Metabolomic signature of exposure and response to citalopram/escitalopram in depressed outpatients.
Level 3 - non-randomized controlled study
Prospective single-arm clinical trial cohort without a randomized control group
PubMed 31273200 · doi:10.1038/s41398-019-0507-5
What was done
Targeted metabolomics (measuring 31 metabolites from neurotransmitter-related pathways using an electrochemistry-based platform) was performed on plasma from 290 outpatients with unipolar major depressive disorder. Patients were profiled at baseline, 4 weeks, and 8 weeks following treatment with citalopram or escitalopram. Symptom severity was assessed using the 17-item Hamilton Depression Rating Scale (HRSD17), alongside partial correlation network and genetic association analyses.
What was found
Metabolic changes were more pronounced at 8 weeks than at 4 weeks. In the tryptophan pathway, serotonin (5HT) decreased, indoles increased, and 5HT, 5-hydroxyindoleacetate (5HIAA), and the 5HIAA/5HT ratio significantly correlated with changes in HRSD17 scores. In the tyrosine pathway, changes were detected in catecholamine end products (MHPG and vinylmandelic acid) and two phenolic acids (4-hydroxyphenylacetic acid and 4-hydroxybenzoic acid) increased. In the purine pathway, hypoxanthine and xanthine levels significantly decreased. Network analysis identified guanosine-homogentisic acid and methionine-tyrosine interactions associated with HRSD17 scores, mapping to two candidate genetic loci. The abstract does not report specific numerical values, effect sizes, or p-values.
Why it matters
The findings identify longitudinal metabolic alterations during SSRI treatment, highlighting potential contributions of gut microbial cometabolism, oxidative stress, and noncanonical metabolic pathways to antidepressant response.
Limits
The study is a single-arm prospective cohort without a placebo or active comparator group, making it difficult to separate drug-specific effects from general clinical recovery or time effects. The abstract omits all numerical data, exact effect sizes, and p-values.
Cited by
- context Selective serotonin reuptake inhibitors (SSRIs) exert their clinical therapeutic effects by altering the gut microbiome to a favorable tryptophan-pathway microbiome rather than by blocking brain serotonin reuptake.