Effects of Lactobacillus plantarum PS128 on Depressive Symptoms and Sleep Quality in Self-Reported Insomniacs: A Randomized, Double-Blind, Placebo-Controlled Pilot Trial

Abstract

Recent animal studies have supported that Lactobacillus plantarum PS128 (PS128) can reduce the severity of anxiety and depression. However, previous studies did not focus on the sleep quality and mood of humans. This study determines whether PS128 reduces the severity of anxiety and depressive symptoms, regulates autonomic nervous system function, and improves sleep quality. Forty participants between 20 and 40 years of age with self-reported insomnia were randomly assigned to two groups, a PS128 group and a placebo group, in a double-blind trial. Participants took two capsules of either PS128 or a placebo after dinner for 30 days. Study measures included subjective depressive symptoms, anxiety and sleep questionnaires, and miniature-polysomnography recordings at baseline and on the 15th and 30th days of taking capsules. Overall, all outcomes were comparable between the two groups at baseline and within the 30-day period, yet some differences were still found. Compared to the control group, the PS128 group showed significant decreases in Beck Depression Inventory-II scores, fatigue levels, brainwave activity, and awakenings during the deep sleep stage. Their improved depressive symptoms were related to changes in brain waves and sleep maintenance. These findings suggest that daily administration of PS128 may lead to a decrease in depressive symptoms, fatigue level, cortical excitation, and an improvement in sleep quality during the deep sleep stage. Daily consumption of PS128 as a dietary supplement may improve the depressive symptoms and sleep quality of insomniacs, although further investigation is warranted.

Effect of Probiotics on Psychiatric Symptoms and Central Nervous System Functions in Human Health and Disease: A Systematic Review and Meta-Analysis

“…The publishing dates of the studies were between 2007 and 2021. Most studies were conducted in Asia ( n = 28; 51.9%) [ 30 , 32 , 33 , 36 , 41 , 43 , 44 , 45 , 47 , 48 , 50 , 51 , 53 , 54 , 55 , 56 , 57 , 58 , 62 , 63 , 69 , 70 , 72 , 74 , 75 , 77 , 78 , 79 ], followed by Europe ( n = 18; 33.3%) [ 18 , 19 , 20 , 22 , 34 , 35 , 37 , 40 , 42 , 46 , 49 , 52 , 59 , 60 , 64 , 65 , 67 , 73 ], America ( n = 7; 12%) [ 21 , 38 , 39 , 61 , 68 ,…”

“…Only four studies examined the impact on CNS function by using functional magnetic resonance imaging [ 18 , 19 , 20 , 21 ], while only six studies used electroencephalography (EEG) [ 33 , 34 , 43 , 49 , 56 , 75 ]. There was also one study applying magnetoencephalography (MEG) [ 22 ], another using actigraphic measurements [ 78 ] and one study with electrodermal responses (EDR) [ 33 ].…”

“…Overall, 41 studies presented data of healthy participants with no diagnosed psychiatric disorder (75.9%) and 13 studies (24.1%) of participants with diagnosed psychiatric disorders according to DSM, such as major depressive disorder ( n = 2; 3.7%) [ 32 , 67 ], depression ( n = 2; 3.7%) [ 48 , 79 ] and schizophrenia ( n = 3; 5.6%) [ 38 , 41 , 71 ]. In addition, studies also included participants with mild cognitive impairment [ 44 ], bipolar I/schizoaffective disorder in a manic episode [ 39 ], general anxiety disorder [ 30 ], chronic fatigue syndrome [ 61 ], chronic primary insomnia [ 43 ] and fibromyalgia [ 65 ]. In addition, five studies only included participants when they achieved a pathological score in questionnaires (9.3%).…”

“…Six studies recorded EEG, three of them during sleep to assess the effects of probiotics on sleep parameters [ 43 , 56 , 75 ]; these studies reported improvements of sleep quality. Two further studies found that probiotic intake improved memory function [ 34 ] and modulated brain regions associated with relaxation and attention [ 33 ].…”

“… Quantitative analysis for anxiety of randomized controlled trials receiving either probiotics or placebo treatment. Eskandarzadeh 2021 [ 30 ], Gualtieri 2020 [ 42 ], Ho 2021 [ 43 ], Karbownik 2020 [ 46 ], Kato-Kataoka 2016 [ 47 ], Messaoudi 2011 [ 52 ], Nishida 2019 [ 56 ], Östlund-Lagerström 2016 [ 59 ], Patterson 2020 [ 60 ], Raygan 2018 [ 62 ], Raygan 2019 [ 63 ], Roman 2018 [ 65 ], Sanchez 2017 [ 68 ], Steenbergen 2015 [ 73 ], Takada 2016 [ 74 ], Takada 2017 [ 75 ], Tran 2019 [ 76 ]. …”