Cerebrospinal fluid somatostatin and psychiatric illness

Somatostatin is a tetradecapeptide that is assuming increasing importance as a regulator of central nervous system activity. Originally identified as the hypothalamic growth hormone release-inhibiting factor, somatostatin has subsequently been shown to be extensively and selectively distributed throughout the central nervous system, to alter neuron excitability, to regulate and be regulated by the activity of classical neurotransmitters and neuropeptides, to exert a number of direct behavioral actions, and to display neuropsychiatric disorder-related alterations. In this article, a three-part study of cerebral spinal fluid (CSF) somatostatin in affective illness and schizophrenia is presented. In part 1, significant reductions in CSF somatostatin were observed in 49 bipolar and unipolar depressed patients relative to 47 controls. Values during depression were also significantly lower than those observed in affective disorder during the improved state or in schizophrenia. Diurnal studies involving paired AM and PM lumbar punctures revealed that depressed patients and normal volunteers had similar somatostatin values in the evening, despite having significantly different values in the morning. In part 2, the effects of several psychopharmacological agents on CSF somatostatin were examined, particularly the tricyclic anticonvulsant carbamazepine. A significant reduction of CSF somatostatin during treatment with carbamazepine was observed. The effect of carbamazepine on somatostatin could be related to its anticonvulsant, analgesic, or psychotropic effects. Part 3 deals with somatostatin as a major regulator of hypothalamic-pituitary-adrenal (HPA) axis activity. Somatostatin affects HPA activity by inhibiting, at a number of cellular levels, the stimulated release of adrenocorticotrophic hormone (ACTH) from the pituitary. A significant negative relationship between CSF somatostatin and the postdexamethasone plasma cortisol level in 22 depressed and 16 schizophrenic patients was observed. This relationship between low CSF somatostatin and escape from dexamethasone suppression was observed irrespective of diagnosis (i.e., depression or schizophrenia). Thus, there is indirect supporting evidence for a role for somatostatin dysregulation in the most consistently observed biological abnormality in depression, escape from dexamethasone suppression. Further study of somatostatin in neuropsychiatric disorders, and particularly depressive illness, offers great promise for better understanding their underlying affective, vegetative, cognitive, and physiological dysregulations.

Reduced TSH and prolactin responses to TRH in patients with panic disorder

The authors studied the TSH and prolactin responses to a standard 500-micrograms thyrotropin-releasing hormone (TRH) stimulation test in 12 patients with panic disorder and 10 control subjects. As a group, panic disorder patients had lower mean TSH and prolactin responses, and female patients accounted for the lower prolactin response. The clinical and theoretical implications of these findings are discussed.

CSF somatostatin and abnormal response to dexamethasone administration in schizophrenic and depressed patients

Low levels of cerebrospinal fluid (CSF) somatostatin and abnormal response to dexamethasone are two neuroendocrine disturbances reported to appear in depression and other neuropsychiatric disorders. We measured the levels of CSF somatostatin in patients with schizophrenia (n = 44) and depression (n = 19). In view of in vitro and animal evidence of the ability of somatostatin to inhibit stimulated corticotropin secretion, we also administered the dexamethasone suppression test to a subgroup of the patients with schizophrenia (n = 16) and the total depressed group. Lower levels of CSF somatostatin were found in dexamethasone nonsuppressors regardless of diagnosis and were negatively correlated with maximum postdexamethasone cortisol level in the total and depressed patient groups. These data suggest a functional relationship between hypothalamic-pituitary-adrenal axis hyperactivity and reduced CSF somatostatin level.

Dopaminergic effects of carbamazepine. Relationship to clinical response in affective illness

Carbamazepine, a drug used widely to treat epilepsy and trigeminal neuralgia, has been shown to be effective in the acute and prophylactic treatment of manic-depressive illness. While the time course of its antimanic effects parallels that of classic neuroleptics, indirect clinical evidence, such as lack of parkinsonian side effects and tardive dyskinesia, suggests that carbamazepine does not act by blocking dopamine receptors. To assess the effects of carbamazepine on dopamine mechanisms, we measured the dopamine metabolite homovanillic acid (HVA) in the cerebrospinal fluid of affectively ill patients before and after treatment. Carbamazepine did not alter basal concentrations of HVA, but decreased probenecid-induced accumulations of HVA, paralleling results in animal studies. In 25 patients, lower baseline cerebrospinal fluid HVA levels were related to subsequent better acute antidepressive responses to carbamazepine. While the precise mechanism of carbamazepine's effects on dopaminergic systems remains to be determined, this study provides further evidence that carbamazepine does not have a biochemical profile typical of neuroleptics.

