PubMed Health⌕ Search

Biomedical subjects

C B Nemeroff

Publications and source records attributed to C B Nemeroff.

At least 37 records · Page 2Linked to original sources

An evaluation of risperidone drug interactions.

Risperidone, an atypical antipsychotic drug, is widely used in the treatment of psychoses associated with schizophrenia, Alzheimer's disease, and other psychiatric disorders. Polypharmacology is a necessary condition for the optimal treatment of many patients with comorbid psychiatric and medical illness. One concern raised by the widespread use of multiple concurrent pharmacotherapies is the potential for drug-drug interactions to adversely affect patient outcome. Accordingly, the biomedical literature was reviewed for reports of drug interactions involving risperidone, and the clinical significance of each report was evaluated. Additionally, the potential for risperidone to participate in drug interactions was evaluated by considering the drug's pharmacokinetic properties. Controlled studies and case reports indicate that risperidone has a low potential for metabolic drug interactions. Drugs that inhibit cytochrome P450 (CYP) 2D6 or induce or inhibit CYP3A4 may alter risperidone plasma concentrations, but the clinical significance of such interactions seems to be minimal. Adherence to a few guidelines for the design of dosage regimens should limit the effect of drug-drug interactions on patient status and contribute to optimal pharmacotherapy with risperidone.

Anticonvulsants↗

The depressed suicidal patient. Assessment and treatment.

Depressive disorders are associated with significant psychosocial impairment and disability. Depression should be thoroughly evaluated, as should current and past suicidality and potential risk factors for suicide. Mortality by suicide characterizes the course of major affective disorders in approximately 15% of those suffering from these illnesses. Several neurobiological correlates of suicidality have been discovered. Treatment of depression with suicidality may involve hospitalization, pharmacotherapy, electroconvulsive therapy, and psychotherapy. Special populations include children and adolescents, the elderly, medically ill patients, patients with comorbid personality disorders, and patients with comorbid substance abuse disorders. Clinicians encountering patients with depressive disorders should be proficient in the assessment and treatment of depression with suicidality.

Adult↗

Neurokinin(1) receptor antagonists as potential antidepressants.

Selective, nonpeptide antagonists for tachykinin receptors first became available ten years ago. Of the three known tachykinin receptors, drug development has focused most intensively on the substance P-preferring receptor, neurokinin(1) (NK(1)). Although originally studied as potential analgesic compounds, recent evidence suggests that NK(1) receptor antagonists may possess antidepressant and anxiolytic properties. If confirmed by further controlled clinical studies, this will represent a mechanism of action distinct from all existing antidepressant agents. As reviewed in this chapter, the existing preclinical and clinical literature is suggestive of, but not conclusive, concerning a role of substance P and NK(1) receptors in the pathophysiology of depression and/or anxiety disorders. The ongoing clinical trials with NK(1) receptor antagonists have served as an impetus for much needed, basic research in this field.

Animals↗

Altered pituitary-adrenal axis responses to provocative challenge tests in adult survivors of childhood abuse.

OBJECTIVE: Early adverse life events may predispose individuals to the development of mood and anxiety disorders in adulthood, perhaps by inducing persistent changes in corticotropin-releasing factor (CRF) neuronal systems. The present study sought to evaluate pituitary-adrenal responses to standard hypothalamic-pituitary-adrenal axis challenge tests in adult female survivors of childhood abuse with and without major depressive disorder. METHOD: Plasma ACTH and cortisol responses to the administration of 1 microg/kg ovine CRF and plasma cortisol responses to the administration of 250 microg ACTH(1-24) were measured in healthy women without early life stress (N=20), women with childhood abuse without major depressive disorder (N=20), women with childhood abuse and major depressive disorder (N=15), and women with major depression but no early life stress (N=11). RESULTS: Abused women without major depressive disorder exhibited greater than usual ACTH responses to CRF administration, whereas abused women with major depressive disorder and depressed women without early life stress demonstrated blunted ACTH responses. In the ACTH(1-24) stimulation test, abused women without major depressive disorder exhibited lower baseline and stimulated plasma cortisol concentrations. Abused women with comorbid depression more often suffered from posttraumatic stress disorder and reported more recent life stress than abused women without major depressive disorder. CONCLUSIONS: These findings suggest sensitization of the anterior pituitary and counterregulative adaptation of the adrenal cortex in abused women without major depressive disorder. On subsequent stress exposure, women with a history of childhood abuse may hypersecrete CRF, resulting in down-regulation of adenohypophyseal CRF receptors and symptoms of depression and anxiety.

