Effects of thyroid state on preference for and sensitivity to ethanol in Fischer-344 rats

1. It has been reported by several groups that thyroid status can alter ethanol preference in rats. However, results using different methods and different strains of rats have not been consistent. 2. In this study, thyroidectomy or T4 augmentation was used to produce hypothyroidism or hyperthyroidism, respectively, in adult male Fischer-344 rats. 3. Preference for weak solutions (4 or 5%) of ethanol or tap water and ethanol-induced sedation and hypothermia were compared in hypothyroid, hyperthyroid and euthyroid rats. 4. No significant differences in preference indices (the ratios of ethanol to total liquid consumed) among the three groups were observed; however, for ethanol to contribute a greater portion of total calories ingested by hypothyroid rats than by euthyroid or hyperthyroid rats. 5. The duration of sleep resulting from a single i.p. injection of 2.5 mg/kg ethanol was increased (by 34%) in hyperthyroid rats and decreased (by 16%) in hypothyroid rats compared to euthyroid controls. Only the effect of hyperthyroidism was significant at the 0.05 level. 6. Colonic temperatures differed with thyroid state (hyperthyroid > euthyroid > hypothyroid) but the decrease produced by ethanol did not differ by thyroid state. 7. Observed differences in ethanol-induced sedation are consistent with differences in brain TRH levels and effects on neurotransmitter systems associated with different thyroid states.

[Psychotic manifestation of hypothyroidism. A case report]

The case of a young woman is reported, who was treated one and a half years with psychopharmacologic agents and psychotherapy until hypothyroidism was diagnosed. Initially the psychopathology with prominent though disorders led to a tentative diagnosis of schizophrenia. Under administration of thyroid hormone the patient was free of psychiatric and somatic symptoms within 3 months. Problems of diagnosis, therapy and prognosis are discussed in relation of the literature.

Subclinical hypothyroidism: neurobehavioral features and beneficial effect of L-thyroxine treatment

Frank hypothyroidism is known to induce neurological and mental dysfunction. The aim of this study was to assess selected neuropsychological and behavioral features by means of standardized tests in a group of 14 patients with subclinical hypothyroidism who were free from neuropsychological complaints and to evaluate the possible effects of L-thyroxine treatment on their performance. Patients were submitted to the Crown and Crisp Experiential Index and to the Wechsler Memory Scale; their ratings on the neurobehavioral tests and their thyroid hormone profile were compared to those of a control group of 50 age- and sex-matched subjects. Comparison was also carried out between pretreatment ratings and those obtained following a 6-month L-thyroxine course (0.1-0.15 mg/day). The Wechsler Memory Scale ratings showed a significant impairment in patients' memory-related abilities [memory quotient (MQ) = 89.1 +/- 2.9; P = 0.002 (patients versus controls)]; the Crown and Crisp Experiential Index ratings demonstrated moderate differences between untreated patients and controls with respect to hysteria (P = 0.03), anxiety (P = 0.05), somatic complaints (P = 0.0005), and depressive features (P = 0.002) scales; the total score was also significantly higher (42.0 +/- 3.8; P = 0.005). After L-thyroxine treatment the patients' performances showed an improvement in memory skills, as evaluated by the Wechsler Memory Scale [MQ = 99.9 +/- 4.0; P = 0.002 (treated versus untreated)]; somatic complaints (P = 0.02) and obsessionality (P = 0.04) ratings and the Crown and Crisp Experiential Index total score (P = 0.04) significantly decreased with respect to untreated patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of perinatal hypo- and hyperthyroidism on the levels of nerve growth factor and its low-affinity receptor in cerebellum

Deficits or excesses of thyroid hormones during critical periods of mammalian cerebellar development can lead to profound biochemical and morphological abnormalities in this system. The goal of this study was to investigate the effects of perinatal hypo- and hyperthyroidism on the ontogeny of nerve growth factor (NGF) and its low-affinity receptor (p75NGFR) in the rat cerebellum. The concentration of NGF and of p75NGFR immunoreactivity (IR) were measured, several days after birth, in cerebella of rats which had received propylthiouracil (PTU) or thyroxine. NGF concentration was markedly enhanced only on postnatal day 2 (P2) in hyperthyroid rats, whereas in hypothyroid (PTU-treated) rats NGF values were similar to age-matched controls. These observations suggest that thyroid hormone affects NGF synthesis during early periods of cerebellar development. In Purkinje cells of control animals, p75NGFR IR peaked at P10. In hypothyroid rats, the expression of p75NGFR was retarded, peaking at P15, whereas in hyperthyroid rats it was advanced, peaking at P8. The increased p75NGFR IR found in Purkinje cell bodies and the delayed disappearance of p75NGFR IR from the external granular layer of hypothyroid rats suggest different roles for thyroid hormone in the developing cerebellum. We conclude that p75NGFR and NGF are independently regulated by thyroid hormone during critical periods of cerebellar development. The effect of thyroid hormone deficiency on p75NGFR content in Purkinje cells may involve complex mechanisms such as impaired efficiency of axonal transport.

