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Biomedical subjects

Melinda Morgan

Publications and source records attributed to Melinda Morgan.

8 recordsLinked to original sources
PubMed2006

Decreased neuroactive steroids induced by combined oral contraceptive pills are not associated with mood changes.

OBJECTIVE: To evaluate the effects of a low-dose combined oral contraceptive pill (OCP) on peripheral neuroactive steroid concentrations, precursors for neuroactive steroid synthesis, and mood in healthy women desiring contraception. These neuroactive steroids are gamma-aminobutyric acid receptor agonists and are important in the modulation of affect and adaptation to stress. DESIGN: Prospective observational study. SETTING: Human ambulatory patient study. PATIENT(S): Healthy OCP-naive women without current or history of affective disorder. INTERVENTION(S): A 0.020-mg ethinyl E2-0.1-mg levonorgestrel containing OCP for 3 months. MAIN OUTCOME MEASURE(S): Serum neuroactive steroids allopregnanolone, allotetrahydrodeoxycorticosterone, and DHEA; neuroactive steroid precursors P and pregnenolone; E2; and mood and anxiety as assessed by the Premenstrual Syndrome Daily Ratings Form, Beck Depression Inventory, Spielberger State-Trait Anxiety Inventory, and Profile of Mood States. RESULT(S): The combined OCP resulted in a decrease in neuroactive steroids and neuroactive steroid precursors as well as in E2. However, this decline was not associated with adverse mood changes on any of the well-validated assessment tools. CONCLUSION(S): Healthy women without underlying mood or anxiety disorder who were given a low-dose OCP did not experience adverse psychological symptoms despite a significant reduction in neuroactive steroids.

Adolescent↗
PubMed2004

Pretreatment neurophysiological and clinical characteristics of placebo responders in treatment trials for major depression.

RATIONALE: High placebo response rates are a confound in treatment trials for major depressive disorder (MDD). A method for prospective identification of placebo responders could enhance the efficiency of clinical trials. OBJECTIVE: The objective was to identify the neurophysiological, symptomatic, and cognitive characteristics of subjects who were likely to respond to placebo in clinical trials for MDD. METHODS: Fifty-one subjects with MDD were treated in clinical trials with either fluoxetine ( n=24) or venlafaxine ( n=27) versus placebo. All subjects underwent pretreatment assessment with quantitative electroencephalographic (QEEG) power and cordance, as well as symptom ratings and neuropsychological testing. After a 1-week single-blind placebo lead-in, subjects were randomized to double-blind placebo controlled treatment with a medication or placebo. At the end of 8 weeks, the blind was broken and treatment response assessed. Response was defined by a final Hamilton Depression Rating Scale score of </=10. RESULTS: Of the medication-treated and placebo-treated subjects, 52% (13/25) and 38% (10/26) responded. Placebo responders had lower pretreatment frontocentral cordance in the theta frequency band than all other subjects ( P<0.006) and medication responders in particular ( P<0.004). Placebo responders also had faster cognitive processing time, as assessed by neuropsychological testing, and lower reporting of late insomnia ( P<0.03). Exploratory examination of a multiple variable model for predicting placebo response was conducted using logistic regression, in which these three pretreatment measures accurately identified 97.6% of eventual placebo responders. CONCLUSIONS: These findings suggest that combined clinical, neurophysiological, and cognitive assessments of prospective subjects for clinical trials may be useful for identifying MDD subjects who are likely to show robust response to placebo. Prospective validation of these results in a larger, independent sample of subjects is necessary to establish the reliability and usefulness of this method for prospective identification of placebo responders.

Adult↗
PubMed2004

Pretreatment neurophysiologic function and ECT response in depression.

OBJECTIVES: Recent brain imaging studies have provided evidence that brain function assessed prior to treatment of depression may be associated with eventual treatment response. The present study tested the hypothesis that brain activity in midline apical quantitative EEG (QEEG) electrodes would be associated with therapeutic response to electroconvulsive therapy (ECT). METHODS: Ten treatment-refractory patients with unipolar or bipolar depression received a Hamilton Rating Scale for Depression (Ham-D) at baseline, during, and following ECT treatment. Resting, eyes-closed, 35-lead QEEG recordings were done 1 day before the initial ECT treatment. Data were analyzed using QEEG power and cordance. RESULTS: The mean of the theta-band pretreatment cordance from the central brain region was strongly associated with percentage decrease in Ham-D score over the course of treatment (r = 0.80, P = 0.005). QEEG cordance from other brain regions and power from all brain regions did not show an association with clinical improvement. CONCLUSIONS: Depressed subjects with higher pretreatment central cordance appear to be more likely to experience therapeutic benefits of ECT. The location of central electrodes over the cingulate cortex may indicate that pretreatment cingulate activity is associated with response to ECT.

Bipolar Disorder↗
PubMed2004

Subject expectations of treatment effectiveness and outcome of treatment with an experimental antidepressant.

