PubMed Health⌕ Search

Biomedical subjects

J Endicott

Publications and source records attributed to J Endicott.

At least 19 recordsLinked to original sources
PubMed2006

Strong effect of resonant impurities on Landau-level quantization.

We investigate experimentally the effect of a random distribution of nitrogen (N) impurities on the Landau-level spectrum of a GaAs quantum well. Our magnetotunneling study reveals complex and nonequally spaced Landau levels and a quenching of the Landau states at a well-defined bias and electron energy which is resonant with that of the N atoms. Analysis of the magnetic field dependence of the tunnel current into the Landau levels of the well also provides quantitative information about the nonresonant component of the N-related scattering potential.

Journal Article↗
PubMed2006

The association between course of illness and subsequent morbidity in bipolar I disorder.

OBJECTIVE: We examined the relationship between certain bipolar I disorder clinical course variables over 5 years with outcome over the subsequent 5-year period. METHODS: Prospective observational follow-up data of 123 bipolar I subjects were analyzed. Predictive clinical variables included the frequency and direction of switches, and the quantity, polarity and length of affective periods. Outcome variables were an affective burden index (ABI) accounting for week-by-week severity and weeks hospitalized. Bivariate analyses guided the selection of predictors for multivariable analyses against the outcome variables. RESULTS: Affective burden index: while the number and direction of switches, the number of polyphasic episodes, weeks in hypomania/mania/mixed state, weeks in minor/major depression, weeks in at least marked affective syndrome, and weeks in any affective syndrome all had bivariate correlation (p<0.01) with the ABI, only weeks in hypomania/mania/mixed state and weeks in minor/major depression made significant contributions in the multivariable analysis (p<0.01) with the ABI. Weeks hospitalized: weeks in at least marked affective syndrome were significantly correlated with weeks hospitalized in bivariate analysis (p<0.01), and maintained a contribution to weeks hospitalized in the multivariable analysis (p<0.01). CONCLUSIONS: The quantity and severity of weeks in symptomatic affective states are possibly greater predictors of affective burden in bipolar I patients than the quantity and direction of affective switches.

Adult↗
PubMed2006

Genome-wide linkage scan in a large bipolar disorder sample from the National Institute of Mental Health genetics initiative suggests putative loci for bipolar disorder, psychosis, suicide, and panic disorder.

We conducted a 9-cM genome scan in a large bipolar pedigree sample from the National Institute of Mental Health genetics initiative (1060 individuals from 154 multiplex families). We performed parametric and nonparametric analyses using both standard diagnostic models and comorbid conditions thought to identify phenotypic subtypes: psychosis, suicidal behavior, and panic disorder. Our strongest linkage signals (genome-wide significance) were observed on chromosomes 10q25, 10p12, 16q24, 16p13, and 16p12 using standard diagnostic models, and on 6q25 (suicidal behavior), 7q21 (panic disorder) and 16p12 (psychosis) using phenotypic subtypes. Several other regions were suggestive of linkage, including 1p13 (psychosis), 1p21 (psychosis), 1q44, 2q24 (suicidal behavior), 2p25 (psychosis), 4p16 (psychosis, suicidal behavior), 5p15, 6p25 (psychosis), 8p22 (psychosis), 8q24, 10q21, 10q25 (suicidal behavior), 10p11 (psychosis), 13q32 and 19p13 (psychosis). Over half the implicated regions were identified using phenotypic subtypes. Several regions - 1p, 1q, 6q, 8p, 13q and 16p - have been previously reported to be linked to bipolar disorder. Our results suggest that dissection of the disease phenotype can enrich the harvest of linkage signals and expedite the search for susceptibility genes. This is the first large-scale linkage scan of bipolar disorder to analyze simultaneously bipolar disorder, psychosis, suicidal behavior, and panic disorder.

Bipolar Disorder↗
PubMed2005

Daily Record of Severity of Problems (DRSP): reliability and validity.

The Daily Record of Severity of Problems (DRSP) form was developed to aid in the diagnosis and evaluation of DSM-IV Premenstrual Dysphoric Disorder (PMDD). The reliability and validity of the procedure was tested in two studies. Study A included 27 subjects who ranged from having few or no premenstrual problems to those who met criteria for PMDD. Study B included 243 subjects, all of whom met criteria for PMDD. Individual items and Summary Scores had high test-retest reliability in both studies. Internal consistency of Summary Scores was also high in both studies. Summary Scores had moderate to high correlations with other measures of severity of illness. In addition, items and Summary Scores have been shown to be sensitive to change and to treatment differences in Study B. The DRSP provides sensitive, reliable, and valid measures of the symptoms and impairment criteria for PMDD.

Adult↗
PubMed2005

The psychotic spectrum: validity and reliability of the Structured Clinical Interview for the Psychotic Spectrum.

