Chapter 2 Literature Review Literature Review
2.3. Current Global State of Mental Illness
2.3.1. Epidemiology
Epidemiology comprises the study of the distribution of disorders in a defined population, together with an examination of the factors that influence that distribution (Rutter & Sandberg, 1985). The ultimate goal of epidemiology is to provide the scientific underpinnings for the prevention and control of disease across the spectrum of healthcare, from infectious diseases like acquired immunodeficiency syndrome (AIDS) to chronic conditions like diabetes (Costello, Egger & Angold, 2005). In the field of mental health, psychiatric epidemiology can be viewed as a subspecialty of epidemiology that involves investigation of the kinds of health and behavioural problems described in the DSM (Singh & Mkhize, 2006), including the ICD. Klessler (2000), Robins and Regier (1991), as well as Elwood, Little and Elwood (1992) point out that psychiatric epidemiology traditionally lags behind other branches of epidemiology because of difficulties encountered in conceptualising and measuring mental disorders. To substantiate this, they argue that much contemporary psychiatric epidemiology continues to be descriptive, focusing on the estimation of disorder prevalences and subtypes, when other branches of epidemiology instead are making progress in documenting risk factors and developing preventative interventions.
Added to problems of psychiatric epidemiological studies, Wittchen, Essau, von Zerssen, Krieg and Zaudig (1992) mention five unresolved issues which make it difficult to offer clear and definitive statements about the prevalence of mental disorders across different countries and settings. The reasons for these difficulties include the use of: (i) different diagnostic procedures; (ii) different sampling procedures; (iii) different criteria in defining caseness; (iv) different time frames for the diagnosis (e.g. lifetime, 6-month, current diagnosis); and (v) differences in the use of severity ratings for diagnostic decisions. These authors add that another critical issue is related to the use of different diagnostic classification systems. They provide the example of European and American epidemiological studies, which are exclusively based on the ICD) and the DSM, respectively. Nevertheless, the situation is changing,descriptive psychiatric epidemiology has undergone an unprecedented period of growth over the past twenty years (Kessler, 2000), and
psychiatric epidemiology is no longer only about count (Insel & Fenton, 2005).
Descriptive issues are being resolved, more analytical questions are being addressed, and preventative interventions are being implemented (Kessler, 2000).
Several instruments have been designed that are now being used with samples from the general populations.
Epidemiological studies serve a number of important uses. Lin and Standley (1962) succinctly summarise the purposes of epidemiological studies in the field of mental health as: (a) to assess the prevalence of different types of mental ill-health in a population as a basis for the prevention, treatment and control of these diseases; (b) to uncover associations between population characteristics and disease that may clarify the origins of mental disorder; (c) to test aetiological hypotheses from laboratory or clinical studies; and (d) to assess rates of spontaneous recovery in order to evaluate the effectiveness of preventative and therapeutic measures. Epidemiological studies also provide baseline data for other investigations, assist administrators in allocating resources, and generate hypotheses for further research (Links, 1983).
Prior to the appearance of the more detailed and explicit set of criteria for mental disorders, the Diagnostic and Statistical Manual of Mental Disorders, third edition (DSM-III), there were what Dohrenwend and Dohrenwend (1982) describe as two generations of epidemiologic studies aimed at investigating the true prevalence of mental disorders in communities all over the world. These studies encountered a host of methodological problems centred around the issue of how to conceptualise and measure mental disorders in communities. These initial studies used measures of overall mental impairment rather than specific diagnoses, and reported impairment rates were independent of diagnosis and could not be translated into equivalent clinical diagnostic categories (Weissman, 1987).
Nevertheless, Dohrenwend and Dohrenwend (1982) provide the following summary of consistent findings that emerged from these first and second generations of epidemiologic studies: (a) serious psychopathology is not rare in community populations; (b) only small minorities of the ‘cases’ have ever been in treatment with members of the mental health professions; and (c) psychopathology in general and its major subtypes are not randomly distributed within communities. Most likely these findings would also apply to the South African context.
Fortunately, there have been a number of new and promising developments in mental health epidemiologic studies. This is due to the
achievements in clinical psychiatry in developing measures to obtain more precise and reliable diagnoses, and the development of methods to collect information on signs and symptoms to make a diagnosis (Weissman, 1987). Notable examples are the Psychiatric Epidemiology Research Interview and the Diagnostic Interview Schedule (Dohrenwend & Dohrenwend, 1982). The latter became the first fully structured research diagnostic interview that could be used by lay interviewers to generate diagnoses according to the definitions and criteria of the DSM-III (Andrade et al., 2003). Instruments such as these have made it possible to assemble estimates of the national prevalence of mental disorders in a number of countries, using consistent diagnostic criteria (Henderson, 2000).
