Construct validity of the Beck Depression Inventory in a depressive population

This study investigates the construct validity of the Beck Depression Inventory (BDI) in a large population of DSM-III unipolar depressive inpatients. The BDI correlates weakly with the Hamilton scale and differentiates between minor, major and melancholic/psychotic unipolar depressive subgroups. Factor analysis of the BDI resulted in psychological/cognitive (BDIPSY) and somatic/vegetative (BDISOM) subscales. The BDISOM subscale displayed a narrower relationship with the depression construct, as evidenced by a better differential validity and by significant effects for the DST non-suppression response. The present findings generally lend support to the construct validity of the BDI in depressive populations.

Cluster analytic validation of the DSM melancholic depression. The threshold model: integration of quantitative and qualitative distinctions between unipolar depressive subtypes

Cluster analysis was performed on the DSM-III symptoms of major depression and symptoms of melancholia identified in a study group consisting of 220 unipolar depressed inpatients a melancholic and non-melancholic cluster. Patients allocated to the melancholic cluster were more severely depressed and they were characterized by psychomotor disorders, a distinct quality of mood, diurnal variation, early morning awakening, and non-reactivity. Our results support the construct validity of the DSM-III melancholic subtype of major depression. This study supports the integrated threshold model:. (i) melancholic and non-melancholic depression may be regarded as continuous classes in terms of overall severity of depression; and (ii) both groups form discrete categories with regard to the melancholic symptoms, which emerge as the severity of depression increases.

Effects of affective-semantic mode of item presentation in balanced self-report scales: biased construct validity of the Zung Self-rating Depression Scale

The widely applied procedure of balancing self-report instruments by including positively and negatively keyed items is exemplified by the Zung Self-rating Depression Scale (SDS). Investigation of the influence of the symptom-positive and symptom-negative item modes on the SDS in a depressed population resulted in two major findings. First, the reversed scoring of the symptom-negative items resulted in higher mean item scores. Secondly, factor analyses of the SDS in the present study and in previous research revealed that the semantic modes of item presentation were represented in the factor structure of the SDS. These findings were confirmed by analyses with the State-Trait Anxiety Inventory (STAI) and by previous factor analytical research with balanced instruments and were interpreted within the framework of the theory of Positive and Negative Affect. The present data cast doubts on the construct validity of the SDS as a measure of depressive symptomatology due to the presence of the negatively keyed items and suggest reconsideration of the use of balanced instruments for minimization of the acquiescence response set.

Stimulatory effects of L-5-hydroxytryptophan on postdexamethasone beta-endorphin levels in major depression

Recently it has been shown that acute administration of 200 mg L-5-hydroxytryptophan (L-5-HTP) PO may increase post-dexamethasone (DST) adrenocorticotropic hormone (ACTH) and cortisol levels in major, but not minor, depressed subjects. This study aimed to examine the effects of 200 mg L-5-HTP PO on post-DST beta-endorphin levels in the same depressed subjects. It was found that in major, but not minor, depressed subjects, L-5-HTP significantly increased post-DST beta-endorphin concentrations as compared to placebo. The L-5-HTP-induced post-DST beta-endorphin responses were significantly higher in major than in minor depressed subjects. There was a significant and positive relationship between L-5-HTP-induced post-DST beta-endorphin and ACTH or cortisol responses. There was a significant and positive relationship between L-5-HTP-induced post-DST beta-endorphin values and the Hamilton Depression Rating Scale (HDRS) score. The results show that the acute administration of L-5-HTP may increase the escape of beta-endorphin secretion from suppression by dexamethasone in major, but not minor, depression.

Lower serum L-tryptophan availability in depression as a marker of a more generalized disorder in protein metabolism

