Cognitive effects of mifepristone in overweight, euthymic adults with depressive disorders

BACKGROUND

Previous studies have shown that individuals with mood disorders have a higher prevalence of both hypercortisolemia and insulin resistance. Insulin resistance is posited to contribute to the cognitive deficits observed in individuals who have depression. However, the mechanistic relationship between cortisol and insulin within the central nervous system remains to be further elucidated. This study aimed to evaluate the effects of the antiglucocorticoid agent, mifepristone, on metabolic function and cognitive performance in individuals receiving treatment for depressive disorders who were euthymic at baseline.

METHODS

Participants were administered a 600 mg/day dose of mifepristone for 28 days. Oral glucose tolerance tests (OGTTs) and cognitive assessments measuring verbal memory and executive functioning were administered at baseline and after 28 days of treatment.

RESULTS

Improvements in attention and verbal learning were associated with reduction of fasting plasma glucose (FPG) in response to mifepristone treatment.

LIMITATIONS

Limitations include the open-label design of this study and a small sample size.

CONCLUSIONS

The findings from this study suggest that improvement in fasting plasma glucose levels, upon administration of mifepristone, is associated with the improvement in early input of verbal information. Further studies are warranted in order to better evaluate the use of mifepristone or other antiglucocorticoid agents in treatment of mood disorders characterized by metabolic dysfunction.

Quantitative validation of immunofluorescence and lectin staining using reduced CLARITY acrylamide formulations

The CLARITY technique enables three-dimensional visualization of fluorescent-labeled biomolecules in clarified intact brain samples, affording a unique view of molecular neuroanatomy and neurocircuitry. It is therefore, essential to find the ideal combination for clearing tissue and detecting the fluorescent-labeled signal. This method requires the formation of a formaldehyde-acrylamide fixative-generated hydrogel mesh through which cellular lipid is removed with sodium dodecyl sulfate. Several laboratories have used differential acrylamide and detergent concentrations to achieve better tissue clearing and antibody penetration, but the potential effects upon fluorescent signal retention is largely unknown. In an effort to optimize CLARITY processing procedures we performed quantitative parvalbumin immunofluorescence and lectin-based vasculature staining using either 4 or 8% sodium dodecyl sulfate detergent in combination with different acrylamide formulas in mouse brain slices. Using both confocal and CLARITY-optimized lightsheet microscope-acquired images, we demonstrate that 2% acrylamide monomer combined with 0.0125% bis-acrylamide and cleared with 4% sodium dodecyl sulfate generally provides the most optimal signal visualization amongst various hydrogel monomer concentrations, lipid removal times, and detergent concentrations.

Anhedonia and general distress show dissociable ventromedial prefrontal cortex connectivity in major depressive disorder

Anhedonia, the reduced ability to experience pleasure in response to otherwise rewarding stimuli, is a core symptom of major depressive disorder (MDD). Although the posterior ventromedial prefrontal cortex (pVMPFC) and its functional connections have been consistently implicated in MDD, their roles in anhedonia remain poorly understood. Furthermore, it is unknown whether anhedonia is primarily associated with intrinsic 'resting-state' pVMPFC functional connectivity or an inability to modulate connectivity in a context-specific manner. To address these gaps, a pVMPFC region of interest was first identified using activation likelihood estimation meta-analysis. pVMPFC connectivity was then examined in relation to anhedonia and general distress symptoms of depression, using both resting-state and task-based functional magnetic resonance imaging involving pleasant music, in current MDD and healthy control groups. In MDD, pVMPFC connectivity was negatively correlated with anhedonia but not general distress during music listening in key reward- and emotion-processing regions, including nucleus accumbens, ventral tegmental area/substantia nigra, orbitofrontal cortex and insula, as well as fronto-temporal regions involved in tracking complex sound sequences, including middle temporal gyrus and inferior frontal gyrus. No such dissociations were observed in the healthy controls, and resting-state pVMPFC connectivity did not dissociate anhedonia from general distress in either group. Our findings demonstrate that anhedonia in MDD is associated with context-specific deficits in pVMPFC connectivity with the mesolimbic reward system when encountering pleasurable stimuli, rather than a static deficit in intrinsic resting-state connectivity. Critically, identification of functional circuits associated with anhedonia better characterizes MDD heterogeneity and may help track of one of its core symptoms.

Childhood trauma predicts antidepressant response in adults with major depression: data from the randomized international study to predict optimized treatment for depression

Few reliable predictors indicate which depressed individuals respond to antidepressants. Several studies suggest that a history of early-life trauma predicts poorer response to antidepressant therapy but results are variable and limited in adults. The major goal of the present study was to evaluate the role of early-life trauma in predicting acute response outcomes to antidepressants in a large sample of well-characterized patients with major depressive disorder (MDD). The international Study to Predict Optimized Treatment for Depression (iSPOT-D) is a randomized clinical trial with enrollment from December 2008 to January 2012 at eight academic and nine private clinical settings in five countries. Patients (n=1008) meeting DSM-IV criteria for MDD and 336 matched healthy controls comprised the study sample. Six participants withdrew due to serious adverse events. Randomization was to 8 weeks of treatment with escitalopram, sertraline or venlafaxine with dosage adjusted by the participant's treating clinician per routine clinical practice. Exposure to 18 types of traumatic events before the age of 18 was assessed using the Early-Life Stress Questionnaire. Impact of early-life stressors-overall trauma 'load' and specific type of abuse-on treatment outcomes measures: response: (⩾50% improvement on the 17-item Hamilton Rating Scale for Depression, HRSD17 or on the 16-item Quick Inventory of Depressive Symptomatology-Self-Rated, QIDS_SR16) and remission (score ⩽7 on the HRSD17 and ⩽5 on the QIDS_SR16). Trauma prevalence in MDD was compared with controls. Depressed participants were significantly more likely to report early-life stress than controls; 62.5% of MDD participants reported more than two traumatic events compared with 28.4% of controls. The higher rate of early-life trauma was most apparent for experiences of interpersonal violation (emotional, sexual and physical abuses). Abuse and notably abuse occurring at ⩽7 years of age predicted poorer outcomes after 8 weeks of antidepressants, across the three treatment arms. In addition, the abuses occurring between ages 4 and 7 years differentially predicted the poorest outcome following the treatment with sertraline. Specific types of early-life trauma, particularly physical, emotional and sexual abuse, especially when occurring at ⩽7 years of age are important moderators of subsequent response to antidepressant therapy for MDD.