Premenstrual mood changes. Characteristic patterns in women with and without premenstrual syndrome

Methodologic errors have compromised previous attempts to establish the relationship between mood and menstruation in women with the premenstrual syndromes. These syndromes cannot be diagnosed by history and require confirmation with longitudinal, prospective ratings. In this paper we present the characteristic pattern of mood changes in women with and without menstrually-related mood syndrome. The theoretical and diagnostic implications of the pattern differences are discussed.

Different neurotransmitter metabolite concentrations in CSF samples from inpatient and outpatient normal volunteers

Cerebrospinal fluid concentrations of the neurotransmitter metabolites 5-hydroxyindoleacetic acid (5HIAA), homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC) and 3-methoxy-4-hydroxyphenylglycol (MHPG) were compared in two groups of healthy volunteer subjects. One group (outpatient) was composed of 27 subjects who were transported to the outpatient clinic on the day of the lumbar puncture (LP). The other group (inpatient) was composed of 10 subjects who were admitted to the NIMH Research Ward on the evening prior to the LP. After statistical adjustment for age, height, sex and season in which LP was performed the inpatient group had significantly higher concentrations of both 5HIAA and HVA (P less than 0.005 and P less than 0.05, respectively) than the outpatient group. The difference in DOPAC concentration approached significance (P = 0.056), but there was no difference in MHPG concentration between the groups. This result indicates the need for strict control of environment in studies of CSF monoamines and their metabolites.

Premenstrual changes: a comparison of five populations

Several studies have suggested that a special relationship exists between premenstrual and major affective disorders. The present report describes the incidence of reported premenstrual symptoms in women with and without prospectively confirmed premenstrual syndrome, women with bipolar or seasonal affective disorder, and controls. The inability of reported symptoms to differentiate women with and without confirmed premenstrual syndrome, as well as the reduced prevalence of reported premenstrual changes in our affective populations relative to previous reports, is discussed.

Relation between plasma prolactin and plasma homovanillic acid in normal subjects

The relation between fasting, a.m. plasma prolactin and plasma/homovanillic acid (HVA) was studied in 9 healthy males on one occasion and in 9 healthy females on two occasions (in the follicular and luteal phase of the menstrual cycle). There was a significant inverse correlation between plasma HVA and plasma prolactin in females in the follicular phase only. The correlation between these two measures, although also in the same direction, was not significant in females in the luteal phase or in males. The theoretical implications of these findings are discussed.

Cortisol response to dexamethasone in women with premenstrual syndrome

There were no significant differences in post-dexamethasone cortisol between the follicular and luteal phase of the menstrual cycle in both women with premenstrual syndrome (PMS) and control subjects tested on these two occasions. Within each menstrual cycle phase, there were also no differences in post-dexamethasone cortisol between the two groups. In a second group of control subjects tested on a single occasion, post-dexamethasone cortisol values were higher when subjects were tested in the middle 2 weeks of the menstrual cycle compared with the first and last weeks of the cycle. This phenomenon, possibly due to estrogen effects, suggests that post-dexamethasone cortisol should be assessed weekly in women with PMS to determine whether they also manifest this normally observed menstrual cycle phase-related pattern, or whether it is absent, reflecting a reproductive endocrine abnormality in this patient group.

Effect of carbamazepine on mean urinary free cortisol excretion in patients with major affective illness

Carbamazepine, a tricyclic anticonvulsant effective in the treatment of major affective disorder, has been observed to induce cortisol non-suppression following dexamethasone administration. The mechanism of this effect has not been clearly established. In this study, the authors report carbamazepine-induced elevations of mean urinary free cortisol in patients with affective illness. The theoretical and practical implications of these findings are discussed.

Premenstrual mood disorder and psychiatric illness

The results of several studies suggest that a special relationship exists between premenstrual syndromes and major psychiatric disorders, particularly affective illness. These studies in general have not employed prospective criteria to diagnose premenstrual syndrome. In this paper the authors report a significant difference in the lifetime history of psychiatric illness between women with prospectively confirmed menstrually related mood disorder and those without it.