Recently, it has been reported that major and melancholic depression are accompanied by a lower availability of total L-tryptophan (L-TRP) to the brain and by significant changes in electrophoretically separated protein fractions, such as albumin and alpha 2-globulin. The aim of this study was to examine the relationships between serum L-TRP availability and total serum protein, albumin, and alpha 2-globulin in 42 depressed and 24 normal subjects. In depressed and normal subjects, alone and together, there were significant and positive correlations between serum L-TRP and total serum protein or albumin concentrations. In the depressed subjects, but not in normal controls, there were significant inverse relationships between the L-TRP/competing amino acid ratio and the alpha 2-globulin fraction. Serum L-TRP and albumin were significantly lower in melancholic subjects than in normal and minor depressed subjects. Depressed subjects had a significantly lower L-TRP/competing amino acid ratio and significantly higher serum alpha 2-globulin than normal controls. Total serum protein was significantly lower in major depressed subjects than in normal controls. The results suggest that lower L-TRP availability to the brain in depression is related to lower serum albumin and to increased alpha 2-globulin fraction, which are both hallmarks of the acute phase response in depression. the results further corroborate the hypothesis that lowered L-TRP availability in depression is related to the acute phase response in that illness.

Lower serum transcortin (CBG) in major depressed females: relationships with baseline and postdexamethasone cortisol values

This study has been carried out to examine (i) transcortin or corticosteroid binding globulin (CBG), the major glucocorticoid transport protein, in major depressed versus minor depressed and normal subjects; and (ii) the relationships between CBG and basal and postdexamethasone cortisol or adrenocorticotropic hormone (ACTH) values. Serum CBG was significantly lower in major depressed than in minor depressed subjects and normal controls. The significant decrease in serum CBG was observed in major depressed women but not in major depressed men. In depressed subjects, there was a significant and negative relationship between serum CBG and severity of illness. There were significant positive relationships between serum CBG and basal 8:00 a.m. plasma cortisol in normal volunteers (r = 0.87, P < 10(-4)) and depressed subjects (r = 0.40, P = 0.0002). There was no significant relationship between serum CBG and 24-h urinary cortisol. In depressed patients, there was a positive relationship between serum CBG and postdexamethasone cortisol (r = 0.31, P = 0.003). It is concluded that, in depression, serum CBG levels should be taken into consideration for the interpretation of baseline and postdexamethasone plasma total cortisol levels.

Fatty acid composition in major depression: decreased omega 3 fractions in cholesteryl esters and increased C20: 4 omega 6/C20:5 omega 3 ratio in cholesteryl esters and phospholipids

Recently, there were some reports that major depression may be accompanied by alterations in serum total cholesterol, cholesterol ester and omega 3 essential fatty acid levels and by an increased C20: 4 omega 6/C20: 5 omega 3, i.e., arachidonic acid/eicosapentaenoic, ratio. The present study aimed to examine fatty acid composition of serum cholesteryl esters and phospholipids in 36 major depressed, 14 minor depressed and 24 normal subjects. Individual saturated (e.g., C14:0; C16:0, C18:0) and unsaturated (e.g., C18:1, C18:2, C20:4) fatty acids in phospholipid and cholesteryl ester fractions were assayed and the sums of the percentages of omega 6 and omega 3, saturated, branched chain and odd chain fatty acids, monoenes as well as the ratios omega 6/omega 3 and C20:4 omega 6/C20:5 omega 3 were calculated. Major depressed subjects had significantly higher C20:4 omega 6/C20:5 omega 3 ratio in both serum cholesteryl esters and phospholipids and a significantly increased omega 6/omega 3 ratio in cholesteryl ester fraction than healthy volunteers and minor depressed subjects. Major depressed subjects had significantly lower C18:3 omega 3 in cholesteryl esters than normal controls. Major depressed subjects showed significantly lower total omega 3 polyunsaturated fatty acids in cholesteryl esters and significantly lower C20:5 omega 3 in serum cholesteryl esters and phospholipids than minor depressed subjects and healthy controls. These findings suggest an abnormal intake or metabolism of essential fatty acids in conjunction with decreased formation of cholesteryl esters in major depression.

Acute administration of buspirone increases the escape of hypothalamic-pituitary-adrenal-axis hormones from suppression by dexamethasone in depression

Recently, our laboratory found a significant enhancing effect of L-5-hydroxy-tryptophan (L-5-HTP) on post-dexamethasone (DST) plasma adrenocorticotropic hormone (ACTH) and cortisol levels in major-but not in minor-depression. To further elucidate the effects of central serotonin (5-HT) activity on the negative feedback of glucocorticoids on hypothalamic-pituitary-adrenal (HPA)-axis function in depression, this study investigates the effects of buspirone, a 5-HT1A receptor agonist, on post-DST ACTH and cortisol levels in 75 depressed subjects. Plasma post-DST ACTH and cortisol concentrations were significantly increased by the acute administration of buspirone (30 mg PO) compared to placebo. There were no differences in buspirone-induced post-DST ACTH or cortisol responses between minor and major depression. There were significant correlations between post-DST ACTH and cortisol, and between post-DST-buspirone ACTH and cortisol. The buspirone-induced post-DST cortisol responses were significantly higher in depressed women than men. It is concluded that buspirone may augment ACTH and, consequently, cortisol escape from suppression by dexamethasone in major as well as in minor depression.

