The psychobiology of dysphoric mania.
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Bipolar Disorder↗
Biomedical subjects
R M Post
Publications and source records attributed to R M Post.
Conditioned components of cocaine sensitization.
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Animals↗
Mechanisms of action of anticonvulsants in affective disorders: comparisons with lithium.
Until recently it appeared that lithium carbonate possessed a unique spectrum of clinical action in the acute and prophylactic treatment of manic and depressive episodes. It is now increasingly apparent that the anticonvulsants carbamazepine and valproate also share components of this spectrum of efficacy in the affective disorders but, in addition, are clinically effective in some lithium nonresponders. This clinical convergence can now drive a reexamination of the potential mechanisms of action of these compounds in the affective disorders. In spite of intensive study over several decades, the mechanism of action of lithium has remained elusive. A basic conundrum in the consideration of the actions of lithium has also been to explain how a simple ion could have such complex effects on multiple neurotransmitter systems and, in particular, have bimodal actions in the treatment of both manic and depressive phases of the illness. We suggest that a fundamental reconceptualization of both mania and depression as overactivated neural systems (either excitatory or inhibitory) could facilitate this conceptualization. Given the recent evidence linking lithium's effects to uncoupling receptor-mediated activity at the level of G-proteins or attenuating it at the level of second messenger systems mediated by adenylate cyclase or phosphoinositide turnover, these mechanisms become ideal candidates for considering how the drug could dampen overactivated systems potentially relevant to either depression or mania. The lag in onset of maximum therapeutic action of lithium, carbamazepine, and valproate further suggests that biologic effects associated with chronic compared with acute administration are the prime candidates for psychotropic effects. Comparison of the acute and chronic effects of carbamazepine with those of valproate is also offered to focus on the most likely receptor, second-messenger, and ion channel mechanisms involved in their anticonvulsant and psychotropic actions. It is hoped that better understanding of the comparative actions of lithium, carbamazepine, and valproate will allow better targeting of individual drugs for individual patients as well as, ultimately, the development of new and more selective treatments for the recurrent affective disorders.
Anticonvulsants↗
Lithium-discontinuation-induced refractoriness: preliminary observations.
The authors used a systematic life-chart methodology to observe four patients with bipolar disorder in whom long periods (6-15 years) of effective lithium prophylaxis were followed by relapses on lithium discontinuation. Once the drug was reinstituted, it was no longer effective. The incidence, predictors, and mechanisms underlying this phenomenon all require further systematic study. The current preliminary observations suggest an additional reason for caution when lithium discontinuation in the well-maintained patient is considered.
Bipolar Disorder↗
Transduction of psychosocial stress into the neurobiology of recurrent affective disorder.
Early clinical observations and recent systematic studies overwhelmingly document a greater role for psychosocial stressors in association with the first episode of major affective disorder than with subsequent episodes. The author postulates that both sensitization to stressors and episode sensitization occur and become encoded at the level of gene expression. In particular, stressors and the biochemical concomitants of the episodes themselves can induce the protooncogene c-fos and related transcription factors, which then affect the expression of transmitters, receptors, and neuropeptides that alter responsivity in a long-lasting fashion. Thus, both stressors and episodes may leave residual traces and vulnerabilities to further occurrences of affective illness. These data and concepts suggest that the biochemical and anatomical substrates underlying the affective disorders evolve over time as a function of recurrences, as does pharmacological responsivity. This formulation highlights the critical importance of early intervention in the illness in order to prevent malignant transformation to rapid cycling, spontaneous episodes, and refractoriness to drug treatment.
Animals↗
Contingent tolerance and reresponse to carbamazepine: a case study in a patient with trigeminal neuralgia and bipolar disorder.
This retrospective single-case study demonstrates the development of tolerance and reresponse to carbamazepine in a patient with coexisting trigeminal neuralgia and manic-depressive illness. After an initial positive response, tolerance to the antinociceptive and psychotropic effects of carbamazepine appeared during treatment, despite increasing doses. As in preclinical studies of contingent tolerance, periods of carbamazepine discontinuation were associated with reresponse following reinstitution. These are the first clinical data interpreted in a contingent tolerance formulation with reresponse following a medication-free interval. Controlled and prospective studies are needed of the reliability and the pathophysiological and therapeutic implications of this phenomenon.
Aged↗
A clarification of alpidem as an antidepressant.
