Introduction

There has been an increased interest in the perceived causation of mental illness by the public in recent times. Studies from the western culture showed that biological factors (diseases of the brain and hereditary influences) and environmental factors (trauma and stress) were more frequently considered to be of causal relevance [4, 10, 22] while in Africa, beliefs in supernatural causation is widely held [3, 11, 20].

However, in Nigeria, the available literature is not conclusive on the beliefs of the community about the causes of mental illness. While mystical causes were most frequently reported in central Nigeria [3], misuse of drugs was the most widely held belief regarding causation of mental illness in northern Nigeria [15]. A recent study among the Yoruba communities in south-western Nigeria [11] found that the most commonly reported causes of mental illness were drug and alcohol misuse (80.8%), possession by evil spirits (30.2%), traumatic event or shock (29.9%), stress (29.2%), and genetic inheritance (26.5%). In this large study, only about one in ten respondents believed that biological factors or brain disease could be the cause of mental illness.

Most studies have concluded that views about causation are strongly associated with stigmatizing attitudes to mental illness [1214]. So it is a widely shared opinion that an increase in literacy and education regarding the cause of mental illness will result in an improvement in attitude toward people with mental illness [22]. Analyses of the recent trends in researches however have faulted the assumption that there is a positive relationship between endorsing biological causes and acceptance of people with mental illness [4, 8].

Available studies in sub-Saharan Africa have suggested a preference for traditional and spiritual healers for the treatment of mental illness [3, 15]. It is known that the bulk (approximately 70%) of mental health services provision in Nigeria is delivered through non-orthodox means such as religious organizations and traditional healers [7]. Traditional healers could recognize symptoms of mental illness, and they also expressed strong beliefs in supernatural factors as a cause of mental illness [2]. Since patients suffering from mental illness and their carers are likely to share the beliefs regarding the causes of mental illness held by the society where they live, knowledge of the preference of the lay public regarding causes of mental illness will be helpful in evaluating the patient’s help seeking behavior.

None of the available studies have examined the correlates of such causal views and identify the population at risk, who will actually benefit from targeted education regarding the causes of mental illness.

The present study aimed at evaluating the lay beliefs regarding the causes of mental illness in south-western Nigeria and examining the factors correlating with such beliefs. The hypotheses of the present study include the following: (1) that the Yoruba communities in Nigeria will have pre-scientific beliefs regarding the causes of mental illness (2) beliefs in supernatural causation will be more common among the rural dwellers and uneducated persons in the community.

Method

Participants and sampling technique

The participants were from three selected communities in Nigeria (an urban, a semi-urban and a rural community). The communities were selected in conformation with the classification according to the 1991 population census in Nigeria [13]. A multistage probability sampling technique was then used to select participants.

The first stage consisted of random selection of seven enumeration areas from each of the three communities. The enumeration areas are geographical units demarcated by the National Population Commission [18] with each area consisting of about 100–120 household units. The second stage involved enumeration of the houses in each area. When more than one household was found in a house, one household was selected by balloting. The third stage involved the selection of one adult (above 18 years) from each household for the interview. From this a total of 2,342 participants were targeted for the interview and these include 854 from urban settlement, 782 from semi-urban settlement, and 715 from rural settlement.

Instruments

Pro-forma

The participants were administered a semi-structured questionnaire inquiring about sociodemographic data such as age, sex, marital status, religion, ethnicity, highest education obtained, and occupation. The questionnaire also inquired whether the participants have ever had a personal encounter with the mentally ill or ever cared for the mentally ill and whether he/she has a family member/friend who has or has had mental illness.

Causal attribution

Respondents’ attributions of the possible causal factors of mental illness were assessed by responses to a nine-item questionnaire detailing possible causes of mental illness. The causes included psychosocial factors (substance and alcohol misuse, life stresses, personal deficit, or failure/lack of willpower), supernatural factors (witchcraft/sorcery/evil spirits, God’s will/divine punishment, and destiny/bad luck), and biological factors (heredity, brain injury, and contact with mentally ill/childbirth). The nine items were drawn from a list of 23 possible causes of mental illness earlier suggested by the patients, the relatives, community opinion leaders, traditional healers, spiritual healers, and the lay public. A panel of six consisting of a psychiatrist and a representative each from the list above harmonized the suggested causal factors into the nine items grouped into three. Although the questionnaire seemed to have face validity, the psychometric properties were not formally examined before use. Using a four-point likert scale (“not a cause”, “rarely a cause”, “likely a cause”, and “definitely a cause”), the respondents were asked to indicate how relevant they considered each potential cause to be. Responses of “likely a cause” and “definitely a cause” are counted as endorsing a cause. The questionnaire was translated into the local Yoruba language by back-translation method involving two independent panels consisting of a psychiatrist and a Yoruba linguist each. Precise idiomatic equivalents were employed as much as possible. In the translation, care was taken to convey a broad meaning of mental illness to differentiate it from psychosis.

