The Relationship between Adult Attention-Decit/Hyperactivity Disorder and anxiety, Depression, Stress and Sleep in Professional Drivers in southern Iran

Background: Adult Attention-Decit/Hyperactivity Disorder (ADHD) is one of the neurodevelopmental disorders which is characterized by low focused concentration, distractibility, reduced self-regulation, and hyperactivity. They experience high rates of sleep and mental problems. Accordingly, the aim of this study was to investigate anxiety, depression, stress, and sleep among professional adult drivers with ADHD in an Iranian sample. Method: in this cross-sectional study, 547 professional adults drivers with ADHD that arm their disorders by Conner adult ADHD rating scale (CAARS) complete survey that provides demographic data, Pittsburgh Sleep Quality Index (PSQI) for assessing quality of sleep, and DASS 21 survey to evaluate Depression, Anxiety and Stress Scale. Results: professional adult drivers with ADHD reveals a signicant association of anxiety, depression, stress with poor sleep quality. Among these drivers, Poor quality of sleep was substantially associated with driving at night (P=0.039), but no substantial correlation was found with age, marital status, education, a model of car, and daytime driving (P>0.05). Conclusion: Given the signicant correlation of anxiety, depression, stress, and ADHD with low quality of sleep, ADHD drivers may be a potential preventive measure that contributes to the identication of vulnerable drivers in terms of psychological state and improvement of their quality of sleep by setting acceptable rules for juggling working hours and supporting acts.

In the last part, the Persian version of the short-form of the Conner Adult ADHD rating scale (CAARS), validated by Sadeghi Bazargani et al., has been used to assess the status of ADHD [15]. It includes 30 questions. The answers have been chosen from Likert's four-point scale that provides for zero (rarely or never), one (occasionally or sometimes), two (most of the times or usually), and three (very often or always). This questionnaire tests had four dimensions that consist of disorder of attention (Dimension A), index of impulsivity (Dimension B), a general index of ADHD symptoms and lack of attention (Dimension C), and index of ADHD (Dimension D).

Statistical analysis
Statistical Package for the Social Sciences Version 19.0 (SPSS Inc., Chicago, IL, USA) was used to analyze the data. Frequency and percentage were used for qualitative variables, including sleep disorder and sub-items, demographic variables, anxiety, depression, and stress. The chi-square test was conducted to evaluate the relationship between poor sleep quality, anxiety, depression, and stress with demographic variables and duration of driving. Also, the association between anxiety, depression, and stress with poor sleep quality and sleep items. An independent sample t-test was done for compression mean score of ADHD and ADHD dimensions with sleep disorder and sleep items. Moreover, covariance analysis was performed to adjust age, marital status, education level, type car, duration driving at night and day to compare ADHD and ADHD dimensions with sleep poor quality, and sleep items. A P-value of less than 0.05 was considered signi cant.

Results
Of the 547 professional drivers who consented to participate in this study, 351 (64.2%) were the bus driver, and the rest of the 196 (35.8) were intercity taxi drivers. The mean ± SD age of drivers was 4.17 ± 9.16 (24 to 68 years old).
In general, the prevalence of poor sleep quality among all drivers were 383 (70.0%). Also, the prevalence of problems in sleep duration, use of sleep Among these drivers, poor sleep quality had a signi cant correlation with driving at night (P = 0.039); conversely, no signi cant association was observed with age, marital status, education, type car, and driving at day (P > 0.05). Also, the prevalence of anxiety had more in age under 30 years old, intercity taxi driver and less than 5 hours driving at night (P < 0.05). The prevalence of depression was seen more in low level education driver and less than 5 hours driving at night (P < 0.05). The prevalence of stress had seen more in intercity taxi driver, less than 5 hours driving at night and less than 6 hours driving at day (P < 0.05).
( Table 1) Table 1 Relationship of poor sleep quality, anxiety, depression, and stress between demographic variables and duration driving.

105(70)
The driver who had poor sleep quality suffered more from mild to moderate and severe anxiety, depression, and stress (P < 0.001). All sleep items except habitual sleep e ciency had a higher rate of mild to moderate and severe anxiety and stress (P < 0.05). But depression had an association with poor sleep quality (P < 0.001), use of sleep medications (P = 0.006), sleep latency (P = 0.011), Sleep Disturbance (P < 0.001), and daytime dysfunction (P < 0.001). (Table 2)  Drivers with poor sleep quality had a higher total ADHD and ADHD dimensions scores (P < 0.001). Moreover, the mean score of ADHD and ADHD dimensions were signi cantly higher for those who had problems in sleep duration, subjective sleep quality, sleep disturbance, and daytime dysfunction (P < 0.05). Also, the correlation between the mean score of ADHD and ADHD dimensions were not signi cant with habitual sleep e ciency and sleep latency (P > 0.05). (Table 3) , helmet usage, driving license were adjusted, and the mean scores for ADHD and ADHD dimensions were higher among drivers who had poor sleep quality (P < 0.001). Also, the drivers with problems in sleep duration, sleep disturbance, and daytime dysfunction had a higher score in ADHD and ADHD dimensions by covariance analysis (P < 0.05). Subjective sleep quality was correlated with total ADHD, dimension B and C (P < 0.05). (Table 3)