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Antidepressive Agents↗
Carbamazepine-induced increases in total serum cholesterol: clinical and theoretical implications.
To assess the effect of carbamazepine (CBZ) upon total serum cholesterol, we examined 38 inpatients with affective illness and one with multiple personality disorder who received a course of CBZ monotherapy. CBZ therapy yielded significant increases in total serum cholesterol that became evident during the second week of therapy, persisted throughout therapy, and reversed in the first few weeks after discontinuation of therapy. CBZ-induced increases in total cholesterol appeared independent of initial mood state, diagnostic subtype, baseline cholesterol or thyroid indices; CBZ levels, doses, and level-to-dose ratios; and the degree of change in mood and thyroid indices. CBZ induction of enzymes mediating cholesterol synthesis is a possible mechanism of the increase in total cholesterol observed with CBZ therapy. Although preclinical studies suggest possible influence of cholesterol on neurotransmitter regulation and behavior, clinical studies have yielded conflicting data. There are insufficient data to support a role for cholesterol in the anticonvulsant and psychotropic mechanisms of CBZ. The increase in total serum cholesterol seen with CBZ therapy is likely due to an increase in the high density lipoprotein fraction and is thus not likely to be clinically problematic in relationship to atherosclerosis.
Adult↗
Synergy of carbamazepine and valproic acid in affective illness: case report and review of the literature.
Carbamazepine and valproic acid are anticonvulsants with mood-stabilizing properties. Basic and clinical research suggest that these medications used together may have synergistic anticonvulsant effects. Psychotropic synergy of the combination has yet to be explored systematically. We present the case of a patient with rapid-cycling bipolar disorder studied under double-blind conditions whose hypomanias and depressions were refractory to either carbamazepine or valproic acid alone, but responded dramatically to the combination. The superior response to the combination appeared to be due to pharmacodynamic rather than pharmacokinetic effects. The clinical and theoretical aspects of the use of carbamazepine and valproic acid in combination are discussed.
Bipolar Disorder↗
Evidence for hypothalamo-growth hormone dysfunction in panic disorder: profile of growth hormone (GH) responses to clonidine, yohimbine, caffeine, glucose, GRF and TRH in panic disorder patients versus healthy volunteers.
Given the abrupt and time-limited nature of daytime-awake and nocturnal-sleep panic attacks, several chemical and neuroendocrine challenge tests have been employed to investigate the neurobiology of "spontaneous" panic attacks. Previously we demonstrated that panic disorder patients have blunted growth hormone (GH) responses to clonidine, an alpha 2-adrenergic agonist. However, the mechanism of this blunted response and the role of hypothalamic-GH dysfunction, if any, remains unclear. To further delineate the status of hypothalamic-GH function in panic disorder, we review the literature and present original data on the GH responses to a number of different chemical and neuroendocrine challenge paradigms. Although stress-mediated increases in GH are thought to be a common correlate of stress in humans, our findings indicate that panic disorder patients have significantly blunted GH responses to clonidine, yohimbine, growth-hormone releasing factor, and caffeine compared to normal control subjects. A similar trend was noted in the delayed rise in GH after glucose challenge. There was no difference in the rate of abnormal GH responses to thyrotropin-releasing hormone in panic disorder compared to normal control subjects. No drug or neuroendocrine challenge, even if associated with marked increases in anxiety, produced a significantly enhanced GH response compared to normal control subjects. These findings provide support for a hyporesponsive hypothalamic-GH system in panic disorder. These observations, combined with preliminary observations from our clinic of short stature in several cases of prepubescent children with anxiety disorders, also underscore the need for assessing early growth patterns in individuals with panic disorder. Strategies for investigating the site(s) of possible neurotransmitter or hypothalamic-GH-somatomedin dysfunction are discussed.
Caffeine↗
Expression of c-fos mRNA in rat brain after intracerebroventricular administration of corticotropin-releasing hormone.
Expression of the proto-oncogene c-fos is known to increase in rat brain following various types of seizures. Measuring c-fos mRNA or protein levels was shown to be a good cellular marker for neurons activated during central nervous system (CNS) excitation. In this study, we used in situ hybridization analysis of c-fos mRNA to determine brain regions activated by a peptide that has been closely linked to stress responsivity and kindling-like seizure activity. Corticotropin-releasing hormone (CRH) was injected into the left lateral ventricle of rats and produced the late onset of seizures between 1.5-5 h after its administration. Rats were sacrificed at various time points after the administration of CRH or sterile water, and c-fos mRNA levels were determined. In the preseizure state, CRH increased c-fos unilaterally in several cerebral cortical structures (most prominently in the dorsal endopiriform nucleus and in the piriform and insular cortices). CRH-induced seizures increased c-fos bilaterally in the same cortical regions, and in addition, in the hippocampus and olfactory bulb. The data are congruous with the hypothesis that intracerebroventricularly (i.c.v.) administered CRH elicits a rapid kindling-like response.
