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Cognitive reactivity (CR) is a psychological vulnerability marker of depression, whereas response to acute tryptophan depletion (ATD; a serotonergic challenge procedure) is a biological vulnerability marker. The aim of this study was to investigate the relationship between these markers. Thirty-nine remitted depressed patients participated in 2 ATD sessions in a double-blind crossover design. CR, assessed prior to the ATD sessions, predicted depressive response to high-dose ATD. CR also diminished the effects of 2 known predictors of ATD response: gender and residual symptoms. Neuroticism and behavioral inhibition were unrelated to ATD response. CR is associated with an increased sensitivity to reductions of serotonin concentrations. These findings present a small step toward unifying cognitive and neurobiological theories of depression. Keywords: depression vulnerability, remitted depressed patients, cognitive reactivity, acute tryptophan depletion, serotonin

Abstract Depression is associated with reduced brain serotonin (5-hydroxytryptamine; 5-HT) function and with cognitive dysfunctions. A diet rich in α-lactalbumin protein has been found to increase the ratio tryptophan /large [...]

The current study tested whether 'suffocation sensations' (respiratory loads) are automatically evaluated in a negative way by people fearing these sensations. It was found that, after having been primed with a slight respiratory load, participants with high suffocation fear (n = 15) reacted more quickly to suffocation words and more slowly to positive words than participants with low suffocation fear (n = 21). However, the effect was present only in participants who had noticed the primes. The findings are relevant to the cognitive model of panic disorder because automatic negative appraisal of sensations may play a role in initiating a panic attack. Keywords: affective priming, panic disorder, catastrophic misinterpretation, suffocation fear, cognitive model

This article describes a reanalysis of seven studies on heart beat perception (HBP) in panic disorder. The pooled sample had 709 participants from eight diagnostic categories. Accurate HBP was uncommon, but more prevalent among panic disorder patients than among healthy controls, depressed patients, patients with palpitations and individuals with infrequent panic attacks. No differences were found between panic disorder patients and patients with other anxiety disorders. Accurate perceivers had higher anxiety sensitivity scores than inaccurate perceivers. The data remain inconclusive as to whether perceived heart rate is correlated with anxiety in inaccurate perceivers. Physical exercise, distraction, variations in instructions and treatment each influenced HBP. However, the influence was different than previously thought. Finally, it is suggested that HBP may be understood in terms of schema-guided information processing.

Abstract It has frequently been demonstrated that acute tryptophan depletion (ATD) induces a transient depressed mood in some patients who are in remission from depression. However, the effects of ATD [...]

Summary: Background: The brain-derived neurotrophic factor (BDNF) is a key protein in maintaining neuronal integrity. The BDNF gene is thought to play an important role in the pathophysiology of mood and anxiety disorders. The aim of this study was to investigate, for the first time in a single study, the association between BDNF Val66Met polymorphism, anxiety, alcohol consumption, and cortisol stress response. Method: 98 healthy university students (54 females and 44 males), genotyped for the Val66Met polymorphism, participated in a physical-stress procedure (cold pressure test, CPT) after having been informed that they would undergo a painful experience. Indices of anxiety and of stress were collected from repeated measurement of salivary cortisol, blood pressure, and heart rate. Results: BDNF Met carriers, were more anxious during the CPT (p <0.001), drank more alcohol per week, (p <0.05), and showed significantly higher anticipatory cortisol response (p <0.05), but not in response to the CPT, than Val/Val homozygotes. The association of BDNF Val66Met polymorphism with HPA axis reactivity to stress was not modulated by gender. These results suggest that Met carriers are particularly sensitive in anticipating stressful events, which extends previous findings on the moderating role of the BDNF Val66Met polymorphism in the face of stressful life events. [Copyright &y& Elsevier]

Abstract: Acute tryptophan depletion (ATD) in currently depressed patients has no immediate effect on symptoms, but leads to transient symptom improvement or worsening the next day. In view of recent findings concerning the cognitive effects of serotonin manipulations, we used ATD in fourteen depressed patients to investigate whether cognitive effects following ATD predict symptom changes. We found that symptom improvement 24h after ATD was associated with an improved recall of positive words and with less attentional bias and recall of negative words, 5h after ATD. These results indicate that serotonergic alterations affect emotional processing which may subsequently lead to symptom changes. [Copyright &y& Elsevier]

Abstract: Background: Suicidal ideation is the most stable symptom of depression across episodes. This relative stability may be brought about by increased cognitive reactivity to sad mood (CR) during periods of remission. The idea is that a network of depressive cognitions, which include suicidal ideation, becomes strengthened with each episode of depression. Consequently, the whole network may be more easily re-activated, for instance by an episode of low mood. We examined the association between reactivity of suicidal cognitions during recovery and the presence of suicidal ideation and behavior during the previous depressive episode. Methods: In a case–control design, the CR profiles of recovered depressed participants with (N =355) and without (N =250) a history of suicidal ideation were compared. Structured clinical interviews were used to determine diagnoses and prior symptoms. Cognitive reactivity profile was measured with the Leiden Index of Depression Sensitivity-Revised (LEIDS-R). Results: Suicidal ideation during a depressive episode was associated with a distinct CR profile during remission: elevated hopelessness reactivity scores. This relationship between prior suicidality and current CR was independent of anxiety disorder comorbidity. Moreover, a history of suicide attempt(s) was also associated with a distinct CR profile. These individuals had both higher hopelessness reactivity and higher aggression reactivity than the non-suicidal and suicidal ideation groups. Limitations: Symptoms during the previous depressive episode were assessed retrospectively. Conclusions: This is the first study to show that CR may underlie the relative stability of suicidal symptoms independent of anxiety comorbidity and that suicidal ideation and suicidal behavior are associated with distinct patterns of CR. Since CR is a potentially treatable vulnerability marker of depression recurrence, this has important clinical implications. [Copyright &y& Elsevier]

