Evaluation of metabolomics-based urinary biomarker models for recognizing major depression disorder and bipolar disorder

BACKGROUND

Major depressive disorder (MDD) and bipolar disorder (BD) are psychiatric disorders with overlapping symptoms, leading to high rates of misdiagnosis due to the lack of biomarkers for differentiation. This study aimed to identify metabolic biomarkers in urine samples for diagnosing MDD and BD, as well as to establish unbiased differential diagnostic models.

METHODS

We utilized a metabolomics approach employing ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) to analyze the metabolic profiles of urine samples from individuals with MDD (n = 50), BD (n = 12), and healthy controls (n = 50). The identification of urine metabolites was verified using MS data analysis tools and online metabolite databases.

RESULTS

Two diagnostic panels consisting of a combination of metabolites and clinical indicators were identified-one for MDD and another for BD. The discriminative capacity of these panels was assessed using the area under the receiver operating characteristic (ROC) curve, yielding an area under the curve (AUC) of 0.9084 for MDD and an AUC value of 0.9017 for BD.

CONCLUSIONS

High-resolution mass spectrometry-based assays show promise in identifying urinary biomarkers for depressive disorders. The combination of urine metabolites and clinical indicators is effective in differentiating healthy controls from individuals with MDD and BD. The metabolic pathway indicating oxidative stress is seen to significantly contribute to depressive disorders.

Elevated levels of 8-oxoGuo and 8-oxodG in individuals with severe mental illness - An autopsy-based study

Elevated systemic oxidative stress levels of 8-oxoGuo and 8-oxodG have been reported in individuals with severe mental illness (SMI). As no previous studies have addressed the link between local levels of 8-oxoGuo and 8-oxodG in the central nervous system (CNS), measured in cerebrospinal fluid (CSF), and urinary systemic levels, we employed autopsy-based material to elucidate this aspect. Additionally, we investigated the impact of 8-oxoGuo and 8-oxodG levels on the prevalence of somatic co-morbidities. Based on post mortem samples from deceased individuals with SMI (N = 107), we found significantly elevated urinary levels of both 8-oxoGuo and 8-oxodG compared to mentally healthy living controls. While we found an association between urinary and CSF 8-oxodG levels (r = 0.50, P < 0.001), a similar correlation was not evident for 8-oxoGuo (r = 0.15, P = 0.16). Additionally, the two r-values were significantly different (P < 0.001). Neither marker in urine or CSF was associated with obesity-related variables, metabolic syndrome or type 2 diabetes. The post mortem interval did not affect the results, but the agonal phase seemingly introduced bias. This study provided novel insights into the cellular oxidative stress levels in individuals with SMI. We demonstrated that increased oxidative stress locally and systemically is correlated and is a clear phenomenon in SMI. Although post mortem measurements contain some weaknesses, our study indicates DNA as the main site of oxidative stress modifications in the CNS in SMI. This may provide novel opportunities for treatment modalities. Additionally, our study demonstrated the applicability of post mortem material investigating systemic and local 8-oxoGuo and 8-oxodG levels.

Humoral Changes in Manic-Depressive Psychosis with Particular Reference to the Excretion of Catechol Amines in Urine

Psychotic patients with periodically changing symptoms offer particular opportunities for psychosomatic and metabolic studies. Following the classical work of Gjessing (1932, 1935, 1939, 1953) other authors (Ashby, 1952; Rowntree and Kay, 1952; Smith, 1954; Gunne and Gemzell, 1956; Crammer, 1957) have studied metabolic changes in periodic catatonia. Cycles of behaviour and metabolism in psychiatric patients and in patients with “periodic disease” have been reviewed by Richter (1957) who also reported on interesting experiments aimed at the induction of periodic cycles of behaviour in rats.

Performance of the biological rhythms interview for assessment in neuropsychiatry: An item response theory and actigraphy analysis

BACKGROUND

Biological rhythm disturbances are widely associated with the pathophysiology of mood disorders. The Biological Rhythms Interview for Assessment in Neuropsychiatry (BRIAN) is a self-report that indexes rhythm disturbance in sleep, activity, social and eating patterns. The aim of this study was to perform an Item Response Theory (IRT) analysis of the BRIAN and investigate its associations with objective sleep and rhythm disturbance measures.

METHODS

103 subjects (31 bipolar, 32 major depression and 40 healthy volunteers) wore an actiwatch for fifteen days, and completed a first morning urine sample and the BRIAN on day 15. IRT analysis assessed individual BRIAN items and their relationship to total score. Individual actiwatch records were processed to produce a sequence of transitions between rest/activity, and a likelihood of transitioning between states was calculated to investigate sleep-wake dynamics. Cosinor analysis produced daily activity rhythms (DARs). Spearman correlations were used to assess the association between sleep/DAR variables and the BRIAN.

RESULTS

IRT analyses showed that 11 of 18 BRIAN items displayed a high level of discrimination between item options across a range of BRIAN total scores. Total BRIAN score correlated with wake after sleep onset, total activity count during sleep, and urinary 6-sulphatoxymelatonin. BRIAN Activity domain correlated with the daytime transition probability from rest to activity.

LIMITATIONS

The sample size may have been underpowered for the graded-response model employed in IRT. The study lacked an objective comparison for BRIAN eating and social domain.

CONCLUSION

The present study reveals the BRIAN displays promising external validity compared to objective parameters of circadian rhythmicity.

Lower estimated glomerular filtration rates in patients on long term lithium: a comparative study and a meta-analysis of literature

BACKGROUND

Several studies have shown that long-term lithium use is associated with a subtle decline in estimated glomerular filtration rate. This study compared mean estimated glomerular filtration rates (eGFR) in patients on long term lithium, against matched controls.

