Prediction of response to paroxetine and venlafaxine by serotonin-related genes in obsessive-compulsive disorder in a randomized, double-blind trial

Objective: Serotonin reuptake inhibitors (SRIs) are the most effective pharmacologic treatment currently available for patients with obsessive-compulsive disorder (OCD). Still, up to 40% to 60% of OCD patients do not respond to SRI treatment. The purpose of the present study was to determine whether polymorphisms of the serotonin transporter (5-HTT), 5-HT1B, and 5-HT2A receptor genes affect the efficacy of SRI treatment in OCD. Method: 91 outpatients with OCD according to DSM-IV criteria consented to the study and were randomly assigned in a 12-week, double-blind trial to receive dosages titrated upward to 300 mg/day of venlafaxine or 60 mg/day of paroxetine. Primary efficacy was assessed by the change from baseline on the Yale-Brown Obsessive Compulsive Scale (YBOCS), and response was defined as a >= 25% reduction on the YBOCS. Responders and nonresponders were stratified according to 5-HTT, 5-HT1B, and 5-HT2A genotypes and differentiated in paroxetine- or venlafaxine-treated groups. The study was conducted from August 1998 to July 2002. Results: In the whole group, 64% of responders carried the S/L genotype of the 5-HTTLPR polymorphism (chi(2) = 7.17, df = 2, p = .028). In the paroxetine-treated patients, the majority of responders carried the G/G genotype of the 5-HT2A polymorphism (chi(2) = 8.66, df = 2, p = .013), whereas in the venlafaxine-treated patients, the majority of responders carried the S/L genotype of the 5-HTTLPR polymorphism (chi(2) = 9.72, df = 2, p = .008). Conclusions: The results of this study suggest that response in venlafaxine-treated OCD patients is associated with the S/L genotype of the 5-HTTLPR polymorphism and in paroxetine-treated OCD patients with the G/G genotype of the 5-HT2A polymorphism

Compulsivity in mouse strains homologous with chromosomes 7p and 15q linked tot obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a severe anxiety disorder characterized by obsessions and compulsions. The core symptom of OCD is compulsivity, the inability to stop thinking or acting when you want to, despite being aware of the uselessness of the content or the adverse consequences. To initiate a systematic search for genetic mechanisms underlying the pathophysiology of compulsivity, a panel of chromosome substitution (CS) strains, derived from mice that suppress (C57BL/6J strain) or maintain (A/J strain) high levels of repetitive wheel running during 2 hr of daily limited food access, was screened for this compulsive behavior. Following the genetic screen, we found linkage between compulsive wheel running and mouse chromosomes 2, 6, and 7 that show overlap with recently identified human linkage regions for OCD on chromosomes 7p and 15q. In the overlapping (human/mouse) genomic region, the CRH receptor 2 (CRHR2) gene was tested in a human case-control study. An initial exploration in OCD cases versus controls failed to detect an association between four-candidate CRH2R SNP's within this homologous linkage region and OCD. Genetic fine mapping of compulsivity in mice provides new opportunities to reveal mechanisms underlying this significant psychiatric trai

Catechol-O-methyltranferase gene expression is associated with response to citalopram in obsessive-compulsive disorder

Objective. To determine whether polymorphisms of the dopamine D-2 receptor (DRD2) and catechol-O-methyl-transferase (COMT) receptor genes affect the efficacy of quetiapine addition to citalopram in patients with OCD. Methods. Sixty-four drug-free or drug-naive patients meeting DSM-IV criteria for OCD were randomized to 10 weeks double-blind treatment with citalopram (60 mg/day) with quetiapine (300-450 mg/day) or with placebo. The change from baseline to endpoint on the total Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and the response to treatment were the primary outcome measures. Response was defined as a 25% decrease in Y-BOCS score. Responders and nonresponders were stratified according to DRD2 TaqI A and COMT Val(158)Met genotypes. Results. No significant differences in genotype distribution or allele frequencies of the COMT or DRD2 receptor were found between responders and nonresponders to citalopram with quetiapine. However, nearly half of responders to citalopram with placebo carried the Met/Met (48%) genotype of the COMT polymorphism compared to none of the nonresponders (chi(2) = 10.06, df = 2, P = 0.007). Conclusions. The Met allele load of the COMT receptor gene was associated with response to 10 weeks of treatment with citalopram in drug-free or drug-naive OCD patients

The bovine protein α-lactalbumin increases the plasma ratio of tryptophan to the other large neutral amino acids, and in vulnerable subjects raises brain serotonin activity, reduces cortisol concentration, and improves mood under stress

Increased brain serotonin may improve the ability to cope with stress, whereas a decline in serotonin activity is involved in depressive mood. The uptake of the serotonin precursor, tryptophan, into the brain is dependent on nutrients that influence the cerebral availability of tryptophan via a change in the ratio of plasma tryptophan to the sum of the other large neutral amino acids (Trp-LNAA ratio). Therefore, a diet-induced increase in tryptophan availability may increase brain serotonin synthesis and improve coping and mood, particularly in stress-vulnerable subjects.We tested whether alpha-lactalbumin, a whey protein with a high tryptophan content, may increase the plasma Trp-LNAA ratio and reduce depressive mood and cortisol concentrations in stress-vulnerable subjects under acute stress.Twenty-nine highly stress-vulnerable subjects and 29 relatively stress-invulnerable subjects participated in a double-blind, placebo-controlled study. Subjects were exposed to experimental stress after the intake of a diet enriched with either alpha-lactalbumin or sodium-caseinate. Diet-induced changes in the plasma Trp-LNAA ratio and prolactin were measured. Changes in mood, pulse rate, skin conductance, and cortisol concentrations were assessed before and after the stressor.The plasma Trp-LNAA ratio was 48% higher after the alpha-lactalbumin diet than after the casein diet (P = 0.0001). In stress-vulnerable subjects this was accompanied by higher prolactin concentrations (P = 0.001), a decrease in cortisol (P = 0.036), and reduced depressive feelings (P = 0.007) under stress.Consumption of a dietary protein enriched in tryptophan increased the plasma Trp-LNAA ratio and, in stress-vulnerable subjects, improved coping ability, probably through alterations in brain serotonin