Premenstrual syndromes: past and future research strategies

Premenstrual Syndrome remains a poorly understood controversial disorder largely because of the errors in design found in research into this subject. The first task is to clearly define the entity to be studied. It is necessary to look at the nature, intensity and time of occurrence of symptoms in relation to menstruation. One must further differentiate the appearance of symptoms premenstrually from the premenstrual exacerbation of symptoms present throughout the menstrual cycle. Research has clearly shown the superiority of prospective versus retrospective data in establishing a linkage between symptoms and menstruation. Premenstrual Syndrome research offers a unique opportunity to study classical psychiatric disorders. A relationship appears to exist between this syndrome and major affective disorders. Studies of the appearance or exacerbation of mood disturbances in relation to the menstrual cycle may inform us about the development, course and vicissitudes of psychiatric illness.

Effects of carbamazepine on cerebrospinal fluid somatostatin

This paper reports the reduction of the concentration of the neuropeptide somatostatin in the CSF of patients with affective illness during treatment with the anticonvulsant carbamazepine. None of the other psychotropic agents used in this study similarly affected CSF somatostatin, although zimelidine appeared to increase CSF somatostatin in a small number of patients. The potential mechanism and significance of the effects of carbamazepine on CSF somatostatin are discussed in relation to the psychotropic, anticonvulsant, and analgesic properties of carbamazepine.

Effects of carbamazepine on noradrenergic mechanisms in affectively ill patients

Noradrenergic mechanisms have been postulated to account for the anticonvulsant and psychotropic effects of carbamazepine. In order to assess this possibility in man, cerebrospinal fluid (CSF) was obtained from affectively ill patients before and during treatment with carbamazepine (average duration 29 days) at doses averaging 860 mg/day, achieving blood levels of 8.86 micrograms/ml. Neither plasma nor CSF norepinephrine (NE) nor CSF 3-methoxy-4-hydroxy-phenylglycol (MHPG) was significantly altered by carbamazepine. Baseline medication-free values in 21 depressed patients were not predictive of the degree of subsequent clinical antidepressant response. CSF NE decreased in four manic patients treated with carbamazepine. The many effects of carbamazepine on noradrenergic mechanisms in animals are discussed in relationship to these first studies of carbamazepine in man.

Relationship between cerebrospinal fluid somatostatin and peripheral thyroid hormones with carbamazepine treatment

The relationship between CSF somatostatin and peripheral thyroid hormones was assessed in 11 affectively ill patients before and during carbamazepine treatment. A direct relationship between CSF somatostatin and plasma thyroxine and free thyroxine, but not triiodothyronine, was observed both while patients were medication-free and during carbamazepine treatment. These first data in man are consistent with those in animals, suggesting a close interrelationship between somatostatin and thyroid regulation.

CSF somatostatin in affective illness and normal volunteers

Somatostatin is a hypothalamic tetradecapeptide with many central nervous system actions. We investigated a potential role for altered somatostatin activity in affective disorder by measuring somatostatin in the cerebrospinal fluid (CSF) of 47 patients with affective disorder and of 39 normal volunteers. Medication-free depressed patients showed significantly lower levels of CSF somatostatin than normal volunteers (p less than .001) or patients during the improved state (p less than .01). Somatostatin levels were significantly and inversely correlated with duration of sleep on the night of the lumbar puncture (p less than .05). Treatment with carbamazepine reduced CSF somatostatin (p less than .01) in contrast to the absence of effect of imipramine, desmethylimipramine, and lithium carbonate and the significant increase in CSF somatostatin seen in a small group of patients treated with zimelidine. The implications of these findings with respect to attempts to explore the neurobiology of depression are discussed.

Possible antidepressant effect of oral contraceptives: case report

An oral contraceptive was used successfully to treat recurrent premenstrual depressions and a subsequent major depressive episode in a 20-year-old woman. The relationship between premenstrual and major depressions is explored and the overlapping CNS effects of gonadal steroids and classical antidepressants are discussed.

Prospective assessment of menstrually related mood disorders

For prospective longitudinal confirmation of menstrually related mood changes, the authors selected a 100-mm visual analogue scale for twice-daily self-rating of mood. The advantages of this method are simplicity; increased compliance; ease of graphic presentation, allowing evaluation of severity and relationship to menstruation; and greater uniformity among studies of menstrually related syndromes. In a preliminary application of this measure to 20 women with self-diagnosed premenstrual syndrome, eight (40%) had a mean depression rating during the week before menstruation that was 30% higher than during the week after cessation of menstruation.

