The relationship of caffeinated beverages with depressive symptoms and decision-making

Abstract

BACKGROUND:

Caffeine can affect depressive symptoms and decision-making.

OBJECTIVE:

This study aims to examine the relationship between caffeinated beverages consumption with depressive symptoms and decision-making styles.

METHODS:

This cross-sectional study was conducted with 432 adults working in office environment. The questionnaire consisting of individuals’ socio-demographic attributes, the frequency and the amount of caffeinated beverages consumption, the “Epidemiological Research Center-Depression (CES-D) Scale” and the “Decision-Making Styles Scale” were used. The frequency and amount of caffeinated beverages were determined using the food frequency questionnaire (FFQ). The participants were asked to choose which cup/mug they prefer to drink their caffeinated beverages and what amount they consume that beverage at a time. All the data were collected using online platforms.

RESULTS:

In the study, 76.7%of the participants were female and the mean age was 31.5±8.0 years. The average daily total caffeine intake of the participants was 425.8±461.4 mg and the total CES-D scale score was 17.7±11.2 points. It was found that as the amount of caffeine consumed increased, intuitive decision-making decreased and depressive symptoms increased (p < 0.05). In linear regression analysis, total caffeine consumption was found to be a significant predictor for the intuitive decision-making score (B: –0.151; p:0.002). When caffeine consumption is controlled, intuitive and rational decision making decreases with increasing depressive symptoms while addiction and avoidance decision making increased (p < 0.05).

CONCLUSIONS:

As a result, the amount of caffeine consumed daily was related to intuitive decision-making but did not effect depression. It has been observed that depressive symptoms affect decision-making styles in different ways. To our knowledge, our study is the first to examine the effects of caffeine consumption on depression and decision-making styles. Accordingly, future studies may focus on the link between caffeine consumption, depression, and decision-making styles in larger populations and the mechanisms that influence this relationship.

Keywords

Caffeine consumption depressive symptoms decision-making styles

1 Introduction

Caffeine, which is found in the most consumed beverages such as coffee, tea, and sodas in the world, has effects on mood [1]. The recommended daily caffeine consumption is 300–400 mg and it is determined that it does not develop an addiction when consumed in these amounts. Low-dose caffeine consumption (50–200 mg/day) is known to have positive effects on alertness, memory, and mood. However, high-dose consumption (400–800 mg/day) has negative effects such as anxiety, and tachycardia. In a study conducted with a large population, it was reported that drinking 2–3 cups of coffee every day reduced depression by 15%[2]. Nevertheless, there are also studies showing that caffeine consumption does not have a positive effect on depression [3, 4]. In a meta-analysis examining the relationship between depression and caffeine, the amount of caffeine consumed was found to be associated with a high risk of depression when 68–509 mg/day was consumed [3].

Depression is a common mental illness that has symptoms such as a chronic state of sadness, loss of interest or pleasure, decreased energy, feelings of guilt, low self-esteem, fatigue, concentration disorders, and prevents from performing their daily tasks [5]. According to the report published by the World Health Organization in 2017, it was found that 4.3%of the world population was depressed and there was an 18%increase compared to last year. Depression ranks third among the mental illness that contributes to the global burden of illness, and it is predicted to be in the first place by the year of 2030 [6]. It is known that depression arises from the interaction of social, psychological, and biological factors. It has been demonstrated that depression is associated with lifestyle behaviors such as eating habits and physical activity [7].

In relation to this, caffeine, which is one of the most consumed psychoactive substances and taken with diet, can positively affect depression by facilitating serotonin release and dopaminergic transition. It provides this effect by modulating the release of some neurotransmitters in the brain [8]. The stimulant role which emerges with the modulation of caffeine has positive effects on cognitive functions [9]. On the other hand, it is known that depression negatively affects cognitive functions such as understanding, problem solving, and decision-making [10].