Temporal variability of glucocorticoid receptor activity is functionally important for the therapeutic action of fluoxetine in the hippocampus

Previous studies have shown inconsistent results regarding the actions of antidepressants on glucocorticoid receptor (GR) signalling. To resolve these inconsistencies, we used a lentiviral-based reporter system to directly monitor rat hippocampal GR activity during stress adaptation. Temporal GR activation was induced significantly by acute stress, as demonstrated by an increase in the intra-individual variability of the acute stress group compared with the variability of the non-stress group. However, the increased intra-individual variability was dampened by exposure to chronic stress, which was partly restored by fluoxetine treatment without affecting glucocorticoid secretion. Immobility in the forced-swim test was negatively correlated with the intra-individual variability, but was not correlated with the quantitative GR activity during fluoxetine therapy; this highlights the temporal variability in the neurobiological links between GR signalling and the therapeutic action of fluoxetine. Furthermore, we demonstrated sequential phosphorylation between GR (S224) and (S232) following fluoxetine treatment, showing a molecular basis for hormone-independent nuclear translocation and transcriptional enhancement. Collectively, these results suggest a neurobiological mechanism by which fluoxetine treatment confers resilience to the chronic stress-mediated attenuation of hypothalamic-pituitary-adrenal axis activity.

Circadian dysregulation of clock genes: clues to rapid treatments in major depressive disorder

Conventional antidepressants require 2-8 weeks for a full clinical response. In contrast, two rapidly acting antidepressant interventions, low-dose ketamine and sleep deprivation (SD) therapy, act within hours to robustly decrease depressive symptoms in a subgroup of major depressive disorder (MDD) patients. Evidence that MDD may be a circadian-related illness is based, in part, on a large set of clinical data showing that diurnal rhythmicity (sleep, temperature, mood and hormone secretion) is altered during depressive episodes. In a microarray study, we observed widespread changes in cyclic gene expression in six regions of postmortem brain tissue of depressed patients matched with controls for time-of-death (TOD). We screened 12 000 transcripts and observed that the core clock genes, essential for controlling virtually all rhythms in the body, showed robust 24-h sinusoidal expression patterns in six brain regions in control subjects. In MDD patients matched for TOD with controls, the expression patterns of the clock genes in brain were significantly dysregulated. Some of the most robust changes were seen in anterior cingulate (ACC). These findings suggest that in addition to structural abnormalities, lesion studies, and the large body of functional brain imaging studies reporting increased activation in the ACC of depressed patients who respond to a wide range of therapies, there may be a circadian dysregulation in clock gene expression in a subgroup of MDDs. Here, we review human, animal and neuronal cell culture data suggesting that both low-dose ketamine and SD can modulate circadian rhythms. We hypothesize that the rapid antidepressant actions of ketamine and SD may act, in part, to reset abnormal clock genes in MDD to restore and stabilize circadian rhythmicity. Conversely, clinical relapse may reflect a desynchronization of the clock, indicative of a reactivation of abnormal clock gene function. Future work could involve identifying specific small molecules capable of resetting and stabilizing clock genes to evaluate if they can rapidly relieve symptoms and sustain improvement.

ABCB1 (MDR1) predicts remission on P-gp substrates in chronic depression

The hypothesis that allelic variation in the multidrug resistance-1 (MDR1 or ABCB1) gene encoding the P-glycoprotein (P-gp) blood-brain barrier efflux pump is associated with remission and side effects was tested in chronic major depression patients treated with P-gp substrates. In 83 patients from the REVAMP trial, frequency of and time to remission as well as side effects was tested among genotype groups at 6 ABCB1 single nucleotide polymorphisms (SNPs). These six SNPs are significantly associated with remission and time to remission, with minor allele carriers on rs2235040 and rs9282564 attaining statistical significance after controlling for the other ABCB1 SNPs. The six ABCB1 SNPs are also significantly associated with the average side effects. However, here common homozygotes on rs2235040 and rs9282564 demonstrated significantly higher side effects after controlling for the effects of the other ABCB1 SNPs. These findings confirm and extend previous observations that minor alleles of two ABCB1 SNPs predict remission to treatment with substrates and demonstrate that common homozygotes on these SNPs experience greater side effects. Results point to the potential importance of ABCB1 variation for personalized medicine approaches to treating depression.

Citalopram plus low-dose pipamperone versus citalopram plus placebo in patients with major depressive disorder: an 8-week, double-blind, randomized study on magnitude and timing of clinical response

BACKGROUND

Selective serotonin reuptake inhibitors take several weeks to achieve their full antidepressant effects. Post-synaptic 5-HT2A receptor activation is thought to be involved in this delayed therapeutic effect. Pipamperone acts as a highly selective 5-HT2A/D4 antagonist when administered in low doses. The purpose of this study was to compare citalopram 40 mg once daily plus pipamperone 5 mg twice daily (PipCit) versus citalopram plus placebo twice daily for magnitude and onset of therapeutic effect.

METHOD

An 8-week, randomized, double-blind study in patients with major depressive disorder was carried out.

RESULTS

The study population comprised 165 patients (citalopram and placebo, n=82; PipCit, n=83) with a mean baseline Montgomery-Asberg Depression Rating Scale (MADRS) score of 32.6 (s.d.=5.5). In the first 4 weeks, more citalopram and placebo than PipCit patients discontinued treatment (18% v. 4%, respectively, p=0.003). PipCit patients had significantly greater improvement in MADRS score at week 1 [observed cases (OC), p=0.021; last observation carried forward (LOCF), p=0.007] and week 4 (LOCF, p=0.025) but not at week 8 compared with citalopram and placebo patients. Significant differences in MADRS scores favoured PipCit in reduced sleep, reduced appetite, concentration difficulties and pessimistic thoughts. Mean Clinical Global Impression-Improvement scores were significantly improved after 1 week of PipCit compared with citalopram and placebo (OC and LOCF, p=0.002).

CONCLUSIONS

Although the MADRS score from baseline to 8 weeks did not differ between groups, PipCit provided superior antidepressant effects and fewer discontinuations compared with citalopram and placebo during the first 4 weeks of treatment, especially in the first week.

Stress-induced changes in primate prefrontal profiles of gene expression

Stressful experiences that consistently increase cortisol levels appear to alter the expression of hundreds of genes in prefrontal limbic brain regions. Here, we investigate this hypothesis in monkeys exposed to intermittent social stress-induced episodes of hypercortisolism or a no-stress control condition. Prefrontal profiles of gene expression compiled from Affymetrix microarray data for monkeys randomized to the no-stress condition were consistent with microarray results published for healthy humans. In monkeys exposed to intermittent social stress, more genes than expected by chance appeared to be differentially expressed in ventromedial prefrontal cortex compared to monkeys not exposed to adult social stress. Most of these stress responsive candidate genes were modestly downregulated, including ubiquitin conjugation enzymes and ligases involved in synaptic plasticity, cell cycle progression and nuclear receptor signaling. Social stress did not affect gene expression beyond that expected by chance in dorsolateral prefrontal cortex or prefrontal white matter. Thirty four of 48 comparisons chosen for verification by quantitative real-time polymerase chain reaction (qPCR) were consistent with the microarray-predicted result. Furthermore, qPCR and microarray data were highly correlated. These results provide new insights on the regulation of gene expression in a prefrontal corticolimbic region involved in the pathophysiology of stress and major depression. Comparisons between these data from monkeys and those for ventromedial prefrontal cortex in humans with a history of major depression may help to distinguish the molecular signature of stress from other confounding factors in human postmortem brain research.