Large epidemiological studies of adult mental disorders in the general population have been carried out in numerous countries throughout the world (Kessler, 2000). These studies indicate that the prevalence of mental illness is on the rise both locally (Bhagwanjee et al., 1998) and internationally (Demyttenaere et al.
2004). This, however, must be interpreted with caution because increasing prevalence rates may also be due to the improvement in detection rates. The WHO estimates that 450 million people worldwide suffer from a mental or behavioural disorder (WHO, 2004). This number is so high that almost the whole population in a country will at some time have direct experience of such a disorder, either in themselves or in someone close to them (Jorm et al., 1997). Due to the limited scope of the current study, only epidemiological studies conducted in the United States of America, Australia and South Africa will be reviewed here.
American studies are reviewed because of their role in the history of psychiatric epidemiology, especially the development of epidemiological instruments used worldwide. Australian studies are included because of their leading role in studies of mental health literacy in general.
2.3.1.1. United States of America.
Prior to the early 1980s, estimates of the number of people in the United States who had mental disorders were based on studies in single geographic regions (Norquist & Regier, 1996). However, mental health epidemiological studies have gone through a period of unprecedented growth since then (Kessler, 2000).
The benchmark epidemiological study of psychiatric disorders is the National Institute for Mental Health’s (NIMH) Epidemiological Catchment Area (ECA) study,
conducted in the United State of America in the early 1980s (Kaliski, 2001) in response to the 1978 President’s Commission on Mental Health to identify research and service gaps (Leeman, 1998; Norquist & Regier, 1996). A total of 18 571 households and 2 290 institutional residents (persons from mental hospitals, nursing homes, and prisons) 18 years and older were randomly selected to participate in this study to provide both regional and standardised estimates of the prevalence and incidence of mental and addictive disorders (Bourdon, Rae, Locke, Narrow &
Regier, 1992; Norquist & Regier, 1996).
The results of the ECA study revealed that approximately 28% of adults in the non-institutionalised community had experienced an active mental or addictive disorder during the past year (Regier et al., 1993). Bourdon et al. (1992) reported that the results of the study indicated that in any 6-month period, 19.5%
of the adult population of the United States of America, or 1 in every 5 people ages 18 and older, suffers from a diagnosable mental disorder. The disorders with the highest lifetime prevalence involve substance use (16.7%), followed by anxiety disorders (14.6%) and depressive disorders (8.3%). For current month (1-month) rates, however, according to Regier et al. (1988), the disorders with the highest prevalence rates were anxiety (7.3%), affective disorders (5.1%) and substance use (3.8%). Schizophrenic disorder, somatisation disorder and antisocial personality disorder occurred in smaller numbers of people (Norquist & Regier, 1996). In general, findings of the ECA survey showed the following: 1) that the rates of depression are twice as high for females as for males; 2) that males are more likely than females to have alcohol dependence; and 3) that substance abuse is more common in persons under the age of 30 than in older persons (Sadock & Sadock, 2003).
A decade after the ECA study, another important set of epidemiological data was derived in the United States of America from the National Comorbidity Survey (NCS) that was conducted between 1990 and 1992 in 48 states. This survey was more extensive; it sampled the entire American population using sophisticated methodological improvements (Butcher et al., 2011). A national probability sample of 8098 respondents participated in this survey (Leeman, 1998). According to Norquist and Regier (1996), the results of the NCS study showed that 29% of adults in the non-institutionalised community had experienced an active mental or addictive disorder during the past year, and 19% reported a disorder at some time
in their life but not within the past year. In addition, 48% of participants reported having had symptoms of a mental or addictive disorder at some time in their lives.
The disorders most frequently reported in the NCS study were affective disorders, substance use disorders and anxiety disorders. The prevalence estimate for lifetime major depression was 17.1%, with a relatively higher prevalence in females, young adults, and persons with less than a college education (Blazer, Kessler, McGonagle & Swartz, 1994). The 12-month prevalence estimates for the same disorder was 10.3%. A detailed summary of these results is included in Figure 2.2 below. According to a report by Kessler et al. (1994), more than half of all lifetime disorders occurred in the 14% of the population who had a history of three or more comorbid disorders. Less than 40% of those with a lifetime disorder had ever received professional treatment, and less than 20% of those with a recent disorder had been in treatment during the past 12 months.