Psychologic and psychoeducational consequences of thyroxine therapy for juvenile acquired hypothyroidism

The observation of severe behavioral reactions or learning problems in three teenagers treated with L-thyroxine for juvenile acquired hypothyroidism prompted us to conduct a prospective study of achievement and behavioral characteristics of patients with newly diagnosed juvenile acquired hypothyroidism. On diagnosis of juvenile acquired hypothyroidism and before treatment with L-thyroxine, 23 children and adolescents underwent a comprehensive battery of psychoeducational tests, which was repeated after 3, 12, and 24 months of replacement therapy. Results revealed that adverse behavioral reactions and learning problems were relatively rare in these children, although symptoms of juvenile acquired hypothyroidism were associated with increased distractibility, hyperactivity, and poorer achievement. The least gain in achievement was made by children with more severe hypothyroidism at diagnosis; children with the best psychologic outcome were those who achieved euthyroidism more slowly. We conclude that severe behavioral manifestations of L-thyroxine therapy for juvenile acquired hypothyroidism are uncommon, but mild behavioral symptoms and poorer school achievement may occur in about 25% of patients, who represent the most severe cases at diagnosis.

Early onset of lithium-associated hypothyroidism

In general practice, psychiatrists are confronted with the difficulty of structuring a rational design for the early detection of hypothyroidism. To determine the period during which a patient receiving lithium is most at risk of developing hypothyroidism, a retrospective study was conducted on the records of 154 patients at two general hospital lithium clinics from January 1980 to August 1991. Forty-two cases of hypothyroidism (clinical hypothyroidism and/or abnormally elevated levels of TSH) were detected. A significant difference was found between the onset of hypothyroidism and age (older patients developed more thyroid dysfunction), but no significant differences were found between thyroid abnormality and sex or diagnostic category and menopausal status, although trends were observed for the two former variables. This longitudinal study is the first to describe an outline of thyroid functioning in terms of the duration of treatment. Lithium-associated hypothyroidism develops most often during the first two years. Of the 42 cases of hypothyroidism, 16 were diagnosed within six months (38%), 23 within the first year (55%), and 31 two years (74%). Since thyroid functioning is an important parameter in the course of affective disorders, its close and frequent monitoring is mandatory during the first two years of treatment.

[Thyroid hormones and depressive disorders--critical overview and perspectives. Part 1: Clinical aspects]

This review gives a critical synopsis of the literature on the interaction between thyroid hormones and depressive illness, a phenomenon that has been well-known for over 100 years. Possible perspectives for clinical practice and research are discussed. The most relevant conclusions and hypotheses being as follows: 1. Thyroid hormone disorders (hypo- and hyperthyroidism) may induce almost any psychiatric symptom or syndrome. However, no disease of the thyroid causes symptoms typical of a specific diagnosis. 2. Depressed patients are euthyroid, at least in terms of their laboratory values. Abnormal values are all not specific for any psychiatric diagnosis. They are probably due to intervening variables such as stress or weight loss, or simply to methodological problems. 3. Attempts to treat depressive patients with TRH or T3 have not produced any results of clinical relevance. However, some preliminary reports of a prophylactic effect of high-dose thyroxine in previously resistant "rapid-cycling" patients are most promising. 4. All antidepressant and prophylactic therapies (antidepressant drugs, sleep deprivation, ECT, lithium, and carbamazepine) affect thyroid hormone concentrations. During treatment with antidepressants, carbamezepine, and lithium, these changes are significantly correlated to clinical response.

[Thyroid hormones and depressive disorders--clinical overview and perspectives. Part 2: Thyroid hormones and the central nervous system--basic research]

This paper briefly reviews present knowledge on the uptake, distribution, metabolization, and functions of thyroid hormones in the central nervous system. So far, multiple isolated effects of these hormones could be shown; e.g. a modulation of noradrenergic, serotonergic, and dopaminergic receptor function, and an influence on second messenger, calcium homeostasis, axonal transport mechanisms, and morphology. All these effects are, however, highly specific with respect to brain area and both the biochemical mechanisms and the physiological importance are poorly understood. Antidepressants and neuroleptics influence thyroid hormone metabolism in the CNS. The respective effects depend on the area under investigation, the circadian rhythm, and the specific drug. Future research should investigate primarily the biochemical mechanisms of thyroid hormone action on the central nervous system. Furthermore, it seems worthwhile to examine whether or not the different effects of psychopharmacological drugs on CNS thyroid hormone metabolism are involved in their mechanisms of action.

