The serotonin hypothesis of (auto)aggression. Critical appraisal of the evidence

Loudness dependence of auditory evoked potentials (LDAEP) in clinical monitoring of suicidal patients with major depression: a pilot study

Loudness dependence of auditory evoked potentials (LDAEP) is a validated in vivo marker of central serotonergic function. We aimed at measuring serotonergic activity in a follow-up study of suicidal patients. It should be investigated whether suicide attempts or suicidal states cause changes in the LDAEP. Thirteen patients (mean age, 40.9 ± 11.3 years; age range, 20-61, 6 male) with a major depressive episode who had attempted suicide or had suicidal plans (Hamilton Depression Rating Scale item 3 [suicidality] ≥3) were included in the study. LDAEP and psychometric measurements took place about 2, 5, 9 and 16 days after attempted suicide or suicidal action. On day 9, LDAEP was significantly higher compared to day 2 and day 16; there was a similar tendency compared to day 5. Instability of central serotonergic function is suggested resulting in reduced serotonergic activity about 1 week after suicide attempt. Further studies are necessary that include larger samples in order to distinguish between different psychiatric diseases and to consider confounding factors like gender, smoking, medication, impulsivity or lethality of suicidal action.

Gene expression and mRNA editing of serotonin receptor 2C in brains of HPRT gene knock-out mice, an animal model of Lesch-Nyhan disease

Lesch-Nyhan disease (LND), a genetic disorder associated with motor and psychiatric disturbance and self-injurious behaviour (SIB) is caused by a complete deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT). The connection between enzyme deficiency and neurological involvement is still unclear. Evidence exists for a role of basal ganglia dysfunction with decreased dopamine and excess serotonin striatal content. In this study, we investigate the role of serotonin receptor 2C (HTR2C) in the brains of HPRT gene knock-out mice, a model of LND. HTR2C expression is analyzed by real-time polymerase chain reaction (PCR) using SYBR-green detection methods. The percentage of edited HTR2C mRNA was determined by direct sequencing of amplification products of the region containing the editing sites. We found a 55% increase in the expression of HTR2C gene but no significant difference in mRNA editing levels between knock-out and control mice. The above alteration found in HPRT-deficient mice is similar to those found in other animal models used to study aggressive and self-injurious behaviour.

Aggressive Behavior in Patients With Stroke: Association With Psychopathology and Results of Antidepressant Treatment on Aggression

OBJECTIVE

To examine, in a post hoc analysis of an antidepressant treatment trial, correlates of irritability and aggression after stroke and changes in irritability scores associated with antidepressant treatment.

DESIGN

Aggressive patients (n=23) were compared with nonaggressive patients (n=69) on numerous measures of psychopathology, poststroke impairment, and neuroimaging findings.

SETTING

All patients were hospitalized at the time of the initial evaluation for acute stroke or for rehabilitation therapy.

PARTICIPANTS

Ninety-two patients from the Iowa City Stroke Study were classified as aggressive or nonaggressive, based on symptoms elicited by the Present State Examination (PSE) and from family or caretaker reports.

INTERVENTION

All patients were randomized to receive nortriptyline, fluoxetine, or placebo using a double-blind methodology.

MAIN OUTCOME MEASURE

The change in aggression score as elicited by the PSE at the beginning and the end of a 12-week treatment trial.

RESULTS

Twenty-five percent (23/92) of patients reported irritability or aggression. Irritable and aggressive patients had higher total PSE scores, Hamilton Depression Rating Scale scores, Hamilton Anxiety Rating Scale (HAMA) scores, and lower Mini-Mental State Examination scores. They also had lesions that were more proximal to the frontal pole. Stepwise regression analysis showed that HAMA scores and proximity of lesion to the frontal pole were significant independent predictors of irritability. Among irritable and aggressive patients with depression who responded to antidepressants, there was a significantly greater reduction in irritability after treatment, compared with patients whose depression did not lessen with treatment.

CONCLUSIONS

Several factors, such as severity of impairment, other psychopathology, and neurobiologic factors, appear to contribute to irritable and aggressive behavior in stroke patients. If depression accompanies aggression, the results of this small study suggest that successful treatment of depression may reduce aggressive behavior.

