Introduction  

The World Health Organization considers mental health as one of the essential components of human health [1]. Based on the WHO, one in five people suffers a mental disorder and 29.2% have had a history of mental illness during their lifetime [2]. Medical science education is very challenging in this field and is considered a stressor that negatively affects students' mental health [1, 3, 4]. Psychiatric disorders such as stress, anxiety, and depression have a significant impact on the learning, academic performance, and physical and mental health of medical students [5-7]. Research suggests a high prevalence of disorders such as stress, anxiety, and depression among students [8]. Medical students, especially those living in dormitories, are exposed to a high level of stress due to their special conditions and social status [9]. Depression is a psychiatric disorder affecting more than 300 million people around the world [10, 11]. Depression is a mood disorder characterized by daily dysfunction with symptoms such as sadness and hopelessness, guilt, and loss of interest. Depression is a common, debilitating, and potentially life-threatening illness that can lead to suicide, addiction, and low self-esteem. Its consequences may be academic failure and impairment in the job, family, and social functions. It, directly and indirectly, imposes huge costs on society [12].

The prevalence of depression in the United States is 7% and about 11 million people suffer from depression each year, indicating an increase in the prevalence of this disease in younger age groups [13]. In Europe, about 30% of medical students suffer from depression and anxiety [14]. Anxiety disorders are a group of psychiatric disorders characterized by an unpleasant feeling of anxiety, worry about future events, or fear of responding to current events [12].  at least 1 in 9 people in the world suffered anxiety disorder [15, 16]. Factors such as the high volume of classes and courses, inability to make decisions, work future, being away from home and family, financial problems, exams, competing with other students, academic problems, and entering a new environment can be stressors affecting students [17]. Hafsa Liaqat et al. showed that 40.4%; 43.82% and 30.33% of dormitory students suffered from depression, anxiety, and stress, respectively [18].

Zahra Jaafari et al. (2021) reported that The prevalence of mild, moderate, and severe depression in Iranian students was estimated at 26.1%, 15.5%, and 6.4%, respectively  [19]. In a research carried out by Rajeshree S et al., it was shown that Anxiety score was normal. anxiety score among students with BMI > 23 kg/m2 and with BMI < 23 kg/m2 in both sexes has been found. Also, there was no significant difference of anxiety score among students with higher WHR (males > 0.88 and females > 0.81) and with lesser WHR (males < 0.88 and females < 0.81) [20]. Happiness is a crucial factor in human life and consists of at least 3 components: emotional, cognitive, and social [21]. Happiness is one of the characteristics of human personality that can help humans overcome life pressures [22]. Medical students are less happy compared to other students due to their special educational and work conditions [23]. Students' level of happiness has a significant impact on their academic achievement [24]. Anxiety is one of the most common psychiatric disorders in the general population. One of the most important groups of society is medical students who have sensitive status in society due to facing the health of a large group of people. Medical students deal with the physical and mental pain of patients as well as their personal and family problems. The level of happiness of medical students can also affect their stress, anxiety, and depression. No study has been conducted at Bam University of Medical Sciences to examine the relationship between happiness and depression, anxiety, and stress. Also, high prevalence and different results have been reported on the correlation of happiness with stress, anxiety, and depression in students, especially medical students. Hence, the present study was conducted to evaluate the level of stress, anxiety, and depression in students of Bam University of Medical Sciences and their relationship with happiness in 2019.