METHODS

Patients with bipolar affective disorder, who are on lithium (for at least a year), were compared against controls that were matched (1:1) for age, gender and presence or absence of diabetes or hypertension. The eGFR was calculated from creatinine values according to the 'modification of diet in renal disease study' (MDRD) formula and was compared between cases and controls. A meta-analysis was performed to compare our findings with similar studies in literature.

RESULTS

Forty seven patients met the inclusion criteria. They were matched with 47 controls. The eGFR values of lithium users were significantly lower (p = 0.04) compared to controls. This difference persisted between the subgroup of lithium users without comorbidities (diabetes and hypertension) and their controls but disappeared for lithium users with comorbidities and their controls. Nonetheless, lithium users had lower eGFR values in both subgroups. A meta-analysis of 9 studies showed a significant lowering in the glomerular filtration rate in lithium users compared to controls [mean difference -10.3 ml/min (95% confidence interval: -15.13 to -5.55, p < 0.0001)].

CONCLUSIONS

Lithium causes a subtle decline in glomerular filtration rate; renal function needs to be monitored in patients on lithium treatment.

Trace elements in bipolar disorder

INTRODUCTION

Trace elements may play an important role in bipolar disorders. The objective of this study is to determine serum copper and zinc, blood lead and cadmium and urine lead, cadmium and thallium concentrations in patients diagnosed with bipolar disorders and to compare these levels with those of a healthy control group.

MATERIALS AND METHODS

A total of 25 patients diagnosed with bipolar disorder and 29 healthy subjects participated in this study. Serum copper and zinc concentrations were measured using flame atomic absorption spectrometry; the blood lead and cadmium concentrations were measured by electrothermal atomization atomic absorption spectrometry with Zeeman background correction; urine lead, cadmium and thallium concentrations were measured by inductively coupled plasma mass spectrometry.

RESULTS

Median blood and urine lead and cadmium levels were significantly higher among the bipolar patients than among the control group: Blood lead (μg/dL): patient median: 3.00 (IQR: 1.40-4.20); control median (μg/dL): 2.20 (IQR: 0.90-3.00) p=0.040. Blood cadmium (μg/L): patient median: 0.39 (IQR: 0.10-1.15); control median: 0.10 (IQR: 0.10-0.17) p<0.001. The median of cadmium (μg/L) in patients who smoked (1.20 IQR: 0.44-2.30) was higher than that in non-smokers (0.12 IQR: 0.10-0.34) p<0.001. There was a statistically significant increase (p=0.001) in zinc levels among patients in the manic phase (mean 111.28, SD: 33.36 μg/dL) with respect to the control group (mean 86.07, SD: 12.39 μg/dL).

CONCLUSIONS

The results suggest that there could be higher levels of some toxic trace elements in the group of patients with bipolar disorder than in the healthy control group.

Elevated urinary ADAM12 protein levels in lithium-treated bipolar patients

ADAM (A Disintegrin And Metalloprotease)12 is a member of a family of integral membrane and secreted glycoproteins. ADAM12 has recently been detected in urine. In the present study we measured ADAM12 protein levels in urine from bipolar patients vs. healthy controls. Nineteen bipolar patients and 22 matched-control subjects were studied. Urine samples were concentrated and Western-blot analysis used to determine ADAM12 protein levels. The 92 kDa form of urine ADAM12 protein levels were highly elevated in Li-treated bipolar patients compared with normal controls. The 68 kDa form of urine ADAM12 protein levels did not differ. Future experiments are needed to explore a potential link between ADAM12 protein level elevation and lithium response.

Quetiapine in bipolar disorder and cocaine dependence

OBJECTIVE

Bipolar disorder is associated with the highest rates of substance abuse of any psychiatric illness. Therefore, treatments that stabilize mood and decrease drug use or cravings are of great interest. Atypical antipsychotics are in widespread use in patients with bipolar disorder. However, minimal data are available on their use in bipolar patients with comorbid substance abuse.

METHODS

Open-label, add-on, quetiapine therapy was examined for 12 weeks in 17 outpatients with bipolar disorder and cocaine dependence. Subjects were evaluated with a structured clinical interview; Hamilton Depression Rating (HDRS), Young Mania Rating (YMRS), Brief Psychiatric Rating (BPRS) scales; and Cocaine Craving Questionnaire (CCQ). Urine samples and self-reported drug use were also obtained. Data were analyzed using a last observation carried forward method on all subjects given medication at baseline.

RESULTS

Significant improvement from baseline to exit was observed in HDRS, YMRS, BPRS and CCQ scores (p < or = 0.05). Dollars spent on cocaine and days/week of cocaine use decreased non-significantly, and urine drug screens did not change significantly from baseline to exit. Quetiapine was well tolerated, with no subjects to our knowledge discontinuing because of side-effects.

CONCLUSIONS

The use of quetiapine was associated with substantial improvement in psychiatric symptoms and cocaine cravings. The findings are promising and suggest larger controlled trials of quetiapine are needed in this population.