Seasonal variation in plasma L-tryptophan availability in healthy volunteers. Relationships to violent suicide occurrence

OBJECTIVE

To investigate the seasonal variation in levels of plasma L-tryptophan and competing amino acids (CAAs) in healthy humans in relation to climatic variables, total serum protein levels, and violent suicide occurrence.

METHODS

Twenty-six healthy volunteers (13 men and 13 women; mean [+/- SD] age, 38.7 +/- 13.4 years) had monthly blood samplings for assays of L-tryptophan, valine, leucine, isoleucine, tyrosine, and phenylalanine during 1 calendar year.

RESULTS

Significant annual rhythms were detected in L-tryptophan, the L-tryptophan/CAA ratio, phenylalanine, valine, and leucine, and semiannual rhythms in L-tryptophan values and in L-tryptophan/CAA ratios. Plasma L-tryptophan and the L-tryptophan/CAA ratio were significantly lower in the spring than in the other seasons. The peak-trough differences in the yearly variation expressed as a percentage of the mean were 17.1% and 16.1% for L-tryptophan values and L-tryptophan/CAA ratios, respectively. The amplitude of the yearly variation in all CAAs was low, ie, less than 7%. An important part of the variance in L-tryptophan availability (ie, 12% to 14%) could be explained by the composite effects of present and past climatic factors; higher ambient temperature and relative humidity in the face of lower air pressure are the most important predictors of low L-tryptophan availability. Important and positive time relationships were noted between total serum protein level and all amino acid concentrations, and a significant time relationship was also noted between the seasonal variation in L-tryptophan availability and the occurrence of violent suicide in Belgium.

CONCLUSION

Our results show a bimodal seasonal pattern in the availability of plasma L-tryptophan that matches seasonal patterns in the prevalence of violent suicide in the local population and depression in other studies.

An augmented escape of androstenedione from suppression by dexamethasone in melancholia: relationships to intact ACTH and cortisol nonsuppression

To further examine the association between basal and postdexamethasone (DST) pituitary and adrenal activity in depression, the authors measured intact adrenocorticotropic hormone (ACTH), androstenedione and cortisol, both in baseline and post-DST conditions, in 63 depressed subjects (14 minor, 33 simple major and 16 melancholic subjects). It was found that post-DST androstenedione, cortisol and ACTH values were significantly higher in melancholic than in minor depressed subjects. There were highly significant correlations between plasma androstenedione and ACTH both in baseline and post-DST conditions. The significant intercategory differences in post-DST androstenedione were determined by differences in post-DST ACTH. Basal and post-DST androstenedione values were significantly higher in men than in women and both values were significantly and negatively related to age. There were highly significant, positive relationships between cortisol and ACTH and between cortisol and androstenedione both in baseline and post-DST conditions. The results corroborate our hypotheses that, in depression, pituitary (ACTH) and adrenal (cortisol and androstenedione) hormonal secretion are tightly coupled in post-DST conditions and that the augmented escape of ACTH-target hormones in melancholia is, in part, related to that of pituitary ACTH.

Components of biological variation in plasma haptoglobin: relationships to plasma fibrinogen and immune variables, including interleukin-6 and its receptor