Adrenocorticotropic Hormone↗

Double-blind, placebo-controlled comparison of imipramine and paroxetine in the treatment of bipolar depression.

OBJECTIVE: This study compared the efficacy and safety of paroxetine and imipramine with that of placebo in the treatment of bipolar depression in adult outpatients stabilized on a regimen of lithium. METHOD: In a double-blind, placebo-controlled study, 117 outpatients with DSM-III-R bipolar disorder, depressive phase, were randomly assigned to treatment with paroxetine (N=35), imipramine (N=39), or placebo (N=43) for 10 weeks. In addition to lithium monotherapy, patients may have received either carbamazepine or valproate in combination with lithium for control of manic symptoms. Patients were stratified on the basis of trough serum lithium levels determined at the screening visit (high: >0.8 meq/liter; low: </=0.8 meq/liter). Primary efficacy was assessed by change from baseline in scores on the Hamilton Rating Scale for Depression and the Clinical Global Impression illness severity scale. RESULTS: Differences in overall efficacy among the three groups were not statistically significant. For patients with high serum lithium levels, antidepressant response at endpoint also did not significantly differ from placebo. However, both paroxetine and imipramine were superior to placebo for patients with low serum lithium levels. Compared to imipramine, paroxetine resulted in a lower incidence of adverse events, most notably emergence of manic symptoms. CONCLUSIONS: Antidepressants may not be useful adjunctive therapy for bipolar depressed patients with high serum lithium levels. However, antidepressant therapy may be beneficial for patients who cannot tolerate high serum lithium levels or who have symptoms that are refractory to the antidepressant effects of lithium.

Adult↗

Higher than normal plasma interleukin-6 concentrations in cancer patients with depression: preliminary findings.

OBJECTIVE: This study investigated whether cancer patients with and without major depression exhibit immune system abnormalities similar to those reported in medically healthy, depressed subjects without cancer. METHOD: The study subjects consisted of patients diagnosed with pancreatic, esophageal, or breast cancer. Other groups consisted of subjects with major depression (without cancer) and healthy comparison subjects. Subjects' diagnoses were made with the Structured Clinical Interview for DSM-III-R. Severity of depression was measured with the Hamilton Depression Rating Scale. Plasma concentrations of interleukin-6 (IL-6) and postdexamethasone cortisol were measured. RESULTS: Cancer patients with depression had markedly higher plasma concentrations of IL-6 than healthy comparison subjects and cancer patients without depression. Although significant correlations were found between Hamilton depression scale scores and plasma concentrations of postdexamethasone cortisol, no significant correlations were found between plasma IL-6 and postdexamethasone cortisol concentrations. CONCLUSIONS: Higher than normal plasma IL-6 concentrations were associated with a diagnosis of major depression in cancer patients. IL-6 may contribute to sickness behavior that has overlapping symptoms with major depression.

Adult↗

Clinical pharmacokinetics of quetiapine: an atypical antipsychotic.

