Papers by Jonathan Stewart
Psychiatry Research, 1988
Social functioning was assessed in 189 nonmelancholically depressed outpatients. Patients were th... more Social functioning was assessed in 189 nonmelancholically depressed outpatients. Patients were then treated for 6 weeks in a double-blind trial of phenelzine, imipramine, or placebo and functioning was reassessed. Before treatment, younger, more severely depressed, more chronically depressed patients and those with a DSM-III diagnosis of major depression plus dysthymic disorder were more functionally impaired than patients without these characteristics. Chronically depressed patients who responded to treatment reported significantly improved functioning while nonresponders did not. These results suggest that for some chronically depressed patients, impaired functioning results at least partly from the Axis I mood disorder instead of being entirely attributable to Axis II character pathology.
Journal of Geotechnical and Geoenvironmental Engineering, 1999
The two papers describe trends of the apparent system periods, , and damping factors, , in record... more The two papers describe trends of the apparent system periods, , and damping factors, , in recorded response of 56T 0 buildings (A1 to A45, and B1 to B14 in of part II) to 15 California earthquakes. The building, foundation, and soil are viewed as an equivalent linear system, excited by horizontal ground motion. Only inertial interaction is considered as ''the more important effect for foundations without large, rigid base slabs or deep embedment'' (by allowing one translation and rocking of the foundation). The kinematic interaction (modification of the free-field motion by the foundation in absence of inertial forces) is neglected as ''second order.'' Rocking and torsional excitation components of the incident motion, differential motions of extended foundations, warping of flexible foundations, and nonlinear soil response due to soilstructure interaction (SSI) are not mentioned. The papers aim to verify the ''simplified analytical procedures similar to those in the BSSC and ATC codes.'' This discussion (1) requests some clarifications; (2) suggests that time-dependent changes in (caused by nonlinear response of soil during SSI) should T have been included in the analysis; and (3) comments on the conditions when kinematic SSI should not be neglected.
Journal of Clinical Psychiatry, 2005
To determine the frequency and demographic and clinical characteristics of depression with atypic... more To determine the frequency and demographic and clinical characteristics of depression with atypical features in a broadly representative sample of outpatients. Data derived from the first 1500 patients with DSM-IV major depressive disorder enrolled in the Sequenced Treatment Alternatives to Relieve Depression trial at 41 primary care and nonresearch psychiatric outpatient clinics. An algorithm based on the 30-item Inventory of Depressive Symptomatology-Clinician Rating (IDS-C30) determined presence or absence of depression with atypical features. Odds ratios determined whether a variety of demographic and clinical parameters differed between patients meeting and not meeting atypical criteria. Over 18% of the sample met criteria for atypical features based on items from the IDS-C30. The atypical group was more likely to be female and have an earlier age at onset, greater comorbidity with anxiety symptoms, and greater symptom severity compared with the nonatypical group. Previously identified features of atypical depression were confirmed in this large and broadly representative, nonresearch clinical population.
Drug and Alcohol Dependence, 1995
A IZweek placebo-controlled, randomized clinical trial was undertaken to evaluate imipramine as a... more A IZweek placebo-controlled, randomized clinical trial was undertaken to evaluate imipramine as a treatment for cocaine abuse, and to examine whether its effect may be limited to subgroups defined by route of use or by diagnosis of depression. One-hundred thirteen patients were randomized, stratified by route of use and depression, All patients received weekly individual counseling. Compared to placebo the imipramine group showed greater reductions in cocaine craving, cocaine euphoria, and depression, but the effect of imipramine on cocaine use was less clear. A favorable response, defined as at least 3 consecutive, urine-confirmed, cocaine-free weeks was achieved by 19% (1 l/59) of patients on imipramine compared to 7% (4/54) on placebo (P < 0.09). The imipramine effect was greater among nasal users -33% (9/27) response on imipramine vs. 5% (l/22) on placebo (P < 0.02). Response was also more frequent, but not significantly so, among depressed users on imipramine (26%, 10/38) than on placebo (13%, 4/31) (P < 0.19). Response rates were low in intravenous and freebase users and those without depression. Considered together with the literature on desipramine, these data suggest tricyclic antidepressants are not promising as a mainstay of treatment for unselected cocaine abusers. However, tricyclics may be useful for selected cocaine abusers with comorbid depression or intranasal use, or in conjunction with a more potent psychosocial intervention.
Journal of Geotechnical and Geoenvironmental Engineering, 2001
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Journal of Clinical Psychopharmacology, 1993
We reanalyzed data from a larger, previously published study in order to directly address whether... more We reanalyzed data from a larger, previously published study in order to directly address whether very chronically depressed patients could benefit from antidepressant medications. This study entered 598 depressed patients into a study randomizing patients to 6 weeks of double-blind treatment with imipramine, phenelzine, or placebo. Patients were assessed for chronicity on a four-point scale from &quot;mostly well&quot; to &quot;virtually always depressed.&quot; The current analyses include only the 153 study completers who were rated as &quot;virtually always depressed.&quot; In these patients, imipramine was effective for significantly more patients than was placebo (22 [46%] of 48 responding to imipramine vs. 9 [17%] of 52 responding to placebo; chi 2 = 9.50; p = 0.002), whereas phenelzine was significantly more effective than imipramine (37 [70%] of 53 responding to phenelzine; chi 2 = 5.96; p = .015). Patients with mild depression, early onset, or histories of panic attacks did not have substantially different outcomes than patients without these characteristics. These findings suggest that some chronically depressed patients may be good candidates for treatment with antidepressant medication. Because the majority (80%) of the sample met Columbia criteria for definite or probable atypical depression, too few chronic depressives were available to evaluate separately antidepressant efficacy in chronically depressed outpatients who did not have atypical depression. Hence, these results may be applicable only to patients with atypical depression.