Materials and Methods

This descriptive-analytical and cross-sectional study was performed to assess the level of depression, anxiety, and stress and their relationship with happiness in students of Bam University of Medical Sciences in 2019. Cochran's formula was used to calculate the sample size. Based on this formula, 300 questionnaires were distributed among students of health, nursing, midwifery, and medical schools. They were selected using a random sampling method. Inclusion criteria included male and female students studying during the study and willingness to participate. Exclusion criteria included incomplete filling out of questionnaire, unwillingness to participate, withdrawal from studying at university, and not returning the questionnaire. Finally, 300 questionnaires were returned (Response Rate = 100%). Before starting the sampling, the researcher received a letter of introduction and an ethics code of IR.MUBAM.REC.1399.013 from the Research and Technology Deputy of Bam University of Medical Sciences while observing ethical considerations. After providing sufficient explanations to the subjects on the aims and process of the research and emphasizing the confidentiality of the collected information before starting the research, the subjects filled out the researcher-made questionnaire, which consisted of three sections of demographic characteristics, Oxford happiness, and psychological reactions. The collected data were entered into the computer and were analyzed in SPSS 23 software using the descriptive and inferential statistical tests appropriate to the research aims. The research questionnaire consists of three sections. The first section included individual characteristics, the second section was Depression, Anxiety, and Stress Scale (DASS-21) and the third section was Oxford Happiness Questionnaire.

Depression, Anxiety, and Stress Scale (DASS-21): consists of 21 questions, divided into three subscales (each subscale includes seven questions) of anxiety, stress, and depression. Questions 3, 5, 10, 13, 16, 17, and 21 assess depression, questions 2, 4, 7, 9, 15, 19, and 20 assess anxiety, and questions 2, 6, 8, 11, 12 , 14, and 18 assess stress. This questionnaire is scored on a Likert scale with options of at all, low, moderate, and high with scores of zero to 3, respectively. Scores ≥21 in depression, ≥15 in anxiety, and ≥26 in stress subscales were considered normal and the alpha coefficient for these three factors was 0.97, 0.92, and 0.95, respectively [25].

Oxford Happiness Scale: The Oxford Happiness Scale includes 29 items that assess five areas of life satisfaction (8 questions: 1, 2, 3, 4, 5, 6, 7, and 8), self-esteem (7 questions: 9, 10, 11, 12, 13 ,14, and 15), efficiency or subjective well-being (5 questions: 16, 17, 18, 19, and 20), satisfaction (4 questions: 21, 22, 23, and 24), and positive mood (5 questions: 25, 26, 27, 28, and 29). It is scored on a four-point Likert scale. Its options are scored from zero to 3, respectively. Accordingly, the option “at all” receives score zero, the option “low” receives score 1, the option “moderate” receives score 2, and the option “high” receives score 3. A subject obtains a total score of between 0 and 87 in this scale, in which a higher score is a sign of greater happiness. Information on internal consistency, reliability, and validity in developing Persian version of the Oxford Happiness Scale have been prepared by a previous study [26].

Results and Discussion

The mean age of students was 22.46 ± 2.05 years and 41.7% of the students were male. Also, 82.7% of the subjects were single, 31.3% lived in dormitories and 96.7% lived in urban areas. The mean of depression, anxiety, stress, and happiness were 5.08 ± 3.75, 4.20 ± 2.96, 7.70 ± 4.23, and 42.57 ± 11.98, respectively (Table 1). Based on the results, there was a significant relationship between happiness, and depression, anxiety, and stress (P <0.05) so that happiness decreased with increasing anxiety, stress, and depression. Based on the obtained results, happiness all its components were significantly and negatively correlated with depression, anxiety, and stress, except for the relationship between the components of happiness and total score. It means that with increasing scores of depression, anxiety, and stress, the score of happiness decreases (p <0.05). Also, the variable of Iranian university entrance exam rank was not related to any of the variables. The results of data analysis showed that living in a rented place was associated with lower scores of depression and stress and higher scores of happiness. In addition, people born in rural areas had higher scores of depression. Moreover, analysis of variance and independent t-test showed that there was a significant difference in these cases (p <0.05). Based on the data analysis, there was no relationship between the parental level of education and job and depression, anxiety, stress, and happiness scores. In addition, parents' quality of  life was associated with depression, anxiety, stress, and happiness scores, so that subjects with dead mothers showed more depression, anxiety, and stress. Statistical results suggest that there was no significant relationship between fields of study and scores of depression, anxiety, stress, and happiness. Single people had a higher score of depression and there was no significant difference between single and married people in terms of other variables (Table 2).