Quetiapine is a dibenzothiazepine derivative that has been evaluated for management of patients with the manifestations of psychotic disorders. In pharmacokinetic studies in humans, quetiapine was rapidly absorbed after oral administration, with median time to reach maximum observed plasma concentration ranging from 1 to 2 hours. The absolute bioavailability is unknown, but the relative bioavailability from orally administered tablets compared with a solution was nearly complete. Food has minimal effects on quetiapine absorption. The drug is approximately 83% bound to serum proteins. Single and multiple dose studies have demonstrated linear pharmacokinetics in the clinical dose range (up to 375mg twice daily). The drug is eliminated with a mean terminal half-life of approximately 7 hours. The primary route of elimination is through hepatic metabolism. In vitro studies show that quetiapine is predominantly metabolised by cytochrome P450 (CYP) 3A4. After administration of [14C]quetiapine, approximately 73% of the radioactivity was excreted in the urine and 21% in faeces. Quetiapine accounted for less than 1% of the excreted radioactivity. 11 metabolites formed through hepatic oxidation have been identified. Two were found to be pharmacologically active, but they circulate in plasma at 2 to 12% of the concentration of quetiapine and are unlikely to contribute substantially to the pharmacological effects of the drug. The pharmacokinetics of quetiapine do not appear to be altered by cigarette smoking. Oral clearance declines with age, and was reduced in 2 of 8 patients with hepatic dysfunction but not in patients with renal impairment. Quetiapine has no effect on the in vitro activity of CYP1A2, 2C9, 2C19, 2D6 and 3A4 at clinically relevant concentrations. The lack of effect of quetiapine on hepatic oxidation was confirmed in vivo by the lack of effect of quetiapine on antipyrine disposition. Quetiapine had no effect on serum lithium concentration. Phenytoin and thioridazine increase the clearance of quetiapine, and ketoconazole decreases clearance. No clinically significant effects of cimetidine, haloperidol, risperidone or imipramine on the pharmacokinetics of quetiapine were noted. Quetiapine dosage adjustment, therefore, may be necessary when coadministered with phenytoin, thioridazine or other potent CYP3A4 inducers or inhibitors. The relationship between the therapeutic effects and the plasma concentrations of quetiapine has been investigated in a multicentre clinical trial. There was no statistically significant association between trough plasma quetiapine concentration and clinical response as measured by traditional assessments of psychotic symptom severity. Subsequent clinical studies of the plasma concentration versus effect relationships for quetiapine may help to further define guidelines for dosage regimen design.

Adolescent↗

Neurotensin and dopamine interactions.

Interactions between the classical monoamine neurotransmitter dopamine (DA) and the peptide neurotransmitter neurotensin (NT) in the central nervous system (CNS) have now been investigated for over two decades. Interest in this topic has been sustained, primarily because of the potential clinical relevance of these interactions to schizophrenia and drug abuse. In the past five years, important new discoveries in the NT field have markedly expanded our previous database. Additional NT receptors have been cloned, and novel and refined techniques have contributed to a more detailed description of the anatomy of the CNS NT system. Additionally, lipophilic NT receptor antagonists, active in the CNS after peripheral administration, have rendered more facile the investigation of the physiologic importance of endogenous NT at electrophysiologic, neurochemical, and behavioral levels. In the present review, the discussion of NT/DA interactions will progress from a discussion of the anatomical interactions between these two systems, to electrophysiologic and neurochemical interactions, and finally to behavioral implications-always with focus toward the potential clinical relevance of the data. The discussion of interactions between NT and DA systems will be limited to those occurring within the CNS. Moreover, because the DA projections from the midbrain to the striatum account for the bulk of the DA innervation in the CNS, we will focus on NT/DA interactions within these brain regions. Last, because of the extensive literature on NT/DA interactions available in the rat, our discussion will be based primarily on studies using this species.

Animals↗

The effects of acute antipsychotic drug administration on the neurotensin system of the developing rat brain.