We investigated the components of biological variation, including seasonality, in plasma haptoglobin (Hp) levels and the relationships between plasma Hp and interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6), sIL-2R, fibrinogen (Fb) and absolute number of peripheral blood mononuclear cells, such as leukocytes, neutrophils, monocytes, lymphocytes, CD4+, CD8+, CD25+ T cells and CD20+ B cells. Monthly blood samples were taken from 26 normal volunteers during one calendar year. The estimated inter- and intra-individual C.V. values for plasma Hp were 27.9% and 20.0%, respectively; the index of individuality was 0.72. No significant seasonal rhythms could be detected in plasma Hp levels. The yearly mean values in plasma Hp were significantly and positively related to those in plasma Fb, absolute number of leukocytes, neutrophils, CD4+ T cells and the CD4+/CD8+ T cell ratio. 49.0% of the variance in the yearly mean values of plasma Hp could be explained by variances in serum IL-6 and number of CD4+ (positively related) and CD8+ (negatively related) T cells. There were significant and positive time relationships between plasma Hp, on the one hand, and plasma Fb, sIL-6R, sIL-2R and number of leukocytes, neutrophils and monocytes, on the other. A smaller part of the within-subject variability in plasma Hp (i.e. 6.0%) could be explained by serum sIL-6R and sIL-2R. It is concluded that there are (1) important between-subject differences in the homeostatic setpoints of plasma Hp, which are related to those in plasma Fb and in immune status and (2) significant within-subject, time relationships between plasma Hp and indicators of immune activation and plasma Fb.

Total serum protein and serum protein fractions in depression: relationships to depressive symptoms and glucocorticoid activity

Recently, it has been reported that major depression is accompanied by changes in plasma protein concentrations indicative of an acute-phase protein (APP) response. The purpose of the present study was to examine total serum protein (TSP) and the electrophoretically separated major fractions of serum proteins (SP), i.e., albumin (Alb), alpha 1, alpha 2, beta and gamma globulin, in depression. Highly significant differences were found in TSP and the separated SP fractions between major depressed patients and normal controls and between melancholic and minor depressed patients. Major depressed subjects showed significantly lower TSP and Alb concentrations and a higher percentage of the alpha 1 globulin fraction than normal controls and minor depressed subjects. Major depressed subjects had significantly higher and lower percentages, respectively, of alpha 2 and gamma globulin fractions than normal controls. In depressed subjects, there were significant negative correlations between TSP or Alb concentrations and severity of illness. Psychomotor retardation and anorexia were psychopathological correlates of lower TSP and Alb concentrations while middle insomnia and psychomotor retardation were related to changes in the alpha 2 globulin fractions. Basal plasma cortisol values were significantly and positively related to serum alpha 2 globulin. The results support the view that major depression is accompanied by an APP response.

Antagonizing the effects of experimentally induced sleep disturbance in healthy volunteers by lormetazepam and zolpidem

The effects on sleep of two well known hypnotics, lormetazepam and zolpidem, during experimentally induced environmental noise were compared with placebo. In a double-blind, crossover study, 12 normal volunteers were subjected to prerecorded traffic noise with a mean noise level of 52 dB(A) and peaks to 77 dB(A) continuously for 8 hours in bed. Both hypnotics increased total sleep time, predominantly stage 2 sleep. A significant decrease in the number of sleep stage transitions, arousals, and awakenings longer than 3 minutes was found only with lormetazepam. No significant effects on rapid eye movement (REM) and slow wave sleep were observed. Latencies to persistent sleep and REM sleep onset were not different for either active treatment compared with placebo. Only after lormetazepam was performance on the morning reaction time test significantly affected. However, no differences were found in the subjective sleep quality and alertness ratings. Changes in the distribution of sleep stages throughout the night were related to the elimination half-life characteristics of the hypnotics, but few trends were detected. Both the protective properties against environmental noise of the hypnotics studied and the validity of the model of induced sleep disturbance in evaluating hypnotic agents are discussed.

Components of biological, including seasonal, variation in hematological measurements and plasma fibrinogen concentrations in normal humans

This study has been carried out in order to examine the components of biological and, in particular, seasonal variation in hematologic measurements in normal humans. Toward this end, 26 normal volunteers had monthly blood samplings during one calendar year for determination of number of red blood cells (RBC) and platelets, hemoglobin (Hb), hematocrit (Ht), mean corpuscular volume (MCV), MC Hb (MCH), MC Hb concentration (MCHC), RBC distribution width (RDW), mean platelet volume (MPV), platelet distribution width (PDW), plateletcrit (PCT), and plasma fibrinogen concentrations. The data were analyzed by means of spectral analyses of a group of time series or a single time series, and by means of repeated measures analyses of variance. Most of the hematologic variables show seasonal rhythms, such as annual rhythms or harmonics, which are expressed as a group phenomenon. An important part of the variance ( > 15%) in Ht, MCV, MCH, MCHC, RDW, number of platelets, MPV and plasma fibrinogen was explained by a yearly variation. The peak-trough differences (expressed as a percentage of the mean) in the yearly variations in number of RBC, Ht, MCV, MCH, MCHC and RDW were very low (all < 8.5%). Number of platelets (14.4%) and plasma fibrinogen values (28%) showed a high-amplitude yearly variation. All hematological variables, except MCHC, show a high interindividual variability which exceeds by far the intraindividual variability.