Effects of short- and long-term lithium treatment on kidney functioning in patients with bipolar mood disorder

Lithium (Li) carbonate has been reported to be able to cause some reversible functional changes in the kidney. In this study, the authors aimed to investigate whether the duration of Li treatment is the primary determinant of the changes in renal functioning due to the Li treatment. For this purpose, 10 Li-naïve (mean age+/-S.D.: 34.50+/-4.85), 10 short-term (mean age+/-S.D.: 31.77+/-7.61) and 10 long-term (mean age+/-S.D.: 36.60+/-10.15) Li-treated bipolar patients were included in the study. Serum blood urea nitrogen (BUN) and creatinine, urine creatinine levels, creatinine clearance, urine osmolality before and after 8-h water deprivation and urine osmolality after desmopressin injection were measured in all patients. Serum BUN and creatinine levels were within the normal limits and not statistically different among the groups. Creatinine clearance of the long-term Li-treated group was significantly lower than both that of the Li-naïve group and that of the short-term Li-treated group. After 8-h water deprivation and also after desmopressin injection, no difference was found among the groups in terms of urine osmolality. However, when each patient was evaluated individually in terms of their renal concentrating ability, partial nephrogenic diabetes insipidus was diagnosed in four patients on long-term and in two patients on short-term Li treatment. To our surprise, hypothalamic diabetes insipidus was also diagnosed in other two patients on long-term Li treatment. These results demonstrate that long-term Li treatment may cause impairment in renal concentrating ability, some of which may originate from the effects of Li on vasopressin on hypothalamic level, and a decrease in glomerular filtration rate (GFR). In the light of these data, we can conclude that long-term administration of Li may be a risk factor for Li-induced renal impairment, which is a progressive effect in nature.

Catecholamines in depression: a cumulative study of urinary norepinephrine and its major metabolites in unipolar and bipolar depressed patients versus healthy volunteers at the NIMH

Studies comparing urinary norepinephrine (NE) and its metabolites in unipolar or bipolar depressed patients and healthy volunteers have not yielded consistent findings. However, in unipolar depressed patients, most studies in non-elderly populations consistently report elevated concentrations of plasma NE, at least following an orthostatic challenge. Expanding upon previous studies which showed elevated plasma NE in depression, we compared the urinary excretion of NE, normetanephrine (NMN), 3-methoxy-4-hydroxyphenylglycol (MHPG), and vanillylmandelic acid (VMA) in age- and sex-matched unipolar and bipolar depressed patients versus healthy volunteers hospitalized at an inpatient unit at the National Institute of Mental Health. Only depressed subjects with a minimum 4-week drug-free period were included. Total turnover (NE + NMN + MHPG + VMA) was reduced in this sample of unipolar and bipolar depressed patients. MHPG concentration did not distinguish unipolar from bipolar depressed patients and was not significantly different from that in healthy volunteers. A construct of the average fractional extraneuronal concentration of NE (NE + NMN/NE + NMN + MHPG + VMA) was significantly higher in unipolar and bipolar depressed patients than in healthy volunteers. This finding extends data suggesting that unmedicated unipolar and bipolar depressed patients have a 'hyperresponsive' noradrenergic system and provides a framework which ties together plasma and urinary findings.

Renal side-effects of long-term lithium treatment

The beta 2-Mg (beta 2-microglobulin) and GAG (glycosaminogyclan) excretions in 107 patients with bipolar disorder who had been on lithium treatment for 1-15 years were compared with 29 matched psychiatric control patients. 24-h urine volume, urine beta 2-Mg, GAG values were significantly higher, and maximal urinary osmolality was significantly lower in patients on lithium than in controls. No relationship was found between creatinine clearances and duration of illness, duration of lithium treatment and daily lithium dosages. Duration of lithium treatment was not related to the concentrating capacity. The beta 2-Mg excretion rates were significantly higher in patients with manifest polyuria and with severe concentration defect.

Nocturnal melatonin and 24-hour 6-sulphatoxymelatonin levels in various phases of bipolar affective disorder

Nine bipolar patients (2 men and 7 women) and 12 healthy control subjects completed overnight sampling for serum melatonin (MT) and urinary 6-sulphatoxymelatonin (aMT6s). The patients were investigated during manic, depressed, and/or euthymic states. Although serum MT levels did not differ significantly across the bipolar groups, in all cases serum MT levels were significantly lower than in control subjects. Differences in MT levels were also present between bipolar patients who were in a depressed phase and control subjects. There were no statistically significant differences in urinary aMT6s levels among the patients and control subjects, although in all cases nocturnal aMT6s levels were significantly higher than daytime levels. This study provides tentative evidence for decreased serum MT as a trait but not a state marker in bipolar affective disorder.

Urinary phenylethylamine and cortisol levels in the early puerperium

Phenylethylamine and cortisol were measured in 24-h urine samples taken from women day 2/3 postpartum, and matched controls. They also completed self-rating blues and highs scales. There was no significant difference in phenylethylamine excretion in those who scored highly with blues or highs, and either postpartum or normal controls. The number of raised values for phenylethylamine output was significantly greater in the postpartum women, who had no psychopathology, than in normal controls. Cortisol levels were significantly raised in postpartum controls compared with normal controls; women with the highs excreted significantly less cortisol than other postpartum women.

Catecholamine changes in patients with depression under the action of high-intensity light

Preponderance in depression of the melancholy affect was characterized by a drop in the level of norepinephrine (NE) and rise in epinephrine (E). Exposure to light was associated with fall in E, with no change recordable in NE. In anxious depression, following light therapy, high levels of excretion of both catecholamines tended to return to normal. Ligh was found to cause opposite changes in the quantitative measures depending upon the initial value for the E:NE ratio (above or below control).