Procedure

Written informed consents were obtained from the participants after the aims and objectives of the study had been explained. The Ethics and Research Committee of the Obafemi Awolowo University Teaching Hospitals Complex approved the study protocol. Research assistants who are medical students in psychiatry postings administered the questionnaire to the participants.

Data analysis

The data were analyzed using the Statistical Package for Social Sciences (SPSS) version 11. For ease of analysis, most of the variables were grouped. Results were calculated as frequencies (%), means, median, and mode. Group’s comparisons were by the chi-square test. Significance was calculated at P < 0.05. Logistic regression was used to calculate the variables independently associated with the perceived causal factors. Odds ratio (OR) and 95% confidence interval (95% CI) were calculated where appropriate.

Results

Sociodemographic details

Out of 2,342 scheduled for interview, only 2,078 were successfully administered the questionnaire. The reasons for failure to administer the questionnaire to the rest 264 (11.2%) of the participants scheduled for interview included not meeting the participants at home after repeated visits and refusal to give informed consents. There were no statistically significant differences in the age, sex, and educational attainment of the respondents and those who could not be interviewed.

The 2,078 included 658 (31.7%) from the rural community (response rate 92.0%), 712 (34.3%) from the semi-urban community (response rate 91.1%), and 708 (34.0%) from the urban community (response rate 82.9%). Analysis (Table 1) showed 1,278 (61.5%) were 50 years old or less, 1,133 (54.5%) were males, and 1,289 (62.0%) were married. There were 1,130 (54.4%) Christians and majority (89.9%) were from the Yoruba ethnic group. Majority (74.3%) had a primary or secondary education. Only 228 (11.0%) of the participants had had an encounter with someone with mental illness while 102 (4.9%) had ever cared for a mentally ill and 612 (29.5%) had a family member or friend with mental illness.

Table 1 Sociodemographic characteristics of the participants and their familiarity with mental illness

Pattern of perceived causation of mental illness

Table 2 showed that the most frequently endorsed causation was misuse of substances and alcohol (72.3%) followed by witchcraft/sorcery/evil spirit (65.5%) and God’s will/divine punishment (50.1%) while personal deficit/failure was the least endorsed (10.2%). Since most of the participants endorsed multiple items cutting across the causal groups, to know the true weight of each of the causal group, the average number of endorsed item in each group was calculated with the result indicating supernatural causes having the highest score with an average of 1.80 (median = 1 and mode = 1) followed by psychosocial causes (mean = 1.52, median = 1, and mode = 1) and biological causes (mean = 1.14, median = 1, and mode = 1). Based on this, endorsement on each causal group was dichotomized as endorsement of more than one more item in a group or not. According to this categorization, 912 (43.9%) participants endorsed more than one item on “psychosocial causation” while more than one item on supernatural and biological causations were endorsed by 1,016 (48.9%) and 632 (30.4%) participants, respectively.

Table 2 Frequency of the perceived causation of mental illness

Correlates of perceived causation of mental illness

Chi-square analysis was used to calculate the univariate association between the sociodemographic variables and multiple endorsement of each of the causal groups and the result (Table 3) showed that endorsing more than one item on psychosocial causal factors was significantly associated with urbanicity, highest education, ever cared for the mentally ill and having a family/friend with mental illness. Endorsing more than one item on supernatural causal factors was significantly associated with age, ethnicity, urbanicity and having an encounter with the mentally ill while endorsing more than one item on biological causal factors was significantly associated with ethnicity, occupational status, highest education, caring for the mentally ill, and having a family/friend with mental illness.

Table 3 Association between perceived causation groups and sociodemographic variables

The significant variables were then entered into logistic regression analysis to determine the variables independently associated with multiple endorsements on each of the causal groups. The remaining variables for psychosocial causal factors were urbanicity (B = 0.621, Wald = 28.237, P < 0.001), care for mentally ill (B = 0.973, Wald = 17.489, P < 0.011), and educational level (B = 0.312, Wald = 9.987, P = 0.002). For supernatural causal factors, encounter with mentally ill (B = −2.237, Wald = 116.204, P < 0.001), age group (B = 0.972, Wald = 93.042, P < 0.001) and urbanicity (B = −0.965, Wald = 33.982, P < 0.001) and for biological causal factors, educational level (B = 3.822, Wald = 127.585, P < 0.001), and occupation (B = 2.700, Wald = 65.406, P < 0.001). Table 4 showed the odds ratio (95% confidence interval) for the variables independently associated with the causal factor groups.