The effects of antipsychotic drugs on the neurotensin (NT) system have been well characterized in adult male animals. There is considerable evidence that the NT system undergoes distinct age-related changes during development of the rat brain. This observation in conjunction with antipsychotic pharmacotherapy in children and breast feeding women led us to characterize the effects of antipsychotic drug administration in neonatal rats. The effects of a single subcutaneous injection of haloperidol (2.0 mg/kg) on the developing NT system were determined between postnatal days 10 and 21. Haloperidol significantly increased NT/neuromedin N (NT/NN) mRNA expression and NT concentrations in the caudate/putamen as early as postnatal day 10. Haloperidol did not increase NT/NN mRNA expression in the nucleus accumbens until postnatal day 15 and did not increase NT concentrations in this brain region until postnatal day 21. These results demonstrate that there is a critical time point in development before which the NT system does not respond to antipsychotic drug administration in the same manner as the mature rat.

Aging↗

Effects of early adverse experiences on brain structure and function: clinical implications.

Child abuse is associated with markedly elevated rates of major depression and other psychiatric disorders in adulthood. This article reviews preclinical studies examining the effects of early stress, factors that modify the impact of these experiences, and neurobiological changes associated with major depression. Preclinical studies demonstrate that early stress can alter the development of the hypothalamic-pituitary-adrenal axis, hypothalamic and extrahypothalamic corticotropin releasing hormone, monoaminergic, and gamma-aminobutyric acid/benzodiazepine systems. Stress has also been shown to promote structural and functional alterations in brain regions similar to those seen in adults with depression. Emerging data suggest, however, that the long-term effects of early stress can be moderated by genetic factors and the quality of the subsequent caregiving environment. These effects also can be prevented or reversed with various pharmacologic interventions. Preclinical studies of early stress can provide valuable insights in understanding the pathophysiology and treatment of major depression. They also can provide an important tool to use to investigate interactions between genes and environments in determining an individual's sensitivity to stress. More research is needed to understand how inherent factors interact with experiences of abuse and other psychosocial factors to confer vulnerability to develop depression.

Age Factors↗

The neurobiology of urocortin.

Urocortin (UCN) is a recently isolated 40 amino acid-containing neuropeptide that is the second endogenous mammalian ligand for the corticotropin-releasing factor (CRF) receptors. While UCN and CRF both display a similar high affinity for the CRF(1) receptor, the affinity of UCN for the CRF(2) receptor is more than 10-fold higher than that of rat/human CRF. UCN mRNA expression is highest in the Edinger-Westphal nucleus and lateral superior olive, with the most prominent terminal fields found in the lateral septum. Because of the higher relative affinity of UCN for the CRF(2) receptor and the corresponding neuroanatomical distribution of the highest density of UCN expression and innervation to brain regions preferentially expressing the CRF(2) receptor subtype, it has been hypothesized that UCN is the preferred endogenous ligand for the CRF(2) receptor. Following central administration, UCN has been demonstrated to produce behavioral and physiological effects that are qualitatively similar to CRF. Quantitatively, however, UCN appears to be a more potent suppressor of ingestive behavior (food and water intake) and a less potent inducer of anxiogenic behavior than CRF.

Animals↗

Growth hormone response to clonidine in adversely reared young adult primates: relationship to serial cerebrospinal fluid corticotropin-releasing factor concentrations.

A reduction of the growth hormone (GH) response to the alpha(2) adrenergic agonist clonidine is a neuroendocrine abnormality observed with reasonable consistency among human patients with mood and anxiety disorders. In previous primate studies, in comparison to predictably reared controls, monkeys exposed as infants to maternal variable foraging demand (VFD) rearing exhibited persistent elevations of cerebrospinal fluid (CSF) corticotropin-releasing factor (CRF), as well as other biological disturbances. As CRF has been demonstrated to inhibit GH release, the authors hypothesized that within VFD-reared subjects, animals with relatively high CRF concentrations would exhibit relatively diminished GH responses to clonidine. The current study examined the relationship between the GH response to clonidine in VFD-reared adult primates in relation to a range of both juvenile and follow-up CSF CRF concentrations. Nine bonnet macaques (Macaca radiata) were given ascending dosages of clonidine under ketamine anesthesia. Plasma samples for GH-like immunoreactivity were obtained throughout the session. A significant positive correlation was noted between juvenile CSF CRF concentrations and the levels of the neuropeptide observed in young adults. The mean of the serial CSF CRF concentrations exhibited a significant inverse relationship towards the GH response to clonidine in young adulthood, with relatively high CSF CRF associated with relatively attenuated GH responses to clonidine. These data raise the possibility that a reduced GH response to clonidine may inversely reflect trait-like increases of central nervous system (CNS) CRF activity.