Serotonin transporter polymorphism, memory and hippocampal volume in the elderly: association and interaction with cortisol

The s allele variant of the serotonin transporter gene (5-HTT) has recently been observed to moderate the relationship of stress to depression and anxiety. To date no study has considered interactive effects of 5-HTT genotype, stress and hypothalamic-pituitary-adrenal (HPA) function on cognition in healthy, older adults, which may reflect developmental, functional or neurodegenerative effects of the serotonin transporter polymorphism. We investigated whether 5-HTT genotype interacts with cumulative life stress and HPA-axis measures of waking and diurnal cortisol slope to impact cognition in 154 non-depressed, older adults. Structural images of hippocampal volume were acquired on a subsample of 56 participants. The 5-HTT s allele was associated with both significantly lower delayed recall and higher waking cortisol levels. Presence of the s allele interacted with higher waking cortisol to negatively impact memory. We also observed a significant interaction of higher waking cortisol and the s allele on lower hippocampal volume. Smaller hippocampi and higher cortisol were associated with lower delayed recall only in s allele carriers. No impact or interactions of cumulative life stress with 5-HTT or cortisol were observed. This is the first investigation to identify an association of the 5-HTT s allele with poorer memory function in older adults. The interactive effects of the s allele and waking cortisol levels on reduced hippocampal volume and lower memory suggest that the negative effect of the serotonin polymorphism on memory is mediated by the HPA axis. Further, given the significant association of the s allele with higher waking cortisol in our investigation, future studies may be needed to evaluate the impact of the serotonin transporter polymorphism on any neuropsychiatric or behavioral outcome which is influenced by HPA axis function in older adults.

Nocturnal sleep apnea/hypopnea is associated with lower memory performance in APOE ε4 carriers

The authors investigated the relationship between obstructive sleep apnea/hypopnea (OSAH) and cognition in 36 older adults, 18 APOE ε4 carriers, and 18 non-carriers. Greater numbers of respiratory events negatively impacted memory function in ε4 carriers only. This is the first study to provide preliminary evidence for a negative interaction of APOE ε4 and OSAH on memory in older adults, which may have important implications for treating cognitive decline and delaying dementia onset.

Functional brain imaging of olfactory processing in monkeys

As a step toward bridging the gap between human and animal studies of olfactory brain systems, we report results from an fMRI study of olfaction in squirrel monkeys. High-resolution fMRI images at 3 T with 1.25 x 1.25 x 1.2 mm(3) voxels were obtained covering the whole brain using an 8-cm-diameter birdcage coil and a gradient-echo spiral pulse sequence. Data were acquired from six sedated adult males using a standard block design. All fMRI data were spatially normalized to a common template and analyzed at the individual and group levels with statistical parametric and nonparametric methods. Robust odorant-induced activations were detected in several brain regions previously implicated in conscious human olfactory processing, including the orbitofrontal cortex, cerebellum, and piriform cortex. Consistent with human data, no stimulus intensity effects were observed in any of these regions. Average signal changes in these regions exceeded 0.6%, more than three times the expected signal change based on human fMRI studies of olfaction adjusting for differences in voxel size. These results demonstrate the feasibility of studying olfaction in sedated monkeys with imaging techniques commonly used at 3 T in humans and help promote direct comparisons between humans and nonhuman primates. Our findings, for example, provide novel support for the hypothesis that the cerebellum is involved in sensory acquisition. More broadly, this study suggests that olfactory processing in sedated monkeys and nonsedated humans shares similar neural substrates both within and beyond the primary olfactory system.

Cortisol feedback during the HPA quiescent period in patients with major depression

OBJECTIVE

The authors tested the hypothesis that patients with major depression have a defect in the mechanism by which cortisol exerts negative feedback on the hypothalamic-pituitary-adrenal (HPA) axis during the HPA axis quiescent period.

METHOD

Twenty-nine patients with major depression and 25 healthy comparison subjects were randomly assigned to administration of 15 mg cortisol or placebo infused over 2 hours beginning at 7:00 p.m. Cortisol and ACTH levels were measured at baseline and every 30 minutes from 7:30 p.m. to 11:00 p.m.

RESULTS

Differences between the patients and the comparison subjects in the ACTH response to the cortisol infusion, relative to the ACTH response to placebo, were not found.

CONCLUSIONS

The results provide some evidence that patients with major depression do not have an abnormality of cortisol feedback during the HPA axis quiescent period.

Early life stress and inherited variation in monkey hippocampal volumes

BACKGROUND

Opportunities for research on the causes and consequences of stress-related hippocampal atrophy are limited in human psychiatric disorders. Therefore, this longitudinal study investigated early life stress and inherited variation in monkey hippocampal volumes.

METHODS

Paternal half-siblings raised apart from one another by different mothers in the absence of fathers were randomized to 1 of 3 postnatal conditions that disrupted diverse aspects of early maternal care (n = 13 monkeys per condition). These conditions were previously shown to produce differences in social behavior, emotional reactivity, and neuroendocrine stress physiology. Hippocampal volumes were subsequently determined in adulthood by high-resolution magnetic resonance imaging.

RESULTS

Adult hippocampal volumes did not differ with respect to the stressful postnatal conditions. Based on paternal half-sibling effects, the estimated proportion of genetic variance, ie, heritability, was 54% for hippocampal size. Paternal half-siblings with small adult hippocampal volumes responded to the removal of all mothers after weaning with initially larger relative increases in cortisol levels. Plasma cortisol levels 3 and 7 days later, and measures of cortisol-negative feedback in adulthood were not, however, correlated with hippocampal size.

CONCLUSIONS

In humans with mood and anxiety disorders, small hippocampal volumes have been taken as evidence that excessive stress levels of cortisol induce hippocampal volume loss. Results from this study of monkeys suggest that small hippocampi also reflect an inherited characteristic of the brain. Genetically informed clinical studies should assess whether inherited variation in hippocampal morphology contributes to excessive stress levels of cortisol through diminished neuroendocrine regulation.

Rapid reversal of psychotic depression using mifepristone

The rationale for treating psychotic major depression with glucocorticoid receptor (GR) antagonists is reviewed. Five patients with psychotic major depression were given 600 mg of mifepristone in a 4-day, double-blind, placebo-controlled crossover study. All the patients completed the protocol and adverse effects were not observed or reported. All of the five patients showed substantial improvements in their Hamilton Rating Scale for Depression scores while they were receiving mifepristone, and four of the five patients showed substantial improvement in their Brief Psychiatric Rating Scale scores. Little, if any, improvement was seen with placebo. These preliminary results suggest that short-term use of GR antagonists may be effective in the treatment of psychotic major depression and that additional study, perhaps using higher doses or more treatment days, seems warranted.

Cortisol activity and cognitive changes in psychotic major depression

OBJECTIVE

The theory that psychotic major depression is a distinct syndrome is supported by reports of statistically significant differences between psychotic and nonpsychotic major depression in presenting features, biological measures, familial transmission, course and outcome, and response to treatment. This study examined differences in performance on a verbal memory test and in cortisol levels between patients with psychotic and nonpsychotic major depression and healthy volunteers.

