Study design and period
A community-based cross-sectional study was used to determine the prevalence of common mental disorders and their associated factors among residents of south the Gondar zone from May 3 to June 3, 2018.
Debre Tabor town is the capital city of the south Gondar zone which is 666 km far from Addis Ababa (the capital city of Ethiopia) and 99 km far from Bahir Dar (the capital city of Amhara region). The zone is divided into 15 districts. According to the 2007 population census report; the total population size of South Gondar is estimated at 2,051,738. From those, 1,041,061 are men and 1,010,677 women. From the total population, 9.53% of the population is urban residents. This zone had seven primary and one referral hospital providing health services during the data collection period.
All adults whose age is 18 years and above in south Gondar zone, Northwest, Ethiopia.
Adults who were living in south Gondar zone selected districts/woredas during the study period.
Sampling procedure and sample size determination
We used a multistage sampling technique to select 731 participants. From 15 districts/woredas we randomly select 3 districts by simple random sampling. After selecting the districts, we selected three sub-districts/kebeles in each of the selected districts. To reach households of each sub-districts, simple random sampling was employed. In each of the areas, household lists were obtained from sub-district offices and health extension workers. We proportionally allocated the sample size to each district and further to the sub-district. The selected household members were further sorted for interviews. In the case of more than one adult study participant in a household, we selected one of them by lottery method (Fig. 1).
We determined the sample size by using the single population proportion formula by taking the prevalence of common mental disorders 32.4%  with a 5% margin of error, and 95% confidence interval. We added a 10% nonresponse rate and considering the design effect of 2, the final sample size was 742.
Inclusion and exclusion criteria
All individuals whose age was 18 years and above were included in the study during the data collection period. Individuals who were seriously ill and unable to communicate were excluded from participating in the study.
Common mental disorders (Yes = 1, No = 0).
Socio-demographic characteristics: age, educational status, sex, ethnicity, marital status, employment status, and residence.
Clinical factors: family history of mental illness, and comorbid medical/surgical illness.
Psychosocial factors: social support and stressful life events.
Behavioral factors: ever and current use of substances (khat, alcohol, and cigarette).
Common mental disorders: assessed using self-reporting questionnaire (SRQ-20), a score of 6 or more considered having CMD .
Social support: measured using Oslo social support scale (OSS-3), a score of 3–8, 9–11, and 12–14 categorized as poor, moderate, and strong social support respectively .
Individual stress levels: were measured using a 12 item List of Threatening Experiences (LTE), if a study participant experienced one or more stressful life events for the last six months .
Current and ever use of substance: assessed using adopted alcohol, smoking, and substance involvement screening test (ASSIST). If a study subject using at least one of the specified substances in the last 3 months and lifetime considered as current and ever of use substance respectively .
Comorbid physical illness: to assess comorbid physical illness, study subjects were asked “Did you have any comorbid physical or surgical illness?” with a response of “Yes” considered having comorbid medical/surgical illness.
Family history of mental illness: was measured by asking “Did you have a family history of mental illness?” with a response of “Yes” considered having a family history of mental illness.
Data collection procedures and instruments
Data were collected by face-to-face interviews using a semi-structured questionnaire that contained socio-demographic, social support, clinical factors, and substance-related factors.
Common mental disorders were assessed using a self-reporting questionnaire (SRQ-20). A 20-item mental disorder screening instrument was developed by WHO to screen CMD. The tool measures depression, anxiety, and psychosomatic symptoms, known as CMD. Each item of SRQ has rated on a two-point scale (yes/no), “0” indicates the absence of the symptom and “1” indicates the presence of the symptom. A score of 6 or more in the self-reporting questionnaire was considered as having common mental disorders in the last one month. The tool was validated in low-and-middle-income countries with a sensitivity 78.6% and a specificity 81.5% [18, 22].
Social support was measured by using three items of the Oslo social support scale (OSS-3). The sum score of Oslo social support ranges from 3 to 14 with higher score indicating strong support and lower score indicating lower support. The instrument categorized as scoring of 12–14 considered “strong support”, the score of 9–11 “moderate social support” and score of 3–8 “poor social support” .
Individual stress levels were measured by using a 12 item List of Threatening Experiences (LTE). The tool measures the individual level of stress for the last six months. Each item of LTE has rated on a two-point scale (yes/no), “1” indicates the presence and “0” indicates absence of stressful life events over the last six months . To assess the current and ever use of substance-using adopted alcohol, smoking, and substance involvement screening test (ASSIST). If a study participant using at least one of the specified substances in the last 3 months and lifetime considered as current and ever of use substance respectively .
Data quality control issues
We recruited degree holder psychiatry professionals for data collection and supervised by Master holder psychiatry professionals. The training was given on the data collection instrument and sampling procedure. Additionally, the questionnaire was designed in English and translated to Amharic language (local language). The supervision was held regularly during the data collection period.
Data processing and analysis
Data were entered into Epi-data 3.1 after checking completeness and consistency and then exported to SPSS—version 20 for analysis. Factors associated with CMDs were selected during bivariate analysis with a value of p ≤ 0.2. In multivariable regression analysis variables with P-value, less than 0.05 at 95% confidence interval with its adjusted odds ratio were considered as statistically significant.
Ethical approval was obtained from the ethical review committee of Debre Tabor University. Ethical clearance was also obtained from the ethical review committees of the University (Ref. No. DTU/RE/1/P5/2017). Permission was obtained from the respective district administration.
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