Adrenergic alpha-Agonists↗

Pituitary-adrenal and autonomic responses to stress in women after sexual and physical abuse in childhood.

CONTEXT: Evidence suggests that early adverse experiences play a preeminent role in development of mood and anxiety disorders and that corticotropin-releasing factor (CRF) systems may mediate this association. OBJECTIVE: To determine whether early-life stress results in a persistent sensitization of the hypothalamic-pituitary-adrenal axis to mild stress in adulthood, thereby contributing to vulnerability to psychopathological conditions. DESIGN AND SETTING: Prospective controlled study conducted from May 1997 to July 1999 at the General Clinical Research Center of Emory University Hospital, Atlanta, Ga. PARTICIPANTS: Forty-nine healthy women aged 18 to 45 years with regular menses, with no history of mania or psychosis, with no active substance abuse or eating disorder within 6 months, and who were free of hormonal and psychotropic medications were recruited into 4 study groups (n = 12 with no history of childhood abuse or psychiatric disorder [controls]; n = 13 with diagnosis of current major depression who were sexually or physically abused as children; n = 14 without current major depression who were sexually or physically abused as children; and n = 10 with diagnosis of current major depression and no history of childhood abuse). MAIN OUTCOME MEASURES: Adrenocorticotropic hormone (ACTH) and cortisol levels and heart rate responses to a standardized psychosocial laboratory stressor compared among the 4 study groups. RESULTS: Women with a history of childhood abuse exhibited increased pituitary-adrenal and autonomic responses to stress compared with controls. This effect was particularly robust in women with current symptoms of depression and anxiety. Women with a history of childhood abuse and a current major depression diagnosis exhibited a more than 6-fold greater ACTH response to stress than age-matched controls (net peak of 9.0 pmol/L [41.0 pg/mL]; 95% confidence interval [CI], 4.7-13.3 pmol/L [21.6-60. 4 pg/mL]; vs net peak of 1.4 pmol/L [6.19 pg/mL]; 95% CI, 0.2-2.5 pmol/L [1.0-11.4 pg/mL]; difference, 8.6 pmol/L [38.9 pg/mL]; 95% CI, 4.6-12.6 pmol/L [20.8-57.1 pg/mL]; P<.001). CONCLUSIONS: Our findings suggest that hypothalamic-pituitary-adrenal axis and autonomic nervous system hyperreactivity, presumably due to CRF hypersecretion, is a persistent consequence of childhood abuse that may contribute to the diathesis for adulthood psychopathological conditions. Furthermore, these results imply a role for CRF receptor antagonists in the prevention and treatment of psychopathological conditions related to early-life stress. JAMA. 2000;284:592-597

Adrenocorticotropic Hormone↗

Increased corticotropin-releasing factor concentrations in the bed nucleus of the stria terminalis of anhedonic rats.

Chronic mild stress in rats is an antidepressant-responsive model for anhedonic symptoms of major depression. Many patients with depression exhibit alterations in hypothalamic-pituitary-adrenal axis activity, and corticotropin-releasing factor (CRF) neuronal function. This study investigated the potential involvement of CRF and CRF receptors in the development of chronic mild stress-induced anhedonia in rats. Rats were subjected to 19 days of chronic mild stress, during which time anhedonia was periodically assessed by determining the threshold for self-stimulation of the ventral tegmental area. Anhedonic rats exhibited a 50% increase in CRF concentrations in the bed nucleus of the stria terminalis compared to control rats. There were no significant changes in hypothalamic-pituitary-adrenal axis activity, CRF or CRF(1) receptor mRNA expression, or CRF receptor binding in the brain regions analyzed. Though preliminary, these results are consistent with the hypothesis that chronic stress-induced modulation of CRF function in specific brain structures such as the bed nucleus of the stria terminalis may contribute to the pathophysiology of depression.