Discussion
The present paper aims to outline the prevalence of poor sleep quality, and its sub-items, anxiety, depression, stress, ADHD, and its four subcategorized dimensions among professional drivers, including bus drivers and intercity taxi drivers, as well as investigating the relationship between poor sleep quality and each of the forenamed psychological conditions. Previous work has failed to address the correlation of all these factors together among the population of professional drivers.
Of the study population, 70% of drivers indicated having poor sleep quality, which is worth considering since many studies have shown the correlation between a higher number of crashes and poor sleep quality. [16][17][18][19][20][21] Philip, P. et al. highlight that the risk of tra c accidents in subjects who reported inferior, poor sleep quality is 3.35 times higher than others. [18] A systematic review conducted by Tabrizi and co-workers has revealed that more than half of the Iranian drivers suffer from sleep quality disorder. [22] Also, the same high prevalence of poor sleep quality has been reported in a similar study in the population of Thailand intercity bus drivers. [23] Reviewing seven sub-items of poor sleep quality, each of the components shows various rates of prevalence among drivers. In the literature, Sleep duration, in comparison to sleep quality, was better associated with accidents and accident risk [24]. Further studies have mentioned physical fatigue, mental fatigue, irritability, insomnia, respiratory disturbances, and snoring as sleep disturbance complaints among drivers. [25] A growing body of literature has evaluated the potential factors correlated with poor sleep quality among drivers, including fatigue, shift work, smoking, history of pulmonary disease, occupational stress, and driving times in a day. [23,[26][27][28][29]. In addition to forenamed factors, our analysis has also revealed a signi cant correlation between poor sleep quality and driving at night, which could be due to the interference of night shifts with circadian rhythm and following hormonal imbalances. [30] Moreover, our tests revealed a signi cant association between all degrees of anxiety, depression, and stress with poor sleep quality, supporting previous ndings in the literature. Gu [28] concludes that the risk of poor sleep quality could be resulted from the risk for more physiological needs, more effort, more depressive symptoms, and more daily stress for drivers. Further tests carried out in other various populations, including police o cers, postpartum women, farmers, elderly, and employees corroborated our ndings. In addition, Poor quality of sleep is in association with anxiety and depression. [31][32][33][34][35][36][37][38][39] Our results share several similarities with Potvin et al.'s ndings, which reported a signi cant association of PSQI subscales with anxiety, particularly sleep duration in hours, sleep disturbance score, and daytime functioning score. [40] Since sleep is a complex biological process, providing an exact pathophysiological theory as a justi cation of reported correlations between poor sleep quality, depression and anxiety have been a subject of controversy. Considering previous studies, sleep patterns of depressive patients have shown increased REM density and diminished delta sleep ratio. [41] Moreover, Hori et al. indicate noticeable disturbances in sleep and circadian rest-activity rhythms of depressive patients [42], which could be a possible reason for the correlation of poor sleep quality and depression. Stress and anxiety have also been reported to in uence normal sleep functions by manipulating neurobiological underpinnings of sleep. [43,44] Therefore, the association between poor sleep quality and anxiety among the population of drivers is consistent with previous results.
Another observation to emerge from the data is the signi cant association between ADHD and poor sleep quality among drivers, matching previous ndings in the literature. [45][46][47][48][49][50][51][52][53] As proposed by Scarpelli et al., ADHD has an association with macrostructural and microstructural sleep features, which affects the quality of sleep. [45] The interlinked association of poor sleep quality, ADHD, and mind wandering has been investigated in recent studies, which could justify our ndings. [48] Not only the overall score of PSQI is in association with ADHD but also some of its sub-scales have shown a signi cant relationship with ADHD; for instance, the correlation between sleep disturbance and daytime sleepiness and ADHD has been highlighted by other ndings too. [54][55][56] Consequently, drivers with ADHD should be certi ed more carefully to prevent further potential dangers due to poor sleep quality while driving.

Conclusion
Considering proceeding ndings on the signi cant association of anxiety, depression, stress, and ADHD with poor sleep quality and the dramatic effect of quality of sleep on risks of accidents among professional drivers, providing screening programs for anxiety, depression, and ADHD while certifying drivers and on the renewal of their certi cations could be a possible preventive measure which leads to recognition of vulnerable drivers in terms of psychological condition and improving their quality of sleep by setting appropriate rules for balancing working hours and further supportive actions.

Declarations
Ethics approval and consent to participate This study was approved by the ethics committee of Shiraz University of Medical Sciences.

Consent to publish
Not applicable Availability of data and materials The datasets used and/or analyzed during the current study available from the corresponding author on reasonable request.

Competing interests
The authors declare that they have no competing interests