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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]

• Adolescents with depression were marginally faster than those in the comparison group to recognise sadness, although this trend disappeared once covarying for age and use of antidepressant medication. • Within the depression group, severity of depression symptoms and borderline personality features were associated with poorer emotional facial expression recognition (EFER) performance. • Discrepancies between group and within-group differences may explain some of the clinical heterogeneity observed in studies of EFER amongst adolescents with depression. • Studying clinical features in relation to EFER in adolescents with depression allows for a more nuanced understanding of social difficulties that may be experienced in depression. Studies have reported that emotional facial expression recognition (EFER) may be altered in individuals with depression. This study examined EFER in adolescent girls with and without depression and further examined associations between relevant clinical features of depression and EFER. Fifty adolescent girls aged 12 to 19 years old meeting criteria for depression or subthreshold levels of symptomatology and 55 adolescent girls with no psychiatric diagnosis completed EFER tasks. Reaction time and accuracy for recognising expressions at high and low intensities, and sensitivity in recognising happiness, sadness, anger and fear were assessed. Data were analysed using linear mixed models. Adolescents with depression were marginally faster than those in the comparison group to recognize sadness, although this trend disappeared once covarying for age and antidepressant use. Amongst adolescents with depression, clinical features were associated with poorer EFER performance. In contrast, anxiety symptoms were linked to better accuracy and heightened sensitivity towards happiness. A better understanding of EFER in adolescent girls with and without depression, and how clinical features might be associated with altered patterns of EFER could help to explain clinical heterogeneity observed in such studies of adolescents with depression. Knowledge of socio-cognitive alterations associated with depression will help to better develop and tailor interventions. [ABSTRACT FROM AUTHOR]

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: Brain serotonin-1A (5-HT1A) autoreceptors internalize when activated by agonist or by their endogenous ligand, serotonin. This positron-emission tomography (PET) study tested the hypothesis that 5-HT1A autoreceptor internalization might be indexed in vivo by a decrease in the specific binding of the 5-HT1A radioligand, 4-[18F]fluoro-N-[2-[1-(2-methoxyphenyl)-1 piperazinyl]ethyl-N-2-pyridinyl-benzamide ([18F]MPPF), in the dorsal raphe nucleus (DRN) of healthy adult men administered a single oral dose of the selective serotonin reuptake inhibitor, fluoxetine. Methods: [18F]MPPF binding potential was measured in the DRN and other brain regions endowed with 5-HT1A receptors in eight healthy volunteers, 5 hours after the randomized, double-blind administration of fluoxetine (20 mg) or placebo. Results: In every subject, [18F]MPPF binding potential was decreased in the DRN only (44% ± 22 SD), in response to fluoxetine. Conclusions: Imaging the functional state of 5-HT1A autoreceptors (i.e., internalization) in the human brain, using [18F]MPPF/PET, may represent a promising avenue for investigating the neurobiology of serotonin-related disorders and notably of major depression. [Copyright &y& Elsevier]