Decision-making is a process in which an individual comprehends conclusions on what action to follow in the future given goals and limits concerning available resources. Although this process is often repeated, the subject includes framing, gathering knowledge, reaching conclusions, and learning from experience [11]. In the literature, there are many decision-making models defined such as rational model, limited rationality model, phased perspective, organizational procedures view, individual differences perspective, natural decision-making, multiple perspective approach [11, 12].

Studies examining the effects of caffeine on mood and cognitive performance have evaluated its effects on depression, anxiety, memory, attention, and judgment, as well as its association with decision-making [13, 14]. While some studies in the literature observed that caffeine has no effect on decision-making [15, 16]; some studies have found a relationship between especially risky decision-making [17, 18]. In addition, it has been examined that depression can have negative effects on decision-making by affecting numerous pathways in the brain [19, 20]. Based on this relationship, it is thought that the relationship between caffeine consumption, depression, and decision-making should be evaluated.

Many people have made caffeinated beverages a part of their daily diet and this way coffee and tea culture have spread around the world [1]. As we mentioned, caffeine is known to affect cognitive functions or neuropsychiatric symptoms through many pathways in the brain. In this framework, our study was conducted to find out the relationship of caffeine consumption with depression symptoms and decision-making styles.

2 Method

2.1 Research design and sample

This descriptive study was conducted between December 2020 and February 2021, with online access office workers and the Committee Approval (No61351342 / 2020-542) for the study was received from Üsküdar University Non-Interventional Research Ethics Committee on 26/11/2020. After the participants were informed about the general information on the study and the rights of the participant and the purposes of the study, the informed consent form approval was requested. The voluntary sampling method which is one of the non-random sampling methods was conducted with online access among office workers and a total of 432 people were reached.

Inclusion criteria is being an office worker such as academicians, bankers etc. over the age of 18 and voluntary approval of the consent form given by the researcher. The exclusion criteria include non-volunteerism and a diagnosed neurological or psychiatric disease. While 12 people who did not meet the inclusion criteria were excluded from the study, a total of 420 people were included in the study.

2.2 Data collection tools

In the study, the questionnaire consisting of individuals’ socio-demographic attributes, the frequency and the amount of caffeinated beverages consumption, the “Epidemiological Research Center-Depression (CES-D) Scale” and the “Decision-Making Styles Scale” were used to collect three main variables, which were caffeine consumption, depressive symptoms, and decision-making styles.

2.3 Descriptive information form and frequency questionnaire for caffeine consumption

The descriptive information form includes questions about the participant’s age, gender, height-weight, occupation, water consumption, and disease status.

The food frequency questionnaire (FFQ) is a global questionnaire applicable to all populations that assesses the frequency, portion sizes, and/or nutrient intake of foods and/or food groups over a period of time [21]. Appropriate foods to be included in FFQ can be made based on past dietary surveys, beliefs, food choices, and literatüre [22]. Accordingly, in our study, the frequency and amount of caffeinated beverages such as coffee, tea, energy drinks, soft drinks, etc. were determined using the FFQ.

The participants were shown various mug and cup photos in the survey and they were asked to choose which cup/mug they prefer to drink their caffeinated beverages and what amount they consume that beverage at a time. In the FFQ, the participants were asked to choose among “every day”, “1–2 times a week”, “3–4 times a week”, “2–3 times a month”, “once a month”, or “never” for the given caffeinated beverages. Total caffeine amount was converted to daily caffeine intake using standard coefficients of FFQ.

The United States Department of Agriculture (USDA) and Nutrition Information System –(BeBiS) databases were used to determine the amount of caffeine in caffeinated beverages [23].

