Executive performance of depressed suicide attempters: the role of suicidal ideation.

OBJECTIVE: Suicidal ideation has been related to cognitive rigidity whereas suicidal behaviour itself was associated with specific executive deficits. Yet it remains unclear if a distinct cognitive suicidal phenotype does exist. The aim of the present study was to further investigate the role of suicidal thinking for the neuropsychological performance in depressive suicide attempters. METHOD: Depressive inpatients after a recent suicide attempt, who either had present suicidal ideation (n=14) or not (n=15) and healthy controls (n=29) were recruited. The groups were assessed by means of executive tasks designed to capture impulsive decision-making, and with verbal memory and attention tests. Self-rating measures of impulsivity and aggression were further applied. RESULTS: Only patients with current suicidal ideation showed executive dysfunctions with impaired decision-making being the most salient. Verbal memory and attention were reasonably intact in all patients. All patients reported increased aggression. CONCLUSION: Suicidal ideation is clearly associated with impaired cognitive performance. Our results suggest that executive deficits seen in depressive suicide attempters have a state-dependent component.

Amygdala control of emotion-induced forgetting and remembering: evidence from Urbach-Wiethe disease.

When presented in a neutral context, emotional items interfere with episodic encoding of temporally contiguous non-emotional items, resulting in dissociable valence-dependent retrograde and arousal-dependent anterograde modulatory effects. By studying two rare patients with congenital lipoid proteinosis (Urbach-Wiethe) and a focal disease emphasis on the basolateral amygdala (BLA), we demonstrate that this bidirectional modification of episodic encoding by emotion depends on the integrity of the amygdala, as both retrograde and anterograde modulatory effects are absent. Our findings implicate the amygdala in a neural circuitry that orchestrates rapid retrograde and anterograde regulation of episodic memory access upon criteria of behavioral significance.

Emotion-induced retrograde amnesia varies as a function of noradrenergic-glucocorticoid activity.

RATIONALE: Privileged episodic encoding of an aversive event often comes at a cost of neutral events flanking the aversive event, resulting in decreased episodic memory for these neutral events. This peri-emotional amnesia is amygdala-dependent and varies as a function of norepinephrine activity. However, less is known about the amnesiogenic potential of cortisol. OBJECTIVE: We used a strategy of pharmacologically potentiating cortisol and norepinephrine activity to probe the putative neurochemical substrates of peri-emotional amnesia. MATERIALS AND METHODS: Fifty-four healthy individuals participated in a randomized double-blind placebo-controlled study. Within the experimental context of an established peri-emotional amnesia paradigm, we tested the amnesiogenic potential of hydrocortisone (30 mg p.o.) in the presence or absence of the norepinephrine-reuptake inhibitor reboxetine (4 mg p.o.). RESULTS: Under dual challenge conditions, we observed a linear dose-response relationship in the magnitude and duration of emotion-induced retrograde amnesia. CONCLUSIONS: Our results are consistent with a phenotypic expression of retrograde amnesia varying as a function of norepinephrine and cortisol coactivation during episodic encoding of aversive events. Our study demonstrates that the adverse cognitive and behavioral sequelae of aversive emotion can be experimentally modeled by a pharmacological manipulation of its putative neurochemical substrates.

Noradrenergic modulation of emotion-induced forgetting and remembering.

We used a free-recall paradigm to establish a behavioral index of the retrograde and anterograde interference of emotion with episodic memory encoding. In two experiments involving 78 subjects, we show that negatively valenced items elicit retrograde amnesia, whereas positively valenced items elicit retrograde hypermnesia. These data indicate item valence is critical in determining retrograde amnesia and retrograde hypermnesia. In contrast, we show that item arousal induces an anterograde amnesic effect, consistent with the idea that a valence-evoked arousal mechanism compromises anterograde episodic encoding. Randomized double-blind administration of the beta-adrenoceptor antagonist propranolol compared with the selective norepinephrine (NE) reuptake-inhibitor reboxetine, and placebo, demonstrated that the magnitude of this emotional amnesia and hypermnesia can be upregulated and downregulated as a function of emotional arousal and central NE signaling. We conclude that a differential processing of emotional arousal and valence influences how the brain remembers and forgets.

Normal prepulse inhibition and habituation of acoustic startle response in suicidal depressive patients without psychotic symptoms.

