Serotonin-related, anxiety/aggression-driven, stressor-precipitated depression. A psycho-biological hypothesis

Irritable Mood and Subthreshold Hypomanic Episodes Correlate with More Severe Major Depression

INTRODUCTION

Irritable mood (IM) and subthreshold hypomanic symptoms are reported in half and two-fifths of major depressed subjects respectively, but their clinical and prognostic meanings remain unclear. The aim of this study was to test the clinical usefulness of 2 specifiers in DSM-IV major depressive disorder (MDD): IM occurring during an index episode (IM+) and lifetime episodes of elated mood or IM with at least 2 concurrent hypomanic symptoms (subthreshold hypomanic episodes [SHEs]).

METHOD

We included 482 outpatients with MDD participating in the Combining Medications to Enhance Depression Outcome study (mean age 43.14 ± 12.46 years, 144 males - 30%). The main aim of the original study was to test whether 2 different medications when given in combination as the first treatment step, compared to 1 medication, would improve antidepressant response.

RESULTS

IM + subjects (N = 349; 70%) were younger and more often females, with a more severe depression, a more marked social impairment, and more psychiatric comorbidities. The IM + group was also characterized by higher levels of suicidal ideation and more cases of emotional abuse. The combination of IM+ and SHEs was associated with an even more severe clinical picture. Limitations include the post hoc method, incomplete assessment of bipolar validators (e.g., family history of bipolar illness), personality disorders and suicide attempts.

CONCLUSIONS

The presence of IM and SHEs in MDD correlate with an overall more severe clinical condition.

Psychophysiological Characteristics of Aggression Associated with Depression before and after Successful Treatment with Sertraline: A Clinical Trial Study

Background: Depression associated with aggression can lead to violent behaviors. The present study was aimed to determine how sertraline, a standard medication for depression treatment, can efficiently decrease aggression and affect psychophysiological parameters in patients with depression. Methods: Patients with depression and aggression were included in a six-week trial with sertraline (50 100 mg/day). Depression diagnosis was confirmed by the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, Text Revision (DSM-IV-TR). Depression severity before and after treatment was assessed using Beck Depression Inventory (BDI). Aggression was evaluated by Spielberger’s State-Trait Anger Expression Inventory-2 (STAXIII). The BDI and STAXI-II were finally applied to evaluate the effectiveness of treatment. For each patient, peripheral and central psychophysiological parameters were recorded using peripheral biofeedback apparatus and electroencephalogram in the initial and final stages of treatment. These recordings were attempted to assess variations of the autonomic nervous system and electrocortical activity in response to treatment. Results: Depressive and aggressive symptoms decreased significantly over the six-week treatment period, as measured by BDI and STAXI-II. Significant changes in some of the peripheral and central psychophysiological variables were observed. Sensorimotor rhythm (SMR)/theta ratio (p=0.01) have decreased during a task, delta (p=0.02) and theta (p=0.008) wave activity and theta/alpha ratio (p=0.01) have increased during task, and theta/beta ratio has increased during both rest and task (p=0.02 for both). Among peripheral psychophysiological variables, skin conductance during task decreased significantly (p=0.03). Conclusion: Several numbers of psychophysiological parameters were influenced significantly after successful pharmacotherapy of aggressiveness in patients with depression.

A discrete serotonergic circuit regulates vulnerability to social stress

Exposure to social stress and dysregulated serotonergic neurotransmission have both been implicated in the etiology of psychiatric disorders. However, the serotonergic circuit involved in stress vulnerability is still unknown. Here, we explored whether a serotonergic input from the dorsal raphe (DR) to ventral tegmental area (VTA) influences vulnerability to social stress. We identified a distinct, anatomically and functionally defined serotonergic subpopulation in the DR that projects to the VTA (5-HTDR→VTA neurons). Moreover, we found that susceptibility to social stress decreased the firing activity of 5-HTDR→VTA neurons. Importantly, the bidirectional manipulation of 5-HTDR→VTA neurons could modulate susceptibility to social stress. Our findings reveal that the activity of 5-HTDR→VTA neurons may be an essential factor in determining individual levels of susceptibility to social stress and suggest that targeting specific serotonergic circuits may aid the development of therapies for the treatment of stress-related disorders.

Discriminating Suicide Attempters and Predicting Suicide Risk Using Altered Frontolimbic Resting-State Functional Connectivity in Patients With Bipolar II Disorder

Bipolar II disorder (BD-II) major depression episode is highly associated with suicidality, and objective neural biomarkers could be key elements to assist in early prevention and intervention. This study aimed to integrate altered brain functionality in the frontolimbic system and machine learning techniques to classify suicidal BD-II patients and predict suicidality risk at the individual level. A cohort of 169 participants were enrolled, including 43 BD-II depression patients with at least one suicide attempt during a current depressive episode (SA), 62 BD-II depression patients without a history of attempted suicide (NSA), and 64 demographically matched healthy controls (HCs). We compared resting-state functional connectivity (rsFC) in the frontolimbic system among the three groups and explored the correlation between abnormal rsFCs and the level of suicide risk (assessed using the Nurses' Global Assessment of Suicide Risk, NGASR) in SA patients. Then, we applied support vector machines (SVMs) to classify SA vs. NSA in BD-II patients and predicted the risk of suicidality. SA patients showed significantly decreased frontolimbic rsFCs compared to NSA patients. The left amygdala-right middle frontal gyrus (orbital part) rsFC was negatively correlated with NGASR in the SA group, but not the severity of depressive or anxiety symptoms. Using frontolimbic rsFCs as features, the SVMs obtained an overall 84% classification accuracy in distinguishing SA and NSA. A significant correlation was observed between the SVMs-predicted NGASR and clinical assessed NGASR (r = 0.51, p = 0.001). Our results demonstrated that decreased rsFCs in the frontolimbic system might be critical objective features of suicidality in BD-II patients, and could be useful for objective prediction of suicidality risk in individuals.