2.4 Center for Epidemiologic Studies Depression Scale (CES-D)

The CES-D scale, which is used to evaluate depression symptoms, was adapted into Turkish by Tatar and Saltukoğlu in 2010 [24], and the scale was validated in Turkish individuals with diabetes by Lehmann et al. in 2011 [25]. The total score of the scale, which includes 20 questions in total, varies between 0 and 60. Scores for each response was determined as 0 for “Never-Rarely (less than 1 day)”, 1 for “A little-A few times (1–2 days)”, 2 for “Occasionally-Sometimes (3–4 days)” and 3 for “A lot-Most of the time (5–7 days)”. Items number 4, 8, 12, and 16 are scored in reverse.

2.5 Decision-making styles scale

The Decision-Making Styles Scale (KVSÖ) is a 25-item scale validated to Turkish by Taşdelen (2002) and it consists of five subscale which are rational, intuitive, dependent, spontaneous, and avoidant decision-making styles. Items were scored according to a 5-point Likert type scale ranked as “strongly disagree” (1), “disagree” (2), “undecided” (3), “agree” (4), “strongly agree” (5). During the reliability and validity study, an item in the original scale was removed from the scale resulting in the total number of items was reduced to 24, and the factor structures were accepted exactly. Internal consistency coefficients calculated for the subscale of the Turkish version of The Decision-Making Styles Scale (rational decision-making style subscale α= 0.76; intuitive decision-making style subscale α= 0.78; dependent decision-making style subscale α= 0.76; avoiding decision-making style subscale α= 0.79; spontaneous spontaneous decision-making style subscale α= 0.79; for the whole scale with 24 items α= 0.74) was accepted as sufficient for the validity and reliability of the scale. The internal consistency coefficients calculated for this research also range between 0.74 and 0.89 [26].

2.6 Statistical evaluation

Statistical analyzes have made using the IBM SPSS Statistics 22 program. In the analysis of the data, percentage of frequency, mean and standard deviation were obtained. Parametric tests were used for normal distributions and non-parametric tests were used for non-normal distributions. Spearman correlation was used between daily caffeine intake with the CES-D scale total score and the decision-making subscale scores. Partial correlation test was used between the CES-D scale total score and the decision-making subscale scores controlling for daily caffeine intake. Multiple linear regression was performed for the CES-D scale total score and the decision-making subscale scores by adjusting for caffeine consumption. As a result of the analysis, a value of p < 0.05 was considered statistically significant.

3 Results

The descriptive characteristics of the participants are given in Table 1. In the study, 76.7%of the participants were female and the mean age was 31.5±8.0 years. While the mean BMI values of the participants were 23.8±4.3 kg/m² and 33.1%of them were overweight. The mean amount of water consumed by the participants was 1583.5±813.8 ml/day and the total amount of caffeine was 425.8±461.4 mg/day. The mean of the CES-D scale total score was 17.7±11.2. The mean scores for the five subscales of the decision-making styles scale were 4.3±0.5 for rational decision-making, 3.7±0.7 for intuitive decision-making, 3.7±0.9 for dependent decision-making, 2.8±1.1 for avoidance decision-making, and 2.7±1.0 for spontaneous decision-making.

Table 1
Characteristics of the participants

Variables (n = 420) Min Max Mean±Std. Dev.

