The effect of COVID-19 lockdown on mental health, gut microbiota composition and serum cortisol levels

Figures & data

Figure 1. Study design; CES-D: The Center for Epidemiologic Studies Depression Scale; STAIX-1: The State-Trait Anxiety Inventory; BD: Body Dissatisfaction; PANAS: The Positive and Negative Affect Schedule; PSS: The Perceived Stress Scale.

Table 1. Lifestyle changes (n = 46).

	All (n = 46) %	M (n = 15) %	F (n = 31) %	p Value
Work changes				0.004*
No changes	32.6	60.0	19.4
Working from home	26.1	6.7	35.5
Partially working from home, partially at the workplace	8.7	13.3	6.5
Not working, receiving compensation	19.6	13.3	22.6
Not working, not receiving compensation	13.0	6.7	16.1
Social interactions at the workplace				0.942
Interactions	32.6	33.3	32.3
No interactions	67.4	66.7	67.7
Social interactions				0.281
Interactions with family	65.2	53.3	71.0
Interactions with family and work colleagues	28.3	40.0	22.6
Interactions with family and friends	6.5	6.7	6.5
Changed lifestyle				0.320
Lifestyle did not change or changed a little	63.0	73.3	58.1
Lifestyle changed a lot or completely	37.0	26.7	41.9
Fear of family’s infection with SARS-CoV-2				0.721
Not worried at all	17.4	13.3	19.4
A little worried	41.3	40.0	41.9
Sometimes worried, sometimes not	23.9	33.3	19.4
Worried a lot	17.4	13.3	19.4

*p < 0.05 is considered statistically significant; M = males, F = females.

Table 2. Psychological measures pre-lockdown and during lockdown (n = 46) and serum cortisol levels (µg/dl) pre-lockdown and post-lockdown (n = 38).

	Pre-lockdown	Lockdown
Psychological measures	M (SD)	M (SD)	T/Z value	p Value
Body dissatisfaction (score)
All (n = 46)	11.3 (8.0)	13.0 (7.3)	2.807	0.007*
Males (n = 15)	7.1 (6.8)	9.7 (7.0)	2.902	0.012*
Females (n = 31)	13.3 (7.8)	14.6 (7.0)	1.609	0.118
Anxiety (score)
All (n = 46)	34.2 (9.9)	37.8 (9.4)	3.211	0.002*
Males (n = 15)	33.3 (8.87)	36.8 (7.4)	2.272	0.039*
Females (n = 31)	34.7 (10.5)	38.3 (10.4)	2.419	0.022*
Depression (score)
All (n = 46)	8.7 (7.5)	9.3 (6.9)	0.357	0.721
Males (n = 15)	7.8 (5.1)	8.8 (6.0)	0.377	0.706
Females (n = 31)	9.1 (8.4)	9.5 (7.4)	0.133	0.895
Positive affect (score)
All (n = 46)	34.3 (5.3)	31.3 (6.0)	−3.380	0.001*
Males (n = 15)	34.5 (4.8)	31.7 (4.3)	−2.423	0.030*
Females (n = 31)	34.1 (5.6)	30.9 (6.7)	−2.871	0.008*
Negative affect (score)
All (n = 46)	21.8 (5.9)	21.0 (5.9)	−0.918	0.359
Males (n = 15)	21.3 (6.1)	20.1 (5.4)	−1.254	0.230
Females (n = 31)	22.0 (5.9)	21.7 (6.0)	−0.361	0.721
	Pre-lockdown	Post-lockdown
Serum cortisol levels (µg/dl)	M (SD)	M (SD)	T/Z value	p Value
All subjects (n = 38)	2.21 (1.54)	2.37 (0.55)	0.790	0.429
Males (n = 14)	3.03 (1.17)	2.64 (1.85)	−2.605	0.009*
Females (n = 24)	1.73 (1.23)	2.23 (1.37)	2.771	0.006*

*p < 0.05 is considered statistically significant.

Figure 2. Correlation between changes in serum cortisol levels (µg/dl) and psychological measures in females (n = 24; darker line with a positive slope) and males (n = 14; lighter line with a negative slope) (a) Correlation between changes in serum cortisol levels (µg/dl) and perceived stress during lockdown; (b) Correlation between changes in serum cortisol levels (µg/dl) and anxiety during lockdown.

Figure 3. Gut microbiota composition changes at the phylum level; the relative abundance of bacterial phyla pre-lockdown and post-lockdown (n = 38; 24 males, 14 females).

Bar chart presents gut microbiota composition at the phylum level. It presents the relative abundance of bacterial phyla pre-lockdown and post-lockdown. Pre-lockdown, Bacteroidetes was the predominant group at the phylum level, with an average abundance of 54.47% (SD 17.76%), followed by Firmicutes with an average abundance of 38.56% (SD 15.79%). Proteobacteria (M 3.69%, SD 3.30%), Tenericutes (M 1.57%, SD 3.09%), Cyanobacteria (M 1.10%, SD 2.72%), Lentisphaerae (M 0.99%, SD 1.0%) and Actinobacteria (M 0.58%, SD 1.37%). Post-lockdown, Proteobacteria abundance significantly increased (Z = 2.027, p = 0.043) from 3.69% (SD 3.30%) to 5.06% (SD 4.97%).

Figure 4. Gut microbiota composition changes at the genus level; the relative abundance of bacterial genera pre-lockdown and post-lockdown (n = 38; 24 males, 14 females).

Bar chart presents gut microbiota composition at the genus level. It presents the relative abundance of the most abundant genera, predominantly of the phyla Bacteroidetes and Firmicutes (Bacteroides, Faecalibacterium, Prevotella 9, Alistipes, Lachnospiraceae NK4A136 group, Parabacteroides, Ruminococcus, Agathobacter, Subdoligranulum, Christensenellaceae R-7 group, Clostridia UCG-014, Roseburia, Oscillospiraceae UCG-002, Blautia, Oscillospiraceae NK4A214 group and Lachnospiraceae uncultured; from most to less abundant genera). No statistically significant differences between pre-lockdown and post-lockdown levels were observed.

Figure 5. Correlation between gut microbiota composition and psychological measures (n = 38; 24 males, 14 females) (a) Correlation between changes in Bacteroidetes abundance and depression during lockdown; (b) Correlation between changes in Firmicutes abundance and depression during lockdown; (c) Correlation between Alistipes abundance post-lockdown and anxiety during lockdown; (d) Correlation between Alistipes abundance post-lockdown and negative affect during lockdown.

Data availability statement

The data presented in this study are available on request from the corresponding author.