BACKGROUND: Until now, there is a lack of useful biological markers to predict suicidal behavior in depressive patients. However, it is consistently found that suicidality is associated with a central serotonin deficit. Animal data suggest that prepulse inhibition (PPI) as well as habituation of the acoustic startle response (ASR), which are established as operational measures for sensorimotor gating, decreases after serotonin depletion. Thus, we investigated PPI and habituation of ASR in suicidal patients with depressive disorders as potential biological markers for suicidal behavior. METHODS: PPI and habituation of ASR was measured in 20 depressive patients who had at least one suicide attempt within the last three month. Eighteen healthy matched controls were examined likewise. RESULTS: Suicidal depressive patients did not differ from healthy controls in PPI, startle reactivity and habituation of ASR. Subgroup analyses showed that factors such as severity of depression, impulsiveness, gender, smoking, lethality of the last suicide attempt, number of suicide attempts, and medication had no influence on the results. CONCLUSIONS: These results suggest that neither PPI nor habituation of ASR could serve as useful markers for suicidality.

Platelet 5-HT2A receptor binding and tryptophan availability in depression are not associated with recent history of suicide attempts but with personality traits characteristic for suicidal behavior.

BACKGROUND: Abnormalities in the serotonergic (5-HT) system have been implicated in the pathogenesis of suicidal behavior. Studies on peripheral serotonergic parameters as a measure for central serotonergic function in suicidal patients appear to be promising, yet failed to show a clear association with suicidality. The objective of this study was to elucidate the role of serotonergic blood parameters in depressed suicidal patients and to examine their usefulness as a potential biological marker for suicidality. A number of personality traits were assessed in order to provide a basis for a psychobiological model of suicidal behavior. METHODS: Depressed patients with a recent suicide attempt (SA; n = 59) were compared to those without history of suicide attempts (NSA; n = 28). 5-HT2A receptor binding in platelets and tryptophan/amino acid ratio in plasma were measured. Acute psychopathology and personality traits as well as characteristics of suicide attempts were assessed. RESULTS: There was no significant difference between SA and NSA in terms of peripheral serotonergic parameters as well as personality traits. However, the whole sample showed associations between certain personality traits and serotonergic platelet parameters. Furthermore, we observed a relation between suicidal ideation, lethality of suicide attempts and peripheral serotonergic markers. LIMITATIONS: The number of cases with data on peripheral markers is relatively low. The potential influence of antidepressant medication previous to study inclusion has to be taken into account. The study focussed on depressed patients only. CONCLUSIONS: Low serotonergic function is involved in the pathogenesis of suicidality, whereas the use of platelet 5-HT2A receptor activity and tryptophan availability as biological markers for suicidality in depressed patients could not be proven an appropriate tool. Alterations in the serotonergic system are associated with trait aggression and other character dimensions.

A multicenter study about Neurobiology of Suicidal Behavior: design, development, and preliminary results.

The subproject 1.5 "Neurobiology of Suicidal Behavior" is a multicenter study assessing peripheral parameters of the serotonergic, noradrenergic, and dopaminergic transmitter systems. Additionally, stress hormones and the lipid system as well as inhibitory and excitatory amino acids will be investigated. The different parameters are collected in cerebral spinal fluid (CSF), blood, and saliva. Patients with a depressive spectrum disorder with and without a suicide attempt (during the last three weeks) and being medication free for two weeks are included in the study. So far, 103 patients and controls have been recruited. The design and development of this project as well as interconnections with the others subprojects are described. Preliminary results about the stress hormone system and suicidality are presented.

Suicide prevention by lithium SUPLI--challenges of a multi-center prospective study.

Several studies have shown that there is a significantly increased risk of suicide related mortality in patients with a positive history of suicide attempts. The SUPLI-Study is the first prospective, randomized, double blind, placebo controlled multi-center trial focusing on the proposed suicide preventive effects of lithium in patients with suicidal behavior but not suffering from bipolar disorder or recurrent major depressive disorder. Patients with a recent history of a suicide attempt are treated with lithium versus placebo during a 12 month period. The hypothesis is that lithium treatment will lead to a 50% reduction of suicidal behavior. The protocol of the study and preliminary results are presented.

Enhanced emotion-induced amnesia in borderline personality disorder.

BACKGROUND: Current biological concepts of borderline personality disorder (BPD) emphasize the interference of emotional hyperarousal and cognitive functions. A prototypical example is episodic memory. Pre-clinical investigations of emotion-episodic memory interactions have shown specific retrograde and anterograde episodic memory changes in response to emotional stimuli. These changes are amygdala dependent and vary as a function of emotional arousal and valence. METHOD: To determine whether there is amygdala hyper-responsiveness to emotional stimuli as the underlying pathological substrate of cognitive dysfunction in BPD, 16 unmedicated female patients with BPD were tested on the behavioural indices of emotion-induced amnesia and hypermnesia established in 16 healthy controls. RESULTS: BPD patients displayed enhanced retrograde and anterograde amnesia in response to presentation of negative stimuli, while positive stimuli elicited no episodic memory-modulating effects. CONCLUSION: These findings suggest that an amygdala hyper-responsiveness to negative stimuli may serve as a crucial aetiological contributor to emotion-induced cognitive dysfunction in BPD.