An evaluation of basal hypothalamic-pituitary-thyroid axis function in depression: results of a large-scaled and controlled study

In order to evaluate the function of the hypothalamic-pituitary-thyroid (HPT)-axis in unipolar depression, the authors measured basal 0800h plasma levels of free thyroxine (FT4), free triiodothyronine (FT3), and thyroid stimulating hormone (TSH) by means of the new, ultrasensitive assays (TSH-IRMA) in 69 healthy controls, 62 minor, 101 simple major, and 57 melancholic depressed subjects. Basal HPT-axis hormone levels of almost all (96.8%) unipolar depressed patients fell within the normal, euthyroid range. None of the major depressed subjects showed subclinical hypothyroidism. It was found that 8.8% of the melancholic subjects exhibited some degree of subclinical hyperthyroidism. Basal TSH-IRMA values were significantly lower in melancholic patients than in healthy controls, minor and simple major depressed patients, and in major vs. minor depressed subjects. FT4 circulating levels were significantly higher in melancholic patients than in all other subjects. Basal TSH-IRMA and FT4 levels were significantly correlated with severity of illness. In depression, there was a significant and negative correlation between basal TSH-IRMA values and FT4 concentrations. No significant gender- or age-related differences in TSH-IRMA or thyroid hormones were detected in depression. It is argued that--in depression research--the assays of basal TSH-IRMA should replace thyrotropin releasing hormone tests.

General health, health care utilization, and medical comorbidity in dysthymia

OBJECTIVE

This article reviews the literature on the general health, health care utilization, prevalence, medical comorbidity, and treatment of dysthymia in medical settings.

METHOD

The literature was searched by using MEDLINE and by reviewing the bibliographies of recent publications. Studies were selected that included health data on patients with dysthymia or chronic depression according to DSM-III, DSM-III-R, ICD-9, or RDC criteria, or patients who were described as having persistent depressive symptoms.

RESULTS

This review shows that dysthymic patients are at increased risk for poor general health and frequently use medical services. Compared to the general population, dysthymia is more prevalent in primary care and among patients with various medical and neurological conditions, sleep disorders, chronic fatigue, hypothyroidism, and somatoform disorders. Pharmacotherapy is effective, but has not been well studied. Non-tricyclic antidepressants might be especially useful. Psychotherapy studies are virtually non-existent.

CONCLUSIONS

Although dysthymia is considered a minor depressive condition, these findings show that it is a significant public health problem, comparable to major depression. Recent efforts to improve the recognition and treatment of major depression in medical settings, therefore, should be extended to include the entire spectrum of depressive disorders. Future studies should investigate the type and pattern of medical comorbidity and health care utilization, different antidepressant and psychosocial therapies, and the clinical and biological correlates of treatment response in different chronic depressive subtypes in medical settings and compare them to major depressive and subsyndromal depressive conditions.

Abnormal taste preference for saccharin in hypothyroid rats

Taste preferences for saccharin in concentrations ranging from 0.16 mM to 50 mM were determined in rats made hypothyroid with radioactive iodine and in their littermate controls. Hypothyroid rats demonstrated taste preferences for saccharin which were similar to those of controls only at very low (0.016 mM) or very high (49.0 mM) saccharin concentrations. At these concentrations of tastant, the preferences for tastant and water were similar to one another. At a concentration of 5.1 mM, preferences were also very similar in both groups but were very high. At intermediate saccharin concentrations of 1.1 and 3.0 mM, hypothyroid animals showed significantly lower percent preferences for the sweet tastant than did controls, mean +/- SEM (62.48 +/- 5.97 vs. 82.92 +/- 4.60, p = 0.0002) for the 1.1 mM concentration and (74.98 +/- 5.12 vs. 89.40 +/- 2.54, p = 0.0029) for the 3.0 mM concentration. These changes in taste preference for saccharin in hypothyroid rats were similar in direction and magnitude to those previously published by this laboratory using sucrose as the tastant. Thus, hypothyroid rats demonstrate abnormalities in taste preference for both the nonnutritive sweetener, sodium saccharin, as well as for the nutritive sweetener, sucrose.