METHOD

Ten patients with psychotic major depression, 17 patients with nonpsychotic major depression, and 10 healthy volunteers were administered the Wallach Memory Recognition Test and had blood drawn at half-hour intervals over the course of an afternoon to assay cortisol levels.

RESULTS

Subjects with psychotic major depression had a higher rate of errors of commission on the verbal memory test (incorrectly identified distracters as targets) than did subjects with nonpsychotic major depression or healthy volunteers; errors of omission were similar among the three groups. Subjects with psychotic major depression had higher cortisol levels throughout the afternoon than subjects with nonpsychotic major depression or healthy volunteers. This effect became even more pronounced later in the afternoon.

CONCLUSIONS

Psychotic major depression is endocrinologically different from nonpsychotic major depression and produces cognitive changes distinct from those seen in nonpsychotic major depression.

Sertraline versus imipramine to prevent relapse in chronic depression

BACKGROUND

Chronic depressions are common, disabling and under-treated, and long-term treatment is little studied. We report the continuation phase results from a long-term treatment study.

METHODS

After 12 weeks of acute phase treatment in a double-blind, randomized, parallel-group, multi-center trial of sertraline or imipramine, patients with chronic depression (> or = 2 years in major depression, or major depression superimposed on dysthymia) continued study drug for 16 weeks. Initially, 635 patients were randomized to sertraline or imipramine in a 2:1 ratio. Nonresponders after 12 weeks entered a 12-week double-blind crossover trial of the alternate medication. Entry into continuation treatment required at least a satisfactory response (partial remission) to initial or crossover treatment.

RESULTS

Of 239 acute or crossover responders to sertraline, 60% entered continuation in full remission and 40% with a partial remission. These proportions were identical for imipramine patients (n = 147). For both drug groups, over two-thirds of those entering in full remission retained it. For those entering in partial remission, over 40% achieved full remission. Patients requiring crossover treatment were less likely to maintain or improve their response during continuation treatment. The two drugs did not differ significantly in response distribution, drop out rates or discontinuation due to side effects during continuation treatment.

LIMITATIONS

The absence of a placebo group constrains interpretation of our results, but chronic depressions have low placebo response rates.

CONCLUSIONS

Most chronic depression patients who remit with 12 weeks of sertraline or imipramine treatment maintain remission during 16 weeks of continuation treatment. Most patients with a satisfactory therapeutic response (partial remission) after 12 weeks of treatment maintain it or further improve. Patients treated with imipramine experienced more side effects, but both drugs were well tolerated.

Corticosteroids and cognition

The brain is a major target organ for corticosteroids. It has been observed that excessive circulatory levels of endogenous and exogenous corticosteroids are frequently associated with cognitive impairment in a wide variety of clinical disease states. Cognition and low levels of corticosteroids have been less well studied. In this paper we review the literature on glucocorticosteroid effects on cognition and delineate specific functions that appear to be causally affected. We draw a possible connection to specific areas of brain perturbation, including the hippocampus and frontal lobe regions. The possibility that cognitive dysfunction caused by glucocorticoids can be pharmacologically managed is introduced.

Glucocorticoid and mineralocorticoid receptor mRNA expression in squirrel monkey brain

Corticosteroids have been implicated in hippocampal atrophy in patients with severe psychiatric disorders, but little is known about receptor expression for corticosteroids in human or nonhuman primate brain. Both the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) were surveyed in this study of squirrel monkey brain using in situ hybridization histochemistry. Regions of high GR mRNA levels included CA1 and CA2 of hippocampus, dentate gyrus, paraventricular hypothalamus, lateral geniculate, lateral>medial amygdala, and cerebellum. Western analysis confirmed that GR immunoreactivity in squirrel monkey brain tissue most likely reflects the alpha isoform. Regions of high MR mRNA levels included all hippocampal pyramidal cell fields, dentate gyrus granule cell layer, lateral septum, medial>lateral amygdala, and to a lesser extent, cerebellum. Low levels of MR were also expressed in caudate and putamen. Receptor expression for corticosteroids in deep brain structures and the hippocampal formation was similar to that previously reported in rodents, but GR and MR mRNA were expressed at higher levels in squirrel monkey cerebral cortex. GR expression was evident in all cortical layers, particularly the pyramidal cell-rich layers II/III and V. MR expression was restricted to the more superficial cortical layers, and was only moderately represented in layer V. Laminar patterns were apparent in all regions of cortex for GR expression in squirrel monkeys, but low MR mRNA levels were found in dorsomedial prefrontal cortex (PFC). Different subregional distributions and distinctive laminar patterns suggest specialized functions or coordinated interactions between GR and MR mediated functions in primate PFC.

Stress-level cortisol treatment impairs inhibitory control of behavior in monkeys

Most studies of cortisol-induced cognitive impairments have focused on hippocampal-dependent memory. This study investigates a different aspect of cognition in a randomized placebo-controlled experiment with monkeys that were treated with cortisol according to a protocol that simulates a prolonged stress response. Young adult and older adult monkeys were assigned randomly to placebo or chronic treatment with cortisol in a 2 x 2 factorial design (n = 8 monkeys per condition). Inhibitory control of behavior was assessed with a test shown previously in primates to reflect prefrontal cortical dysfunction. Failure to inhibit a specific goal-directed response was evident more often in older adults. Treatment with cortisol increased this propensity in both older and young adult monkeys. Age-related differences in response inhibition were consistent across blocks of repeated test trials, but the treatment effects were clearly expressed only after prolonged exposure to cortisol. Aspects of performance that did not require inhibition were not altered by age or treatment with cortisol, which concurs with effects on response inhibition rather than nonspecific changes in behavior. These findings lend support to related reports that cortisol-induced disruptions in prefrontal dopamine neurotransmission may contribute to deficits in response inhibition and play a role in cognitive impairments associated with endogenous hypercortisolism in humans.

Gender differences in chronic major and double depression

BACKGROUND

While the sex difference in prevalence rates of unipolar depression is well established, few studies have examined gender differences in clinical features of depression. Even less is known about gender differences in chronic forms of depression.

METHODS

235 male and 400 female outpatients with DSM-III-R chronic major depression or double depression (i.e., major depression superimposed on dysthymia) were administered an extensive battery of clinician-rated and self-report measures.

RESULTS

Women were less likely to be married and had a younger age at onset and greater family history of affective disorder compared to men. Symptom profile was similar in men and women, with the exception of more sleep changes, psychomotor retardation and anxiety/somatization in women. Women reported greater severity of illness and were more likely to have received previous treatment for depression with medications and/or psychotherapy. Greater functional impairment was noted by women in the area of marital adjustment, while men showed more work impairment.

LIMITATIONS

Since our population consisted of patients enrolling in a clinical trial, study exclusion criteria may have affected gender-related differences found.

CONCLUSIONS

Chronicity of depression appears to affect women more seriously than men, as manifested by an earlier age of onset, greater family history of affective disorders, greater symptom reporting, poorer social adjustment and poorer quality of life. These findings represent the largest study to date of gender differences in a population with chronic depressive conditions.

