title: Sex differences in the effect of acute tryptophan depletion on declarative episodic memory: a pooled analysis of nine studies.
abstract: Acute tryptophan depletion (ATD) studies have shown that serotonin plays a role in learning and memory processes. In this study, we performed a pooled analysis of nine ATD studies in order to examine the nature of the memory-impairing effects of ATD and mediating factors, such as gender, age and vulnerability for disease in which disturbed serotonin was hypothesized to play a role. All studies that were used in this pooled analysis assessed declarative episodic memory using a verbal learning task paradigm. Immediate recall, delayed recall, and delayed recognition scores were examined. A total of 211 participants were included in the analysis. The analysis revealed that ATD impaired not only delayed recall, but also immediate recall. The ATD-induced impairments were larger in females than in males. Furthermore, ATD did not interact with any other serotonergic vulnerability and age. This suggests that the only factor that actually has the properties of a serotonergic vulnerability factor for declarative memory performance is female gender. The findings provide further support for a critical role of serotonin in declarative episodic memory.
authors.affiliation: Department of Neurocognition, Faculty of Psychology, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands. anke.sambeth@psychology.unimaas.nl
authors.forename: Anke
authors.initials: A
authors.lastname: Sambeth
authors.forename: Arjan
authors.initials: A
authors.lastname: Blokland
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Harmer
authors.forename: Tessa O C
authors.initials: TO
authors.lastname: Kilkens
authors.forename: Pradeep J
authors.initials: PJ
authors.lastname: Nathan
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Porter
authors.forename: Jeroen A J
authors.initials: JA
authors.lastname: Schmitt
authors.forename: Bart
authors.initials: B
authors.lastname: Scholtissen
authors.forename: Sjacko
authors.initials: S
authors.lastname: Sobczak
authors.forename: Allan H
authors.initials: AH
authors.lastname: Young
authors.forename: Wim J
authors.initials: WJ
authors.lastname: Riedel
mesh_terms: D000293:Adolescent; D000328:Adult; D000339:Affect / Q000502:physiology; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D018592:Cross-Over Studies; D003863:Depression / Q000378:metabolism; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D012701:Serotonin / Q000502:physiology*; D012737:Sex Factors; D014364:Tryptophan / Q000172:deficiency* / Q000378:metabolism
chemical_list: D012701:Serotonin; D014364:Tryptophan