OBJECTIVE: To evaluate the association between treatment expectations and response in a 9-week, single-blind experimental antidepressant treatment study. METHOD: Twenty-five adult subjects meeting DSM-IV criteria for major depressive disorder with Hamilton Rating Scale for Depression (HAM-D) scores of >/= 17 completed a treatment trial using the experimental antidepressant reboxetine. Following a 1-week placebo lead-in, subjects received single-blind treatment for 8 weeks with reboxetine 8 to 10 mg/day. During the screening visit, subjects were asked to self-rate their expectations of the effectiveness of the study medication. Forced-choice responses were "not at all effective," "somewhat effective," or "very effective." Response to treatment was defined as a final HAM-D score of </= 10 at the end of the 9-week trial. Data were collected from October 1999 to July 2001. RESULTS: Subjects with a higher pretreatment expectation of medication effectiveness had a greater likelihood of response. Of the subjects who reported an expectation that the medication would be very effective, 90.0% (N = 9) responded to treatment, while only 33.3% (N = 5) of those who reported expecting medication to be somewhat effective responded to treatment (chi(2) = 7.819, p <.005). There was no association between the level of depression severity, duration of current episode, number of prior episodes, or basic demographic factors and treatment outcome. CONCLUSIONS: These findings indicate that individuals with high baseline expectations of improvement demonstrate a significantly higher level of response to reboxetine than those with lower expectations of improvement with treatment. The data in this study suggest that a subject's expectation of efficacy is associated with the outcome of experimental antidepressant treatment.

Adolescent↗
PubMed2002

Early changes in prefrontal activity characterize clinical responders to antidepressants.

Previous studies have shown that changes in brain function precede clinical response to antidepressant medications. Here we examined quantitative EEG (QEEG) absolute and relative power and a new measure, cordance, for detecting regional changes associated with treatment response. Fifty-one adults with unipolar depression completed treatment trials using either fluoxetine or venlafaxine vs. placebo. Data were recorded at baseline and after 48 h and 1 week on drug or placebo. Baseline and change from baseline values were examined for specific brain regions in four subject groups (medication and placebo responders and nonresponders). No regional baseline QEEG differences were found among the groups; there also were no significant changes in theta power over time. In contrast, medication responders uniquely showed significant decreases in prefrontal cordance at 48 h and 1 week. Clinical differences did not emerge until after four weeks. Subjects with greater changes in cordance had the most complete 8-week responses. These findings implicate the prefrontal region in mediating response to antidepressant medications. Cordance may have clinical applicability as a leading indicator of individual response.

Adult↗
PubMed2002

Changes in brain function of depressed subjects during treatment with placebo.

OBJECTIVE: It has been proposed that 50%-75% of the efficacy of antidepressant medication represents the placebo effect, since many depressed patients improve when treated with either medication or placebo. This study examined brain function in depressed subjects receiving either active medication or placebo and sought to determine whether quantitative electroencephalography (QEEG) could detect differences in brain function between medication and placebo responders. Both QEEG power and cordance, a new measure that reflects cerebral perfusion and is sensitive to the effect of antidepressant medication, were examined. METHOD: Fifty-one subjects with major depression were enrolled in one of two independent, 9-week double-blind, placebo-controlled studies in which either fluoxetine (N=24) or venlafaxine (N=27) was the active medication. Serial QEEG recordings were performed during the course of treatment. After 9 weeks, the blind was broken and subjects were classified as medication responders, placebo responders, medication nonresponders, or placebo nonresponders. RESULTS: No significant pretreatment differences in clinical or QEEG measures were found among the four outcome groups. Placebo responders, however, showed a significant increase in prefrontal cordance starting early in treatment that was not seen in medication responders (who showed decreased cordance) or in medication nonresponders or placebo nonresponders (who showed no significant change). There was no significant change in QEEG power during treatment. CONCLUSIONS: These findings suggest that "effective" placebo treatment induces changes in brain function that are distinct from those associated with antidepressant medication. If these results are confirmed, cordance may be useful for differentiating between medication and placebo responders.

Adult↗
PubMedDate not supplied

Cognitive flexibility, reaction time, and attention in women with premenstrual dysphoric disorder.

OBJECTIVE: To evaluate cognitive functioning throughout the menstrual cycle in women who suffer from premenstrual dysphoric disorder (PDD) and controls. RESEARCH HYPOTHESIS: Measures of cognitive function will discriminate between women with prospectively documented PDD and women without PDD during the late-luteal phase of the menstrual cycle. PARTICIPANTS: The participants consisted of 37 women who met operationalized, prospectively documented criteria of premenstrual dysphoric disorder and 32 women without PDD who served as controls. DESIGN: A series of neurocognitive tasks were used to assess selective, sustained attention, reaction time, and cognitive flexibility in women with PDD and controls. Tests were administered on two occasions: once during the follicular phase of the menstrual cycle, and once during the late-luteal phase. RESULTS: Repeated measures and discriminant analyses failed to demonstrate significant group differences between women with PDD and controls in neurocognitive functioning. CONCLUSIONS: The findings indicated that cognitive functioning in the late-luteal phase was not compromised in either group, in spite of subjective reports from the PDD group. The findings suggest that complaints of cognitive dysfunction may be mediated by altered perceptions and sociocultural expectations rather than by identifiable cognitive deficits.

Adult↗