Urinary excretion of albumin and transferrin in lithium maintenance treatment: daily versus alternate-day lithium dosing schedule

Urinary excretion of albumin and transferrin was determined by means of sensitive immunochemical methods in 40 manic-depressive patients prior to and following 6 months of daily or alternate-day lithium carbonate treatment. The median dose of lithium carbonate was 700 mg in the daily treatment group and 1200 mg in the alternate-day group, the corresponding median 12-h serum lithium concentration being 0.6 mmol l-1 and 0.7 mmol l-1, respectively. Urinary excretion of albumin and transferrin was significantly elevated in the lithium-treated patients as compared to a control group (Mann-Whitney). The change in urinary albumin:creatinine and transferrin:creatinine ratios between allocation and 6 months of treatment did not correlate significantly with the lithium dosing schedule (multiple linear regression), but did correlate with total lithium carbonate dose. In conclusion, the study provides no evidence of any difference in glomerular function (permeability) in the daily and alternate-day lithium dosing schedules, and lends no support to the hypothesis that alternate-day treatment diminishes the effect of lithium on renal function.

Urinary catecholamines and plasma hormones predict mood state in rapid cycling bipolar affective disorder

Over the course of 1 year, a patient with a rapid cycling bipolar affective disorder was followed at weekly intervals to examine whether plasma hormones and urinary catecholamines could predict current or future mood. Higher cortisol levels were found to predict depressed mood 3 days after blood sampling, higher urinary dopamine predicted a manic mood 3 days after blood sampling, urinary norepinephrine was associated with severity of current mood and prolactin was lower with concurrent depressed mood. In multivariate analyses of mood against cortisol, prolactin and three urinary catecholamines, > 50% of the variance in mood state in 3 days was explained by combinations of these biologic measures, especially cortisol and urinary dopamine, while all five biologic variables contributed to explaining 50% of the variance in current mood state. Based on the interrelationships between urinary dopamine, norepinephrine and mood, we postulate the existence of an overcompensating mechanism which is reflected in opposing correlations between urinary dopamine and norepinephrine with mood, despite the two urinary catecholamines being positively correlated.

Drug-induced actions on brain neurotransmitter systems and changes in the behaviors and emotions of depressed patients

Despite cumulative evidence that the tricyclic drugs result in significant changes in the functioning of brain serotonergic (5-HT) and nordrenergic (NE) systems, such changes have not been found to be associated with recovery from depression. Based upon evidence that the 5-HT and NE systems were associated with different emotions, it was hypothesized that changes in these systems were associated with different components of behavior in drug-responsive patients and not with changes in the "whole" disorder. Findings from this multihospital study of 104 unipolar and bipolar depressed patients showed early drug-associated reductions in anxiety and hostility in treatment responders to precede changes in motor retardation and depressed mood. Adopting this approach of looking for relationships between changes in components of major depression and changes in neurotransmitter system function, decreases in 5-HT and NE metabolite concentrations in cerebrospinal fluid (CSF) in patients treated with tricyclics, were found to be correlated with changes in specific behaviors. Results indicated the following: (1) drug-induced changes in the 5-HT system to be associated with mood aspects, notably anxiety, and depressed mood; changes in NE primarily with the psychomotor, secondarily with the mood components of the depressed state; (2) the pattern of relationships between changes in 5-HT and in mood in the unipolar was different than that in the bipolar subtype. The results indicate that in determining the relationships of biochemical changes to behavioral ones, that it is important to take into account the type of depression (bipolar or unipolar), as well as examining individually and over time those components that make up the disorder of depression. These results support evidence that tricyclics have multiple behavioral actions, that response is mediated through changes in specific behaviors and that this approach warrants further application in prospective studies of antidepressant drug mechanisms and their therapeutic actions.

Effects of tricyclic antidepressant treatment on tyramine-O-sulfate excretion in depressed patients

The urinary excretion of tyramine-O-sulfate following an oral load of tyramine (Tyramine Challenge Test, 'TCT') was measured in a group of fourteen inpatients with unipolar and bipolar major depressive episode. TCT was done both during a pretreatment baseline period and following four weeks of treatment with tricyclic antidepressants. The change in TCT values after treatment correlated with improvement in depression. The previously described ability of TCT to discriminate between endogenous and nonendogenous depressed patients was confirmed at baseline. However, following tricyclic antidepressant treatment, TCT values were not significantly different between endogenous and nonendogenous patients.

Changes in norepinephrine output following light therapy for fall/winter seasonal depression

Recurrent fall/winter depressions that remit during spring and summer have been called Seasonal Affective Disorders (SAD) (Wehr and Rosenthal 1989). The pathophysiology of SAD, its relationship to nonseasonal affective disorders, and the mechanism of action of light therapy, which is effective in treating SAD, remain to be elucidated (Depue et al 1989; Jacobsen et al 1987; James et al 1986; Joseph-Vanderpool et al 1991; Skwerer et al 1988, Terman et al 1989). Norepinephrine (NE) may play a role in the mechanisms of action of many antidepressant treatments (Schildkraut 1965) that alter NE metabolism (Schildkraut et al 1964 and 1965) and decrease the urinary output of NE and its metabolites, i.e., "whole-body NE turnover" (WBNET) (Golden et al 1988; Potter et al 1988). The present study explored whether light therapy also reduces the urinary output of NE and its metabolites.