Postmortem serotonin (5-HT) concentrations in the cerebrospinal fluid of medicolegal cases

In a medicolegal study the postmortem serotonin (5-HT) cerebrospinal fluid (CSF) concentrations were determined in routine autopsies using a high performance liquid chromatographic procedure with electrochemical detection. There was no correlation between 5-HT concentrations and age, sex or blood alcohol concentration using a postmortem delay < or = 3 days. In suicides the suboccipital CSF concentrations were significantly decreased compared to the levels measured in the control group (8.55+/-5.99 ng/ml versus 20.15+/-13.56 ng/ml). Additionally, a decrease of 5-HT was found in the suboccipital CSF of opiate fatalities (15.56+/-13.52 ng/ml). The results support the hypothesis that decreased 5-HT concentrations in the CSF are characteristic in suicides. However, due to a rather broad overlapping of values between suicides and controls the results failed to define a possible cut-off level in the 5-HT CSF concentration to distinguish between a suicidal and a non-suicidal incident.

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.

Behavioral profile of Alzheimer's disease in Chinese elderly--a validation study of the Chinese version of the Alzheimer's disease behavioral pathology rating scale

OBJECTIVES

This study aims to examine the psychometric properties of the Chinese version of the Alzheimer's disease behavioral pathology rating scale (CBehave-AD) and the behavioral profile of Chinese patients with AD.

METHODS

Seventy-one subjects with NINCDS-ADRDA diagnosis of probable and possible AD were assessed for validation of the CBehave-AD. A behavioral symptom frequency checklist, the Chinese version of the Blessed Roth dementia scale (CDS) and the Cantonese version of the Mini-Mental State Examination (CMMSE) were used for comparison. An extended sample of 120 AD patients was then evaluated with the CBehave-AD.

RESULTS

High correlations between the CBehave-AD and checklist scores were found (paranoid and delusional ideation, hallucinations, activity disturbances, aggressiveness and diurnal rhythm disturbances). The scale also demonstrated satisfactory inter-rater and test-retest reliabilities. The mean (SD) CMMSE score of the 120 patients was 9.4 (7.1). Among them, 32% have delusions, 15% had hallucinations, 54% had activity disturbances, 61% had aggressive behavior, 44% had sleep disturbance, 24% had affective disturbances, 19% had anxiety and phobias. Delusional ideation was significantly associated with hallucinations, aggressiveness, and affective disturbances. Diurnal rhythm disturbances were associated with activity disturbances and aggressiveness. CBehave-AD total scores were not significantly correlated with severity of AD, but individual symptom categories showed different pattern of correlation. Delusions, hallucinations, anxiety and phobias were significantly correlated with dementia staging.

CONCLUSION

The findings suggest that the CBehave-AD is a valid assessment tool for behavioral disturbances in patients with AD. Variable associations between different symptom categories and dementia staging suggest a need for further exploration of the complex interactions between behavioral and cognitive disturbances in dementia.

Plasma pyridoxine deficiency is related to increased psychological distress in recently bereaved homosexual men

OBJECTIVE

Previous research has demonstrated that a theoretical model including measures of life stressors, social support, and coping style significantly predicts psychological distress. This study tested plasma pyridoxine (vitamin B6) deficiency status as a predictor of overall psychological distress and specific mood states in this model, controlling for HIV-1 serostatus.

METHOD

Subjects included HIV-1+ (N = 76) and HIV-1- (N = 58) recently bereaved homosexual men. At baseline, subjects completed a battery of psychosocial questionnaires, together with a physical examination and venipuncture. The Profile of Mood States (POMS) provided measures of overall psychological distress as well as specific mood states. Pyridoxine deficiency status (a categorical measure of deficient vs. adequate status) was determined with a bioassay of erythrocyte aspartate aminotransferase activity.

RESULTS

Pyridoxine deficiency was a significant predictor of increased overall psychological distress in this model, controlling for life stressors, social support, coping style, and HIV-1 serostatus. In post hoc analyses of specific mood state effects, pyridoxine deficiency status was significantly associated with increases in depressed, fatigued, and confused mood levels, but not with those of anxiety, anger, or vigor.

DISCUSSION

These findings suggest that adequate pyridoxine status may be necessary to avert psychological distress in the setting of bereavement. Inasmuch as pyridoxine is a cofactor for 5-hydroxytryptophan decarboxylase--an enzyme in the biosynthesis pathway of serotonin--serotonin level in the brain is implicated as the mediating factor.

Altered serotonergic activity in women with dysphoric premenstrual syndromes

OBJECTIVE

Dysphoric Premenstrual Syndromes (PMS) are quite prevalent and in some women they are severe enough to warrant treatment. Their pathophysiology is still unknown, despite increased interest and research. Here we review the possible role of serotonin in the multidimensional interactive pathophysiology of PMS.

METHOD

Over 170 articles are reviewed. An extensive library search has been conducted and articles are included because of their relevance to: 1) the phenomenology of PMS; 2) the putative association of serotonergic (5-HT) activity with syndromes that occur premenstrually; 3) changes in 5-HT activity along the menstrual cycle, especially the late luteal phase; 4) influence of gonadal hormones on serotonergic functions; 5) endocrine strategies for assessment of 5-HT abnormalities; and 6) treatment studies of PMS with serotonergic agonists.

