Evaluation of the circadian rhythm disturbance impacts on the human reward system, impulsivity and cognitive performance

The general aim of this study was to determine the effect of circadian rhythm disturbance on human reward system, impulsivity and cognitive function and the specific objectives are as follows Determination of circadian rhythm disorders in the subjects Determining the incidence of impulsivity in the subjects Determining the reward system in the subjects Determining cognitive function in the subjects Determining the reward circuit in the subjects Determining readiness for substance use and addictive behaviors

Double-blind randomized controlled trial, the sample size in this study was selected with 80% power, significance level 0.05 and impact size 0.9 (17 people in each group) in the total sample size of 34,participants as Random blocks will be divided into intervention and control groups.

This study will be performed on the research site of Shahroud University of Medical Sciences for eleven days and during the experimental period, variables such as ambient light intensity, eating time and sleeping time will change in the experimental group but will not change in the control group.In this study, participants and analysts will not be aware of the study results of groups

inclusion: Male right handed Age category between 18 and 25 years Regular rhythm of sleep and wakefulness in the past month Exclusion: Having a general medical disorder that endangers a person's health during the experiment

The duration of this study is eleven days and variables such as ambient light intensity, eating and sleeping time as previously described will change for the participants of the experimental group and for the participants of the group. Control will remain unchanged.

Cognitive functions, reward system, mood rhytmicity, substance use readiness, impulsivity

To equal the sample size in the two groups, the block method with a volume of 4 is used. For this purpose, 6 to four blocks will be created as follows 1- AABB 2- ABAB 3- ABBA 4- BBAA 5- BABA 6- BAAB Where A is for the intervention group and B is for the control group The random assignment will be done in such a way that a random number will be created in Excel from 0 to 9 first. Depending on which block the random number belongs to, the sequence of that block is used to assign the subjects to the control and intervention group.For example, if the random number generated is 6, the first person will be assigned to group B, the second person to group A, the third person to group A, and the fourth person to group B. To reach the calculated sample size, the random number creation will be repeated 9 times Because each time the task is assigned, four diseases are identified. It should be noted that if the random number generated is 7, 8, 9 and 0, it will be ignored. Envelopes in which the specified group is placed are used to conceal the allocation. Envelopes are numbered. After filling in the basic information of the people, an envelope is opened according to the word order of the people and the person is assigned to the desired group. To do this, 34 envelopes will be ready and individuals will be assigned to two groups. The methodology consultant determines the allocation sequence. The registration of participants and their entry according to the entry and exit criteria and obtaining informed consent is the responsibility of a trained psychologist. Then, if they are eligible, it assigns them to groups based on closed envelopes.

n this study, participants and analysts will not be aware of the results of the study. Also, in all outcome assessments conducted by questionnaires or interviews by a psychologist colleague, the research colleagues are unaware of how the participants are placed in the groups.

All personal data of the participants will share without name and personal information (unidentified)

the access period start 6 months after results publication

researcher who are working in academic and scientific institutions

the use of all data or documents for researcher for using in their research with reference to the source is allowed

To researcher of this study,Mohammad Niroumand Sarvandani refer to email address: m.niroumand@shmu.ac.ir

by sending an email to m.niroumand@shmu.ac.ir. all the demanded files will be provided to the applicant within 10 working days