Urinary excretion of albumin and retinol-binding protein in lithium-treated patients: a longitudinal study

The urinary excretion of albumin and retinol-binding protein was determined by means of sensitive immunochemical methods in a 2-year longitudinal study of 22 lithium-treated patients. During lithium treatment, there were no significant changes in the median albumin:creatinine ratios or retinol-binding protein:creatinine ratios. However, the median albumin:creatinine ratios were significantly higher in lithium-treated patients than in 22 normal subjects, which indicates that glomerular permeability is increased; no correlation with serum lithium level or duration of lithium treatment could be shown. In patients treated with slow-release tablets, the urinary excretion of albumin was significantly higher after 2 years than in patients given lithium carbonate. The median retinol-binding protein:creatinine ratios did not differ significantly between lithium-treated patients and normal subjects, suggesting that lithium does not affect the catabolism of low-molecular-weight proteins in the proximal tubules. In conclusion, the study supports the hypothesis that lithium treatment produces a small but significant and nonprogressive elevation of the urinary excretion of albumin.

Urinary 3-methoxy-4-hydroxyphenylglycol and the depression-type score as predictors of differential responses to antidepressants

Pretreatment 24 hr urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) levels and the Depression-type (D-type) scores (derived from a multivariate discriminant function equation based on levels of urinary catecholamines and metabolites) were examined as possible predictors of antidepressant responses to either imipramine or alprazolam. In the case of imipramine, the responders had significantly lower pretreatment urinary MHPG levels (p = 0.002) and D-type scores (p less than 0.001) than did nonresponders. In contrast, responders to the antidepressant effects of alprazolam had significantly higher pretreatment urinary MHPG levels (p less than 0.05) and D-type scores (p = 0.02) than did nonresponders. For each antidepressant treatment, D-type scores appeared to provide a better separation of responders from nonresponders than did urinary MHPG levels. For each drug, the effect size for the difference in mean log-transformed D-type scores between responders and nonresponders was greater than the effect size for the difference in mean log-transformed MHPG levels. The difference between the effect sizes was statistically significant for imipramine (p = 0.02) and tended toward significance for alprazolam using two-tailed tests. These results suggest that the D-type equation, which was initially derived to separate bipolar manic-depressive depressions from other subgroups of depressive disorders, can also be used to predict differential responses to certain antidepressant drugs in patients with unipolar depressions.

Effects of total sleep deprivation on urinary cortisol, self-rated arousal, and mood in depressed patients

The possibility that the clinical response to total sleep deprivation (TSD) is mediated by dimensions of arousal was investigated in a group of 16 depressed patients. Self-reports of activation, stress, and mood were assessed 3 days before, during, and 2 days after TSD. Urinary cortisol excretion and responses to the dexamethasone suppression test (DST) were also measured. TSD increased cortisol excretion in depressed patients and advanced the time of the maximal excretion of cortisol. No such changes have been reported for normal subjects. Neither the increased excretion nor the time shift was related to the mood response to TSD. The DST results were also unrelated to this response. Indications that the mood response to TSD may be mediated by dimensions of arousal are the significant relationships between this response and the responses of subjective stress and activation to TSD. The TSD-induced cortisol increase was not related to the subjective arousal response to TSD. The increased cortisol excretion itself could be predicted by the averaged baseline levels of subjective stress: the lower the stress levels before TSD, the larger the cortisol response to TSD.

Lithium treatment reduces the renal kallikrein excretion rate

Lithium salts are widely used agents for the prophylactic treatment of affective disorders. Lithium salts may be associated with distal nephron dysfunction. Kallikrein is a protease which is generated by the distal nephron. We used an amidolytic assay of chromatographically purified enzyme to determine the urinary excretion rate of active kallikrein in relation to lithium treatment. All plasma lithium concentrations were within the therapeutic range (0.4 to 0.9 mmol/liter). In 15 patients the urinary excretion rate of active kallikrein was 267.4 +/- 65.6 mU/24 hrs before lithium treatment, and fell to 117.8 +/- 39.6 mU/24 hrs (P less than 0.05) on day 14 of lithium treatment. This reduction was associated with a decrease of immunoreactive kallikrein in the same urines by 66%. In another 15 patients who had undergone lithium therapy for an average period of 5.6 years, the urinary excretion rate of active kallikrein was 86.1 +/- 14.5 mU/24 hrs, while 21 age-matched healthy controls had an excretion rate of 364.1 +/- 58.4 mU/24 hrs (P less than 0.05). Measurements of immunoreactive kallikrein in the same urine samples demonstrated a reduction of kallikrein after long-term lithium treatment by 78%. These observations could not be attributed to changes in creatinine clearance, renal sodium or potassium excretion rates or plasma concentrations of aldosterone and vasopressin. Addition of lithium to the urine in vitro had no demonstrable effect on kallikrein measurement by amidolytic assay. We conclude that lithium in therapeutic plasma concentrations may directly suppress the secretion of kallikrein by renal connecting tubule cells.

Toward a biochemical classification of depressive disorders. X. Urinary catecholamines, their metabolites, and D-type scores in subgroups of depressive disorders

Data on 24-hour urinary levels of catecholamines and metabolites were determined in 114 depressed patients. For each patient, a D-type score was calculated, using a discriminant function equation that was previously derived using data from an independent group of depressed patients. Of all measures, D-type scores provided the highest sensitivity and specificity for separating bipolar/schizoaffective-depressed patients from all remaining patients or from those patients with unipolar nonendogenous depressions. Using Research Diagnostic Criteria (RDC), bipolar I patients demonstrated significantly lower D-type scores than did all other RDC depressive subtypes, including bipolar II disorders. Similar findings were observed using the Clinical Inventory for the Diagnosis and Classification of Affective Disorders (CIDCAD) system: bipolar/schizoaffective patients demonstrated significantly lower D-type scores than all remaining subtypes, including diagnostically unclassifiable, probable bipolar patients (a category somewhat akin to RDC bipolar II disorder). Data pointed to the heterogeneity of bipolar disorders. Catecholamine and metabolite data in this study were compared with recent studies of others.