Nicotine patch and paroxetine for smoking cessation

Smokers (N = 224) were randomized to 1 of 3 groups: (a) transdermal system (TNS) + placebo; (b) TNS + paroxetine (20 mg); (c) TNS + paroxetine (40 mg). Assignment to treatment was double-blind. Nicotine patch (TNS) treatment was provided for 8 weeks; paroxetine or placebo was provided for 9 weeks. Abstinence rates at Weeks 4, 10, and 26 were as follows: (a) TNS + placebo: 45%, 36%, and 25%; (b) TNS + paroxetine (20 mg): 48%, 33%, and 21%; (c) TNS + paroxetine (40 mg): 57%, 39%, and 27%. The differences were not statistically significant. The combined treatment was more effective in reducing both craving and depression symptoms associated with smoking cessation. A subgroup analysis comparing compliant participants was also conducted. Abstinence rates at Weeks 4, 10, and 26 were as follows: (a) TNS + placebo: 46%, 35%, and 24%; (b) TNS + paroxetine (20 mg): 64%, 43%, and 33%; (c) TNS + paroxetine (40 mg): 74%, 51%, and 38%. The differences between paroxetine groups and placebo at Week 4 were statistically significant. Although paroxetine may add value to the current standard of care in excess of potential risk, more conclusive evidence is needed.

Pharmacotherapy of depression and mixed states in bipolar disorder

The treatment of bipolar depression requires the resolution of depression and the establishment of mood stability. A basic problem is that the treatments used in treating bipolar depression were developed and proven effective for other disease states: antidepressants for unipolar depression, and mood stabilizers for mania. The panel addressed four unresolved questions regarding depression in relation to bipolar disorder: (1) the relative effectiveness of different antidepressant treatments; (2) the relative likelihood of mood destabilization with different antidepressant treatments; (3) the effectiveness and role of mood-stabilizing medicines as antidepressants; and (4) the optimal approach to mixed states. The selection of an antidepressant depends both on its relative lack of mania- or hypomania-provoking potential and on its effectiveness against bipolar depression. There is little definitive evidence distinguishing effectiveness of the major groups of antidepressive agents, so side-effect profiles and pharmacokinetics are major considerations. The underlying bipolar disorder should be treated with mood stabilizers started simultaneously with any antidepressive treatments. Lithium, divalproex sodium and carbamazepine have all been found to be helpful, to some extent, in treating bipolar depressive episodes as well as for long-term mood stabilization. There is little evidence for long-term benefits of antidepressive agents in bipolar disorder, and some evidence that they may destabilize the disorder. Therefore, in contrast to the long-term use of mood-stabilizers, antidepressant use is recommended on a temporary basis. The duration of antidepressant treatment is determined by past history in terms of liability for mood destabilization, and by the ability of the patient to tolerate gradual antidepressant discontinuation without return of depression. Mixed states, where symptoms of depression and mania coexist, are regarded as a predictor of relatively poor response to lithium, and divalproex has been found to be more effective. Carbamazepine may too be useful in mixed states. Most patients with mixed states in actual practice require combinations of mood stabilizers, though there is little controlled data regarding such co-prescription, especially from a long-term perspective.

Gender differences in treatment response to sertraline versus imipramine in chronic depression

OBJECTIVE

The authors examined gender differences in treatment response to sertraline, a selective serotonin reuptake inhibitor (SSRI), and to imipramine, a tricyclic antidepressant, in chronic depression.

METHOD

A total of 235 male and 400 female outpatients with DSM-III-R chronic major depression or double depression (i.e., major depression superimposed on dysthymia) were randomly assigned to 12 weeks of double-blind treatment with sertraline or with imipramine after placebo washout.

RESULTS

Women were significantly more likely to show a favorable response to sertraline than to imipramine, and men were significantly more likely to show a favorable response to imipramine than to sertraline. Gender and type of medication were also significantly related to dropout rates; women who were taking imipramine and men who were taking sertraline were more likely to withdraw from the study. Gender differences in time to response were seen with imipramine, with women responding significantly more slowly than men. Comparison of treatment response rates by menopausal status showed that premenopausal women responded significantly better to sertraline than to imipramine and that postmenopausal women had similar rates of response to the two medications.

CONCLUSIONS

Men and women with chronic depression show differential responsivity to and tolerability of SSRIs and tricyclic antidepressants. The differing response rates between the drug classes in women was observed primarily in premenopausal women. Thus, female sex hormones may enhance response to SSRIs or inhibit response to tricyclics. Both gender and menopausal status should be considered when choosing an appropriate antidepressant for a depressed patient.

Salivary cortisol levels in socially phobic adolescent girls

Anxiety disorders such as social phobia (SP) often have their onset during adolescence and frequently precede the onset of major depression. Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is well-documented in major depression. Consequently, there is considerable interest in HPA function in anxiety disorders. We examined salivary cortisol levels in 27 SP adolescent girls and 21 matched controls during normal daily activities, and immediately before and after a modified Trier Social Stress Test (TSST). Both SP subjects and controls showed significant elevations in cortisol levels prior to the TSST, and prior to attending school. These results suggest that salivary cortisol is a sensitive measure of anticipatory anxiety, but we failed to find significant differences between SP subjects and controls.

New indications for antidepressants

The second and third generation of antidepressants, i.e., the selective serotonin reuptake inhibitors, nefazodone, venlafaxine, and mirtazapine, are proving to be useful in a variety of seemingly diverse disorders, including most anxiety disorders. In addition to receiving approval from the U.S. Food and Drug Administration (FDA) for major depressive disorder, some of the newer antidepressants have received FDA approval for other disorders, e.g., generalized anxiety disorder (venlafaxine), bulimia nervosa (fluoxetine), obsessive-compulsive disorder (fluvoxamine, paroxetine, sertraline, and fluoxetine), social phobia (paroxetine), panic disorder (sertraline, paroxetine), and posttraumatic stress disorder (sertraline). In controlled studies, these agents have also shown usefulness in premenstrual dysphoric disorder, borderline personality disorder, obesity, smoking cessation, and alcoholism. This article describes the new and potential indications for recently developed antidepressants and the studies that suggested these indications.

Clinical efficacy of reboxetine in major depression

The past decade has witnessed the advent of selective serotonin reuptake inhibitors (SSRIs) as first-line treatments for major depression. Still, there is considerable debate as to whether these agents are as effective or as potent as the first-generation tricyclic antidepressants (TCAs) or the mixed reuptake inhibitor, venlafaxine, all of which exert considerable effect on norepinephrine (NE) reuptake. Recently, reboxetine, a selective NE reuptake inhibitor (selective NRI), has been introduced in Europe. This drug has only a minimal affinity for muscarinic acetylcholine receptors and therefore causes less dry mouth, constipation, or other such effects than do the TCAs. Reboxetine does not block serotonin reuptake or alpha1 receptors and, thus, does not appear to produce significant nausea, diarrhea, or hypotension. Unlike other antidepressants, reboxetine appears to be nonsedating. Data on acute and long-term clinical efficacy and safety from double-blind, placebo-controlled, and active comparator studies with reboxetine are reviewed. These studies indicate that reboxetine is significantly more effective than placebo and as effective as fluoxetine in reducing depressive symptoms. Improvements in social adjustments were reported to be more favorable with reboxetine than with fluoxetine. Further, data from controlled clinical trials have shown that the side effect profile for reboxetine is relatively benign. The clinical implications of studies on reboxetine are discussed with an eye toward understanding the potential role NE reuptake blockers may play in the treatment of patients with major depression.

