV ADHD: a twin study of female adolescents.

OBJECTIVE: In an attempt to validate the current DSM-IV criteria for attention-deficit/hyperactivity disorder (ADHD) in females and to determine whether symptoms are continuously distributed or categorically discrete, the authors performed factor and latent class analysis on ADHD symptom data from a large general population of adolescent female twins (1,629 pairs). METHOD: A structured diagnostic assessment of DSM-IV ADHD was completed with at least one parent of 1,629 pairs by telephone. ADHD symptoms from 1,549 pairs were subjected to latent class and factor analysis. RESULTS: Latent class and factor analyses were consistent with the presence of separate continuous domains of inattention (ATT), hyperactivity-impulsivity (H-I), and combined ATT with H-I problems. Severe latent classes corresponding to the predominantly inattentive, predominantly hyperactive-impulsive, and combined types were identified with lifetime prevalence estimates of 4.0%, 2.2%, and 3.7%, respectively. Membership in the severe ATT class predicted academic problems, family problems, and referral to health care providers. Membership in the H-I and combined classes also predicted impaired social relationships. CONCLUSIONS: These results suggest that DSM-IV ADHD subtypes can be thought of as existing on separate continua of inattention, hyperactivity-impulsivity, and combined type problems. Membership in any of there severe ADHD latent classes did not preclude academic excellence, but it was associated with different types of impairment and health care-seeking behavior. These data have implications in the areas of diagnosis, classification, treatment, and research.

Suicide attempts in an adolescent female twin sample.

OBJECTIVE: To examine suicide attempts in an epidemiologically and genetically informative youth sample. METHOD: 3,416 Missouri female adolescent twins (85% participation rate) were interviewed from 1995 to 2000 with a telephone version of the Child Semi-Structured Assessment for the Genetics of Alcoholism, which includes a detailed suicidal behavior section. Mean age was 15.5 years at assessment. RESULTS: At least one suicide attempt was reported by 4.2% of the subjects. First suicide attempts were all made before age 18 (and at a mean age of 13.6). Major depressive disorder, alcohol dependence, childhood physical abuse, social phobia, conduct disorder, and African-American ethnicity were the factors most associated with a suicide attempt history. Suicide attempt liability was familial, with genetic and shared environmental influences together accounting for 35% to 75% of the variance in risk. The twin/cotwin suicide attempt odds ratio was 5.6 (95% confidence interval [CI] 1.75-17.8) for monozygotic twins and 4.0 (95% CI 1.1 -14.7) for dizygotic twins after controlling for other psychiatric risk factors. CONCLUSIONS: In women, the predisposition to attempt suicide seems usually to manifest itself first during adolescence. The data show that youth suicide attempts are familial and possibly influenced by genetic factors, even when controlling for other psychopathology.

Evaluation of ADHD typology in three contrasting samples: a latent class approach.

OBJECTIVE: To identify subtypes of attention-deficit/hyperactivity disorder (ADHD) and characterize them as either categorical or continuous; to investigate familial resemblance for ADHD among sibling pairs; and to test the robustness of all results by using contrasting data sets. METHOD: Latent class analysis was applied to the ADHD symptom profiles obtained from parents or best informant about their offspring in 3 samples: a population-based set of female adolescent twins (724 monozygotic pairs, 594 dizygotic pairs) and male (N = 425) and female (N = 430) child and adolescent offspring ascertained from high-risk alcoholic families. RESULTS: Latent class analysis revealed 2 categories of clinically significant ADHD which were replicated in all 3 study groups: a subtype with high endorsements of ADHD inattention symptoms and a second combined type with high endorsements of both inattention and hyperactivity-impulsivity items. Both appeared to be continuous across all 3 data groups. The high-risk families contained a class in which members heavily endorsed the ADHD "fidget" item but not other ADHD items. A large proportion of the monozygotic sibs (80%) versus a smaller proportion of dizygotic sibs (52%) were assigned to the same latent class. Among the high-risk children and adolescents, 51% of the female and 41% of the male siblings were concordant for class membership. CONCLUSIONS: The pattern of latent classes suggested that ADHD consists of an inattentive and a combined subtype, within each of which lies a dimensional domain. These analyses further support that genetic factors are significant determinants of latent class membership.

Risk domains associated with an adolescent alcohol dependence diagnosis.

AIMS: To determine the contribution of familial, interpersonal, academic and early substance use factors to relative risk for an alcohol dependence (AD) diagnosis in adolescents. METHODS: Information on 619 adolescents and their 390 sets of biological parents was obtained using the adolescent version of the Child Semi-Structured Assessment for the Genetics of Alcoholism (C-SSAGA) and the adult counterpart of this instrument, the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA). The C-SSAGA elicits a wide range of environmental, social, and psychiatric diagnostic information. Specific domain scale scores associated with an adolescent AD were computed, and generalized estimating equations (GEE) modeling was used to determine the odds ratio (relative risk) of the specified risk domains for an alcohol dependence diagnosis. FINDINGS: Risk factors for a DSM-III-R AD diagnosis included being at least 16 years of age, as well as negative parent-child interactions, school and personal-related difficulties (including the presence of an externalizing or internalizing DSM-III-R non-alcohol-related diagnosis), and early experimentations with a variety of substances. CONCLUSIONS: An array of familial, interpersonal, academic and early substance use factors were strongly associated with adolescent AD. Given the findings of this study, further research to determine temporal relationships that might influence the onset of adolescent alcohol dependence is warranted.

Rules for making psychiatric diagnoses in children on the basis of multiple sources of information: preliminary strategies.

Inherent in the structured diagnostic interviewing of children is the problem of how to resolve differences between the child's own report and that of the parent about the child. A related problem concerns the use of outside source of information about the child, such as information from the teacher. In this study, the authors review the decision-making process used in the assignment of summary psychiatric diagnoses based on the child and parent reports, as well as a number of other sources of information about the child. Provisional rules for making summary diagnoses of children are presented.