This study evaluates the validity and the reliability of a new instrument developed to assess the psychotic spectrum: the Structured Clinical Interview for the Psychotic Spectrum (SCI-PSY). The instrument is based on a spectrum model that emphasizes soft signs, low-grade symptoms, subthreshold syndromes, as well as temperamental and personality traits comprising the clinical and subsyndromal psychotic manifestations. The items of the interview include, in addition to a subset of the DSM-IV criteria for psychotic syndromes, a number of features derived from clinical experience and from a review of the phenomenological descriptions of psychoses. Study participants were enrolled at 11 Italian Departments of Psychiatry located at 9 sites and included 77 consecutive patients with schizophrenia or schizoaffective disorder, 66 with borderline personality disorder, 59 with psychotic mood disorders, 98 with non-psychotic mood disorders and 57 with panic disorder. A comparison group of 102 unselected controls was enrolled at the same sites. The SCI-PSY significantly discriminated subjects with any psychiatric diagnosis from controls and subjects with from those without psychotic disorders. The hypothesized structure of the instrument was confirmed empirically.

Adolescent↗
PubMed2005

Validity and reliability of the Italian version of the Quality of Life, Enjoyment and Satisfaction Questionnaire.

The Quality of Life, Enjoyment and Satisfaction Questionnaire (Q-LES-Q) is increasingly used in psychiatry because it gives emphasis to the subjective perspective of patients on physical, psychological and social domains. This paper reports on the validation of the Italian version of the Q-LES-Q in a large multicenter study (EQUIP) conducted at five Italian sites on outpatients in treatment for anxiety disorders. Study participants underwent a broad assessment of psychopathology including the MINI-International Neuropsychiatric Interview, the Symptom Checklist (SCL-90) and the Clinical Global Impression (CGI). Cronbach's alpha was used to determine the internal consistency of the Q-LES-Q areas and Pearson's r was used to analyze the correlation between the areas of Q-LES-Q and those of the other instruments. The internal consistency of the Q-LES-Q proved to be substantial (>0.80 in each of the areas) as well as the test-retest reliability. The convergent validity of the Q-LES-Q vs. the Work and Social Adjustment Scale was examined. High correlations were found between scales measuring similar constructs in the two instruments and lower correlation between scales measuring different constructs. In conclusion, the Italian version of the Q-LES-Q proved to be as valid and reliable as the original English version.

Adult↗
PubMed2004

Linkage analysis of psychosis in bipolar pedigrees suggests novel putative loci for bipolar disorder and shared susceptibility with schizophrenia.

The low-to-moderate resolution of linkage analysis in complex traits has underscored the need to identify disease phenotypes with presumed genetic homogeneity. Bipolar disorder (BP) accompanied by psychosis (psychotic BP) may be one such phenotype. We previously reported a genome-wide screen in a large bipolar pedigree sample. In this follow-up study, we reclassified the disease phenotype based on the presence or absence of psychotic features and subgrouped pedigrees according to familial load of psychosis. Evidence for significant linkage to psychotic BP (genome-wide P<0.05) was obtained on chromosomes 9q31 (lod=3.55) and 8p21 (lod=3.46). Several other sites were supportive of linkage, including 5q33 (lod=1.78), 6q21 (lod=1.81), 8p12 (lod=2.06), 8q24 (lod=2.01), 13q32 (lod=1.96), 15q26 (lod=1.96), 17p12 (lod=2.42), 18q21 (lod=2.4), and 20q13 (lod=1.98). For most loci, the highest lod scores, including those with genome-wide significance (at 9q31 and 8p21), occurred in the subgroup of families with the largest concentration of psychotic individuals (> or =3 in a family). Interestingly, all regions but six--5q33, 6q21, 8p21, 8q24, 13q32 and 18q21--appear to be novel; namely, they did not show notable linkage to BP in other genome scans, which did not employ psychosis for disease classification. Also of interest is possible overlap with schizophrenia, another major psychotic disorder: seven of the regions presumed linked in this study--5q, 6q, 8p, 13q, 15q, 17p, and 18q--are also implicated in schizophrenia, as are 2p13 and 10q26, which showed more modest support for linkage. Our results suggest that BP in conjunction with psychosis is a potentially useful phenotype that may: (1) expedite the detection of susceptibility loci for BP and (2) cast light on the genetic relationship between BP and schizophrenia.

Bipolar Disorder↗
PubMed2003

Magnetotunneling spectroscopy of dilute Ga(AsN) quantum wells.