Age (year) 18.0 69.0 31.5±8.0

Height (cm) 147.0 205.0 167.7±8.2

Weight (kg) 41.0 125.0 67.4±15.0

Body mass index (kg/m²) 15.8 38.2 23.8±4.3

Water (ml/d) 1000.0 6000.0 1583.5±813.8

Total caffeine consumption (mg/d) 0.0 3401.7 425.8±461.4

Total CES-D score 0.0 53.0 17.7±11.2

Rational decision-making score 2.2 5.0 4.3±0.5

Intuitive decision-making score 1.6 5.0 3.7±0.7

Dependent decision score 1.0 5.0 3.7±0.9

Avoidance decision score 1.0 5.0 2.8±1.1

Spontaneous decision score 1.0 5.0 2.7±1.0

Variables (n = 420) n %

Gender Female 322 76.7

Male 98 23.3

Body mass index Underweight (<18.5 kg/m²) 26 6.2

Normal (18.5–24.9 kg/m²) 255 60.7

Obese (25.0–50.0 kg/m²) 139 33.1

Education status High school 16 3.8

Bachelor 227 54.0

Master 123 29.3

Doctorate 54 12.9

Profession Engineer –Programmer 59 14.0

Academician –Teacher 97 23.1

Health Employee 133 31.7

Expert –Manager 25 6.0

Officer, etc. 106 25.2

Variables (n = 420)	Min	Max	Mean±Std. Dev.
Age (year)	18.0	69.0	31.5±8.0
Height (cm)	147.0	205.0	167.7±8.2
Weight (kg)	41.0	125.0	67.4±15.0
Body mass index (kg/m²)	15.8	38.2	23.8±4.3
Water (ml/d)	1000.0	6000.0	1583.5±813.8
Total caffeine consumption (mg/d)	0.0	3401.7	425.8±461.4
Total CES-D score	0.0	53.0	17.7±11.2
Rational decision-making score	2.2	5.0	4.3±0.5
Intuitive decision-making score	1.6	5.0	3.7±0.7
Dependent decision score	1.0	5.0	3.7±0.9
Avoidance decision score	1.0	5.0	2.8±1.1
Spontaneous decision score	1.0	5.0	2.7±1.0

Variables (n = 420)		n	%
Gender	Female	322	76.7
	Male	98	23.3
Body mass index	Underweight (<18.5 kg/m²)	26	6.2
	Normal (18.5–24.9 kg/m²)	255	60.7
	Obese (25.0–50.0 kg/m²)	139	33.1
Education status	High school	16	3.8
	Bachelor	227	54.0
	Master	123	29.3
	Doctorate	54	12.9
Profession	Engineer –Programmer	59	14.0
	Academician –Teacher	97	23.1
	Health Employee	133	31.7
	Expert –Manager	25	6.0
	Officer, etc.	106	25.2

Table 2 shows the correlation between daily caffeine intake and CES-D and decision-making subscale scores. There is a low level of positive correlation between the amount of caffeine consumed daily and the CES-D total score (r = 0.106; p = 0.030). There is a negative but low-level significant relationship between the amount of caffeine consumed daily and the intuitive decision-making score (r = –0.128; p = 0.008). No significant correlation was found between other decision-making styles and daily caffeine intake (p > 0.05).

Table 2

Relationship between daily caffeine intake and CES-D scale and decision-making styles scale scores

	Total caffeine consumption (mg/d)
Variables (n = 420)	r	p
Total CES-D score	0,106	0,030
Rational decision-making score	–0,036	0,458
Intuitive decision-making score	–0,128	0,008
Dependent decision-making score	–0,071	0,147
Avoidance decision-making score	–0,052	0,291
Spontaneous decision-making score	0,005	0,923

^*Spearman correlation; Sig. (2-tailed) p < 0,05. r: Correlation coefficient.

Table 3 shows the linear regression of CES-D total score and decision-making subgroup scores adjusted to daily caffeine intake. According to the results of the analysis, it was determined that daily caffeine intake was a predictor of intuitive decision-making score. When the daily caffeine intake increases by one unit, the intuitive decision-making score decreases by 0.151 points. The total CES-D score have been lost its significance when adjusting for daily caffeine intake.

As seen in Table 4, there is a significant negative but low-level correlation found between CES-D total score and rational decision-making (r = –0.139; p = 0.004) and intuitive decision-making score (r = –0.140; p = 0.004) when daily caffeine consumption was controlled. While there was a low-level positive and significant correlation between CES-D total score and dependent decision-making score (r = 0.211; p = 0.000); a moderately positive and significant correlation was found between the avoidance decision-making score (r = 0.384; p = 0.000) when daily caffeine consumption was controlled. No significant difference was found between the CES-D total score and the self-decision score.

