Inequalities in mental health

1. Key messages

The prevalence of anxiety and depressive disorders and of suicidal thoughts differs by socio-economic group, with a higher prevalence among people in the lowest than in the highest socio-economic level. 
 
In 2018, socio-economic inequalities in mental health conditions were larger than for the physical health conditions with relative differences around 2. 
 
When looking at the evolution, absolute inequalities in anxiety and depressive disorders have strongly increased between 2008 and 2013, and stayed stable at a higher level between 2013 and 2018, which is a disappointing evolution. Between 2013 and 2018, the relative inequalities in depressive disorders have also worsened. 

2. Background

Socio-economic (SE) health inequalities refer to systematic disparities in health between SE groups, most often in disfavour of those on the lower position of the social and/or economic scale. SE health inequalities have been consistently observed in industrialized societies for the whole scope of health-related indicators, ranging from health determinants to mortality [1;2]. Tackling health inequalities is a priority for the WHO [3], the European Union [4], and for Belgium [5-7]. In order to assess progress towards reducing health inequalities, it is important to measure and monitor them [8,9].
 
Inequalities in mental health (MH) have been computed from the data of the Belgian Health Interview Surveys 1997-2018. Methodological details are given in this annexe. The inequalities are described for three indicators: the prevalence of depressive disorders (based on the PHQ-9 scale) and anxiety disorders (based on the GAD-7 scale) in the last two weeks were selected in reason of their high frequency; the prevalence of suicidal thoughts in the last twelve months was also chosen because it indicates severe mental distress, and the suicide rate is quite high in Belgium. The educational level (EL) (in three levels) was chosen as a marker of the socio-economic position to examine inequalities.

Beside the prevalence of mental health conditions by socio-economic level, we also calculated the magnitude of the inequalities by computing inequality indices, we considered :

  • the absolute and relative differences in age-adjusted prevalence rates between the lowest and the highest ELs,
  • the Population Attributable Fraction (PAF), i.e. the percentage of gain in health expected in the whole population if all groups experienced the health of the most educated group.

3. Results

Situation in 2018

In 2018, absolute inequalities in mental health conditions were larger than for physical conditions, ranging from 9.8 percentage points (ppt) for depressive disorders to 3.5 ppt for suicidal thoughts.

Relative inequalities in mental health conditions were particularly high. The lowest EL group included 2.5 times more people with depressive disorders, 2.0 times more people having suicidal thoughts, and 1.8 times more people experiencing anxiety disorders than the highest EL group. If all groups had the same proportion of people with mental health conditions as the highest EL group, then the prevalence of depressive disorders in the whole population would be reduced by 30%, anxiety disorders by 24%, and suicidal thoughts by 20%.

Socio-economic inequalities in mental health conditions, people aged 15 years and over, Health Interview Survey, Belgium, 2018
Source: Own calculation based on Health Interview Survey [10]
* statistically different from 0% for absolute difference and PAF, and statistically different from 1 for the relative difference (p<0.05)

  Age-adjusted prevalence rate low EL Age-adjusted prevalence rate high EL Absolute difference Relative difference PAF
Depressive disorders in the last two weeks (% people ≥ 15) 16.2% 6.4% 9.8%* 2.5* 30.2%*
Anxiety disorders in the last two weeks (% people ≥ 15) 15.3% 8.4% 6.9%* 1.8* 23.8%*
Suicidal thoughts in the last twelve months (% people ≥ 18) 6.9% 3.4% 3.5%* 2.0* 19.9%*

Trends

Trends in anxiety disorders:
  • The age-adjusted prevalence has increased in all ELs from 2008 to 2018.
  • The absolute inequalities have increased between 2008 and 2013 then stayed stable.
  • The relative inequalities have slightly and non-significantly decreased from 2004 to 2018. 
In conclusion, there is no worsening in the inequalities related to anxiety disorders in the last 5 years. The evolution is however not satisfactory, as a decrease in absolute inequalities would be the minimal progress expected.
 
