Pronounced Cognitive Deficits Following an Intravenous L-Tryptophan Challenge in First-Degree Relatives of Bipolar Patients Compared to Healthy Controls

Sobczak, Sjacko; Honig, Adriaan; Schmitt, J.A.J.; Riedel, Wim J.

doi:10.1038/sj.npp.1300055

Cited by 63 publications

(69 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Daily ratings of positive mood, while conceptually different than trait measures, have also been associated with prolactin response to a fenfluramine challenge (Flory et al, 2004). Tryptophan has also been shown to alter positive mood when administered acutely and chronically, see (Sobczak, Honig, Schmitt, & Riedel, 2003;Young & Leyton, 2002). Currently less is understood regarding the relation between serotonergic activity and traits not related to negative affectivity.…”

Section: Discussionmentioning

confidence: 99%

Associations among central nervous system serotonergic function and neuroticism are moderated by gender

Brummett

Boyle

Kuhn

et al. 2008

Biological Psychology

View full text Add to dashboard Cite

Serotonergic dysregulation is associated with negative affect. Plasma prolactin responses to a tryptophan enhancement challenge are used as a measure of central nervous system serotonergic activity. We examined prolactin responses to a tryptophan challenge as they relate to the personality domains of Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness. Participants were 67 volunteers. Regression models assessed peak prolactin response to intravenous tryptophan infusion as a predictor of Neuroticism, Extraversion, Openness, Agreeableness, and conscientiousness. Prolactin X gender product terms included to examine moderation by gender. Models were adjusted for baseline levels of prolactin, age, and race. Gender moderated the association between N and prolactin level (p<.03). Higher levels of N were associated with decreased levels of prolactin responses in females, whereas the opposite was true for males. Remaining personality domains were not related to prolactin levels. Findings add to literature suggesting the serotonin system functions differently, in important ways, in males and females.

show abstract

Section: Discussionmentioning

confidence: 99%

Associations among central nervous system serotonergic function and neuroticism are moderated by gender

Brummett

Boyle

Kuhn

et al. 2008

Biological Psychology

View full text Add to dashboard Cite

show abstract

“…Of note, first-degree relatives of patients with BD type I had more pronounced memory impairment than first-degree relatives of patients with BD type II. 170,171 Ferrier et al, 172 however, did not find verbal declarative memory deficits in a sample of unaffected relatives of BD probands, and they suggest that the discrepancy may be secondary to the use of different tests across studies although they did use a relatively standard list learning procedure.…”

Section: Cognitive Endophenotypesmentioning

confidence: 96%

The phenotypes of bipolar disorder: relevance for genetic investigations

2005

View full text Add to dashboard Cite

The search for susceptibility genes for bipolar disorder (BD) depends on appropriate definitions of the phenotype. In this paper, we review data on diagnosis and clinical features of BD that could be used in genetic studies to better characterize patients or to define homogeneous subgroups. Clinical symptoms, long-term course, comorbid conditions, and response to prophylactic treatment may define groups associated with more or less specific loci. One such group is characterized by symptoms of psychosis and linkage to 13q and 22q. A second group includes mainly bipolar II patients with comorbid panic disorder, rapid mood switching, and evidence of chromosome 18 linkage. A third group comprises typical BD with an episodic course and favourable response to lithium prophylaxis. Reproducibility of cognitive deficits across studies raises the possibility of using cognitive profiles as endophenotypes of BD, with deficits in verbal explicit memory and executive function commonly reported. Brain imaging provides a more ambiguous data set consistent with heterogeneity of the illness. Keywords: bipolar disorder; genetics; endophenotype; neurocognitive function; brain imaging Bipolar disorder (BD) has a genetic basis with heritability of at least 80%. 1 A number of studies have attempted to map the susceptibility loci giving evidence of linkage in multiple genomic regions. In particular, findings in 4p, 4q, 8q, 10p, 12q24, 13q, 18p, 18q, 21q, and 22q have been supported by more than one study. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] However, these studies have not identified any specific genes, and a recent metaanalysis of available genome scans showed no regions with a conclusive evidence of linkage. 20 The relatively slow progress of gene-mapping efforts is often explained by the 'complex' nature of the illness and of the genotype-phenotype relation. The complexity most likely includes heterogeneity, interactions of multiple loci, incomplete penetrance, as well as phenotypes resulting from environmental effects-either alone or in interaction with the genetic predisposition. The goal of psychiatric genetic research is identification of (heritable) variations in DNA sequence or function that influence behaviour or give rise to mental illness. By definition, in complex (multifactorial) traits, this link is not unique and specific. That is, a particular change in gene sequence does not necessarily lead to a specific behaviour, and similar behaviours (symptoms) may be due to distinct (sets of) genes. Moreover, we must consider the possibility that the path between the genotype and behaviour is not unidirectional. Emerging examples point not only to general effects of environment, for instance stress, on behaviour, but also to specific behaviours influencing gene function that can be transmitted onto the next generation. 21 No single method is considered clearly superior in identifying susceptibility genes for complex traits such as BD. Most researchers agree that a combination of strategies is most lik...

show abstract

“…Thus, it seems that both an increase and decrease in Trp impair the same cognitive domains that are regulated by the frontal lobe (Sobczak et al, 2003b). The specificity of ATD has been pointed out by Klaassen et al (1999).…”

Section: Point 1: Specificity Of L-trp Challengementioning

confidence: 96%

Reply: Pronounced Cognitive Deficits Following an Intravenous L-Tryptophan Challenge in First-degree Relatives of Bipolar Patients Compared to Healthy Controls

Sobczak

Honig

Riedel

2003

Neuropsychopharmacol

Self Cite

View full text Add to dashboard Cite

Pronounced Cognitive Deficits Following an Intravenous L-Tryptophan Challenge in First-Degree Relatives of Bipolar Patients Compared to Healthy Controls

Cited by 63 publications

References 50 publications

Associations among central nervous system serotonergic function and neuroticism are moderated by gender

Associations among central nervous system serotonergic function and neuroticism are moderated by gender

The phenotypes of bipolar disorder: relevance for genetic investigations

Reply: Pronounced Cognitive Deficits Following an Intravenous L-Tryptophan Challenge in First-degree Relatives of Bipolar Patients Compared to Healthy Controls

Contact Info

Product

Resources

About