Animals↗
The effects of carbamazepine on resting metabolic rate and thyroid function in depressed patients.
Resting metabolic rate and thyroid hormone levels were studied in 11 patients with affective disorders before and during treatment with carbamazepine (CBZ). CBZ has been previously reported to reduce thyroid hormones, but the metabolic consequence of this effect has not been explored. During CBZ treatment, thyroid hormones decreased significantly (T4, 7.53 versus 5.74 micrograms/dl, p less than 0.001), whereas the resting metabolic rate (RMR) did not (31.6 versus 30.7 kcal/m2/hr). Baseline RMRs were low and the expected positive relationship between RMR and weight was disrupted in females. The extent of previous exposure to tricyclic and monoamine oxidase inhibitors antidepressant treatment was significantly associated with lower baseline RMRs. We conclude that CBZ has no significant effect on RMR despite robust decreases in thyroid function.
Adult↗
Onset of panic disorder associated with rare use of cocaine.
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Adult↗
Contingent tolerance to carbamazepine: a peripheral-type benzodiazepine mechanism.
Rats were tested for anticonvulsant responsivity to agents active at central and peripheral-type benzodiazepine receptors before and after they were made tolerant to the anticonvulsant effects of carbamazepine on amygdala-kindled seizures. Tolerance to carbamazepine in this paradigm is a contingent process; it occurs when the drug is administered prior to, but not following the kindled seizure. In animals tolerant to carbamazepine, cross-tolerance was observed to the anticonvulsant effects of PK11195, which is active at peripheral-type benzodiazepine receptors, but not to diazepam, which affects central-type benzodiazepine receptors. In animals treated with carbamazepine after the kindled seizure (not tolerant), no alteration in the anticonvulsant effect of PK11195 was observed. These data extend previous biochemical and pharmacological findings suggesting the importance of peripheral-type benzodiazepine receptor mechanisms in the anticonvulsant effects of carbamazepine and suggest a role for this site in the process of contingent tolerance development.
Amygdala↗
Contingent tolerance to carbamazepine is associated with lowering of amygdala-kindled seizure thresholds.
Amygdala-kindled seizure thresholds were studied in animals which were or were not tolerant to the anticonvulsant effects of carbamazepine. The seizure threshold was defined as the lowest current that elicited a major motor seizure (stage 3 or greater). Amygdala-kindled rats received carbamazepine, once daily, either before each electrical stimulation (carba-before) or after each stimulation (carba-after). The rats given carbamazepine before, but not after, each once-daily kindling stimulation became tolerant to its anticonvulsant effects. Following this manipulation, seizure thresholds were redetermined in both groups of animals while medication-free. The carba-before (i.e., tolerant) animals showed a decreased seizure threshold, while the carba-after (i.e., nontolerant) animals showed no change. Tolerance to carbamazepine was reversed by giving the rats kindled seizures for a period of 7 days without drug; nontolerant animals received the same stimulation and seizures. When seizure thresholds were reevaluated, the carba-before animals (now not tolerant) had returned to their pretolerance values, while the carba-after group again showed no change. This effect of carbamazepine tolerance and its reversal being associated with respective decreases and increases in basal seizure threshold was replicated two more times. In each case the change in the generalized seizure threshold mirrored the change in responsivity of the animals to carbamazepine. These findings, consistent with the formulations of Siegel regarding conditioned compensatory response mechanisms mediating contingent drug tolerance, may have important clinical and theoretical implications.
Amygdala↗
Regional expression of c-fos mRNA in rat brain during the evolution of amygdala kindled seizures.