Effects of serotonin precursors on the negative feedback effects of glucocorticoids on hypothalamic-pituitary-adrenal axis function in depression

In order to investigate the relationships between brain serotonergic turnover and hypothalamic-pituitary-adrenal (HPA) axis function in unipolar depression, the authors measured intact adrenocorticotropic hormone (ACTH) and cortisol levels in baseline conditions and after combined dexamethasone (1 mg PO) and L-5-hydroxytryptophan (L-5-HTP, 200 mg PO) administration in 13 minor, 17 simple major, and 17 melancholic subjects. L-5-HTP significantly enhanced post-DST ACTH and cortisol secretion in major--but not in minor--depressed subjects. Major depressed subjects with or without melancholia exhibited significantly higher post-DST ACTH and cortisol responses to L-5-HTP than minor depressed subjects. L-5-HTP administration converted some major depressed ACTH or cortisol suppressors into nonsuppressors. L-5-HTP stimulated ACTH or cortisol secretion to the same extent in major depressed HPA-axis suppressors and nonsuppressors. It is concluded that L-5-HTP loading may augment ACTH and, consequently, cortisol escape from suppression by dexamethasone in major but not in minor depressed subjects. The findings show that serotonergic mechanisms modulate the negative feedback of glucocorticoids on central HPA-axis regulation. It is hypothesized that the higher L-5-HTP-induced post-DST HPA-axis hormone responses in major depression reflect upregulated 5-HT2 receptor-driven breakthrough secretion of pituitary ACTH from suppression by dexamethasone.

Adrenocorticotropic hormone, beta-endorphin and cortisol responses to oCRH in unipolar depressed patients pretreated with dexamethasone

1. Corticotropin-releasing hormone (ovine CRH, 100 micrograms intravenous bolus) was given to 63 unipolar depressed inpatients following the 1 mg overnight dexamethasone suppression test (DST). The depressed patients included 18 minor, 24 simple major and 21 melancholic subtypes. 2. Baseline or postdexamethasone plasma levels of intact adrenocorticotropic hormone (ACTH), beta-endorphin/beta-lipotropin (beta END/beta LPH), cortisol, and dexamethasone were measured, as well as the post DST+CRH hormone responses. 3. CRH administration 9.5 hr after dexamethasone resulted in a significant enhancement of ACTH, beta END/beta LPH and cortisol secretion. The post DST+CRH ACTH and beta END/beta LPH- but not cortisol-values exceeded their baseline hormone levels. The post DST+CRH ACTH--but not beta END/beta LPH or cortisol-levels were significantly higher in major depressives compared to minor depressives. The post DST+CRH ACTH and beta END/beta LPH--but not cortisol-levels were significantly higher in DST nonsuppressors than suppressors. The post DST+CRH ACTH levels were significantly and positively related to severity of illness. 4. The results provide evidence that the pathophysiology underlying the abnormal DST+CRH and DST tests in melancholia is localized at the pituitary level and may consist of a CRH-driven breakthrough of corticotropic cell secretion synergized by central and peripheral agents, in conjunction with a decrease in glucocorticoid feedback suppressibility.