Adrenocorticotropic Hormone↗

Sensitivity to glucocorticoid-mediated fast-feedback regulation of the hypothalamic-pituitary-adrenal axis is dependent upon stressor specific neurocircuitry.

UNLABELLED: Fos-protein immunoreactivity (Fos-IR) was used to identify neurocircuits potentially participating in the regulation of hypothalamic-pituitary-adrenal (HPA) axis sensitivity to glucocorticoid-mediated fast-feedback in rats exposed to the physical stressor, hemorrhage, or the psychological stressor, airpuff startle. Marked regional brain differences in the Fos-IR expression were observed in response to these stressors. Specifically, after hemorrhage, nuclear Fos-IR increased in the nucleus of the solitary tract and other brainstem regions known to regulate hemodynamic processes including the supraoptic nucleus, and the magnocellular division of hypothalamic paraventricular nucleus (PVN). In contrast, after airpuff startle Fos-IR increased in the dorsomedial and lateral hypothalamus as well as in the lateral septum. Thus, activation of brainstem neurocircuits predominated after hemorrhage whereas activation of forebrain neurocircuits predominated after airpuff startle. In other regions, the magnitude of stressor-induced Fos-IR expression varied in a region-specific manner. When stressor exposure was preceded by administration of corticosterone to achieve levels within the physiological range after stressors, HPA axis responses were suppressed in response to the airpuff startle but not to either a small or moderate hemorrhage. IN CONCLUSION: (1) fast-feedback mediated inhibition of HPA axis activity is critically dependent upon stressor modality; (2) this apparent selectivity is reflected by differences in the nature of the neurocircuitry mediating these stressors. It is suggested that determination of the central actions of glucocorticoids in mediating fast-feedback regulation of the HPA axis requires evaluation of the interactions between activated glucocorticoid receptors and intracellular signaling cascades evoked by convergent neuronal input.

Air Movements↗

A comparison of nefazodone, the cognitive behavioral-analysis system of psychotherapy, and their combination for the treatment of chronic depression.

BACKGROUND: Patients with chronic forms of major depression are difficult to treat, and the relative efficacy of medications and psychotherapy is uncertain. METHODS: We randomly assigned 681 adults with a chronic nonpsychotic major depressive disorder to 12 weeks of outpatient treatment with nefazodone (maximal dose, 600 mg per day), the cognitive behavioral-analysis system of psychotherapy (16 to 20 sessions), or both. At base line, all patients had scores of at least 20 on the 24-item Hamilton Rating Scale for Depression (indicating clinically significant depression). Remission was defined as a score of 8 or less at weeks 10 and 12. For patients who did not have remission, a satisfactory response was defined as a reduction in the score by at least 50 percent from base line and a score of 15 or less. Raters were unaware of the patients' treatment assignments. RESULTS: Of the 681 patients, 662 attended at least one treatment session and were included in the analysis of response. The overall rate of response (both remission and satisfactory response) was 48 percent in both the nefazodone group and in the psychotherapy group, as compared with 73 percent in the combined-treatment group. (P<0.001 for both comparisons). Among the 519 subjects who completed the study, the rates of response were 55 percent in the nefazodone group and 52 percent in the psychotherapy group, as compared with 85 percent in the combined-treatment group (P<0.001 for both comparisons). The rates of withdrawal were similar in the three groups. Adverse events in the nefazodone group were consistent with the known side effects of the drug (e.g., headache, somnolence, dry mouth, nausea, and dizziness). CONCLUSIONS: Although about half of patients with chronic forms of major depression have a response to short-term treatment with either nefazodone or a cognitive behavioral-analysis system of psychotherapy, the combination of the two is significantly more efficacious than either treatment alone.

Adult↗