??-Lactalbumin is a tryptophan-rich protein fraction. A diet enriched with ??-lactalbumin increases the ratio of tryptophan to the other large neutral amino acids, which may in turn increase brain serotonin content. In stress-vulnerable individuals, ??-lactalbumin improved mood and attenuated the cortisol response after experimental stress. The aim of the present study was to investigate the effects of an ??-lactalbumin-enriched diet on mood and stress response in recovered depressed subjects and healthy controls. Forty-three subjects (twenty-three recovered depressed and twenty healthy subjects) received ??-lactalbumin and casein (placebo) on separate days, in a double-blind randomised crossover design. On both occasions, subjects underwent a stress test (an unsolvable mental arithmetic task with loud noise). The stress test affected mood in both conditions. Although the ??-lactalbumin diet led to the expected rises in tryptophan and tryptophan:large neutral amino acids ratio, only minimal effects were found on mood and cortisol response to experimental stress. The results were the same for recovered depressed patients and controls. A 1 d diet enriched with ??-lactalbumin is not sufficient to prevent a stress-induced mood deterioration or a cortisol response in unmedicated, recovered depressed subjects. Future studies may investigate the effects of longer-term diets or may investigate different samples (e.g. medicated patients). [ABSTRACT FROM PUBLISHER]

Abstract: Background: It has frequently been demonstrated that experimental lowering of serotonin (5-HT) neurotransmission by acute tryptophan depletion (ATD) induces a transient depressed mood in 50–60% of patients treated with a selective serotonin reuptake inhibitor (SSRI) who are in remission from depression. In unmedicated depressed patients, ATD has no immediate effect on symptoms. The effects in currently depressed medicated patients have not been investigated. Methods: Fourteen currently depressed patients (seven patients treated with a selective serotonin–noradrenalin reuptake inhibitor (SSNRI); seven other treatment, non-SSNRI) received ATD in a double-blind, crossover design. Different strengths of the ATD mixture (aimed at 50% and 90% reduction of tryptophan) were used on separate days. Psychiatric symptoms were assessed at both sessions prior to, at +6.5 h, and at +24 h after ATD. Results: The ATD mixtures induced the expected reductions of plasma tryptophan levels. Full but not partial depletion improved mood and other psychiatric symptoms at +24 h in patients who received SSNRI treatment, as indicated by clinical ratings and self-report. Subjective sleep quality also improved. Conclusions: The effects of ATD on psychiatric symptoms in currently depressed patients are remarkably different from the results in recently remitted SSRI-treated patients. ATD in currently depressed patients treated with serotonergic antidepressants possibly provides important information about the mechanism of action of SSRIs. [Copyright &y& Elsevier]

Investigates voluntary breath-holding (VBH) duration in patients with panic disorder, patients with a mood disorder and normal controls. Influence of motivational and cognitive factors on VBH; Depressive symptoms and fear of bodily sensation on breath holding duration; Suitability of VBH as a test to measure carbon dioxide sensitivity of suffocation alarm.

Background: Acute tryptophan depletion (ATD) induces depressive symptoms in remitted depressed patients treated with serotonergic medications, but not in patients treated with noradrenergic medications or electroconvulsive therapy. A recent study suggests that cognitive therapy (CT) protects against the effects of ATD, but the evidence is questionable. The present study compared the effect of ATD in patients who were treated with antidepressant medication and CT (n = 17) versus antidepressant medication alone (n = 23) during their latest episode. Methods: Forty remitted depressed patients underwent high-dose and low-dose ATD in a randomized double-blind crossover design. Results: There were no differences in response to ATD between treatment groups. This applied to groups defined by lifetime and by recent CT experience. Conclusions: Cognitive therapy does not protect against the effects of rapidly lowered plasma tryptophan levels in remitted depressed patients who are also treated with antidepressant medication. [Copyright &y& Elsevier]

Background: Depression is a major risk factor for cardiovascular disease. An important risk factor for cardiovascular disease, low heart rate variability, often has been found in depressed patients and has been associated with impulsivity. The present study investigated whether experimental lowering of serotonin would decrease heart rate variability and increase impulsivity in remitted depressed patients, in particular in those patients with disturbed impulse control. Methods: Nineteen patients in remission from depression received high-dose and low-dose acute tryptophan depletion in a randomized, counterbalanced, double-blind crossover design. Heart rate variability and impulsivity were assessed during each acute tryptophan depletion session and during a baseline session. Suicidal ideation during past depression was used as an index for individual differences in impulse control. Results: High-dose acute tryptophan depletion led to a larger increase in depressive symptoms than did low-dose acute tryptophan depletion. High-dose acute tryptophan depletion decreased heart rate variability and increased impulsivity and anxiety, but only in patients with a history of suicidal ideation. Symptom effects of high-dose acute tryptophan depletion correlated with low heart rate variability at baseline. Conclusions: Depressed patients who have problems with controlling impulsivity might be more at risk for developing cardiovascular disease, possibly related to increased vulnerability to impaired 5-hydroxytryptamine function. [Copyright &y& Elsevier]