Biomedical subjects

D E Williamson

Publications and source records attributed to D E Williamson.

At least 19 recordsLinked to original sources

PubMed1995

Stressful life events and EEG sleep in depressed and normal control adolescents.

EEG sleep measures in 35 depressed and 33 normal control adolescents were examined in relation to stressful life events occurring in the year before sleep studies. There was a significant interaction between stressful life events and diagnostic status for REM latency and total REM time. In the normal controls, the presence of stressful life events was significantly associated with reduced REM latency and increased total REM time. Among the depressed adolescents, there were no significant effects of stressful life events on REM latency or total REM time. The depressed adolescents with no stressful life events (n = 9) had significantly lower REM latency values compared to normal control adolescents with no stressful life events (n = 13)(61.7 +/- 50.0 vs. 132.1 +/- 79.0, p < or = .01). It appears that stressful life events influence at least some measures of adolescent sleep and should be considered in future controlled studies aimed at understanding sleep changes in adolescent depression.

Adolescent↗

PubMed1995

Unipolar depression in adolescents: clinical outcome in adulthood.

OBJECTIVE: This study examined the longitudinal clinical course and adult sequelae of adolescent unipolar major depressive disorder (MDD) using a controlled longitudinal design. METHOD: Subjects were 28 adolescents (15.4 +/- 1.3 years) with systematically diagnosed unipolar MDD and 35 group-matched control subjects who participated in a cross-sectional electroencephalogram sleep and neuroendocrine study. Using standardized instruments, interviewers who were blind to subjects' initial diagnoses conducted follow-up clinical assessments 7.0 +/- 0.5 years later in 94% of the original cohort. RESULTS: The depressed group showed high rates of recurrence of MDD episodes during the interval period (69%). They also had elevated rates of new-onset bipolar disorder (19%). Twenty-three percent of subjects with an initial diagnosis of MDD had no additional depressive episodes after the index assessment. The rate of new onset of depression in the controls was 21%. Low socioeconomic status predicted recurrence of depressive episodes in the MDD group. MDD subjects with recurrence(s) and controls with new onset of depression during the follow-up period had significant psychosocial morbidity, as evidenced by disruption in interpersonal relationships and dissatisfaction with life and decrease in global functioning, compared with both MDD subjects with no further episodes and control subjects who had never been psychiatrically ill. These psychosocial deficits persisted remission from depressive episode(s). CONCLUSIONS: Adolescent unipolar MDD predicts continued risk for recurrences with persistence of depressive episodes and psychosocial morbidity into adulthood. A sizable minority, however, have sustained periods of remission associated with good social adjustment.

Adolescent↗

PubMed1995

Stressful life events in depressed adolescents: the role of dependent events during the depressive episode.

OBJECTIVE: To examine the relationship between stressful life events and major depressive disorder (MDD) in adolescents. METHOD: Adolescents (aged 12 to 18 years) with a current episode of MDD based on Research Diagnostic Criteria (n = 39) and normal controls free of any Axis I lifetime psychiatric disorder (n = 35) were assessed using the Life Events Record. RESULTS: MDD and normal control adolescents had similar rates of total stressful life events in the year before being interviewed. Stressful life events were dichotomized into those that were most likely either independent of or dependent on the adolescent's influence/behavior. Depressed adolescents had significantly more dependent stressful life events during the previous year than did the normal controls. Further analyses showed that depressed adolescents with dependent stressful life events scored lower on symptom clusters and accordingly were less severely depressed than depressed adolescents without dependent life events. CONCLUSIONS: The results of this study indicate that depressed adolescents have an increased risk for experiencing dependent life events. Furthermore, these data suggest that dependent life events in depressed adolescents are differentially associated with the type and severity of symptom presentation. The temporal occurrence, severity, and type of stressful life events as they relate to the onset, phenotypic expression, and maintenance of depression in adolescents need to be more fully understood.

Adolescent↗

PubMed1992

Nocturnal urinary excretion of 6-hydroxymelatonin sulfate in prepubertal major depressive disorder.

Levels of the melatonin metabolite, 6-hydroxymelatonin sulfate, were measured in overnight urine from 31 prepubertal children with major depressive disorder and 15 normal control children with very low family loading for affective disorder. The two groups did not differ with regard to their nocturnal excretion of this compound, nor was any depressive subgroup identified whose 6-hydroxymelatonin sulfate excretion differed from that of the control group. Previous studies of pineal function in depression are reviewed and discussed in the context of the present investigation.

Adolescent↗

PubMed1992

Dexamethasone suppression test in children with major depressive disorder.