Trends in depressive disorders:
  • The age-adjusted prevalence has increased in all ELs from 2004 to 2013 and then decreased in 2018.
  • The absolute inequalities have increased between 2008 and 2013 then stayed stable.
  • The relative inequalities have decreased from 2004 to 2013 then increased in 2018. This can be attributed to a smaller proportional decrease of the prevalence of depressive disorders in the low than in the high EL.
In conclusion, while the prevalence of depressive disorders improved in all ELs during the last 5 years, the evolution of inequalities is disappointing: the absolute inequalities did not decline (what would be the minimal improvement aimed, and would correspond to a larger decrease in depressive disorders in the less than in the more advantaged people), and the relative inequalities even increased.
 
The age-adjusted prevalence of suicidal thoughts has increased in all ELs from 2008 to 2018. Inequality in suicidal thoughts does not show notable trends.
 
When looking at inequalities at population level, the Population Attributable Fraction (PAF) tends to decrease since 2004 for all indicators, which is partly due to a change in the population composition, with the low educated groups containing a decreasing share of the population over time. In the last 5 years period however, it remained stable for depressive disorders, as the change in the population composition was compensated by an increase of the relative inequalities.

 

  • Anxiety disorders
  • Depressive disorders
  • Suicidal thoughts

Prevalence of anxiety disorders in the last 2 weeks (based on the GAD-7 scale) among people aged 15 and over by educational level, 1997-2018, Belgium
Source: Own calculation based on Health Interview Survey, Sciensano [10]

Prevalence of depressive disorders in the last 2 weeks (based on the PHQ-9 scale) among people aged 15 and over by educational level, 1997-2018, Belgium
Source: Own calculation based on Health Interview Survey, Sciensano [10]

Prevalence of suicidal thoughts in the last twelve months among people aged 18 and over by educational level, 2008-2018, Belgium
Source: Own calculation based on Health Interview Survey, Sciensano [10]

 

 

  • Absolute difference
  • Relative difference
  • PAF

Absolute differences in anxiety and depressive disorders among low-versus-high EL groups, Belgium, 1997-2018
Source: Own calculation based on Health Interview Survey, Sciensano [10]

Relative differences in anxiety and depressive disorders among low-versus-high EL groups, Belgium, 1997-2018
Source: Own calculation based on Health Interview Survey, Sciensano [10]

PAF in anxiety and depressive disorders, Belgium, 1997-2018
Source: Own calculation based on Health Interview Survey, Sciensano [10]

4. Read more

View the metadata for this indicator

HISIA: Interactive Analysis of the Belgian Health Interview Survey

Definitions

Percentage-point
The Percentage-point (ppt) is the arithmetic difference between two percentages, for instance with 16% in group A and 8% in group B, the difference is 8 ppt, corresponding to a relative excess of 100%.

References

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  3. WHO Commission on Social Determinants on Health. Closing the gap in a generation: health equity through action on the social determinants of health. Geneva: WHO; 2008.
  4. Executive Agency for Health and Consumer. Second Programme of Community Action in the Field of Health 2008-2013. European Commission; 2007.
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  6. Gouvernement wallon. Plan prévention et promotion de la santé en Wallonie. Partie 1: définition des priorités en santé. Namur; 2017. 
  7. Arrêté royal du 18 juillet 2013 portant fixation de la vision stratégique fédérale à long terme de développement durable: http://www.etaamb.be/fr/arrete-royal-du-18-juillet-2013_n2013011468.html. Moniteur Belge. 2013 Oct 8;
  8. Braveman PA. Monitoring equity in health and healthcare: a conceptual framework. JHealth PopulNutr. 2003
  9. Maeseneer JD, Willems S. Terugdringen Sociale Gezondheidskloof: van concept naar politieke implementatie. Ghent University; 2021
  10. Health Interview Survey, Sciensano, 1997-2018. https://www.sciensano.be/en/projects/health-interview-survey