Effects of a rat model of gestational hypothyroidism on forebrain dopaminergic, GABAergic, and serotonergic systems and related behaviors

We investigated the effects of maternal hypothyroidism on forebrain dopaminergic, GABAergic, and serotonergic systems and related behavior in adult rat offspring. Experimental gestational hypothyroidism (EGH) was induced by administering 0.02% methimazole (MMI) to pregnant rats from gestational day 9 to delivery. Neurotransmitter-related protein and gene expression were evaluated in offspring forebrain at postnatal day (P) 120. Exploratory behavior, contextual fear conditioning, locomotion, and 30-day reserpine Parkinson induction were assessed from P75-P120. Protein and gene expression assessments of medial prefrontal cortex showed group differences in dopaminergic, GABAergic, and serotonergic receptors, catabolic enzymes, and transporters. Striatum of MMI offspring showed an isolated decrease in the dopaminergic enzyme, tyrosine hydroxylase. MMI exposure increased GABA and dopamine receptor expression in amygdala. MMI offspring also had decreased state anxiety and poor contextual fear conditioning. We found that baseline locomotion was not changed, but reserpine treatment significantly reduced locomotion only in MMI offspring. Our results indicated that restriction of maternal thyroid hormones reduced dopaminergic, GABAergic, and serotoninergic forebrain components in offspring. Tyrosine hydroxylase deficiency in the striatum may underlie enhanced reserpine induction of Parkinson-like movement in these same offspring. Deficits across different neurotransmitter systems in medial prefrontal cortex and amygdala may underlie decreased state anxiety-like behavior and reduced fear conditioning in offspring, but no changes in trait anxiety-like behavior occurred with maternal MMI exposure. These findings strongly support the hypothesis that adequate delivery of maternal thyroid hormones to the fetus is crucial to the development of the central nervous system critical for emotion and motor regulation.

"The Masks We Wear": A Qualitative Study of Suicide in Australian Farmers

PURPOSE

Farmer suicide is a major public issue in Australia. Using the psychological autopsy method, this study aimed to examine the life and death circumstances of Australian male farmers who died by suicide through verbal reports from their close significant others.

METHODS

Individual semistructured interviews were conducted with 12 relatives of male farmers who had died by suicide in Queensland or New South Wales, Australia (2006-2014). This study followed the COREQ checklist criteria for the reporting of qualitative research.

FINDINGS

Six interrelated themes were identified: (1) masculinity, (2) uncertainty and lack of control in farming, (3) feelings of failure in relationships and farming, (4) escalating health problems, (5) maladaptive coping, and (6) acquired capability with access to means.

CONCLUSIONS

Effective clinical interventions, as well as suicide prevention strategies, need to consider the importance of 3 key issues in suicide among farmers: adherence to masculine norms and socialization; expectations of self in maintaining family traditions and occupation; and a male subtype of depression.

Evaluation of adaptogenic-like property of methyl jasmonate in mice exposed to unpredictable chronic mild stress

This study was undertaken to evaluate the adaptogenic-like activity of methyl jasmonate (MJ) in mice exposed to unpredictable chronic mild stress (UCMS). Male Swiss mice were treated with MJ (25-100mg/kg, i.p.) 30 min before exposure to UCMS daily for 14 days prior to testing for memory and anxiety. Thereafter, the blood glucose and serum corticosterone levels were estimated using glucometer and ELISA. The brain concentrations of malondialdehyde (MDA) and glutathione (GSH) were estimated using spectrophotometer. Brain histology and the population of healthy neurons in the hippocampal regions were also assessed. MJ reversed anxiety and memory impairment produced by UCMS, which suggest adaptogenic-like property. The reduction in the weight of adrenal gland and liver in MJ-treated groups further indicates adaptogenic activity. It further decreases the blood glucose and serum corticosterone levels in UCMS-mice. Also, MJ decreases the concentrations of MDA and elevated the levels of GSH in the brain of mice exposed to UCMS. Brain histology revealed that MJ attenuated UCMS-induced degeneration and death of neuronal cells in the pyramidal layer of the cornu ammonis 3 (CA3) and the sub-granular zone of the dentate gyrus of the hippocampus. Moreover, MJ decreased the population of dead neuronal cells of the pyramidal layer of the CA3 and the sub-granular zone of the dentate gyrus of the UCMS-mice, which suggests neuroprotection. Taken together, these findings suggest that MJ demonstrated adaptogenic-like activity in mice; which might be related to modulation of serum corticosterone levels, inhibition of oxidative stress and neuroprotection.