Clinical evidence for thyroid dysfunction in patients with seasonal affective disorder

Of 49 consecutive patients over a 21-mo period satisfying conservative criteria for seasonal affective disorder (SAD), a well-characterized syndrome involving seasonal neurovegetative dysregulation, 17 (35%) were found to have elevated serum TSH compatible with mild primary hypothyroidism (TSH > 4.6 microIU/ml). An additional eight patients (16%) met criteria for "conjectural" hypothyroidism (TSH > 3.5 microIU/ml or exaggerated TSH response to TRH). The frequency of cases with supranormal TSH within the SAD group, both with and without inclusion of the "conjectural" cases, proved statistically significant when compared to that within psychiatric patients not satisfying criteria for SAD (N = 381) or to that within the population at large. The author suggests that SAD may in part represent a reformulation in modern neuropsychiatric terms of a previously noted fall-winter decrement, both biochemical and clinical, among hypothyroid patients.

Major depression and subclinical (grade 2) hypothyroidism

Subclinical hypothyroidism (SCH) has been reported to occur in patients with a variety of affective syndromes. However, the clinical correlates of SCH in patients with major depression have received limited attention. We therefore examined demographic, clinical and treatment response variables in a cohort of patients with unipolar, nonpsychotic major depression with and without SCH. Of 139 subjects, 19 had SCH defined as an elevated basal TSH with normal circulating levels of T3 and T4. Major depression with SCH differed from that without SCH by the presence of a concurrent panic disorder and a poorer antidepressant response.

School achievement in children with hypothyroidism detected at birth and search for predictive factors

Neonatal screening of hypothyroidism started in 1975, and now sufficient hindsight is gained to assess school results in children with hypothyroidism and compare them to IQ tests. From the 85 cases of hypothyroidism detected in the Midi-Pyrénées area, 40 have enrolled in or finished primary school and 18 started secondary school. School achievement was assessed by school test results in French and mathematics using specific grids for each class and by retention rates. These results were compared to control groups. The hypothyroid group obtained identical results in French to those of the control groups but scored lower in mathematics. Grade retention rated higher in hypothyroid children (20%) than in the control groups (12.5%), especially in the first primary school grade. The search for predictive severity factors revealed significant differences between the grade repeater group and the nonrepeater group: more cases of athyrosis (75 vs. 25% for ectopia), lower T4 levels at birth, lower bone surface, lower IQ at 4 and 7 years, neurological troubles of fine motricity and coordination, and lower socioeconomic level. These results should shortly be taken into consideration in order to isolate a group at risk and undertake specialized care to improve school results in this group.

T3 augmentation of antidepressant treatment in T4-replaced thyroid patients

BACKGROUND

Clinicians may not consider using the thyroid hormone liothyronine sodium (levorotary isomer of triiodothyronine [T3]) for augmentation of antidepressant drugs in depressed patients who are also receiving the precursor hormone levothyroxine (levorotary isomer of thyroxine [T4]) for thyroid disease. We now report on the successful use of T3 augmentation therapy in seven of nine depressed patients who were also receiving T4 for thyroid disease.

METHOD

Following an earlier single case report, we prescribed T3 augmentation therapy for eight depressed patients who had not responded to an adequate antidepressant drug trial and who were receiving T4 therapy for thyroid disease. T3 was prescribed in open-label fashion, and response was judged by the clinician, whose assessment was supplemented by the use of standardized rating scales.

RESULTS

Seven of the nine patients were judged to respond to T3 augmentation.

CONCLUSION

These results are consistent with a report of differential effects for T3 versus T4 augmentation in depressed patients free of thyroid disease. The results have implications for the treatment of depression in the presence of thyroid disease and for the mechanism of thyroid hormone potentiation of antidepressants.

Psychosis in a 15 year old hypothyroid girl: myxoedematous madness?

The case of a fifteen year old girl with sudden onset of a psychotic illness thought to be related to marked hypothyroidism is reported. Apart from the age several features of this case warrant discussion and the value of screening for thyroid disease in psychotic illnesses is highlighted.

[Long-range intelligence development of children with congenital hypothyroidism]

The intellectual development of 105 children with congenital hypothyroidism was assessed. In 70 children the assessment was repeated in several times. Correlations between development of intelligence and influence of biological and/or psychosocial risks were verified.