Table 3

Multiple linear regression for the CES-D scale and the decision-making subscales by adjusting for caffeine consumption

Independent Variable	Dependent Variable	B	%95 CI (lower; upper)	p
Total caffeine consumption (mg/d)	Total CES-D score	0.071	–0.001; 0.004	0.141
	Rational decision-making score	–0.034	0.0; 0.0	0.491
	Intuitive decision-making score	– 0.151	0.0; 0.0	0.002
	Dependent decision-making score	–0.086	0.0; 0.0	0.077
	Avoidance decision-making score	–0.073	0.0; 0.0	0.132
	Spontaneous decision-making score	–0.032	0.0; 0.0	0.509

Linear regression; Standardized Coefficients Beta; CI:Confidence Interval for B.

Table 4

The relationship between the CES-D scale total score and the decision-making styles scale scores controlling for daily caffeine intake

		Total CES-D score
	Variables (n = 420)	r	p
Total caffeine consumption (mg/d)	Rational decision-making score	–0,139	0,004
	Intuitive decision-making score	–0,140	0,004
	Dependent decision-making score	0,211	0,000
	Avoidance decision-making score	0,384	0,000
	Spontaneous decision-making score	0,063	0,195

^*Partial correlation; Sig. (2-tailed) p < 0,05. r: Correlation coefficient.

4 Discussion

In our study, the daily caffeine intake of the office workers was determined and the relationship between caffeine intake and depression and decision-making was evaluated.

Although the results of studies examining the relationship between caffeine intake and depression differ in the literature, the general assumption is that moderate caffeine intake has positive effects on depression [1 , 28]. According to a comprehensive study using data from the Korea National Health and Nutrition Survey; the prevalence of depression was found to be 32%lower among those who consume coffee frequently (≥2 cups/day) than those who do not drink coffee [29]. In another study in which coffee consumption was associated with the risk of depression, it was stated that the risk of depression in individuals consuming 2 cups of coffee per day was lower than those consuming 1 cup [4]. In a meta-analysis, it was stated that when caffeine consumption is 68–509 mg daily, the risk of depression decreases faster and the relationship between caffeine consumption and depression gets more significant [3]. Contrary to these studies, another study conducted with adolescents to evaluate the effects of caffeine intake on psychological state; high caffeine intake was found to be related to increased depression and anxiety scores [30]. Similarly, in our study, it was found that when caffeine consumption increased, the total score for depressive symptoms also increased. However, this relationship was weak and lost its significance when adjusted for daily caffeine consumption. In this context, according to the results of our study, the daily amount of caffeine has no effect on depressive symptoms. Since the mechanisms underlying the relationship between caffeine consumption and depression have not been fully understood; there are two possible explanations on this issue. First, it is thought that coffee, which contains significant amounts of bioactive components, has anti-inflammatory and antioxidant effects through these chemicals and may thus contribute to the pathophysiology of depression [31, 32]. The second is that caffeine may contribute to a reduction in the risk of depression by modulating the dopaminergic system and acting on adenosine receptors in the brain [33].

It is known that depressive symptoms affect cognitive functions such as problem solving, planning, and decision-making [34, 35]. In particular, identifying changes in decision-making has proven useful in understanding the basis of these disorders [36, 37]. In a study examining the effect of mood on decision-making, it was found that depressive symptoms cause abnormal decision-making in individuals [38]. In another study conducted with adults with major depressive disorder, it was shown that the decision-making time of depressed adults was longer than that of healthy controls [19]. In addition, in a non-randomized controlled study investigating the effects of major depression on decision-making, it was observed that the decision-making processes of individuals were negatively affected in the presence of depression [39]. In a study examining the effect of depression severity on decision-making styles; it has been observed that depressed individuals become more anxious when faced with a certain decision and remain passive about making decisions or delay decision-making, and avoid decisions. According to this study, it was also found that depressed individuals are more likely to distrust their intuition in the decision-making process [40]. Similarly, in a study conducted with university students, it was reported that individuals with high depressive symptom scores were more dependent on other individuals in the decision-making process and were less confident in their own intuition [41]. In our study, it was found a negative correlation between depressive symptoms and rational and intuitive decision-making scores when the daily caffeine intake is controlled. At the same time, an increase in depression scores concluded with an increase in dependent and avoidance decision-making scores. Similar to the literature, depression seems to affect decision-making styles.