Depressive symptoms in the transition to menopause: the roles of irritability, personality vulnerability, and self-regulation

Although the transition to menopause represents a period of risk for depressive symptoms, there is little research into personality or trait-like factors that may confer vulnerability to depression during the transition to menopause. This study investigated whether the personality trait of self-criticism moderated the effects of irritability on depressive symptoms in women transitioning to menopause and whether these effects were mediated by lower levels of emotional regulation. Participants were 376 women, of whom 157 had entered the transition phase to menopause. These women in the transition phase completed measures of self-criticism, irritable mood, emotional regulation, and depressive symptoms. All analyses controlled for attitudes toward menopause and somatic symptoms. Moderated mediation regression analyses showed that higher levels of irritability were associated with poorer emotional regulation in highly self-critical women, but not in less self-critical women, and poorer emotional regulation was, in turn, related to higher levels depressive symptoms. Findings suggest that the transition to menopause may represent an especially vulnerable period for women with high levels of self-criticism. Although irritability is transitory for most women, for women who are highly self-critical, irritability may tax their ability to self-regulate and lead to more encompassing symptoms of depression.

Relapse (number of detoxifications) in abstinent male alcohol-dependent patients as related to personality traits and types of tolerance to frustration

BACKGROUND

Personality traits like depression on the one hand and aggression and impulsivity on the other are assumed to be predisposing factors for different types of alcohol dependence. Both types are associated with sensitivity to frustration, but this may be different for the two types of personality according to whether they are confronted with frustrations caused by withdrawal from positive or infliction of negative events. It has not been shown so far if both types of personality factors and the two different sources of frustration are differently relevant for the propensity of relapse. This was investigated here in a study on 60 abstinent male alcohol-dependent patients.

METHODS

Correlations between the number of previous detoxifications reflecting liability to relapse and questionnaire scores on personality factors and on reactions to frustration were computed.

RESULTS

Bonferroni-corrected correlations yielded significant relationships between the number of detoxifications and the personality factor of aggression as well as pronounced depressive reactions to frustrating conditions of non-reward caused by humans. Controlling for impulsivity, aggression and depression revealed that depressive reactions to frustration are genuine predictors for probability of relapse independent of underlying personality factors. Persons particularly sensitive to frustrations from human denial of positive reinforcers are liable to relapse which fits the theory of sensitivity to reward in drug-addicted individuals.

CONCLUSION

Results demonstrate that relapse is clearly more related to aggression than to impulsivity, depression and anxiety and may be facilitated if persons are sensitive to frustrating conditions of non-reward caused by social partners.

During the long way to Mars: effects of 520 days of confinement (Mars500) on the assessment of affective stimuli and stage alteration in mood and plasma hormone levels

For future interplanetary manned spaceflight, mental issues, as well as physiological problems, must inevitably be considered and solved. Mars500 is a high-fidelity ground simulation experiment that involved 520 days of confined isolation for six multinational crewmembers. This experiment provided a good opportunity to perform psycho-physiological and psycho-social researches on such missions. To investigate emotional responses and psychological adaptation over long-term confinement, the International Affective Pictures System (IAPS) was selected as the visual emotional stimuli in this study. Additional data collected and analyzed included the Profile of Mood States (POMS) questionnaire and the levels of four types of plasma hormones: cortisol, 5-hydroxy tryptamine, dopamine, and norepinephrine. The results demonstrated an obvious bias on valence rating for unpleasant stimuli with time (p<0.05), and the correlation between psychological and biochemical data was identified (p<0.05). Overall, we concluded that the confined crew tended to assign positive ratings to negative pictures with time, which might be driven by a defensive system. There was a stage-changing pattern of psychological adaptation of the Mars500 crew, which is similar to the third-quarter phenomenon.

Stress, serotonin, and hippocampal neurogenesis in relation to depression and antidepressant effects

Chronic stressful life events are risk factors for developing major depression, the pathophysiology of which is strongly linked to impairments in serotonin (5-HT) neurotransmission. Exposure to chronic unpredictable stress (CUS) has been found to induce depressive-like behaviours, including passive behavioural coping and anhedonia in animal models, along with many other affective, cognitive, and behavioural symptoms. The heterogeneity of these symptoms represents the plurality of corticolimbic structures involved in mood regulation that are adversely affected in the disorder. Chronic stress has also been shown to negatively regulate adult hippocampal neurogenesis, a phenomenon that is involved in antidepressant effects and regulates subsequent stress responses. Although there exists an enormous body of data on stress-induced alterations of 5-HT activity, there has not been extensive exploration of 5-HT adaptations occurring presynaptically or at the level of the raphe nuclei after exposure to CUS. Similarly, although hippocampal neurogenesis is known to be negatively regulated by stress and positively regulated by antidepressant treatment, the role of neurogenesis in mediating affective behaviour in the context of stress remains an active area of investigation. The goal of this review is to link the serotonergic and neurogenic hypotheses of depression and antidepressant effects in the context of stress. Specifically, chronic stress significantly attenuates 5-HT neurotransmission and 5-HT1A autoreceptor sensitivity, and this effect could represent an endophenotypic hallmark for mood disorders. In addition, by decreasing neurogenesis, CUS decreases hippocampal inhibition of the hypothalamic-pituitary-adrenal (HPA) axis, exacerbating stress axis overactivity. Similarly, we discuss the possibility that adult hippocampal neurogenesis mediates antidepressant effects via the ventral (in rodents; anterior in humans) hippocampus' influence on the HPA axis, and mechanisms by which antidepressants may reverse chronic stress-induced 5-HT and neurogenic changes. Although data are as yet equivocal, antidepressant modulation of 5-HT neurotransmission may well serve as one of the factors that could drive neurogenesis-dependent antidepressant effects through these stress regulation-related mechanisms.