We use magnetotunneling spectroscopy to explore the admixing of the extended GaAs conduction band states with the localized N-impurity states in dilute GaAs(1-y)N(y) quantum wells. In our resonant tunneling diodes, electrons can tunnel into the N-induced E- and E+ subbands in a GaAs(1-y)N(y) quantum well layer, leading to resonant peaks in the current-voltage characteristics. By varying the magnetic field applied perpendicular to the current direction, we can tune an electron to tunnel into a given k state of the well; since the applied voltage tunes the energy, we can map out the form of the energy-momentum dispersion curves of E- and E+. The data reveal that for a small N content (approximately 0.1%) the E- and E+ subbands are highly nonparabolic and that the heavy effective mass E+ states have a significant Gamma-conduction band character even at k=0.

Journal Article↗
PubMed2003

A self-administered screener for migraine in primary care: The ID Migraine validation study.

BACKGROUND: Migraine is a highly prevalent and disabling illness that remains substantially undiagnosed in primary care. Because of the potential value of a screening tool, the current study was designed to establish the validity and reliability of a brief, self-administered migraine screener in patients with headache complaints in the primary care setting. METHODS: A total of 563 patients presenting for routine primary care appointments and reporting headaches in the past 3 months completed a self-administered migraine screener. All patients were then referred for an independent diagnostic evaluation by a headache expert, of whom 451 (80%) completed a full evaluation. Migraine diagnosis was assigned based on International Headache Society criteria after completing a semi-structured diagnostic interview. RESULTS: Of nine diagnostic screening questions, a three-item subset of disability, nausea, and sensitivity to light provided optimum performance, with a sensitivity of 0.81 (95% CI, 0.77 to 0.85), a specificity of 0.75 (95% CI, 0.64 to 0.84), and positive predictive value of 0.93 (95% CI, 89.9 to 95.8). Test-retest reliability was good, with a kappa of 0.68 (95% CI, 0.54 to 0.82). The sensitivity and specificity of the three-item migraine screener was similar regardless of sex, age, presence of other comorbid headaches, or previous diagnostic status. CONCLUSIONS: The three-item ID Migraine migraine screener was found to be a valid and reliable screening instrument for migraine headaches. Its ease of use and operating characteristics suggest that it could significantly improve migraine recognition in primary care.

Adolescent↗
PubMed2003

Acceptability, validity and reliability of the Structured Clinical Interview for the Spectrum of Substance Use (SCI-SUBS): a pilot study.

This paper reports on the acceptability, reliability and validity of the Structured Clinical Interview for the Spectrum of Substance Use (SCI-SUBS), a new instrument exploring the interactive pathway between substance abuse and psychiatric disorders. Psychiatric outpatients with (n = 21) and without (n = 32) substance abuse comorbidity according to the DSM-IV, non-psychiatric subjects with opioid dependence (OD, n = 14) and normal controls (n = 33) were assessed with the SCI-SUBS. The presence or absence of psychiatric disorders was determined with the Structured Clinical Interview for DSM IV (SCID). The SCI-SUBS was well accepted by participants. The internal consistency of the domains was satisfactory (between 0.64 and 0.93). Domain scores of OD subjects were significantly higher than those of controls and of psychiatric patients without substance abuse. The cut-off point on the SCI-SUBS total score at which there was optimal discrimination between the presence and the absence of a DSM-IV diagnosis of substance abuse was 45. The pilot version of the SCI-SUBS has satisfactory internal consistency and construct validity.

Adult↗
PubMed2003

Evidence for a putative bipolar disorder locus on 2p13-16 and other potential loci on 4q31, 7q34, 8q13, 9q31, 10q21-24, 13q32, 14q21 and 17q11-12.

Bipolar disorder (BP) is a severe and common psychiatric disorder characterized by extreme mood swings. Family, twin and adoption studies strongly support a genetic component. The mode of inheritance is complex and likely involves multiple, as yet unidentified genes. To identify susceptibility loci, we conducted a genome-wide scan with 343 microsatellite markers in one of the largest, well-characterized pedigree samples assembled to date (373 individuals in 40 pedigrees). To increase power to detect linkage, scan statistics were used to examine the logarithm of odds (lod) scores based on evidence at adjacent chromosomal loci. This analysis yielded significant evidence of linkage (genome-wide P&<0.05) for markers on 2p13-16. Standard linkage analysis was also supportive of linkage to 2p13-16 (lod=3.20), and identified several other interesting regions: 4q31 (lod=3.16), 7q34 (lod=2.78), 8q13 (lod=2.06), 9q31 (lod=2.07), 10q24 (lod=2.79), 13q32 (lod=2.2), 14q21 (lod=2.36) and 17q11-12 (lod=2.75). In this systematic, large-scale study, we identified novel putative loci for BP (on 2p13-16, 8q13 and 14q21) and found support for previously proposed loci (on 4q31, 7q34, 9q31, 10q21-24, 13q32 and 17q11-12). Two of the regions implicated in our study, 2p13-14 and 13q32, have also been linked to schizophrenia, suggesting that the two disorders may have susceptibility genes in common.

