Epidemiology of schizophrenia

Schizophrenia affects around 0.3–0.7% of people at some point in their life,[1] or 21 million people worldwide as of 2011 (about one of every 285).[2] By using precise methods in its diagnosis and a large, representative population, schizophrenia seems to occur with relative consistency over time during the last half-century.[3]

DALY for schizophrenia per 100,000 inhabitants in 2004.
  no data
  ≤ 185
  185–197
  197–207
  207–218
  218–229
  229–240
  240–251
  251–262
  262–273
  273–284
  284–295
  ≥ 295

While it is claimed that schizophrenia occurs at similar rates worldwide, its prevalence and incidence varies across the world,[4] within countries,[5] and at the local and neighborhood level.[6] It causes approximately 1% of worldwide disability-adjusted life years (DALYs).[7] The rate of schizophrenia varies up to threefold depending on how it is defined.[1]

By age and genderEdit

Schizophrenia is diagnosed 1.4 times more frequently in males than females, and typically appears earlier in men[7]—the peak ages of onset are 20–28 years for males and 26–32 years for females.[8] Onset in childhood, before the age of 13 can sometimes occur.[9][10] A later onset can occur between the ages of 40 and 60, known as late onset, and also after 60 known as very late onset.[11]

Generally, the mean age of first hospital admission for treatment of schizophrenia is between 25 and 35. Studies have suggested that lower income individuals tend to have their disorder diagnosed later after the onset of symptoms, relative to those of better economic standings. As a result, the lower social classes are more likely to be living with their illness untreated.[3]

It is generally accepted that women tend to present with schizophrenia anywhere between 4–10 years after their male counterparts.[12] However, using broad criteria for diagnosing schizophrenia shows that males have a bimodal age of onset, with peaks at 21.4 years and 39.2 years old, while females have a trimodal age of onset with peaks at 22.4, 36.6, and 61.5 years old.[13]

This additional post-menopausal peak of late-onset schizophrenia in women calls into question the etiology of the disease and raises a debate about "subtypes" of schizophrenia, with men and women being susceptible to different types (see causes of schizophrenia). This is further supported by the variability in presentation of the disease between the genders.[14]

Other theories that may explain this difference include protective or predisposing factors in men or women that may render them more (or less) susceptible to the disease at different points in life. For example, estrogen may be a protective factor for women, as estradiol has been found to be effective in treating schizophrenia when added to antipsychotic therapy.[14]

By countryEdit

In 2000, the World Health Organization found the prevalence and incidence of schizophrenia to be roughly similar around the world, with age-standardized prevalence per 100,000 ranging from 343 in Africa to 544 in Japan and Oceania for men and from 378 in Africa to 527 in Southeastern Europe for women.[15]

However, the impact of schizophrenia tends to be highest in Oceania, the Middle East, and East Asia, while the nations of Australia, Japan, the United States, and most of Europe typically have low impact. Despite relative geographical proximity, the DALY rate of schizophrenia in Indonesia is nearly double that of Australia (the nations with the highest and lowest respective DALY rates). Discrepancies between DALY rates and prevalence may arise from differences in availability of medical treatment: years lived with mental disorders carry significantly higher DALY values when unmedicated than when medicated.[15]

The following tables record the age-standardised disability-adjusted life years rates per 100,000 inhabitants (recorded in 2004).[16]