Saliva cortisol and male depressive syndrome in a community study. The Sudurnesjamenn study

BACKGROUND

The degree and direction of hypothalamic-pituitary-adrenal (HPA) dysfunction to male mental health is unclear.

AIMS

The aim of the study was to investigate the relationship between cortisol and male mental health.

METHODS

In this community study, 534 males were screened, using the Beck Depression Inventory (BDI), Gotland Male Depression Scale (GMDS) and a general health questionnaire. Those with signs of depression (n = 65) and controls (n = 69) were evaluated in a psychiatric examination according to the DSM-IV criteria for depressive disorder (DD). In a sub-sample (n = 51) saliva cortisol was measured five times on a single day.

RESULTS

Evening cortisol was significantly higher in untreated individuals with DD. Significantly higher evening cortisol (at 22 h) correlated also with a history of physical disorder, a history of any mental disorder and MADRS score ≥ 20 (Montgomery-Åsberg Depression Rating Scale). High cortisol, measured as AUC (area under curve), correlated with a high MADRS score but not with any other health variable tested. Morning cortisol did not correlate with any health variable; however, cortisol awakening response (CAR) could not be investigated. The BDI and GMDS scores did not correlate with cortisol measurements.

CONCLUSION

Evening saliva cortisol measurement seems most informative, as it correlates with male depressive syndrome in our study but replications with larger studies are needed.

Big effects of small RNAs: a review of microRNAs in anxiety

Epigenetic and regulatory elements provide an additional layer of complexity to the heterogeneity of anxiety disorders. MicroRNAs (miRNAs) are a class of small, noncoding RNAs that have recently drawn interest as epigenetic modulators of gene expression in psychiatric disorders. miRNAs elicit their effects by binding to target messenger RNAs (mRNAs) and hindering translation or accelerating degradation. Considering their role in neuronal differentiation and synaptic plasticity, miRNAs have opened up new investigative avenues in the aetiology and treatment of anxiety disorders. In this review, we provide a thorough analysis of miRNAs, their targets and their functions in the central nervous system (CNS), focusing on their role in anxiety disorders. The involvement of miRNAs in CNS functions (such as neurogenesis, neurite outgrowth, synaptogenesis and synaptic and neural plasticity) and their intricate regulatory role under stressful conditions strongly support their importance in the aetiology of anxiety disorders. Furthermore, miRNAs could provide new avenues for the development of therapeutic targets in anxiety disorders.

Clinical and physiological correlates of irritability in depression: results from the Netherlands study of depression and anxiety

Objective. Irritable and nonirritable depressed patients differ on demographic and clinical characteristics. We investigated whether this extends to psychological and physiological measures. Method. We compared irritable and nonirritable unipolar depressed patients on symptomatology, personality, and (psycho)physiological measures (cortisol, cholesterol, and heart rate variability). Symptomatology was reassessed after one year, and we also compared depressed patients who were irritable or non-irritable at both time points (Irr++ versus Irr--). Results. Almost half (46%; N = 420) of the sample was classified as irritable. These patients scored higher on depression severity, anxiety, hypomanic symptoms, and psychological variables. No differences were observed on physiological markers after correction for depression severity. The same pattern was found when comparing Irr++ and Irr-- groups. Conclusion. Irritable and non-irritable depressed patients differ on clinical and psychological variables, but not on the currently investigated physiological markers. The clinical relevance of the distinction and the significance of the hypomanic symptoms remain to be demonstrated.

Depressive and aggressive responses to frustration: development of a questionnaire and its validation in a sample of male alcoholics

Since clinical and biochemical observations point to much overlap between depression and aggression, both characterised by intolerance to frustration, a questionnaire was developed to test if different patterns of depressive and aggressive reactions elicited by exposure to negative events and deprivation from expected positive ones in human and nonhuman conditions, respectively, would result in specific response patterns in depressive and aggressive persons. The questionnaire was tested for internal consistency in a pilot healthy sample and for correlations of responses with the personality factors of Aggression and Depression in 60 abstinent male alcoholics. Aggressive and depressive responses were highly correlated across all stimulus conditions, and not specifically but rather equally associated with the personality factors of Aggression and Depression, confirming the close association between these dimensions.

Fronto-limbic brain structures in suicidal and non-suicidal female patients with major depressive disorder

Our knowledge about the neurobiology of suicide is limited. It has been proposed that suicidal behavior generally requires biological abnormalities concomitant with the personality trait of impulsivity/aggression, besides an acute psychiatric illness or psychosocial stressor. We investigated fronto-limbic anatomical brain abnormalities in suicidal and non-suicidal adult female patients with unipolar depression. Our sample consisted of seven suicidal unipolar patients, 10 non-suicidal unipolar patients and 17 healthy female comparison subjects. The criterion for suicidality was one or more documented lifetime suicide attempts. A 1.5T GE Signa Imaging System running version Signa 5.4.3 software was used to acquire the magnetic resonance imaging images. All anatomical structures were measured blindly, with the subjects' identities and group assignments masked. We used analysis of covariance with age and intracranial volume as covariates and the Tukey-Kramer procedure to compare suicidal patients, non-suicidal patients and healthy comparison subjects. Suicidal patients had smaller right and left orbitofrontal cortex gray matter volumes compared with healthy comparison subjects. Suicidal patients had larger right amygdala volumes than non-suicidal patients. Abnormalities in the orbitofrontal cortex and amygdala in suicidal patients may impair decision-making and predispose these patients to act more impulsively and to attempt suicide.