Acute antidepressant effects of intravenous hydrocortisone and CRH in depressed patients: a double-blind, placebo-controlled study

OBJECTIVE

The primary objective of this investigation was to examine the acute antidepressant effects of intravenous hydrocortisone and ovine corticotropin releasing hormone (CRH) infusions in patients with major depression.

METHOD

Twenty-two patients who met DSM-III-R criteria for nonpsychotic major depression were randomly assigned to receive intravenously 1 mg/kg of ovine CRH, 15 mg of hydrocortisone, or saline under double-blind conditions on day 1. Standard depression rating scales were completed on day 1 before the study medications were administered and again the following day (day 2).

RESULTS

Patients treated with hydrocortisone demonstrated a significantly greater reduction in total 21-item Hamilton Depression Rating Scale scores (mean reduction=8.4 points or 37%) than patients given ovine CRH (mean=1.2 points) or placebo (mean=1.3 points).

CONCLUSIONS

Acute hydrocortisone infusion is associated with a rapid and robust reduction in depressive symptoms. The authors discuss the therapeutic implications of these findings.

24-Hour monitoring of cortisol and corticotropin secretion in psychotic and nonpsychotic major depression

BACKGROUND

Considerable research has been devoted to the hypothalamic-pituitary-adrenal (HPA) axis in depression, but relatively little attention has been given to intensive monitoring of hormone secretion over time. Such research is potentially important because the HPA axis has prominent circadian and ultradian periodicity. Comparison of depressed patients with and without psychotic features is also important because HPA axis abnormalities may be especially pronounced in psychotic depressed patients.

METHODS

Eleven patients with psychotic major depression (PMD patients), 38 patients with nonpsychotic major depression (NPMD patients), and 33 healthy control subjects, all drug free, were studied. Patients with PMD and NPMD were outpatients recruited primarily by advertisement. Subjects were admitted to a General Clinical Research Center and had blood drawn through an intravenous line for determination of cortisol and corticotropin (ACTH) levels every hour for 24 hours.

RESULTS

Among NPMD patients, the 24-hour cortisol amplitude was significantly (P =.02) reduced in comparison with control subjects, while ACTH indices did not differ between NPMD patients and the control group. Among PMD patients, the ACTH 24-hour mean was significantly (P =.03) increased compared with controls, while PMD patients and the control group did not differ significantly in cortisol indices.

CONCLUSION

In the population studied, PMD and NPMD patients have distinct profiles of HPA axis dysregulation.

Early environmental regulation of glucocorticoid feedback sensitivity in young adult monkeys

Variations in maternal care induce in neonatal rodents life-long changes in glucocorticoid feedback regulation of the hypothalamic-pituitary-adrenal axis. This aspect of plasticity in neuroendocrine development has not been established in primates. We assessed, in young adult squirrel monkeys, postnatal rearing effects on cortisol-induced suppression of corticotropin-releasing factor (CRF) stimulated secretion of adrenocorticotropic hormone (ACTH). Offspring of randomly bred monkeys were periodically removed from natal groups between 13 and 21 weeks of age. In two other postnatal rearing conditions, systematic differences in maternal availability were produced by manipulating the effort required of lactating mothers to successfully find food. All offspring were subsequently administered, 3-5 years later on two occasions, an intravenous ovine CRF injection preceded 60 min earlier by placebo or cortisol pretreatment. The difference between CRF-stimulated time-integrated secretion of ACTH following placebo vs cortisol pretreatment served as an index of glucocorticoid negative feedback. Difference scores were greatest in monkeys previously separated from natal groups. This finding was not attributable to significant rearing condition differences in plasma cortisol levels achieved following pretreatment with exogenous cortisol, nor plasma ACTH levels produced when the CRF injection was preceded by pretreatment with placebo. The results suggest that postnatal experiences altered glucocorticoid feedback in monkeys at least through early adulthood. This conclusion supports retrospective reports indicating that, for humans with major mood and anxiety disorders, systematic differences in glucocorticoid feedback may reflect neural mechanisms in development linking early life stress with psychopathology in adulthood.

Neuropsychological deficits in psychotic versus nonpsychotic major depression and no mental illness

OBJECTIVE

At least three studies have indicated that patients with psychotic major depression studied under non-drug-free conditions differ from patients with nonpsychotic major depression and healthy comparison subjects on several measures of neuropsychological performance. The current study explored specific impairments in cognitive function in subjects with psychotic major depression, subjects with nonpsychotic major depression, and healthy comparison subjects studied under drug-free conditions.

METHOD

A battery of neuropsychological tests was administered to 11 patients with psychotic major depression, 32 patients with nonpsychotic major depression, and 23 normal comparison subjects under drug-free conditions. The three groups did not differ statistically in age, sex, or level of education. To ensure that participants had minimal levels of severity and endogenicity, all patients were required to have a score of at least 20 on the 21-item Hamilton Depression Rating Scale and a score of at least 7 on the Core Endogenomorphic Scale, which uses eight items from the Hamilton depression scale.

RESULTS

Patients with psychotic major depression demonstrated significantly greater impairment than patients with nonpsychotic major depression and/or comparison subjects in attention and response inhibition (as measured by the Stroop color-word subscale score) as well as in verbal declarative memory (as measured by the Paragraph Recall Test).

CONCLUSIONS

These data indicate that patients with psychotic major depression demonstrate impairment in functions thought to be mediated by the frontal cortex and mediotemporal lobes.

Cognitive-behavioral group therapy for social phobia in female adolescents: results of a pilot study

OBJECTIVES

To examine the efficacy of cognitive-behavioral group therapy for adolescents (CBGT-A) in females with social phobia and the effect of this treatment on the risk for major depression.

METHOD

Female adolescents with social phobia (N = 35) were randomly assigned to treatment (n = 12) or no treatment (n = 23) groups. Assessments were conducted at baseline, after treatment, and at a 1-year follow-up.

RESULTS

Eleven subjects completed treatment. Sixteen weeks of treatment produced a significant improvement in interference and reduction in symptoms of social anxiety. There was a significant reduction in the number of subjects meeting DSM-IV criteria for social phobia in the CBGT-A versus the untreated group; however, at the 1-year follow-up there were no significant differences by treatment condition. There was also suggestive evidence that treatment of social phobia lowers the risk for relapse of major depression among those with a history of major depression. Combining social phobia and major depression as the outcome produced more robust treatment effects in the 1-year follow-up.

CONCLUSIONS

This pilot study provides evidence for a moderate short-term effect of CBGT-A for treating female adolescents suffering from social phobia and indicates that treatment of social phobia may result in a reduction of major depression.