RESULTS AND CONCLUSIONS

The data presented here suggest that post-synaptic serotonergic responsivity might be altered during the late-luteal-premenstrual phase of the menstrual cycle. Some serotonergic functions of women with PMS might be altered during the entire cycle and be associated with a vulnerability trait. It is hypothesized that gonadal hormones might cause changes in levels of activity of 5-HT systems as part of a multidimensional interactive system. Strategies to evaluate 5-HT activities in the context of the menstrual cycle are discussed--leading to the conclusion that the most promising approach is active stimulation with specific post-synaptic serotonin agonists. Treatment outcome studies of some imperfect compounds that are currently applied as a symptomatic treatment of PMS support the notion that 5-HT is involved in the pathophysiology of these syndromes.

Serotonergic measures in suicide brain: the concentration of 5-HIAA, HVA, and tryptophan in frontal cortex of suicide victims

Concentrations of 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and tryptophan (TRP) were determined in the frontal cortex of individuals who died by suicide, homicide, accident, or the result of physical diseases. Females had significantly higher tryptophan concentrations than males. There was a significant correlation HVA and the interval between death to refrigeration of the body. Mean HVA levels were higher from noon to 5 PM. Suicide and homicide victims had significantly higher cortical HVA concentrations than those who died of physical disease but not accident victims. This was not accounted for by gender, age, postmortem interval from death to refrigeration of the body or to autopsy, specimen storage time, or drug effects. The ratio of HVA/5-HIAA was also significantly higher in suicides compared with those who died of physical disease. No differences in cortical 5-HIAA or tryptophan concentrations between the four groups were found. There were no differences in the levels of the three substances in violent and nonviolent suicides. There were no significant correlations between 5-HIAA, HVA and TRP concentrations in all subjects or any of the four subgroups. The implications of these findings for the role of serotonin and dopamine in suicide and violence are discussed.

Nosological tunnel vision in biological psychiatry. A plea for a functional psychopathology

Classical nosology has been the major cornerstone of biological psychiatric research; finding biological markers and eventually causes of disease entities has been the major goal. Another approach, one we have designated as "functional," seems possible, attempting to correlate biological variables with psychological dysfunctions, the latter being considered to be the basic units of classification in psychopathology. We have pursued this route for many years, and based on the resulting findings we formulated the following hypothesis. Signs of diminished dopamine, serotonine, and noradrenaline metabolism, as have been found in psychiatric disorders, are not disorder-specific, but rather are related to psychopathological dimensions; i.e., hypoactivity/inertia; increased aggression/anxiety and anhedonia, independent of the nosological framework in which these dysfunctions occur (van Praag et al. 1990). In this paper only the 5-HT data have been discussed. Implications of the functional approach for psychiatry are discussed, including a shift from nosological to functional application of psychotropic drugs. Functional psychopharmacology will be dysfunction-oriented and therefore inevitably geared towards utilizing drug combinations. This prospect is hailed as progress, both practically and scientifically.

The dexamethasone suppression test and completed suicide

The present study was undertaken to further explore the relationship between the dexamethasone suppression test (DST) and suicide. Depressed inpatients who had undergone the DST at index admission and later committed suicide (n = 13) were matched for age, gender, diagnosis, and type of DST (1 mg, 2 mg) with depressed inpatients from the same hospital and study time period to form 2 groups: a suicide attempter group (n = 25) and a nonattempter group (n = 28). The suicide completers group had significantly higher 1600 postdexamethasone cortisol levels than the suicide attempters group and a significantly higher 1600 rate of DST nonsuppression compared with the suicide attempter + nonattempter combined group. Although the rate of DST nonsuppression did not differ between the suicide attempter and nonattempter groups, serious attempters had significantly higher 1600 cortisol levels and a statistically higher proportion of patients who completed suicide than nonserious attempters.(ABSTRACT TRUNCATED AT 250 WORDS)

Possible neurotransmitter basis of behavioral changes in Alzheimer's disease

Serotonin, 5-hydroxyindoleacetic acid, and homovanillic acid concentrations have been determined in 10 areas of the cerebral cortex from 17 subjects with Alzheimer's disease and 18 control subjects. The dopamine metabolite was not reduced in any area, whereas both indoleamines were reduced in the superior frontal, inferior temporal, and fusiform gyri, and the temporal pole. These areas and areas of the parietal cortex, where there were no changes in concentration, have not previously been reported on. We argue that the large loss of indoleamines from the frontal lobe (to 50-63% of control values) is rather unexpected based on other biochemical measurements and may relate to behavioral changes.