[Mental development of children with congenital hypothyroidism--a neuropsychological follow-up study]

57 children with congenital, clinical diagnosed hypothyroidism were assessed with the Luria-Nebraska-Neuropsychological Battery-Children's Revision. The results of the psychomotor assessment were in conformity with the mental development. Univariate correlations between begin of therapy and mental development were not found in all groups.

Maternal hypothyroxinemia: psychoneurological deficits of progeny

Maternal thyroid function was evaluated clinically, by reproductive history, and by serial measurements of serum butanol-extractable iodine (thyroxine-like iodine), two before and two after 24 gestational weeks during 1,349 pregnancies. Three percent of the women were hypothyroxinemic. Developmental, intellectual, and motor abilities of progeny born to (Group I) 210 euthyroxinemic, (Group II) 15 hypothyroxinemic given adequate thyroid replacement therapy, and (Group III) 21 inadequately treated hypothyroxinemic women were compared. The groups of mothers exhibited no significant differences in intelligence, years of education, or chronological age. Mean developmental and intellectual scores at eight months, four and seven years of Group II progeny evidenced remarkably consistent similarity to scores of siblings and controls. At each age, mean developmental and intellectual scores were lower for Group III progeny, and motor scores of the latter were lowest. Some progeny of Group II mothers, treated only after 12 or 29 weeks, failed the ball catch and line walk tests; some had strabismus and other ocular disturbances. Could these deficits have originated with maternal hypothyroxinemia during first semester weeks before the thyroid-pituitary axis matures? Now in 1990-1991, early findings fit into the modern concepts of significant maternal gestational transfer of thyroxine to the fetus. The authors encourage prenatal and/or early gestational screening for maternal hypothyroxinemia and urge prescription of adequate thyroid replacement therapy for hypothyroxinemic women.

[Preclinical hypothyroidism: early involvement of memory function, behavioral responsiveness and myocardial contractility]

Subclinical hypothyroidism in characterized by elevated TSH levels in the face of normal thyroid hormone concentrations. The purpose of this study was to evaluate whether these subjects show alterations of neuropsychological and behavioural features and of myocardial contractility as patients with overt hypothyroidism do. We evaluated in 14 subjects the hormonal profile (total and free T3 and T4, TSH), memory ability (Wechsler Memory Scale), behavioural reactivity (Crown & Crisp Experimental Index) and the pre-ejection period (isometric systole). We found an evident impairment of some cognitive functions correlated to memory and a behavioural alteration, perhaps secondary to the disease state, and moreover an early defect of myocardial contractility, represented by prolonged pre-ejection period. These results suggest that these patients should be treated with adequate doses of L-Thyroxine, like in overt hypothyroidism.

Hyperactivity and spatial maze learning impairment of adult rats with temporary neonatal hypothyroidism

Temporary hypothyroidism was induced in neonatal rats by 0.02% propylthiouracil (PTU) administration to lactating dams during days 0-19 after delivery, and its effects on the behavior and learning of their male offspring were examined. The serum T4 (thyroxine) level was returned to normal around 1 week after the last PTU administration, but the body weight gain was still depressed. The open field and Biel water maze tests at the age of 6 weeks showed an increased number of ambulations and an increase in errors with prolonged swimming time in the PTU rats. The radial arm maze test started at 13 weeks revealed that the PTU animals required more trials until they showed the first well-performed trial. The total number of choices was also larger, with less correct choices, and treatment effects on the response distribution and pattern were significant. Thus, the rats, which had suffered from temporary hypothyroidism in the neonatal period, showed hyperactivity and irreversible impairment in maze learning. These results suggest an involvement of temporary neonatal hypothyroidism in hippocampal dysfunction.

Psychological development at 7 years of age in children with congenital hypothyroidism. Timing and dosage of initial treatment

Sixty of 68 consecutive patients detected during the first two years of the Swedish screening programme for congenital hypothyroidism were Griffiths tested at the age 6.5-7.5 years. The test quotients of the patients could not be distinguished from those of a reference population. Replacement therapy with 8.7 +/- 2.8 micrograms of L-thyroxine (mean +/- SD)/kg/d had been started at 15.0 +/- 7.1 days of life. Furthermore, normal results on Griffiths tests were also found in 13 patients with delayed normalization of serum TSH, i.e. greater than 19 mU/l at the age of six weeks, as well as in patients with retarded skeletal maturity and/or very low neonatal serum levels of thyroxine, i.e. less than 18 nmol/l and tri-iodothyronine, i.e. less than 0.92 nmol/l. Our findings indicate that a replacement dose of 6-11 micrograms L-thyroxine/kg/d is adequate and allows normal psychological development if treatment is started early.