Figure 2.2: The lifetime and 12-month prevalence estimates of the NCS study
Source: Kessler et al. (1994, p.12).
Another epidemiologic study of mental illness in the United States of America is the National Comorbidity Survey Replication (NCS-R). This was a nationally representative face-to-face household survey conducted between
2001 and 2003 using the fully structured World Health Organization World Mental Survey Initiative version of the Composite International Diagnostic Interview (CIDI) (Kessler, Chiu, Demler & Walters, 2005). The results of the NCS-R, as reported by Kessler et al. (2005), show lifetime prevalence estimates as follows: anxiety disorders (28.8%), mood disorders (20.8%), impulse control disorders (24.8%), substance use disorders (14.6%), and any disorder (46.4%). Median age of onset for anxiety and impulse control disorders was 11 years, and 20 and 30 years for substance use and mood disorders respectively. In general, the lifetime prevalence estimates are higher in this study than in earlier studies.
2.3.1.2. Australia.
In an attempt to avoid relying on imported estimates from other countries, in 1992 Australia decided that it should establish its own estimates of the distribution of mental disorders. However, the actual study was only conducted later in 1997.
Henderson, Andrews and Hall (1999) report that a household sample of 10 600 persons aged 18 years and over completed the Composite International Diagnostic Interview in its automated presentation (CIDI-A). According to these authors, the CIDI-A was developed in Sydney and it systematically explored the diagnostic criteria required for the most common mental disorders defined by the ICD-10 and the DSM-IV. The results of this study revealed that in any twelve months, 17% of adult Australians had a mental disorder and by far the most common were anxiety or affective disorders and substance misuse (Andrews, Hall, Teesson &
Anderson, 1999). Men (11.1%) were much more likely to have a substance-use disorder than women (4.5%), and women (12.1%) were much more likely than men (7.1%) to have an anxiety or affective disorder, with a prevalence rate of 7.4% and 4.2% for women and men respectively (Henderson et al., 2009). Furthermore, 1 in 4 of all the participants suffered from more than one mental disorder. The prevalence of mental disorder decreased with age. Young adults aged 18-24 years had the highest prevalence of mental disorder (27%), declining steadily to 6.1% of those aged 65 years and older (McLennan, 1997).
Another important Australian study, the 2007 National Survey of Mental Health and Wellbeing, was designed to update the evidence on mental health in Australia, with a particular focus on service use information (Slade, Johnston, Teesson et al., 2009). In that study, a nationally representative household survey of 8841 individuals between the ages 16 and 85 years was carried out using the World
Mental Health Survey Initiative version of the Composite International Diagnostic Interview (Slade, Johnston, Browne, Andrews & Whiteford, 2009). The results of that survey, according to Slade, Johnston, Teesson et al. (2009), reported that one in five (20.0%) Australians continued to experience mental illness. Slade, Johnston, Browne et al. (2009) added that the prevalence of any 12-month mental disorder was 20.0%, with anxiety disorder (14.4%) being the most common class of mental disorder followed by affective disorders (6.2%) and substance use disorders (5.1%).
One in four people (25.4%) with 12 month mental disorders had more than one class of mental disorder (Teesson, Slade & Mills, 2009).
Regarding help-seeking, Burgess et al. (2009) reported that the 2007 survey showed that 11.9% of the general Australian adult population made use of any service available for mental health problems in a 12-month period, and approximately one-third of people (34.9%) meeting criteria for a mental disorder did so. They also reported that those with affective disorders were most likely to make use of services (58.6%), followed by those with anxiety (37.8%). More females (40.7%) than males (27.5%) were likely to use services for mental health problems (Slade, Johnston, Teesson et al., 2009). Mental health hospitalisations were less common than consultations with community-based providers (2.6%), whereas 34.6% of participants had consulted a community-based provider, particularly general practitioners (24.7%), and 13.2% had consulted psychologists (Burgess et al., 2009). However, interestingly, Slade, Johnston, Teesson et al. (2009) note that not all people who accessed services were assessed as having a mental disorder.
They state that many people had sought care for mental health problems, but were not sufficiently unwell to be diagnosed with a mental disorder.