Increased neopterin and interferon-gamma secretion and lower availability of L-tryptophan in major depression: further evidence for an immune response

There is now some evidence that major depression may be accompanied by an immune response. The latter condition is suggested by elevated secretion of neopterin and interferon-gamma (IFN gamma) and by lower L-tryptophan (L-TRP) plasma levels. This study investigated the plasma levels of neopterin, L-TRP, and the L-TRP/competing amino acids (CAA) ratio in 30 normal control subjects and 47 depressed subjects (16 minor depressed, 13 simple major depressed, and 18 melancholic subjects), and IFN gamma secretion by mitogen-stimulated peripheral blood mononuclear cells in 7 normal control subjects and 13 major depressed subjects. Plasma neopterin levels were significantly higher in depressed subjects than in normal controls; 61% of melancholic patients had increased neopterin levels (> or = 7 nmol/l) with a specificity of 90%. Patients with major depression had significantly lower L-TRP and L-TRP/CAA values compared with normal control subjects. The amino acid values were significantly and negatively correlated with plasma neopterin levels. Major depressed subjects exhibited significantly higher IFN gamma secretion than did normal control subjects. The results further support the hypothesis that major depression is accompanied by an immune response and that the lower L-TRP availability in that illness may be an epiphenomenon of immune activation.

Synchronized annual rhythms in violent suicide rate, ambient temperature and the light-dark span

To investigate whether violent and nonviolent suicide and homicide are related to atmospheric or geomagnetic activity, we investigated the relationships between weekly number of suicides or homicides for all Belgium for the period 1979-1987, and ambient temperature, relative humidity, air pressure, hours of sunlight and precipitation per day, wind speed and geomagnetic index. The occurrence of violent suicide was significantly and positively related to ambient temperature, sunlight duration, an increase in temperature over the few past weeks, and negatively to relative humidity. Higher ambient temperature and an increase in air temperature over the few past weeks were the most significant climatic predictors of violent suicide rate. A highly significant common annual rhythm with a common acrophase of 190 degrees was detected in violent suicide rate, ambient temperature and sunlight duration. No significant time-relationships between nonviolent suicide or homicide and any of the weather variables were found. It is concluded that i) violent suicide may be related to short-term fluctuations in the weather and in particular to temperature; and ii) the annual rhythm in violent suicide may be synchronized by the annual rhythms in ambient temperature and light-dark span.

Lower degree of esterification of serum cholesterol in depression: relevance for depression and suicide research

Previous studies have suggested that depression and suicide are related to alterations in total cholesterol serum concentrations, and that an altered distribution of haptoglobin (Hp) phenotypes in major depression indicates that variation on chromosome 16 may be associated with that illness. Lecithin:cholesterol acyl transferase (LCAT, EC 2.3.1.43), the enzyme that catalyzes the esterifying reaction of cholesterol in serum, is located close to the Hp gene. This study examined the serum concentrations of total and free cholesterol and the esterified cholesterol ratio in 26 healthy controls, 47 unipolar depressed subjects (16 minor, 14 simple major and 17 melancholic depressed subjects) and 12 relatives of melancholic subjects. Depressed subjects (regardless of subtype) and relatives of depressed subjects had a significantly lower esterified cholesterol ratio than normal controls. No significant differences in total or free cholesterol concentrations were found between the above study groups. In depressed subjects, there were no significant relationships between the esterified cholesterol ratio, total or free cholesterol and postdexamethasone adrenocorticotropic or cortisol values, Hp phenotypes, severity of illness or suicidal symptoms. It is hypothesized that lower esterification in serum cholesterol may constitute a vulnerability factor for depression through alterations in cell membrane microviscosity.

Seasonal variation in peripheral blood leukocyte subsets and in serum interleukin-6, and soluble interleukin-2 and -6 receptor concentrations in normal volunteers

This study has been carried out in order to investigate seasonal variation in peripheral blood immune cells, such as leukocytes, monocytes, neutrophils, lymphocytes, CD3+ T, CD4+ T, CD8+ T, CD25+ T, CD20+ B, and serum interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R) and sIL-2R levels in normal volunteers. Toward this end, 26 normal volunteers (13 men, 13 women) had monthly blood samplings during one calendar year for peripheral blood count, flow cytometric enumeration of peripheral leukocyte subsets and immunoassays of IL-6, sIL-6R and sIL-2R. It was found that most of the immune variables change rhythmically during the seasons as a group phenomenon. Statistically significant yearly variations with seasonal rhythms, i.e. annual rhythms or harmonics, such as semiannual, tetramensual and trimensual rhythms, were found in the number of leukocytes, neutrophils, monocytes, lymphocytes, CD4+ T, CD8+ T, CD25+ T, CD20+ B cells, in the CD4+/CD8+ ratio, and serum IL-6 and sIL-6R levels. It is concluded that the immune system is characterized by a multifrequency time-structure with significant high-amplitude yearly variations in the number of some peripheral blood leukocyte subsets.