When the relationship between caffeine-depression and depression/decision-making is examined; we thought that decision-making styles may also be affected by caffeine intake but concluded that studies examining the relationship between caffeine intake and decision-making styles are limited in the literature. In the only study conducted in this regard, consumption of stimulants such as nicotine or caffeine was associated with imperfect decision-making. According to this study, the hypervigilance (panic) decision-making problem, which is the pressure to act by making choices without thinking, has been observed in individuals addicted to caffeine. Also, it has been determined that psychological problems such as anxiety and depression risk are higher in individuals with a caffeine addiction and their decision-making self-esteem is low [42].

In our study, a negative relationship was found between caffeine consumption and intuitive decision-making. This significance does not disappear even when adjusting for caffeine consumption, indicating that caffeine consumption is a predictor of intuitive decision making. Intuitive decision making is also negatively affected by depressive symptoms. According to our study, reguler functioning of the intuitive decision-making process is associated with an increase in caffeine intake and a decrease in depressive symptoms. However, further studies are needed to draw a clear conclusion and to elucidate the underlying mechanism.

One of the limitations of our study is the inability to question caffeine intake in detail due to the small sample size and the inability to record caffeine consumption face-to-face. In addition, our study may not reflect the general population as it is applied to a specific professional group.

5 Conclusions

To our knowledge, our study is the first to examine the effects of caffeine consumption on depression and decision-making styles. It was determined that as the amount of caffeine consumed increased, intuitive decision-making decreased and depressive symptoms increased. However, an inverse relationship was found between caffeine intake and only intuitive decision-making when adjusted for daily caffeine consumption. It was found that with the increase of depressive symptoms, intuitive and rational decision-making decreased, while dependent and avoidant decision-making increased when caffeine consumption was controlled. In this context, it can be said that the improvement of depressive symptoms and consumption of caffeine may have an important role in healthy decision-making. As a result, a relationship between depression and decision-making was found and caffeine intake affected this relationship. Future studies may focus on the mechanisms that influence caffeine intake-specific changes between depression symptoms and decision-making and decision-making styles in larger populations. There is no acknowledgement.

Footnotes

Acknowledgments

There is no acknowledgement.

Financial support

There is no financial support.

Conflict of interest

There is no conflict of interest.

Authorship: All authors of the manuscript titled The Relationship of Caffeinated Beverages with Depressive Symptoms and Decision-Making. Certify that they qualify for authorship because of substantial contribution to the work submitted. The authors undersigned declare that this manuscript has not been published nor is under simultaneous consideration for publication elsewhere. The authors agree to transfer the copyright to Mediterranean Journal of Nutrition and Metabolism to be effective if and when the manuscript is accepted for publication and that the manuscript will not be published elsewhere in any other language without the consent of Mediterranean Journal of Nutrition and Metabolism. The final form of the manuscript has been seen and approved by all authors.

Authors, Name, Surname	Contribution
1. Hatice ÇOLAK	20%
2. Emel ERDENIZ	20%
3. Esra Tansu SARIYER	20%
4. Ekin ÇEVIK	20%
5. Didem YANGIN	20%

Ethical standards disclosure

This study was conducted according to the guidelines laid down in the Declaration of Helsinki and all procedures involving research study participants were approved by the Uskudar University Non-invasive Clinical Research Ethics Committee and Scientific Research Evaluation Commission of the Ministry of Health. Written informed consent was obtained from all subjects.

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