Adolescent↗
PubMed2001

A follow-up linkage study supports evidence for a bipolar affective disorder locus on chromosome 21q22.

Evidence for linkage between bipolar affective disorder (BP) and 21q22 was first reported by our group in a single large pedigree with a lod score of 3.41 with the PFKL locus. In a subsequent study, with denser marker coverage in 40 multiplex BP pedigrees, we reported supporting evidence with a two-point lod score of 2.76 at the D21S1260 locus, about 6 cM proximal to PFKL. For cost-efficiency, the individuals genotyped in that study comprised a subset of our large pedigree sample. To augment our previous analysis, we now report a follow-up study including a larger sample set with an additional 331 typed individuals from the original 40 families, improved marker coverage, and an additional 16 pedigrees. The analysis of all 56 pedigrees (a total of 862 genotyped individuals vs. the 372 genotyped previously), the largest multigenerational BP pedigree sample reportedly analyzed to date, supports our previous results, with a two-point lod score of 3.56 with D21S1260. The 16 new pedigrees analyzed separately gave a maximum two-point lod score of 1.89 at D21S266, less than 1 cM proximal to D21S1260. Our results are consistent with a putative BP locus on 21q22.

Bipolar Disorder↗
PubMed2001

Good diagnoses require good diagnosticians: collecting and integrating the data.

The use of sets of diagnostic criteria and excellent structured clinical interviews will not result in data that is adequate for valid diagnoses or for dimensional measures if the rater collecting the data does not have adequate clinical skills. In the absence of biological measures or tests we are dependent on the rater's diagnostic and interviewing skills-both with subjects about themselves and with family informants asked to provide information about others. Best estimate diagnosticians (who usually have more experience and training) cannot compensate for inadequate or incorrect information and may even be misled by the information provided to them. In reviewing videotaped interviews sent by "trained" and "experienced" raters who were seeking "certification," approximately 40% of the raters were judged to have failed to conduct an adequate diagnostic evaluation. Principal Investigators should make every effort to assure that their diagnostic data is being collected by experienced and well-trained professional raters and that the raters' ongoing work is subjected to close supervision and review.

Clinical Competence↗
PubMed2001

The significance of psychotic features in manic episodes: a report from the NIMH collaborative study.

BACKGROUND: Psychotic features in the context of major depressive syndromes have correlates in symptom severity, acute treatment response and long-term prognosis. Little is known as to whether psychotic features have similar importance when they occur within manic syndromes. METHODS: These data derive from a multi-center, long-term follow-up of patients with major affective disorder. Raters conducted follow-up interviews at 6-month intervals for the first 5 years and annually thereafter. A sub-set of probands participated in a family study in which all available, adult, first-degree relatives were interviewed as well. RESULTS: Of 139 who entered the study in an episode of mania, 90 patients had psychotic features. Symptom severity ratings at intake were more severe for this group. Though time to first recovery and time to first relapse did not distinguish the groups, psychotic features were associated with a greater number of weeks ill during follow-up and the strength of this association was similar to that seen for psychotic features within depressed patients described in an earlier publication. Patients with psychotic mania at intake did not differ significantly from those with nonpsychotic mania by response to acute lithium treatment, suicidal behavior during follow-up, or risks for affective disorder among first-degree relatives. Psychotic features within manic syndromes were not associated with high psychosis ratings during follow-up. In contrast, when psychotic features accompanied depressive syndromes, they strongly predicted the number of weeks with psychosis during follow-up, particularly among individuals whose episodes at intake were less acute. CONCLUSIONS: As with major depressive syndromes, psychotic features in mania are associated with greater symptom severity and higher morbidity in the long-term. Psychotic features are much less predictive of future psychosis when they occur within a manic syndrome than when they occur within a depressive syndrome.

Activities of Daily Living↗
PubMed2001

Lithium and suicidal behavior in major affective disorder: a case-control study.

OBJECTIVE: A number of studies have suggested that lithium may be particularly effective in reducing suicide risks among patients with major affective disorders. The design of many of these studies left them open to biases associated with treatment compliance, however. METHOD: Subjects were drawn from a naturalistic, long-term follow-up of patients with major affective disorders. Fifteen who committed suicide while receiving somatotherapy where matched to non-suicidal patients who were similarly receiving somatotherapy at the same point in follow-up. The same procedure was followed for 41 patients who made a serious suicide attempt during follow-up. RESULTS: Six (40.0%) of the patients who committed suicide, and eight (53.3%) of their controls, were thought to have been taking lithium in the preceding week. Among attempters and their controls, nine (22.0%) and eight (19.5%), respectively, were taking lithium. CONCLUSION: These results do not support previous suggestions that lithium has uniquely antisuicidal properties. Other existing datasets should be explored with this design to establish whether lithium does, or does not, offer special protection against suicide.

Adult↗