Depression and tetrahydrobiopterin: the folate connection

Total biopterin, neopterin and creatinine were measured in spot urine samples from affective disorder patients on lithium therapy and control subjects. Folic acid was also measured in plasma in a sample of the patients. The mean neopterin: biopterin ratio was significantly higher in the 76 patients (3.2 +/- 0.5) than in the 61 controls (1.8 +/- 0.1). In female patients biopterin levels were significantly lower than in controls. In the control groups there was a significant correlation between the molar concentration of neopterin and biopterin. No such correlation was found in the patients. These data indicate that tetrahydrobiopterin (BH4) biosynthesis is reduced in this group. A significant positive correlation was found between plasma folate and urinary biopterin. It is suggested that folate deficiency may impair the synthesis of BH4, a cofactor essential for the synthesis of 5-HT and other monoamines that are involved in the pathogenesis of affective disorders.

Increase in urinary beta-phenylethylamine preceding the switch from mania to depression: a "rapid cycler"

beta-Phenylethylamine (PEA), an endogenous amphetamine-like substance, is known to increase central catecholamine metabolism and has been hypothesized to have an etiological importance in affective disorders. A case of a "rapid cycler" who showed increased PEA excretion before the switch from mania into depression was reported. In order to evaluate whether the patient's cycle of moods could be prevented by modulating PEA metabolism, carbidopa (peripheral dopa decarboxylase inhibitor) and safrazine (monoamine oxidase inhibitor) were administered during the manic and depressive periods of the patient, respectively. Carbidopa exacerbated the manic symptoms, although it decreased PEA excretion. Safrazine induced the increase of PEA without any beneficial effect on the depressive symptoms. These findings may suggest that PEA plays the role of a biochemical trigger in the switch mechanism of a rapid cycler, especially in the switch from mania to depression.

Arginine vasopressin in manic-depressive psychosis

Urinary excretions of arginine vasopressin (AVP), sodium, potassium, osmoles and creatinine were measured in three in-patients with bipolar manic-depressive psychosis on at least eight 24-hour periods in each affective phase. Mood and body weight were recorded twice daily. The excretion by each patient of sodium, water and osmoles was greater in mania than during depression. Comparison of electrolytes and osmoles suggested that the increase was due to increased intake of salt and water rather than of total diet. There was a fall of mean AVP excretion during mania, the magnitude of the fall being related to the increase of water throughput. Compared with controls, AVP excretion was high and variable. It did not show the normal relationship to urine osmolality. Days with very high AVP were not associated with any characteristic feature of the other measurements; nor were they confined to any one point in the manic-depressive cycle. AVP does not appear to play a major role in the salt and water changes characteristic of manic-depressive psychosis and we have no evidence of its having any direct relationship to mood changes. We suggest that the observed abnormalities of AVP excretion are another manifestation of the central defect of this disease.

Changes in urinary catecholamines and their metabolites in depressed patients treated with amitriptyline or imipramine

The effects of treatment with amitriptyline (AMI) or imipramine (IMI) on changes in catecholamines and their metabolites in urine were studied in 95 unipolar and bipolar depressed patients. For the entire group, not separated by drug, substantial reduction in concentrations of all metabolites, but not catecholamines, occurred. Although catecholamine and metabolite change was similar for most substances assayed, there were some specific drug and diagnostic group differences. Vanillylmandelic acid (VMA) reduction was limited to bipolar patients; metanephrine (M) reduction to unipolar patients. Greater M and 3-methoxy-4-hydroxyphenylglycol (MHPG) reduction were associated with response in unipolar, but not bipolar patients. In bipolar, but not unipolar patients, norepinephrine (NE) rose in responders in contrast to reductions among nonresponding bipolar patients. The results suggest that effectiveness of blockade of reuptake of norepinephrine may be relatively more important for recovery in bipolar than in unipolar patients. Study of a battery of amine substances may contribute more information to our understanding of antidepressant drug effects on aminergic systems than analyses of MHPG alone.

Sustained urinary norepinephrine and epinephrine elevation in post-traumatic stress disorder

Urinary norepinephrine and epinephrine levels (microgram/day) were measured at two-week intervals during the course of hospitalization in the following patient groups: post-traumatic stress disorder (PTSD); major depressive disorder (MDD); bipolar I, manic (BP); paranoid schizophrenia (PS); and undifferentiated schizophrenia (US). The mean norepinephrine level during hospitalization was significantly higher in PTSD (76 +/- 10.4 micrograms/day) than in BP (60.6 +/- 8.4 micrograms/day), MDD (41.2 +/- 4.7 micrograms/day), PS (33.4 +/- 4.9 micrograms/day) and US (34.3 +/- 5.9 micrograms/day) groups, according to Duncan's multiple range test, (F(4,39) = 6.94, p less than 0.0003). The norepinephrine elevations in the PTSD group were sustained throughout hospitalization. The only other group to show mean levels in this range was the BP group in the first sample after hospital admission. This finding supports prior psychophysiological studies indicating increased sympathetic nervous system activity in PTSD patients. The mean epinephrine level during hospitalization was also significantly higher in PTSD (22.7 +/- 2.4 micrograms/day) than in MDD (13.6 +/- 1.7 micrograms/day), PS (14.7 +/- 2.4 micrograms/day), and US (18.9 +/- 1.8 micrograms/day), but not higher than in BP (21.5 +/- 2.7 micrograms/day). The relationship of epinephrine levels among diagnostic groups was sustained throughout hospitalization. It appears likely that the main underlying mechanisms for elevations of both hormones are psychological, but further work will be required to establish the exact nature of these mechanisms.