The authors report a study of 24-hour serial cortisol determinations, measured during baseline and after the administration of 0.25 and 0.5 mg of dexamethasone in a sample of predominantly outpatient children with major depressive disorder, nonaffective psychiatric controls, and normal controls. In this sample, 24-hour baseline cortisol and the dexamethasone suppression test (DST) do not discriminate between the three groups. In addition, the authors measured 24-hour serum dexamethasone levels. There were no significant between group differences in serum dexamethasone. These results raise questions as to the utility of this test in the diagnosis of affective disorders in children. Possible reasons for the discrepancies in the dexamethasone suppression test results between in- and outpatient studies are discussed.

Administration, Oral↗

PubMed1992

A secular increase in child and adolescent onset affective disorder.

Both longitudinal and cross-sectional studies utilizing population and family study samples have found evidence for a secular increase in major affective disorders in adults. Applying techniques used in cross-sectional studies in adults to family study data of children and adolescents, the authors demonstrate evidence of a parallel secular increase for child and adolescent onset affective disorders. Normal and depressed prepubertal probands were identified. All full siblings were directly interviewed for lifetime episodes of affective disorder. Analysis of the siblings (probands not further analyzed in this article) by the Cox proportional hazards model demonstrates that the risk for affective disorder is higher in siblings born more recently.

Bias↗

PubMed1992

Regulation of sleep and growth hormone in adolescent depression.

This article reviews findings of sleep, growth hormone (GH), and cortisol measures from a number of separate controlled studies of prepubertal and adolescent depression carried out by Puig-Antich and colleagues since 1978. New data are presented comparing 24-hour GH measures in adolescents with major depressive disorder (MDD) (N = 44; mean age = 14.8 +/- 2.0) to normal control adolescents (N = 37; mean age = 15.3 +/- 1.5). There were no significant overall group differences in summary GH measures between MDD and normal controls. Splitting the MDD group on the basis of suicidality (definite plan or attempt) (N = 20), revealed a significant blunting of sleep GH compared to the nonsuicidal group (N = 24). These results are discussed in the context of the other sleep and neuroendocrine findings in this population, with evidence for dysregulation around sleep onset. The influences of development on sleep and GH regulation are also considered.

Adolescent↗

PubMed1992

Corticotropin releasing hormone stimulation test and nocturnal cortisol levels in normal children.

This study examined hypothalamic-pituitary-adrenal axis functioning in a group (n = 25) of very carefully screened normal children with considerable attention to issues of adaptation and procedural stress. The subjects (mean age 10.3 +/- 1.6 y) were selected as "supernormal" controls as a part of a large psychobiologic study of childhood depression. After careful acclimatization over 24 h, the subjects underwent all-night sampling of plasma cortisol every 20 min, then the following evening had a corticotropin releasing hormone (CRH) stimulation test (using human CRH). Human CRH resulted in a rapid stimulation of adrenocorticotropin and cortisol. Adrenocorticotropin levels increased from 6.8 +/- 3.5 (+/- SD) pmol/L (30.7 +/- 16.1 pg/dL) to a peak of 11.6 +/- 5.5 pmol/L (52.9 +/- 24.8 pg/mL) at 15 min with return to baseline levels by 60 min. Cortisol levels increased from 131.4 +/- 59.7 nmol/L (4.8 +/- 2.2 micrograms/dL) to a peak of 427.0 +/- 113.5 nmol/L (15.5 +/- 4.1 micrograms/dL) at 30 min with return to baseline by 120 min. The cortisol peak was significantly greater (p less than 0.05) in boys [474.6 +/- 129.7 nmol/L (17.2 +/- 4.7 micrograms/dL)] than in girls [366.9 +/- 52.4 nmol/L (13.3 +/- 1.9 micrograms/dL, p less than 0.05)]. Age, body mass index, and pubertal status were not significantly related to hypothalmic-pituitary-adrenal axis measures. Nocturnal cortisol reached a nadir at 160 +/- 60 min after sleep onset (0102 h) and a peak 480 +/- 60 min after sleep onset (0612 h). Nocturnal cortisol levels were significantly (positively) correlated with human CRH-stimulated cortisol (r = 0.56, p = 0.004).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Electroencephalographic sleep measures in prepubertal depression.