Binding of [3H]paroxetine to platelets of depressed patients: seasonal differences and effects of diagnostic classification

[3H]Paroxetine is a more reliable ligand for studying the serotonin (5-HT) transporter complex than [3H]imipramine. The present study investigates [3H]paroxetine binding to platelets in 54 depressed in-patients (18 minor, 16 simple major and 20 melancholic depressed patients) and 16 healthy controls. There were no significant differences in maximal number of binding sites between depressed subjects and normal controls. There was no correlation between [3H]paroxetine binding to platelet membranes and severity of depression. [3H]Paroxetine binding to platelets was significantly higher in spring than in summer, fall and winter.

Natural killer cell activity in major depression: relation to circulating natural killer cells, cellular indices of the immune response, and depressive phenomenology

1. Recently, blunted natural killer cell activity (NKCA) has been found in major depression. The present study investigates the relationships between ex vivo blunted NKCA in major depression, number or percentage of NKC, in vivo indices of systemic immune activation and depressive phenomenology. 2. Toward this end, NKCA, absolute number of leukocytes and number or percentage of lymphocytes, monocytes, neutrophils, activated T lymphocytes (HLA-DR+, CD25+) and NKC (CD3-CD56+) were determined in 13 normal controls and 36 depressed inpatients. 3. NKCA was significantly and positively related to number and percentage of NKC in the peripheral blood. The major depression-related reduction in NKCA was not related to alterations in peripheral NKC. There were significant negative correlations between NKCA and number or percentage of leukocytes, monocytes, neutrophils and HLA-DR+ T cells. Up to 50% of the variance in NKCA could be explained by the regression on the number of monocytes, percentage of HLA-DR+ T and NKC cells, and diagnostic classification. Up to 43% of the variance in NKCA was explained by depressed mood, somatic anxiety and less diurnal variation. 4. The results show that blunted NKCA in major depression is not related to alterations in peripheral NKC, but reflects in part the systemic immune activation in that illness.

Hypozincemia in depression

This study investigates serum levels of zinc in 48 unipolar depressed subjects (16 minor, 14 simple major and 18 melancholic subjects) and 32 normal volunteers, and the relationships between zincemia and plasma neopterin levels, postdexamethasone adrenocorticotropic hormone and cortisol values, and anorexia-weight loss. Serum zinc levels were significantly lower in major depressed subjects than in normal controls, whereas minor depressed subjects showed intermediate values. There were significant negative correlations between serum zinc, and severity of depression and plasma neopterin concentrations. No significant relationships between zincemia and either postdexamethasone hormone values or anorexia/weight loss were found. The findings suggest that hypozincemia in major depression may be related to activation of cell-mediated immunity in that illness.

Lower serum prolyl endopeptidase enzyme activity in major depression: further evidence that peptidases play a role in the pathophysiology of depression

Prolyl endopeptidase (PEP) is a serine proteinase, which may cleave peptides that are involved in the pathophysiology of major depression, such as arginine vasopressin, beta-endorphin, luteinizing hormone-releasing hormone, thyrotropin-releasing hormone, and maybe corticotropin-releasing hormone. PEP may be involved in activation of cell-mediated immunity, autoimmune and inflammatory responses, which repeatedly occur in severe depression. The present study investigates serum PEP activity in 33 normal controls, 16 minor, 14 simple major, and 18 melancholic depressed subjects. Pre-dexamethasone and post-dexamethasone (DST) intact adrenocorticotropic hormone (ACTH) and cortisol values were determined in 33 depressed subjects. Serum PEP activity was significantly lower in depressed subjects compared to normal controls and in melancholic depressed subjects compared to minor and simple major depressed subjects. Up to 61.1% of the melancholic patients had serum PEP activities below the mean PEP values of normal controls minus two SDs. In the depressed study group, significant negative correlations between serum PEP activity and severity of illness, post-DST cortisol, and ACTH values were observed. There was a trend toward higher serum PEP activity with increasing age. It is hypothesized that lower serum PEP activity, and lower serum activity of other peptidases, may play a role in the neuroendocrine and immune pathophysiology of major depression.