Urinary phenylethylamine correlates positively with hypomania, and negatively with depression, paranoia, and social introversion on the MMPI

It has been suggested that phenylethylamine (PEA) may play a role in the modulation of affective behavior. The aim of the present study was to test this hypothesis. Urinary PEA excretion was determined in 32 drug-free healthy volunteers, and the MMPI was used for personality assessment. In support of this hypothesis, a significant positive correlation between PEA and hypomania (r = 0.50; P less than 0.05) and a significant negative correlation between PEA and depression (r = -0.58; P less than 0.01) was observed in the female subgroup. Furthermore, PEA correlated significantly negatively with hypochondriasis (r = -0.65; P less than 0.01), paranoia (r = 0.49; P less than 0.05), and social introversion (r = -0.60; P less than 0.05). These results are the first evidence in normal individuals either that PEA itself might play a role in the modulation of affective behavior, or alternatively that PEA could be related to mechanisms responsible for the modulation of affective behavior.

Urinary free-cortisol levels in posttraumatic stress disorder patients

Urinary free-cortisol levels (micrograms per day) were measured by radioimmunoassay at 2-week intervals during the course of hospitalization in the following patient groups: posttraumatic stress disorder (PTSD); major depressive disorder; bipolar I, manic; paranoid schizophrenia; and undifferentiated schizophrenia. The mean cortisol level during hospitalization was significantly lower in PTSD (33.3 +/- 3.2) than in major depressive disorder (49.6 +/- 5.9), bipolar I, manic (62.7 +/- 6.7), and undifferentiated schizophrenia (50.1 +/- 8.9), but was similar to that in paranoid schizophrenia (37.5 +/- 3.9). The same differences across groups are evident in the first sample following hospital admission. This finding of low, stable cortisol levels in PTSD patients is especially noteworthy, first because of the overt signs of anxiety and depression, which would usually be expected to accompany cortisol elevations, and second because of the concomitant chronic increase in sympathetic nervous system activity shown in prior psychophysiological studies of PTSD and reflected in marked and sustained urinary catecholamine elevations previously reported in our own PTSD sample. The findings suggest a possible role of defensive organization as a basis for the low, constricted cortisol levels in PTSD and paranoid schizophrenic patients. The data also suggest the possible usefulness of hormonal criteria as an adjunct to the clinical diagnosis of PTSD.

Peptide-containing fractions in depression

A mixture of peptides and glycoproteins has been found in benzoic acid-precipitable material from urines of psychomotorically agitated and retarded endogenous depressive patients. This complex mixture of compounds is fractionated on a Sephadex G-25 gel, from which the different peaks are further separated on Biogel P2. The G-25 elution profiles ultraviolet absorbance, 280 nm) from depressive patients deviated from the normal pattern. The increase in hydrolyzable ninhydrin-colorable material of the P2 fractionation step encountered in psychotic depression was several-fold that of the normal population. Neurochemically active peptide-containing fractions were found. As explanation of these findings, it is probable that a genetically determined peptidase insufficiency is present, causing a peptide overflow when the secretion outstrips the breakdown. This model could easily combine more psychodynamic models with the genetic-biological models. The variability of the peptide patterns could possibly reflect the considerable clinical variability of the syndrome. Furthermore, the presence of a group of active compounds with different neuropharmacological activities might reflect the composite nature of the depressive syndrome.

[Lithium levels in biological media and treatment surveillance]

The authors present their collection procedures and the results concerning plasma, red blood cell or urinary lithium levels. They point out the interest of determination of red blood cell lithium for the prevention of toxical effects and the control of treatment in lithium intoxications. Clearance determination methodologies are also discussed.

Trace elements in manic depressive psychosis

The concentrations of 16 elements (Al, Ba, Br, Ca, Cl, Cu, I, Pb, Mg, Mn, Mo, Rb, Se, Na, S and Ti) were estimated by neutron activation analysis in samples of hair, whole blood, serum and urine from normal controls, from patients suffering from mania and depression and from patients who had recovered from mania and from depression. Significant differences between groups were shown but apart from molybdenum, no element showed a significant change in more than one tissue. The differences in molybdenum concentrations appear to be of potential interest but the results must be interpreted with caution.

MHPG excretion in endogenous depression: relationship to clinical state and the effects of ECT

In a group of 70 patients with endogenous depression entering a controlled trial of real versus sham ECT, urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) excretion was significantly reduced by comparison with previously studied groups of control subjects, of acute and chronic schizophrenic patients and of anxious patients. However, urinary MHPG was unrelated to severity of depression, or to the presence of delusions, retardation or agitation. MHPG excretion did not predict clinical outcome, or the response to ECT. Urinary MHPG content at trial entry was unrelated to past tricyclic antidepressant or benzodiazepine medication, although an influence of the latter on the findings cannot be excluded, since all patients received benzodiazepine (nitrazepam) night sedation during the trial. During the 4-week trial MHPG excretion remained low and did not increase in relation to change in clinical state, although there was a small but significant increase in patients who received real ECT. The findings confirm that urinary MHPG excretion is reduced in depression, but establish that such reductions are not state dependent. Since the increase in MHPG excretion with ECT is not related to changes in clinical state, the former presumably does not reflect the mechanism of action of ECT.