2.3.1.3. South Africa.
Psychiatric epidemiology as a sub-discipline of psychiatry and epidemiology is relatively under-developed in South Africa and other low and middle income countries (Flisher, 2007). Ehrlich, Katzenellenbogen, Tollman and Gear (2007) substantiate this idea by arguing that until the 1950s to the mid-1970s, epidemiology did not feature prominently in South African health research. They state that information about the distribution, causation and control of many disorders was inadequate, with little useful baseline information available to assess the effectiveness of any intervention in South Africa. Parry (1996) adds that there are no studies focusing on a similar range of psychiatric disorders and also none
equivalent to the ECA study in scientific rigour and national representativeness that have been conducted in Africa. Nevertheless, available epidemiological and other studies that have been conducted in Africa suggest that while there are local variations in the nature and prevalence of psychiatric disorders across the continent, the burden of mental health problems and psychiatric disorders is similar to or greater than that reported in the ECA study in the United State of America (Kaliski, 2001).
According to Stein et al. (2008), no nationally representative household surveys were conducted prior to 2002 on the prevalence of mental disorders in South Africa. The first seems to be the South African Stress and Health Study (SASH) conducted as part of the WHO World Mental Health (WMH) Survey Initiative between January 2002 and June 2004 (Williams et al., 2008). A nationally representative household sample of 4351 adults of all racial groups aged 18 years and older participated in the SASH (Tomlinson, Grimsrud, Stein, Williams & Myer, 2009). Prevalence and severity of the DSM-IV disorders, treatment and sociodemographic correlates were assessed with Version 3.0 of the WHO Composite International Diagnostic Interview (CIDI 3.0) (Williams et al, 2008). The interviews were conducted face-to-face by extensively trained fieldworkers in seven different languages: English, Afrikaans, Zulu, Xhosa, Northern Sotho, Southern Sotho and Tswana (Seedat et al., 2008).
The SASH revealed prevalence lifetime estimates of 15.8% for anxiety disorders, as well as 9.8% and 13.4% for mood disorders and substance use disorders respectively and 30.3% for any disorder (Stein et al., 2008). For 12-month prevalence of any DSM-IV disorder, the most common disorders were agoraphobia (4.8%), major depressive disorder (4.9%) and alcohol abuse or dependence at 4.5% (Williams et al., 2008). Stein et al. (2008) reported that the median age at onset was earlier for substance use disorders (21 years) than for anxiety (32 years) or mood disorder (37 years). Regarding treatment, one-fourth (25.5%) of respondents with a disorder prevalent in the previous 12 month period had received treatment either from a psychiatrist (3.8%), non-psychiatrist mental health specialist (2.9%), general medical practitioner (16.6%), human services provider (6.6%), or complementary-alternative medical provider (5.9%) (Seedat et al., 2008). It is worth noting that treatment was mostly provided by general medical practitioners with few people receiving treatment from mental health providers.
Blacks were significantly more likely than other racial groups to access the
complementary-alternative medical sector while Whites were more likely to have seen a psychiatrist (Seedat et al., 2008).
A number of other important small scale studies of the prevalence of mental disorders have also been conducted locally. For example, an epidemiological study conducted by Havenaar, Geerlings, Vivian, Collinson and Robertson (2008) in historically disadvantaged urban and rural communities in South Africa revealed a high prevalence of mental health and substance abuse problems. More than one-third (34.9%) of their community sample reported high levels of anxiety or depression symptoms. Other local researchers estimated that about 17% of the total population experienced a psychological disorder in 2007 (Lund et al., 2008).
An important conclusion to note is that the high prevalence of psychiatric conditions in Africa is equivalent with that of international communities (Hugo et al., 2003; Kaliski, 2001; Williams et al., 2008).
High prevalence rates for mental illness reported in reviewed epidemiological studies should signify a need for the adequate distribution of knowledge and services pertaining to mental health. However, it is disconcerting that despite evidence of high prevalence of mental illness, the public still lacks mental health literacy and mental health services remain low on the priorities of most governments in low and middle income countries, South Africa included (Gureje & Alem, 2000; Mkhize & Kometsi, 2008). Moreover, while mental health literacy has been studied widely and comprehensively elsewhere (Bartlett, Travers, Cartwright & Smith, 2006; Jorm, 2000; Jorm, Barney, Christensen et al., 2006), it is a subject that has not received sufficient attention locally.