Can stress cause depression?

The central issue raised in this paper is: can stress cause depression? Phrased more precisely: can stress cause brain disturbances thought to underlie (certain forms of) depression or particular components of the depressive syndrome. Focussing on 5-HT and the stress hormones, this question was answered in the affirmative, based on the following two considerations: (1) changes in the 5-HT and stress hormone systems produced by sustained stress, mimic to a substantial extent the disturbances in these systems that may be observed in depression; (2) substantial evidence indicates that the 5-HT and stress hormone disturbances in depression are of pathophysiological significance and not merely a consequence of the depressed state or a product of stress generated by the depressed state. Furthermore, the question was raised whether a depression type could be identified particularly stress-inducible. This question, too, was answered in the affirmative. The depression type in question was named anxiety/aggression-driven depression and characterized on three levels: psychopathologically, biologically and psychologically. Preferential treatment of this depression type was discussed. In studying stress-inducible depression biological depression research should shift focus from depression per se to the neurobiological sequelae of stress. Treatment of stress-inducible depressions and particularly its prevention should be geared towards reduction of stress and stress sensitiveness, utilising both biological and psychological means.

The cognitive paradox in posttraumatic stress disorder: a hypothesis

Posttraumatic stress disorder (PTSD) is characterized by a peculiar cognitive state. The traumatic event(s) are partly hypermemorized, partly blurred, whereas the ability to store and retrieve new information is impaired. The question is raised as to what the biological systems might be that 'carry' this cognitive paradox. Four possible candidate systems are discussed. It is concluded that understimulation of the corticosteroid receptors, particularly the glucocorticoid receptors (GRs), overactivity of the noradrenaline (NA) and vasopressin (VA) systems, and deficits in the 5-Hydroxytryptamine (5-HT) system, particularly the 5-HT(1A) system, could generate a cognitive syndrome similar to the one observed in PTSD. A dual hypothesis is launched holding that (a) in PTSD, downregulation of the 5-HT(1A) receptor system is the primary lesion, while the other dysfunctions mentioned are subsidiaries and that (b) underdevelopment of or damage to the 5-HT(1A) receptor system will make a person PTSD-prone.

Can stress cause depression?

The central issue raised in this paper is: can stress cause depression? Phrased more precisely: can stress cause brain disturbances thought to underlie (certain forms of) depression or particular components of the depressive syndrome. Focussing on 5-hydroxytryptamine (5-HT) and the stress hormones, this question was answered in the affirmative, based on the following two considerations: changes in the 5-HT and stress hormone systems produced by sustained stress mimic to a substantial extent the disturbances in these systems that may be observed in depression. Substantial evidence indicates that the 5-HT and stress hormone disturbances in depression are of pathophysiological significance and not merely a consequence of the depressed state or a product of stress generated by the depressed state. Furthermore, the question was raised whether a depression type could be identified particularly stress-inducible. This question, too, was answered in the affirmative. The depression type in question was named anxiety/aggression-driven depression and characterized on three levels: psychopathologically, biologically and psychologically. Preferential treatment of this depression type was discussed. In studying stress-inducible depression, biological depression research should shift focus from depression per se to the neurobiological sequelae of stress. Treatment of stress-inducible depressions and particularly its prevention should be geared towards reduction of stress and stress sensitiveness, utilising both biological and psychological means.

Serotonergic platelet markers of suicidal behavior--do they really exist?

BACKGROUND

Abnormal changes in platelets used as peripheral markers of central serotonergic functions are said to be associated with suicidality and depression, but this association has not been supported by consistent findings.

AIM

This review based on selected, often quoted publications in this area focuses firstly, on obviously contradictory findings and, secondly, on potential methodological flaws explaining these discrepancies.

RESULTS

The platelet 5-HT transporter has been found to have an inconsistent association with suicidality; furthermore, the specificity of imipramine for the 5-HT transporter is most likely low, since the number of platelet impramine binding sites has not been reliably associated with platelet serotonin uptake (Vmax). Significant changes of platelet serotonin content in suicidal individuals, as described in various studies, are most likely due to washout periods that are too short to eliminate the effects of a previous drug intake, or, in violent suicide attempters, due to blood loss and dilution. Similar methodological shortcomings might account for an often-reported elevated number of platelet 5-HT(2) receptor binding sites in suicidal individuals. In many studies, the results have not been sufficiently controlled for drug effects on platelet 5-HT(2) receptors, and associations of platelet 5-HT(2) binding with selective classifications of suicidal behavior are often generalized as further evidence for an association of platelet 5-HT(2) receptors with 'suicidality'. Finally, changes in platelet MAO-B-activity in suicidal patients have not been reproducibly found, and the impact of smoking on MAO-B activity has not been controlled in any studies.