Cortisol hypersecretion and cognitive impairment in depression

We attempted to investigate the relationship between hypothalamic-pituitary-adrenal axis activity and cognitive function by measuring mean urinary free cortisol (MUFC) excretion and performance on the Halstead Category Test in depressed patients and normal controls. We observed a significant relationship between category test errors and MUFC in the depressed patients, but not in the controls. While an even more robust correlation was observed between age and category test errors in the patients, it appeared that age and depression interacted to produce severe cognitive impairment. Depression-related cortisol hypersecretion or its underlying determinants may contribute to depression-related cognitive dysfunction.

Premenstrual syndromes: overview from a methodologic perspective

The authors review the available evidence regarding the nature, cause, and treatment of the premenstrual syndromes. They attribute the contradictory results of various studies and the current theoretical confusion in the area to the failure of investigators to carefully define the syndromes, formulate a set of answerable questions, and select a homogeneous population before initiating their studies. The relationship between premenstrual syndromes and major psychiatric disorders, as well as the clinical and theoretical relevance of the menstrual cycle to major psychiatric disorders, is discussed. The authors offer recommendations to both investigators and clinicians for more careful observation and documentation of the relationship between mood disorders and the menstrual cycle.

CSF 5HIAA and personal and family history of suicide in affectively ill patients: a negative study

Personal and family histories of suicidality were gathered in 45 patients who met Research Diagnostic Criteria for major affective disorder (n = 32, bipolar; n = 13, unipolar) and compared to CSF values of 5HIAA obtained by two different assays (n = 20, fluorometric; n = 25, high performance liquid chromatography). In separate analyses of the two assay groups, patients who had made a suicide attempt were not significantly different from those who had not in terms of 5HIAA value or family history of suicidality. Furthermore, in suicide attempters, 5HIAA was unrelated to the severity of the attempt.

Carbamazepine diminishes the sensitivity of the plasma arginine vasopressin response to osmotic stimulation

Carbamazepine, a drug used to treat manic-depressive illness, has been reported to possess antidiuretic properties, but its effects on arginine vasopressin (AVP) secretion are controversial. Consequently, we examined plasma AVP secretion during hypertonic (5%) saline infusion in seven manic-depressive patients while on placebo and after 3-5 weeks of carbamazepine treatment. We also measured carbamazepine's effects on basal levels of the hormone in cerebrospinal fluid. Carbamazepine significantly reduced the sensitivity of the plasma AVP response to osmotic stimulation without affecting the osmotic threshold for AVP secretion. Moreover, carbamazepine did not affect baseline weight, plasma osmolality, plasma sodium, urine output, plasma AVP, or cerebrospinal fluid AVP. Although the functional significance of these findings remain to be fully determined, the fact that carbamazepine significantly reduced AVP secretion without inducing diuresis supports previous suggestions that carbamazepine enhances renal responsivity to available AVP. In addition, since carbamazepine failed to affect the osmotic threshold, the reported cases of carbamazepine-induced inappropriate AVP secretion and water intoxication must be very uncommon and probably represent idiosyncratic responses.

RBC membrane adenosine triphosphatase activities in patients with major affective disorders

Red blood cell Na+, K+-, Mg2+-, and Ca2+-adenosine triphosphatase (ATPase) activities were studied longitudinally in eight patients with affective disorders and 12 healthy volunteers. The patients had a higher mean Ca2+-ATPase activity than the volunteers, and the fluctuations in all three ATPase activities were greater in the patients than in the volunteers. Even though the mean Ca2+-ATPase activity was higher during manias and euthymic periods than during depressions, mood and ATPase activities did not correlate with each other in all patients. Lithium carbonate treatment did not alter the ATPase activities, and the quantity of vanadium present in the membranes could not account for the variations in the enzyme activities observed. We suggest that either the RBCs of manic-depressive patients are very sensitive to fluctuations of a lipophilic ATPase activity--regulating factor present in plasma or the patients have at times high levels of such a factor. In some patients, the level of this hypothesized regulator may fluctuate in synchrony with mood changes.

Research strategies at the interface of medicine and psychiatry

The rapid growth of the neurosciences in the past decade has served to blur the differences and enhance the similarities between research in medicine and in psychiatry. As the number of relevant biological variables and the questions asked in relation to them has expanded, so has the number of medical disorders of interest to the clinical researcher in psychiatry. In addition to these new areas of common interest, consultation-liaison psychiatry and clinical psychiatric research share a common conceptual foundation based upon model development and testing. It is proposed, therefore, that research at the interface between medicine and psychiatry represents a new frontier for both consultation-liaison psychiatry and clinical psychiatric research. Goals and strategies for research at the interface are discussed with specific reference to current research efforts at the National Institutes of Health.