Clozapine in the treatment of refractory psychotic mania

OBJECTIVE

The efficacy of clozapine was examined in a group of patients with treatment-refractory bipolar disorder, manic type with psychotic features.

METHOD

Twenty-two subjects with treatment-refractory bipolar disorder with active manic and psychotic symptoms participated in a 12-week open-label trial of clozapine. After a 2-10-day drug washout period, patients began treatment with clozapine at 25 mg/day; the dose was increased 25 mg/day (as tolerated) to a maximum level of 550 mg/day. Patients were evaluated longitudinally over the course of the study with the Brief Psychiatric Rating Scale (BPRS), the Young Mania Rating Scale, and the Clinical Global Impressions (CGI) scale.

RESULTS

Fourteen of the 22 subjects in the study continued taking clozapine for at least 10 of the 12 weeks. Among the entire group, mean improvements of 56. 7%, 56.6%, and 39.1% were seen on the BPRS, Young Mania Rating Scale, and CGI, respectively. Seventeen of the 22 subjects (77.3%) experienced at least a 20% improvement in scores on all three scales.

CONCLUSIONS

The findings from this open-label study, which are consistent with previous retrospective studies, case reports, and one other open-label prospective study, suggest that clozapine is an effective agent for patients with treatment-refractory psychotic mania.

Use of placebo control groups in evaluating efficacy of treatment of unipolar major depression

Double-blind, random-assignment placebo-controlled trials are routinely used in evaluating efficacy of potential antidepressant agents. In recent years concern has risen that placebo response rates in unipolar depression are too high, and this has eroded confidence in both old and new agents. At the same time, the use of placebos has been questioned by patients and their advocates. We review factors that have been commonly explored as associated with placebo response (e.g., length of episode, severity, subtype), as well as issues in methodology (e.g., interrater reliability, statistical artifacts). We discuss possible methods of dealing with the problem of placebo response, emphasizing reconceptualizing effect sizes to design more powerful single trials and a systematic sequence of trials to achieve the right answers.

Social functioning in depression: a review

OBJECTIVE

This article reviews the available data on social functioning in depression and provides clinical guidelines and opinion on this important and expanding field.

DATA SOURCES

A MEDLINE search was conducted to identify all English-language articles (1988-1999) using the search terms depression and social functioning, depression and social adjustment, depression and psychosocial functioning, and social functioning and antidepressant. Further articles were obtained from the bibliographies of relevant articles.

DATA SYNTHESIS

Depressive disorders are frequently associated with significant and pervasive impairments in social functioning, often substantially worse than those experienced by patients with other chronic medical conditions. The enormous personal, social, and economic impact of depression, due in no small part to the associated impairments in social functioning, is often underappreciated. Both pharmacologic and psychotherapeutic approaches can improve social impairments, although there is a lack of extended, randomized controlled trials in this area using consistent assessment criteria.

CONCLUSION

Despite this lack, it is becoming clear that not all treatments are equally effective in relieving the impaired social functioning associated with depressive disorders. Furthermore, efficacy in relieving the core symptoms of depression does not necessarily guarantee efficacy in relieving impaired social functioning.

Impaired transactivation of the glucocorticoid receptor cloned from the Guyanese squirrel monkey

Squirrel monkeys are among a diverse group of New World primates that demonstrate unusually high levels of circulating corticosteroids and glucocorticoid receptor (GR) insensitivity. Recent evidence suggests that overexpression of an immunophilin impairs dexamethasone binding to GR in the Bolivian squirrel monkey (Saimiri boliviensis). Here we describe the cloning, expression, and functional characterization of GR from the closely related Guyanese squirrel monkey (S. sciureus). The cloned Guyanese squirrel monkey GR (gsmGR) cDNA closely resembles human GR (hGR) cDNA, and yields a high affinity dexamethasone binding receptor when expressed in COS-1 cells. Transactivation analysis of hGR and gsmGR expressed in CV-1 cells and cultured squirrel monkey kidney (SMK) cells indicates that: (1) SMK cells elaborate a functional high activity GR from human GR cDNA; (2) gsmGR is an order of magnitude less efficient than hGR at transactivation in CV-1 and SMK cells; and (3) maximal transactivation by gsmGR is attenuated in both cell lines. Glucocorticoid resistance in S. sciureus is at least partly attributable to a naturally occurring mutation in the GR gene that results in impaired GR transactivation.

Dilative cardiomyopathy leading to congestive heart failure in a male squirrel monkey (Saimiri sciureus)

A 17-year-old, 1-kg, colony-housed, male squirrel monkey (Samiri sciureus) developed clinical signs of congestive heart failure. The monkey presented with lethargy, increased heart and respiratory rates, and mild abdominal distention. The clinical history, laboratory analysis, and radiographic findings were consistent with heart failure due to dilative cardiomyopathy. Gross and microscopic examination of the heart confirmed a dilative cardiomyopathy. This is the first report describing congestive heart failure caused by dilative cardiomyopathy in a squirrel monkey. Spontaneous dilative cardiomyopathy may be infrequently observed in the squirrel monkeys because they are not routinely housed in the research environment during their advancing years.

Postnatal experiences and genetic effects on squirrel monkey social affinities and emotional distress

Most nonhuman primate research on risk factors underlying vulnerability to stress has focused on early psychosocial experiences in various species of macaques. To test for genetic and experiential effects on emotional vulnerability in randomly bred squirrel monkeys, here we combined a paternal half-sibling analysis with three postnatal rearing protocols that altered aspects of maternal availability. In one condition offspring were periodically removed from natal groups, whereas differences in maternal availability were produced in two other conditions by manipulating the effort required of lactating mothers to successfully locate food. After completion of these protocols at 21 weeks of age, social affinities, maternal separation induced peep-calls, and plasma levels of cortisol were assessed from 29 to 37 weeks of age. Significant postnatal rearing effects and the lowest heritabilities were detected in peak elevations of cortisol measured 1 day after the removal of mothers from otherwise undisturbed groups. Individual differences in cortisol 3-7 days later revealed negligible postnatal rearing effects and the highest heritabilities (h(2) approximately. 70), as offspring sired by certain fathers failed to return to the preseparation level found in undisturbed natal groups. Paternal half-siblings that responded with long lasting increases in cortisol spent more time near their mother in undisturbed groups and exhibited long-lasting increases in separation induced peep-calls. These findings concur with human twin studies that suggest genetic and experiential factors contribute to individual differences in vulnerability to emotional distress.

Age of onset in chronic major depression: relation to demographic and clinical variables, family history, and treatment response

BACKGROUND

The clinical and etiological significance of the early-late onset distinction in chronic major depressive disorder was explored.

METHOD

Subjects were 289 outpatients with DSM-III-R chronic major depression drawn from a multi-site study comparing the efficacy of sertraline and imipramine in the acute and long-term treatment of chronic depression. Patients received comprehensive evaluations using semi-structured interviews and rating scales.