Table 4 Odds ratio (OR) and 95% confidence interval for variables independently associated with perceived causal factor groups

Discussion

To our knowledge, our study was the first attempt to examine the patter and correlates of lay beliefs regarding causes of mental illness in sub-Saharan Africa. Previous studies have correlated beliefs with stigma, but have not evaluated the pattern and correlates of the beliefs in order to identify the target groups for intervention.

Pattern of beliefs regarding mental illness

We found a widespread belief regarding supernatural factors and the misuse of psychoactive substances and alcohol as the main cause of mental illness in this study and this is in agreement with previous researches in this area [3, 11, 15, 20]. Compared to the prevalent belief in biological factors in Germany [5] and constitutional and environmental factors in Canada [22], our findings suggest that there may be cross-cultural variations in the pathway between causal belief and help seeking. Since the views about causation are strongly associated with stigmatizing attitudes to mental illness, these beliefs might be major contributors to the increasing stigmatizing attitude in Africa [12]. A belief that mental illness is due to misuse of drugs or alcohol may translate to the notion that mental illnesses are self-inflicted and this may elicit condemnation rather than understanding or empathy [23]. Also, the belief in supernatural causation of mental illness might make close association with the mentally ill unattractive and perceived to be risky. This may also imply that “western” medical care would be futile and may inform preference for traditional and spiritual healers for treatment. Likewise, studies have also shown that the traditional healers themselves considered that actions of the enemies, usually employing meta-physical means, are a major cause of mental illness [17].

Correlates of perceived causation of mental illness

Our study showed that our participants believed in multiple factors as causes of mental illness. While previous studies on causal beliefs have controlled these beliefs for influences of socio-demographic variables, we have grouped causal beliefs into three groups and examined for socio-demographic correlates of these groups. This methodological difference was necessary because many of our respondents hold multiple and diverging beliefs regarding the causes of mental illness.

We found urbanicity, educational status, occupational status, age, and familiarity with mental illness as the important independent correlates of multiple perceived causation of mental illness. While urban dwellers were more likely to endorse multiple psychosocial factors than rural dwellers (50.0% vs. 38.4%), the rural dwellers were likely to endorse multiple supernatural factors (54.4% vs. 44.6%). This finding should not be surprising since compared to the more traditionally oriented rural dwellers, people living in urban cities were more likely to be more “western” in their approach to life.

Related to this was the finding of multiple endorsements of psychosocial and biological causal factors in those with higher education. But a critical analysis showed that educational level had no effect on the endorsement of supernatural causal factors. This suggests that although higher education may have made our participants endorse more psychosocial and biological causal factors, it had no effect on the belief in supernatural causes which was widely held irrespective of the educational level. This queries the assumption that western education changes the beliefs in supernatural causes of mental illness.

Our study found that older people (>50 years) were more likely to have multiple endorsements of supernatural factors as causes of mental illness (OR 2.59, 95% CI 2.15–3.12). Older people are more likely to hold traditional and pre-scientific views about the causes of mental illness which may not be easily amenable to changes. Not surprisingly, older age had been correlated with poor attitude toward mental illness in studies in western [9, 10, 22] and non-western cultures [15, 19].

From our study, while more familiarity with mental illness (having a family member or ever care for the mentally ill) was associated with multiple endorsements of biological and psychosocial causal factors, lack of a personal encounter with the mentally ill was associated with multiple endorsement of supernatural causation. Previously, it is known that having personal experience or contact with the mentally ill reduce stigmatizing attitude [1, 16, 21], now our study have suggested that it might also affect the perception of the causes of mental illness.

Limitations and strength

There were a number of limitations to this study. First, one should be careful about generalizing the results of this study to other ethnic group in Nigeria or sub-Saharan Africa. There are several cultural differences in Nigeria and sub-Saharan Africa and this may affect their beliefs regarding causation of mental illness. Information is required for each cultural group and a larger, multi-centered cross-ethnic study will be desirable in the future. Also, caution must be taken in inferring causality as this was a cross-sectional study and the related factors were just correlates. This study also focused on mental illness in general whereas it is known that the public have different views and attitudes toward different specific mental disorders [6]. The strength of the study was in its large sample size, in its being community based and coming from a culture not well studied.

Conclusion

The results of this survey suggest that the public in south-western Nigeria hold multiple views regarding the causes of mental illness. It also further confirms that supernatural factors and the misuse of psychoactive substances and alcohol were perceived as the main causes of mental illness in sub-Saharan Africa. While urban dwelling, higher educational status, and more familiarity with mental illness correlated with belief in biological and psychosocial causes of mental illness, older age, rural dwelling, and lack of familiarity with mental illness correlated with a belief in supernatural causation. Educational status did not have an effect on the belief in supernatural causation. The current anti-stigma programme by the World Psychiatric Association (WPA) needs to incorporate the factors associated with views about causation in the anti-stigma educational programme so as to identify the population at risk, who will actually benefit from targeted education regarding the causes of mental illness.