CONCLUSIONS

Methodological flaws such as small sample sizes, insufficient matching criteria for controls, use of inadequate ligands in binding experiments, nonconsideration of comorbidity etc. and considerable methodological differences between studies limit their validity and comparability. It does not seem possible, at present, to integrate published findings and concepts into a plausible biological model of suicidality.

Monoamine depletion in psychiatric and healthy populations: review

A number of techniques temporarily lower the functioning of monoamines: acute tryptophan depletion (ATD), alpha-methyl-para-tyrosine (AMPT) and acute phenylalanine/tyrosine depletion (APTD). This paper reviews the results of monoamine depletion studies in humans for the period 1966 until December 2002. The evidence suggests that all three interventions are specific, in terms of their short-term effects on one or two neurotransmitter systems, rather than on brain protein metabolism in general. The AMPT procedure is somewhat less specific, affecting both the dopamine and norepinephrine systems. The behavioral effects of ATD and AMPT are remarkably similar. Neither procedure has an immediate effect on the symptoms of depressed patients; however, both induce transient depressive symptoms in some remitted depressed patients. The magnitude of the effects, response rate and quality of response are also comparable. APTD has not been studied in recovered major depressive patients. Despite the similarities, the effects are distinctive in that ATD affects a subgroup of recently remitted patients treated with serotonergic medications, whereas AMPT affects recently remitted patients treated with noradrenergic medications. The evidence also suggests that ATD and APTD affect different cognitive functions, in particular different memory systems. Few studies investigated cognitive effects of the procedures in patients. Patients who are in remission for longer may also be vulnerable to ATD and AMPT, but the relationship with prior treatment is much weaker. For these patients, individual vulnerability markers are the more important determinants of depressive response, making these techniques potentially useful models of vulnerability to depression.

Prefrontal 5-HT2a receptor binding index, hopelessness and personality characteristics in attempted suicide

BACKGROUND

Depression, hopelessness, impaired problem solving capacities and deficient serotonergic functions have been identified as major causes of suicidal behaviour. In general, the relation between biological markers of attempted suicide and psychological functions has been investigated using indirect peripheral markers of, e.g. the serotonergic system. Recently, functional neuroimaging techniques with radioligands allow direct in vivo assessment of the neurobiological status of the central nervous system.

METHODS

We studied the binding index of serotonin-(2a) (5-HT(2a)) receptors in the frontal cortex of attempted suicide patients (n=9) and normal controls (n=13) using [123I]5-I-R91150, a highly selective 5-HT(2a) receptor ligand. Moreover, we measured personality characteristics (using Cloninger's Temperament and Character Inventory) and levels of hopelessness (using Beck's Hopelessness Scale), and studied the association between 5-HT(2a) receptor binding index, hopelessness and these personality dimensions.

RESULTS

When compared to normal controls, attempted suicide patients had a significantly lower binding potential of frontal 5-HT(2a) receptors, a higher level of hopelessness, a higher score on the temperament dimension harm avoidance and lower scores on the character dimensions self-directedness and cooperativeness. A significant correlation was found between harm avoidance, hopelessness and binding index in the population of patients that attempted suicide.

LIMITATIONS

The limited number of patients and potential ingestion of psychotropic drugs may influence the results of the study.

CONCLUSIONS

Lower central serotonergic function, hopelessness and harm avoidance are interrelated phenomena, which may increase the probability of the occurrence of attempted suicide.

Thrombozytäre Serotoninkonzentration bei depressiven Kindern und Jugendlichen

Zusammenfassung: Fragestellung: In dieser Studie wurde der Frage nachgegangen, inwieweit ein Zusammenhang zwischen thrombozytärem Serotoningehalt und depressivem bzw. suizidalem Verhalten bei Kindern und Jugendlichen besteht. Methodik: Innerhalb von 16 Monaten wurde bei allen stationär aufgenommenen Patienten im Alter von 4 bis 19 Jahren (n = 145) das thrombozytäre Serotonin mittels Fluoreszenzspektroskopie bestimmt. Zeitnah wurde bei einem Teil der Patienten der Schweregrad der depressiven Symptome durch das DIKJ erhoben. Die verschiedenen Diagnosegruppen wurden anhand der Kriterien der ICD-10 gebildet. Ergebnisse: Mit zunehmendem Alter zeigte sich ein Abfall des Serotiningehaltes im Thrombozyten. Die männlichen Patienten wiesen höhere Serotoninwerte im Vergleich zu den weiblichen auf, wobei die Mädchen allerdings höhere Depressivitätsscores im DIKJ zeigten. Es bestand eine negative Korrelation zwischen dem thrombozytären Serotonin und dem im DIKJ gemessenen Depressivitätsgrad über alle Diagnosegruppen. Unabhängig von der klinischen Diagnose ergaben sich signifikant niedrigere Serotoninkonzentrationen bei den Kindern und Jugendlichen, die unmittelbar vor der stationären Aufnahme einen Suizidversuch unternommen hatten. Auch bei der Gruppe der depressiven Störungen kristallisierte sich eine Untergruppe mit signifikant niedrigerem Serotoningehalt heraus, die kurz zuvor einen Suizidversuch verübt hatten. Schlussfolgerungen: Die vorliegenden Untersuchungen stützen die Auffassung, dass Depressivität in der Kindheit und Jugend mit einem Mangel an Serotonin im Thrombozyten bzw. analog zum Thrombozytenmodell in zentralen Strukturen verbunden ist und ein relatives Defizit an Serotonin ein Suizidalitätsmarker sein könnte.