The biochemical alterations eliciting the growth and spread of afterdischarge and accompanying the evolution of behavioral seizure stages in electrical kindling are not known. In situ hybridization for c-fos mRNA was used to map potential brain structures recruited during the evolution of major seizures from electrical kindling of the amygdala in rats. Two different patterns of c-fos induction were observed in the earliest stages of kindling (stages 1 and 2). A unilateral cortical distribution included the insular, temporal, perirhinal and parietal cortices and the amygdala. No changes in the hippocampus were noted in this group. The second distribution pattern was limited to the hippocampus (either unilateral or bilateral) and amygdala (unilateral) with no changes in the cortical areas. The afterdischarge durations were significantly (2 fold) longer in the 'hippocampal' group as compared to the 'cortical' group. In the later stages of kindling (stages 4 and 5) the distribution of c-fos mRNA was uniformly bilateral and involved a combination of the hippocampal and cortical distributions observed in the earlier stages and including the amygdala bilaterally as well. The induction of c-fos mRNA appears to provide a map of two different routes in the sequential pathways involved in the evolution of kindled seizures; it may also ultimately prove to be an important component of the kindling process itself. Additionally, c-fos mRNA was elevated bilaterally in the inferior colliculus of animals exhibiting running fits with their seizures. The inferior colliculus was previously shown by others to be involved in running fits accompanying convulsions.
Amygdala↗
Lack of beneficial effects of l-baclofen in affective disorder.
GABAB mechanisms have been implicated in the antinociceptive, but not anticonvulsant effects of carbamazepine. A variety of antidepressants have been reported to upregulate GABAB receptors after chronic administration. The GABAB agonist l-baclofen was studied in depressed patients based on two separate rationales. l-Baclofen, in doses ranging from 10-55 mg/day, was administered to five patients with primary affective disorder. No patient showed a positive clinical response, while three patients showed a pattern of increasing depression or cycling during treatment and improvement during withdrawal. These preliminary data suggest that GABAB agonism is unlikely to produce antidepressant effects and may be unrelated to the mechanism of carbamazepine's antidepressant action. These data, taken with a reinterpretation of other findings that antidepressant modalities upregulate GABAB receptors in brain following chronic administration, suggest that GABAB antagonism rather than agonism may be a fruitful clinical strategy to explore in depression.
Adult↗
Cerebrospinal fluid immunoreactive corticotropin-releasing hormone and adrenocorticotropin secretion in Cushing's disease and major depression: potential clinical implications.
To explore whether possible differences in central nervous system neuromodulators contribute to the differential presentation of affective symptomatology in Cushing's disease and major depression, we examined the levels of immunoreactive CRH and ACTH in the cerebrospinal fluid (CSF) of 11 patients with Cushing's disease, a patient with ectopic ACTH secretion, 34 patients with major depression, and 60 healthy subjects. We elected to measure these peptides not only because both are classically involved in pituitary-adrenal regulation, but also because their primarily arousal-producing and anorexigenic behavioral effects in experimental animals suggest that they may play a role in the symptom complex of depressive syndromes. We also explored whether the CSF levels of these peptides were more helpful in determining the often difficult differential diagnosis between major depression and Cushing's disease than the plasma ACTH response to ovine CRH, a currently used but somewhat insensitive laboratory means of distinguishing these disorders. CSF levels of immunoreactive CRH and ACTH were significantly lower in Cushing's disease patients [21.9 +/- 2.7 and 15.4 +/- 1.8 pg/mL, (mean +/- SEM), respectively] compared to patients with major depression [38.4 +/- 2.3 pg/mL (P less than 0.01) and 24.5 +/- 1.6 pg/mL (P less than 0.01), respectively] and controls [38.4 +/- 1.6 pg/mL (P less than 0.001) and 26.3 +/- 1.1 pg/mL (P less than 0.001), respectively]. The coexistence of high plasma ACTH and low CSF ACTH in Cushing's disease yielded a CSF/plasma ACTH ratio consistently less than that in depressed patients, with only 2 of 31 subjects comprising both groups showing values that overlapped. In contrast, 9 of the combined patients showed ACTH responses to ovine CRH that overlapped. These data suggest that differences in centrally directed CRH secretion may account for the differential presentation of the dysphoric syndromes seen in major depression and Cushing's disease. Hence, the classic form of major depression (melancholia), is often associated with evidence of pathological hyperarousal, such as intense anxiety, sleeplessness, and anorexia, while that of Cushing's disease is associated with evidence of pathological hyperarousal, including hyperphagia, fatigue, and inertia. Moreover, measurement of the CSF/plasma ACTH ratio may serve as a clinically useful adjunct to the ovine CRH stimulation test and other laboratory measures in determining the differential diagnosis between major depression and Cushing's disease.
Adolescent↗