Phenylethylamine excretion in depression

Urinary phenylethylamine (PEA) excretion was evaluated in two populations of depressed hospitalized patients. Seven of 53 patients had PEA values exceeding three times the highest value found in 16 normal controls. The patients with high PEA excretion were all females. They were not, however, otherwise clinically distinguishable from depressed patients with low PEA. In a subsample of 31 patients and 10 controls, PEA excretion was not correlated with phenylacetic acid (PAA) excretion. These results suggest that depression is not associated with a generalized PEA deficit and that PAA reductions, previously reported in a depressed patient population, may not reflect a PEA abnormality.

Pretreatment neurotransmitter metabolite levels and response to tricyclic antidepressant drugs

Relationships between pretreatment neurotransmitter metabolite levels and response to imipramine and amitriptyline were studied in 104 depressed patients. Normal values for urinary norepinephrine and low values for urinary MHPG were associated with greater incidence of drug response in bipolar, but not unipolar, patients. For unipolar, but not bipolar, patients low CSF 5-HIAA and high urinary metanephrine values were associated with a greater incidence of drug response. These data indicate that the pretreatment functional state of catecholamine and serotonin systems is associated with type of response to drug treatment. The authors present hypotheses about the association of alterations in serotonin and norepinephrine systems and definable subtypes of depression.

The tyramine challenge test as a marker for melancholia

A previous study reported that unipolar depressives excrete significantly lower amounts of urinary tyramine-O-sulfate following oral administration of a tyramine hydrochloride load than do normal control subjects. This study replicates and extends those findings by showing that within the heterogeneous group of unipolar depressives, patients with melancholia and bipolar patients with a history of melancholia manifest a tyramine excretion deficit. A small subgroup of medication-free patients in remission from episodes of melancholia had abnormally low tyramine sulfate excretion levels while they were euthymic, supporting the suggestion that reduced tyramine sulfate excretion following oral tyramine loading is a trait marker for depression. Further study of the role of trace amines in affective illness is warranted. Clinical application is not warranted until further evaluation of the sensitivity, specificity, and reproducibility of this oral tyramine challenge test.

Urinary 3-methoxy-4-hydroxyphenylglycol and major affective disorders. A replication and new findings

We studied group and subgroup differences in urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) levels in patients with major affective disorder (66 depressed, 13 manic) and normal volunteers (27 subjects). Bipolar I depressed patients excreted less MHPG than unipolar depressed patients, manic patients, or normal volunteers. The mean (+/- SEM) MHPG excretion rate was 1.44 +/- 0.10 mg/day in 19 depressed bipolar I patients, 1.79 +/- 0.11 mg/day in 28 unipolar depressed patients, 2.11 +/- 0.19 mg/day in 13 manic patients, and 1.85 +/- 0.12 mg/day in 27 normal volunteers. Other sources of variance that affected urinary MHPG levels did not explain subgroup or state differences. There was only a trend for a low pretreatment MHPG level to be associated with positive response to imipramine hydrochloride or desipramine hydrochloride in the 19 patients treated with these drugs. The application of this biological test value for prediction of differential response to antidepressant drugs would therefore seem premature.

Amelioration of psychosis with carbidopa. A case report

We have recently demonstrated that some patients with atypical bipolar affective disorders, characterized by psychotic manias and depressions, have fluctuating and episodic high urinary phenylethlamine (PEA) excretion. We treated a 30 year old woman, who has this disorder, with 200 mg/24 hours of carbidopa. Her psychosis was ameliorated and the urinary PEA output stabilized to a low normal level. Upon withdrawal of carbidopa her psychosis worsened and improved again when carbidopa treatment was reinstated. Carbidopa did not affect the duration or severity of the patient's mood cycles.

Urinary excretion of biopterin and neopterin in psychiatric disorders

Levels of urinary neopterin and biopterin were determined in patients having a diagnosis of schizophrenia, unipolar depression, or bipolar depression. Both neopterin and biopterin levels were significantly higher in the urine of patients with unipolar depression than in the urine of the control group. Subclassification of patients into primary and secondary depression demonstrated a significant elevation of urinary biopterin in both groups, whereas urinary neopterin was elevated only in those patients with primary depression. In patients with bipolar depression, neopterin excretion was elevated, but biopterin excretion did not differ from controls. No significant differences were found in schizophrenic patients.

Failure to correlate urinary MHPG with clinical response to amitriptyline

On the basis of studies carried out in a group of 44 patients with endogenous depressive illness, the authors conclude that MHPG in urine is not a good predictor of response to amitriptyline treatment. There are no correlations between MHPG level and clinical improvement after 2 weeks' treatment and with final results of the therapy.

Seasonal variation in urinary excretion of calcium, magnesium and phosphate in manic-melancholic patients

The 24-hr urinary excretion of calcium, magnesium and phosphate was measured in 76 normal control persons, 95 manic-melancholic patients not on lithium treatment and 74 lithium-treated manic-melancholic patients. The mean value of the urinary excretion for each of the four seasons during a 5-year period was calculated. The normal control persons had a higher excretion of calcium during the summer months than during the rest of the year; this seasonal variation was not present in the two groups of manic-melancholic patients. Previously reported changes in electrolyte metabolism during lithium treatment were confirmed, but some of the results varied with the season.

Urinary MHPG and ward behavior in unmedicated psychiatric patients

The relationship between urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) and overt behaviors emitted in two hospital environments was examined in a group of 27 drug-free psychiatric patients. Depressed patients with high MHPG excretion ate less and engaged in less visual activity in the lunch environment. Schizophrenic patients but not depressive patients with high MHPG tended to have greater body activity during the gym environment. The implications of these findings for the identification of subtypes of depression and schizophrenia, and for an improved methodology in investigation of biobehavioral relations in clinical populations, are discussed.