Stress, cortisol and memory as markers of serotonergic vulnerability

OBJECTIVES

In the present paper the association of stress-induced cortisol with memory impairment is discussed Methods: An experiment is described in which an attempt is made to block stress-induced cortisol by lowering 5-HT neurotransmission by means of acute tryptophan depletion (ATD). Forty-five healthy control subjects participated in the experiment.

RESULTS

Stress-induced peak cortisol and immediate memory performance were negatively associated. ATD tended to block stress-induced cortisol response. ATD also blocked the association between peak cortisol response and memory impairment.

CONCLUSIONS

Stress-induced cortisol and its association with memory impairment is mediated at least partially by serotonin.

Crossroads of corticotropin releasing hormone, corticosteroids and monoamines. About a biological interface between stress and depression

Mental disorders are frequently preceded by stressful events or situations. Depression is a typical case in point. This raises the question, is depression - or possibly better: are certain forms of depression - caused by stress? Can stress be a true pathogenic factor? Phrased differently: can stress destabilize neuronal systems in the central nervous system to such an extent that depressive symptoms are generated? This question is discussed with the corticotrophin releasing hormone (CRH) and MA systems and hypothalamic-pituitary-adrenal (HPA) axis as major foci. The following issues are explored: the effect of antidepressants on corticosteroid receptor gene expression; the behavioral sequellae of CRH administration; CRH disturbances in depression; the impact of early life adversity on the development of the CRH system and on stress reactivity; the interrelationships of stress hormones and monoaminergic (MA ergic) transmission and finally the therapeutic potential of CRH and cortisol antagonists. The available data suggest that CRH overdrive and cortisol overproduction may play a pathogenic role in the occurrence of certain types of depression, directly and/or indirectly, i.e. by induction or exacerbation of disturbances in MA ergic transmission. Stress should, thus, become a major focus of biological depression research.

Anxiety/aggression--driven depression. A paradigm of functionalization and verticalization of psychiatric diagnosis

A new subtype of depression is proposed, named: anxiety/aggression-driven depression. The psychopathological, psychopharmacological and biochemical evidence on which this construct is based, is being discussed. Selective postsynaptic 5-HT1A agonists together with CRH and/or cortisol antagonists are hypothesized to be a specific biological treatment for this depression type, in conjunction with psychological interventions to raise the stressor-threshold and to increase coping skills. The development of this depression construct has been contingent on the introduction of two new diagnostic procedures, called functionalization and verticalization of psychiatric diagnosis. These procedures are explained and it is stressed that they are essential to psychiatric diagnosing, in order to put this process on a scientific footing.

Cortisol in violent suicidal behaviour: association with personality and monoaminergic activity

BACKGROUND

According to recent theories, suicidal behaviour is associated with depressive disorders that are commonly induced by social stressors in persons with a trait-dependent vulnerability. Stressor-induced increased cortisol secretion may interfere with this vulnerability that can be defined in terms of (possibly inter-related) biological and psychological or personality-related characteristics. Delineation of such trait-like characteristics may increase the specificity in the prediction of suicidal behaviour and thus lead to new approaches to the treatment and prevention of suicidal behaviour.

METHODS

Psychiatric symptomatology, personality dimensions (Cloninger's Temperament and Character), peripheral markers of serotonergic (whole blood serotonin, platelet MAO activity) and noradrenergic (plasma MHPG) activity, and urinary cortisol were measured in a random sample of patients with a history of violent suicidal behaviour and compared to those of patients without such a history.

RESULTS

When compared to patients without a history of violent suicidal behaviour (n=23), patients with such a history (n=17) were characterised by higher urinary cortisol levels, a significantly lower mean score on Reward Dependence, a borderline significantly increased score on Novelty Seeking and a significantly lower mean plasma MHPG level. Urinary cortisol level correlated significantly with Reward Dependence and Novelty Seeking scores. There were no differences between patient groups regarding severity of anxiety or depressive symptomatology. No differences with regard to the biological parameters were found between patients who recently attempted suicide and those with a history of suicidal behaviour.

LIMITATIONS

Limitations of this study included a relatively small number of study subjects and the use of peripheral markers to assess central neurotransmission functions.

CONCLUSIONS

Violent suicidal behaviour is associated with increased cortisol secretion, a personality profile defined by low Reward Dependence (reflecting the degree of sensitivity to social stressors) and a tendency of increased Novelty Seeking (related to impulsivity and the regulation of anger), and reduced noradrenergic functioning (possibly reflecting an inability to adapt to stressors).

Psychoneurendocrinology: a science of the past or a new pathway for the future?

Psychoneuroendocrinology is a branch of neuroscience that developed in the beginning of the last century, which investigates the possibility of a cause-effect link between endocrinopathies and mental disorders - with these studies ending in negative results. Psychoneuroendocrinology was then used as a methodological approach for the investigation of neurotransmitter function, on the basis of the observation that neurotransmitters regulate neurohormone and peripheral hormone secretions. Data were obtained for hypothalamic noradrenergic, serotoninergic, dopaminergic, gabaergic and acetylcholinergic functions, which could not be automatically extended to higher brain centers whose impairments might be etiopathogenetically involved in the development of mental disorders. Future studies should focus on new methodological approaches to brain biochemistry, on investigation of genetic, molecular biology, brain imaging, psychoneuroimmunoendocrinology, neuropeptide and neurosteroid secretion in relation to brain endocrine function in mental diseases.