Two nights of electroencephalographic (EEG) sleep recording were performed in a group of prepubertal subjects with major depressive disorder (MDD) (n = 36, mean age = 10.4, SD = 1.5) and age-matched normal control children (n = 18, mean age = 10.1, SD = 1.6). All subjects were medically healthy and free of medications at the time of the study. There were no significant group differences for any major sleep variable after the initial adaptation night in this study. One subgroup of MDD subjects (n = 8) showed reduced REM latency on both recording nights, decreased stage 4 sleep, and increased REM time; this subgroup had significantly higher severity scores for depression but did not otherwise appear to be clinically distinct from the rest of the MDD subjects. Overall, the results indicate that the EEG sleep changes associated with depression in adults occurred less frequently in prepubertal MDD subjects.

Adolescent↗

PubMed1991

Synaptic organization of two types of amacrine cells with CRF-like immunoreactivity in the turtle retina.

The ultrastructural features and synaptic contacts of two amacrine cell types with corticotropin-releasing factor-like immunoreactivity in the turtle retina were examined using electron immunocytochemistry. Type A cells were found only in the visual streak and had elongated dendritic arborizations that ran parallel to the visual streak. These cells arborized primarily in stratum 1 and near the border of strata 2 and 3 of the inner plexiform layer, with some processes extending into stratum 5. Type B cells were found only ventral to the visual streak and arborized primarily in a wide band in strata 4 and 5, with sparse dendritic arborizations in stratum 1. There was a diffuse cytoplasmic reaction product within each cell type; however, large labeled vesicles were rarely observed. Type A amacrine cells received many conventional synaptic contacts from amacrine cells in stratum 1 and at the border of strata 2 and 3, but only a small number of contacts in stratum 5. Bipolar synaptic contacts onto type A amacrine cells were observed in strata 1 and at the border of strata 2 and 3. The only positively identified synaptic outputs of type A cells were conventional synapses onto amacrine cells in strata 1 and at the border of 2 and 3. Type B amacrine cells received synaptic contacts from amacrine cells in strata 1 and 5, and bipolar cell synaptic input in stratum 5. They made conventional synapses onto amacrine cells in strata 1 and 5, and onto bipolar cells in stratum 5. We also found conventional synaptic contacts between unlabeled amacrine cells and type B amacrine cells outside of the primary layers of stratification. In addition, there were specialized junctions observed between type A cell profiles in stratum 1 and between type B cell profiles in stratum 5. The unique regional distributions of the type A and B cells, as well as their differences in synaptic connectivity, suggested that these amacrine cells play distinct physiological roles although they contain the same neuropeptide.

Animals↗

PubMed1991

Hormonal responses to dextroamphetamine in depressed and normal adolescents.

Because of its neuroendocrine effects, amphetamine infusion has been used as a probe to investigate neurobiological correlates of depressive illness. In two separate studies, a total of 72 adolescents with major depressive disorder and 66 normal adolescents were given dextroamphetamine, 0.15 mg/kg, intravenously. Their cortisol, growth hormone, and prolactin responses were measured. These endocrine responses did not reliably distinguish adolescents with major depressive disorder from those without it, nor did they reliably delineate any specific depressive subgroup. These findings are compared with those from similar studies of adult depression.

Adolescent↗

PubMed1989

Amacrine and ganglion cells with corticotropin-releasing-factor-like immunoreactivity in the turtle retina.

This study, which uses immunocytochemical methods at the light microscopical, level, examines the cell types in the turtle retina that contain corticotropin-releasing factor (CRF)-like immunoreactivity. Two anatomically distinct amacrine cell types are labeled when antiserum directed against ovine CRF is used to label the turtle retina. These cell types each have a different dendritic arborization pattern and regional distribution. Type A cells are found only in the visual streak and have elongated dendritic arborizations that run parallel to the visual streak. These cells arborize primarily in stratum 1 and near the border of strata 2 and 3, with some processes extending into stratum 5. Type B amacrine cells are found only ventral to the visual streak and arborize primarily in a wide band in strata 4 and 5 with sparse dendritic arborizations in stratum 1. No labeled amacrine cells of any type were found dorsal to the visual streak. The asymmetric dendritic arborizations of the type A amacrine cells and the different regional distributions of the A and B cell types suggest that these two amacrine cell types perform distinct physiological functions. In addition to these labeled amacrine cells, there are also some immunoreactive cell bodies in the ganglion cell layer. Rhodamine crystals were applied to the optic tectum to retrogradely label the ganglion cell bodies. Double label studies indicate that some of the rhodamine-labeled ganglion cells also contain CRF-like immunoreactivity. The localization of CRF-like immunoreactivity in two distinct amacrine cell types and in ganglion cells suggests that it may play multiple roles in visual processing in the turtle retina.

Animals↗

PubMed1988