Session Information
Date: Monday, September 23, 2019
Session Title: Clinical Trials, Pharmacology and Treatment
Session Time: 1:45pm-3:15pm
Location: Agora 3 West, Level 3
Objective: The purpose of this study was to compare the effects of 5-HTP to placebo on depression and apathy in patients with PD.
Background: Parkinson’s disease (PD) is a chronic neurodegenerative disorder characterized by the motor symptoms of bradykinesia, tremor, rigidity and postural instability. However, non-motor symptoms such as depression and apathy are also frequent and play a significant role. Several studies have indicated that altered serotonergic neurotransmission may contribute to non-motor features commonly associated with PD such as apathy and depression.The 5-Hydroxytryptophan (5-HTP) is the intermediate metabolite of L-tryptophan in the production of serotonin. Studies in other populations indicate that 5-HTP might be useful in the treatment of depression. To date, there has been inconsistent research on the use of 5-HTP in PD.
Method: A single-center, randomized, double-blind, placebo-controlled, cross-over trial was employed; 25 subjects were subsequently enrolled into the study, 23 subjects completed the 16-week protocol. Patients received placebo and 50 mg of 5-HTP daily in a cross-over design over a period of 4 weeks. We decided for a washout period of 4 weeks in order to minimize the carry-over effects. For the assessment of efficacy on the depression and apathy the Beck Depression Inventory II (BDI-II), the 21-item version of Hamilton Depression Rating Scale (HDRS21) and Apathy Scale (AS) were respectively obtained at screening, baseline and weeks 4, 8, 12 and 16 (T-end).
Results: Repeated measures analysis revealed a significant improvement of depressive symptoms during the 50 mg 5-HTP treatment compared to placebo as assessed by the HDRS21. There were no significant effects of 5-HTP compared to placebo on apathy symptoms as assessed by the AS.
Conclusion: This study provides preliminary evidence of clinical benefit with 5-HTP for treating depressive symptoms in PD. Larger studies with a longer treatment duration are needed to corroborate these early findings.
To cite this abstract in AMA style:
M. Meloni, M. Puligheddu, M. Carta, M. Figorilli, G. Defazio. Efficacy and safety of the 5-Hydroxytryptophan on Depression and Apathy in Idiopathic Parkinson’s disease. [abstract]. Mov Disord. 2019; 34 (suppl 2). https://www.mdsabstracts.org/abstract/efficacy-and-safety-of-the-5-hydroxytryptophan-on-depression-and-apathy-in-idiopathic-parkinsons-disease/. Accessed June 15, 2025.« Back to 2019 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/efficacy-and-safety-of-the-5-hydroxytryptophan-on-depression-and-apathy-in-idiopathic-parkinsons-disease/