Association between multiple suicide attempts and negative affects in adolescents

OBJECTIVE

To compare the level of negative emotions-anxiety, depression, aggression, and impulsivity-in hospitalized adolescents with a history of either a single or multiple suicide attempts.

METHOD

Thirty-two adolescents hospitalized for a first suicide attempt, 19 hospitalized for a repeated attempt (fifth or more), 109 nonsuicidal psychiatric inpatients, and 85 community controls were assessed for level of depression, anxiety, aggression, and impulsivity with the Beck Depression Inventory, the State-Trait Anxiety Inventory, the Multidimensional Anger Inventory, and the Suicide Potential Scale.

RESULTS

Both suicidal groups demonstrated higher levels of most of the negative emotions than both the normal controls and the nonsuicidal inpatients. When the first attempters were compared with the multiple attempters, similarly high levels were noted for most dimensions of anxiety and depression. A trend toward increased aggression was noted among the multiple suicide attempters on all parameters evaluated; some of these differences were significant.

CONCLUSION

In already highly anxious and depressed suicidal inpatients, a high level of aggression might significantly increase the risk of recidivism.

Anchorpoints: an introspective

This, then, is what it has been all about. Today I mark the end of an academic career that ranged over 45 years. 1952 was the starting point. In that year, as a medical student, I was accepted as a research assistent by Prof. G.G.J. Rademaker, a neurophysiologist and at the time head of the Department of Neurology at the Academic Hospital in Leiden. The neurological research period was followed by a mycological one. Having received my MD degree and doing my military service, I was asked to carry out a study into the prevalence, prevention and treatment of mycological infections in military personel. For this reason I worked for more than 1, 5 years in Baarn at the section Medical Mycology of the Phytopathological Laboratory, an interacademic institution of the Universities of Amsterdam and Utrecht (1956-1958). Immediately after the military service I became a resident in psychiatry and started - together with the biochemist Prof. B. Leijnse - a research program into the biological determinants of depression. The period of psychiatric investigation lasted until this very day, albeit in different locations, i.e. Rotterdam, Groningen, Utrecht, New York and Maastricht respectively.

Biological and psychopharmacological aspects of impulse-control disorders

Over the past decades extensive research has been performed on the presumed relationship between neurotransmitter functionality in the central nervous system and psychopathological states. Originally, in the mid-sixties it was hypothesized that depressive states may be associated with disorders in brain noradrenalin and/or serotonin (5-hydroxytryptamine; 5-HT) metabolism or function resulting in the socalled monoamine hypothesis of depression. Subsequent investigations revealed that altered 5-HT metabolism is not related to mood disorder per se, but to components of the depressive syndrome and more specifically to increased anxiety and/or signs of dysregulated aggression, including violent suicidal attempts. Concerning aggression and other types of disruptive or impulsive behavior, research on their neurobiological determinants has been focussed mainly on indicators of central 5-HT function.

Faulty cortisol/serotonin interplay. Psychopathological and biological characterisation of a new, hypothetical depression subtype (SeCA depression)

The hypothesis is proposed of a new subtype of depression named: stressor-precipitated, cortisol-induced, serotonin-related, anxiety/aggression-driven depression (SeCA depression). Biologically, these patients are characterized by impaired 5-HT synthesis and reduced 5-HT1A receptor sensitivity. Under normal conditions these functions proceed marginally; in times of stress they easily fail, due to sustained overproduction of cortisol. Psychopathologically this depression type shows the following characteristics: anxiety and aggression, not mood lowering, heralding a depressive episode; the personality structure shows 'character neurotic' impairments and tolerance for (certain) traumatic life events is low. As specific therapeutic agents selective 5-HT1A agonists and cortisol or CRH antagonists are proposed. Prophylactically, maintenance treatment with 5-HT1A agonists seems indicated as well as psychological interventions to increase the stressor threshold.

Mean genes and the biology of aggression: a critical review of recent animal and human research

Recent genetic work has suggested that abnormalities in serotonin biochemistry are directly causally linked to aggressive behavior, and there appears to be a consensus in the psychiatric literature that low levels of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid are specifically associated with impulsive violent behavior. We review the limitations of the genetic studies and conduct a meta-analysis of 39 studies linking 5-HIAA to aggression in humans. No differences in mean 5-HIAA levels were found between groups of violent impulsive psychiatric patients and groups of subjects diagnosed with other psychiatric or medical conditions not considered to involve violence once these levels had been corrected for three nonpsychiatric sources of variation (age, sex and height). However, mean 5-HIAA levels in both of these groups were lower than the mean corrected level in groups of normal healthy volunteers. The results confirm an association between low 5-HIAA levels and psychiatric disorders, but fail to support any specific relationship between low 5-HIAA levels and impulsive aggression or criminality. It is premature and misleading to speak of "mean genes" (Hen 1996) or a specific neurochemistry of aggressive behavior.