RESULTS

Early-onset chronic major depression was associated with a longer index major depressive episode and higher rates of recurrent major depressive episodes, comorbid personality disorders, lifetime substance use disorders, depressive personality traits, and a history of psychiatric hospitalization. In addition, more early-onset patients tended to have a family history of mood disorders. The early-late onset distinction was not associated with differences in symptom severity, functional impairment, or treatment response.

LIMITATIONS

Family members were not interviewed directly; there were a large number of statistical comparisons; and interrater reliability of the assessments was not evaluated.

CONCLUSIONS

Early-onset chronic major depression has a more malignant course and is associated with greater comorbidity than late-onset chronic major depression.

Glucocorticoid effects on mesotelencephalic dopamine neurotransmission

Multiple neurochemical estimates were used to examine peripheral corticosterone (CORT) effects in dopaminergic terminal regions. Acute CORT administration, which elevated plasma CORT (5 h), slightly decreased dihydroxyphenylacetic acid (DOPAC) to dopamine (DA) ratios in the striatum but not in other regions examined. Two weeks of adrenalectomy (ADX) increased both medial prefrontal cortex DOPAC/DA and homovanillic acid (HVA)/DA and striatal HVA/DA. A reciprocal pattern of changes was observed with CORT replacement in ADX animals. In contrast, CORT replacement in ADX animals did not significantly influence tyrosine hydroxylase content, basal dihydroxyphenylalanine (DOPA) accumulation after NSD 1015 treatment or the decline in DA after alpha-methyl-para-tyrosine, suggesting that neither DA neuronal activity nor release are altered by CORT. Moreover, neither gamma-hydroxybutyric acid lactone-induced increases in DOPA accumulation or stress-induced increases in DA utilization were influenced by CORT replacement, indicating that neither autoreceptor regulation of DA synthesis nor acute stress regulation of DA utilization are changed by CORT. The findings are most consistent with direct inhibition of basal DA metabolism in the medial prefrontal cortex and striatum. The possible physiological and behavioral significance of this inhibition is being further explored.

Phenomenology and treatment of agitation

Agitation is a troublesome, common symptom in major depression that can be difficult to manage. It is sometimes a side effect of antidepressant treatment and may occasionally represent a mixed bipolar episode. If agitation fails to respond to an antidepressant alone, treatment may be augmented with a benzodiazepine, a neuroleptic, or lithium. Preliminary evidence indicates that divalproex, which has been found useful for bipolar disorder and for agitation associated with Alzheimer's disease, may also be effective for agitated depression. A controlled trial is now underway.

Strain differences in mesotelencephalic dopaminergic neuronal regulation between Fischer 344 and Lewis rats

Differences in the behavioral responses of Lewis and Fischer (F344) inbred rat strains to stress and psychoactive drugs have been related to differences in the expression of various regulatory proteins in regions containing mesolimbic dopamine (DA) neurons. The present study compared basal and stimulated neurochemical estimates of DA utilization and synthesis in mesocortical, mesolimbic and nigrostriatal DA terminal regions of these two strains. In unstressed control animals, the Lewis strain had lower DA concentrations in the dorsal striatum (ST; 80.3% of F344) and lower basal dihydroxyphenylalanine (DOPA) accumulation after m-hydroxybenzylhydrazine (NSD 1015) treatment in the medial prefrontal cortex (mPfx; 75.3% of F344). Similar differences were observed in vehicle-injected animals. No strain differences in basal neurochemistry were apparent in the nucleus accumbens shell (NAs) or core (NAc). In response to restraint stress, dihydroxyphenylacetic acid (DOPAC) to DA ratios in the mPfx, NAs and ST increased in the F344 but not the Lewis strain. However, restraint stress did not significantly increase DOPA accumulation in the F344 strain. This latter finding was not due to a deficit in synthesis capacity, as gamma-hydroxybutyric acid lactone (GBL) increased DOPA accumulation significantly more in F344 than Lewis animals. Finally, haloperidol increased DA utilization similarly in the two strains. Together these findings suggest that the inbred, behaviorally divergent F344 and Lewis rats have selective differences in mesocortical, nigrostriatal and mesolimbic DA neuronal regulation.

Antidepressant effectiveness in severe depression and melancholia

While outcome has improved in patients with depressive disorders since the introduction of the newer antidepressants, some physicians still treat severely depressed patients with the older tricyclic antidepressants because of conflicting reports about the efficacy of the newer agents, particularly the selective serotonin reuptake inhibitors, in severe depression. However, a standardized operational definition of severe depression is lacking, and treatment studies are difficult to evaluate due to variation in methodology. Remission rates are relatively low in many of the short-term clinical trials of the newer antidepressants in severe depression, but may improve if the research design were to include a longer trial and aggressive dosing. There is some evidence that venlafaxine, a serotonin-norepinephrine antidepressant, may offer some advantage for severely depressed patients.

Separation induced changes in squirrel monkey hypothalamic-pituitary-adrenal physiology resemble aspects of hypercortisolism in humans

When separated from groups, squirrel monkeys respond with significant increases in plasma cortisol and adrenocorticotropic hormone (ACTH). While cortisol remains elevated above pre-separation levels, significant reductions occur in ACTH. Monkeys that respond with greater increases in cortisol subsequently exhibit greater reductions in ACTH, which suggests that reductions in ACTH are mediated by corticosteroid feedback. Monkeys that respond with greater increases in cortisol also tend to exhibit greater cerebrospinal fluid levels of the dopamine metabolite HVA, but not the norepinephrine metabolite MHPG, or corticotropin-releasing factor (CRF). Attenuation of corticosteroid feedback with metyrapone results in significant increases in circulating ACTH, and in older monkeys increases plasma HVA. Similar findings in humans have been reported in clinical studies of hypercortisolism and major depression.

Hypothalamic-pituitary-adrenal axis effects on plasma homovanillic acid in man

BACKGROUND

Effects of the hypothalamic-pituitary-adrenal (HPA) axis on central dopaminergic systems have been proposed to underlie the development of psychotic symptoms in depression. This study examined HPA axis hormone effects on plasma levels of homovanillic acid (HVA), the dopamine metabolite, in healthy volunteers, using a placebo-controlled, double-blind, random-assignment, crossover design. On the basis of preliminary studies, we hypothesized that HPA axis hormones would produce delayed effects on plasma HVA levels measured in the afternoon.

METHODS

Ten healthy subjects underwent a standard protocol on four occasions and each time received ovine corticotropin-releasing hormone, synthetic adrenocorticotropic hormone (ACTH), cortisol, or placebo. Plasma HVA was measured at 9 AM and 4 PM on Day 1, immediately prior to administration of the test substance at 7 PM, then at 30-60-min intervals until 11 PM. Plasma HVA levels were subsequently obtained at 9 AM and 4 PM on Days 2 and 3.

RESULTS

As predicted, there were significant differences between test substances in delayed effects on afternoon HVA levels measured on Days 2 and 3, with cortisol and ACTH producing greater increases in HVA than placebo. Acute effects of HPA axis hormones on HVA were not found, while differences between test substances in delayed effects on morning HVA levels approached significance.

CONCLUSIONS

HPA axis hormones exert delayed effects on plasma HVA levels in healthy humans.