Survey of Anesthesiology, 1993
The authors&#39; goal was to analyze the acute phase of antidepressant drug treatment to iden... more The authors&#39; goal was to analyze the acute phase of antidepressant drug treatment to identify placebo responses. Patients rated as improved after 6 weeks of double-blind treatment with imipramine or phenelzine were followed for an additional 6 weeks of double-blind treatment. Initial responses were classified according to the speed of improvement (abrupt or gradual), the persistence or nonpersistence of improvement, and the timing of improvement (early or late onset). It was predicted that patients with nonpersistent, abrupt responses to the drugs were actually experiencing a placebo response and would have the worst prognosis. In fact, this group accounted for a disproportionate number of the relapses. Nonpersistent responders to a drug had a 23.7% relapse rate, but persistent responders had only a 9.0% relapse rate, a significant difference. The authors conclude that a significant proportion of relapses within the first 6 weeks of treatment with an active drug are not related to loss of a true drug effect. Rather, some are related to loss of nonspecific placebo effects, and abrupt nonpersistent responses during drug treatment are most likely the result of placebo effects.
Earthquake Spectra, 2005
Nonlinear Site Amplification as Function of 30 m Shear Wave Velocity. [Earthquake Spectra 21, 1 (... more Nonlinear Site Amplification as Function of 30 m Shear Wave Velocity. [Earthquake Spectra 21, 1 (2005)]. Yoojoong Choi, Jonathan P. Stewart. Abstract. We develop empirical relationships to predict nonlinear (ie, amplitude-dependant ...
Archives of General Psychiatry, 1998
Delayed and persistent (&quot;true drug&quot;) improvement characterizes the response to ... more Delayed and persistent (&quot;true drug&quot;) improvement characterizes the response to antidepressant medication. Early or nonpersistent (&quot;placebo&quot;) benefit is typical of a placebo response. The prediction was that patients with a true drug response would sustain their benefit best if they continued to receive the drug and that patients with a placebo response would have an equivalent prognosis whether they continued to receive the drug or were switched to placebo. Patients with major depression who met the study&#39;s response criteria (a modified Hamilton Depression Rating Scale score &lt; or =7 and failure to meet major depression criteria after each of the last 3 weeks following 12 to 14 weeks of treatment with fluoxetine hydrochloride, 20 mg/d) were enrolled in a 50-week randomized placebo substitution trial during which the return of depressive symptoms defined relapse. The timing and persistency of response during initial treatment defined true drug or placebo response patterns. Patients with a true drug response pattern relapsed significantly more frequently if they were switched to placebo than if they continued to receive fluoxetine (P&lt;.001 for weeks 12-26, P&lt;.005 for weeks 26-50, and P&lt;.41 for weeks 50-62). Patients with a placebo response pattern had an equivalent outcome whether maintained on fluoxetine therapy or placebo (P&lt; .20 for weeks 12-26, test invalid for weeks 26-50, and P&lt;.67 for weeks 50-62). Patients with a placebo response pattern relapsed more often when they continued to receive fluoxetine than patients with a true drug response pattern (P&lt;.01 for weeks 12-26, P&lt;.10 for weeks 26-50, and P&lt;.36 for weeks 50-62). These findings confirm that pattern analysis validly differentiates true drug from nonspecific initial responses and extend its use to the continuation and maintenance phases of treatment for depression. Investigations into the mechanisms of antidepressant activity might best be limited to those that can account for delayed efficacy. Fluoxetine&#39;s efficacy during the continuation and maintenance phases of treatment may be limited to patients with a true drug pattern of initial response.
International Journal of Psychophysiology, 2000
Depression may involve dysfunction of right parietotemporal cortex, a region activated during per... more Depression may involve dysfunction of right parietotemporal cortex, a region activated during perception of Ž . affective stimuli. To further test this hypothesis, event-related brain potentials ERPs were measured in a paradigm previously shown to produce ERP asymmetries to affective stimuli over parietal sites in healthy adults. Pictures of Ž . Ž . patients with dermatological diseases showing disordered or healed facial areas before negative or after neutral surgical treatment were briefly exposed for 250 ms to either the left or right hemifield. ERPs of 30 unmedicated, unipolar depressed patients and 16 healthy adults, all right-handed, were recorded from 30 electrodes. A principal components analysis extracted factors which closely corresponded to distinctive ERP components previously reported Ž . for this task N1, N2, early P3, late P3, slow wave . Significant effects of emotional content, i.e. enhanced amplitudes to negative than neutral stimuli, were found for early and late P3. Control subjects showed significant hemispheric Ž . asymmetries of emotional processing for late P3 peak latency 460 ms , with the largest emotional content effects over the right parietal region. In striking contrast to control subjects, depressed patients did not show an increase in late P3 for negative compared to neutral stimuli over either hemisphere and had smaller late P3 amplitude than Ž . control subjects. Patients did, however, show larger early P3 peak latency 330 ms to negative than neutral stimuli. J. Kayser 0167-8760r00r$ -see front matter ᮊ 2000 Elsevier Science B.V. All rights reserved. Ž . PII: S 0 1 6 7 -8 7 6 0 0 0 0 0 0 7 8 -7 ( ) J. Kayser et al. r International Journal of Psychophysiology 36 2000 211᎐236 212
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Papers by Jonathan Stewart