Rank Country DALY rate
1   Indonesia 321.870
2   Philippines 317.079
3   Thailand 315.533
4   Malaysia 314.199
5   Sri Lanka 312.278
6   Brunei 312.101
7   Singapore 311.872
8   Tuvalu 287.660
9   Laos 287.175
10   Uzbekistan 286.942
11   Marshall Islands 284.733
12   Burma 281.795
13   Papua New Guinea 281.681
14   Kyrgyzstan 279.941
15   Iraq 279.362
16   Samoa 279.080
17   Palau 278.983
18   Tonga 278.129
19   Federated States of Micronesia 277.711
20   Vanuatu 277.423
21   Syria 277.308
22   Niue 276.384
23   Vietnam 275.786
24   Lebanon 275.768
25   Iran 275.672
26   Solomon Islands 275.561
27   Yemen 275.117
28   Cambodia 274.896
29   Cook Islands 274.401
30   Tunisia 273.845
31   Morocco 273.587
32   Libya 273.506
33   Egypt 273.441
34   Jordan 273.298
35   Cyprus 273.036
36   Saudi Arabia 270.202
37   Mongolia 270.025
38   Oman 270.003
39   Bahrain 269.861
40   Armenia 269.694
41   Azerbaijan 269.573
42   Kuwait 269.369
43   China 269.146
44   North Korea 269.064
45   Kiribati 268.930
46   Nauru 268.930
47   India 268.903
48   Suriname 268.690
49   Fiji 268.504
50   South Korea 268.395
51   Qatar 267.384
52   U.A.E. 267.316
53   Pakistan 266.348
54   Tajikistan 266.302
55   Bangladesh 265.704
56     Nepal 265.396
57   Bhutan 264.924
58   Turkmenistan 264.634
59   East Timor 259.483
60   Maldives 257.915
61   Uruguay 257.220
62   Nicaragua 256.836
63   Cuba 256.254
64   Honduras 256.040
65   Brazil 255.328
66   Mexico 254.998
67   Trinidad and Tobago 254.966
68   Dominican Republic 254.906
69   Grenada 254.731
70   Saint Vincent and the Grenadines 254.731
71   Guatemala 254.603
72   El Salvador 254.538
73   Saint Lucia 254.249
74   Chile 254.056
75   Jamaica 254.052
76   Afghanistan 253.778
77   Ecuador 253.573
78   Colombia 253.524
79   Haiti 253.521
80   Venezuela 253.432
81   Argentina 253.404
82   Bolivia 253.353
83   Bahamas 253.284
84   Dominica 253.184
85   Antigua and Barbuda 253.183
86   Saint Kitts and Nevis 253.183
87   Peru 253.060
88   Panama 252.960
89   Barbados 252.912
90   Belize 252.768
91   Costa Rica 252.764
92   Guyana 252.626
93   Paraguay 252.615
94   Angola 252.602
95   Sierra Leone 250.554
96   Mali 248.112
97   Albania 247.412
98   Liberia 247.215
99   Niger 247.160
100   Equatorial Guinea 247.009
101   Chad 246.930
102   Guinea-Bissau 246.913
103   Nigeria 246.675
104   Burkina Faso 246.534
105   Guinea 244.827
106   Benin 244.670
107   Cameroon 244.614
108   Senegal 244.417
109   Togo 244.322
110   Gambia 244.157
111   Madagascar 244.013
112   Burundi 242.958
113   Mauritania 242.681
114   Côte d'Ivoire 242.415
115   Comoros 242.247
116   D.R. of the Congo 241.964
117   Bosnia and Herzegovina 241.524
118   Gabon 241.036
119   Rwanda 240.859
120   South Africa 240.510
121   C.A.R. 239.919
122   Algeria 239.752
123   Tanzania 239.346
124   Cape Verde 239.200
125   Mozambique 239.198
126   Bulgaria 238.471
127   Ethiopia 238.315
128   Zimbabwe 238.167
129   Zambia 238.155
130   Swaziland 237.481
131   Malawi 237.361
132   Romania 237.228
133   Lesotho 237.095
134   Uganda 236.848
135   Mauritius 236.587
136   Seychelles 236.317
137   Georgia 235.629
138   Eritrea 235.605
139   Djibouti 235.323
140   Kenya 234.975
141   Somalia 234.846
142   São Tomé and Príncipe 234.730
143   Rep. of the Congo 234.554
144   Botswana 234.546
145   Sudan 234.492
146   Serbia and Montenegro 234.431
147   Macedonia 234.208
148   Turkey 234.024
149   Ghana 234.009
150   Poland 233.876
151   Slovakia 233.549
152   Namibia 233.280
153   Kazakhstan 210.649
154   Ukraine 209.780
155   Russia 206.910
156   Hungary 206.746
157   Belarus 206.098
158   Lithuania 205.798
159   Latvia 203.750
160   Moldova 202.684
161   Estonia 201.738
162   New Zealand 193.707
163   Japan 193.509
164   France 189.104
165    Switzerland 188.713
166   Israel 188.005
167   Croatia 187.935
168   Finland 187.699
169   Denmark 187.542
170   Norway 187.493
171   Slovenia 187.209
172   Spain 186.362
173   Netherlands 186.282
174   Portugal 186.253
175   Belgium 186.130
176   Sweden 186.011
177   Canada 185.942
178   Czech Republic 185.826
179   Germany 185.762
180   Andorra 185.725
181   United States 185.629
182   Ireland 185.626
183   Italy 185.589
184   Luxembourg 185.307
185   United Kingdom 185.182
186   Austria 185.116
187   Greece 185.063
188   Malta 184.870
189   San Marino 184.854
190   Monaco 184.831
191   Iceland 184.830
192   Australia 164.255

United StatesEdit

In 2010, there were approximately 397,200 hospitalizations for schizophrenia in the United States. About 88,600 (22.3%) were readmitted within 30 days.[17]

By raceEdit

In Western Europe it has been documented that immigrant groups are more likely to be diagnosed with schizophrenia. The immigrant groups that are predominate in the increased schizophrenia diagnosis are of black origin.[18] The highest rates of schizophrenia diagnosis come from those of Afro-Caribbean ethnicity and those with black African descent.[18] In the US, African Americans have been found to be three times more likely to be diagnosed with schizophrenia, and when taking socioeconomic status into account they are two times more likely than their white counterparts.[18] However, those diagnosed with schizophrenia in developing countries have been found to have better course and outcome than their counterparts in industrialized countries.[19] These improved outcomes may be because these countries place emphasis on harmonious interpersonal relationships.[19]

Prenatal careEdit

In two natural experiments conducted on populations that experienced famine, the rates of schizophrenia diagnosed were observed. During both the Chinese Famine (1950s) and the Dutch Hunger Winter (1944-1945) the cohorts of the exposed group were twice as likely to develop schizophrenia as compared to the unexposed cohorts.[20] It is possible that prenatal nutritional deficiency plays a role in the development of schizophrenia, in particular the lack of micronutrients. Countries with poor prenatal care, low food supply, or developing countries could have a higher incidence of schizophrenia, but more research is needed to confirm this hypothesis.

Cannabis UseEdit

There have been several studies done that show a connection between schizophrenia and cannabis. The genetic liability for people with cannabis use disorder was strongly correlated to schizophrenia. It was also found to show mixed evidence that pointed to an occasional connection between cannabis use disorder and schizophrenia.[21]

See alsoEdit

ReferencesEdit

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  2. ^ "Schizophrenia". World Health Organization. 2011. Retrieved February 27, 2011.
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  8. ^ Castle D, Wessely S, Der G, Murray RM (December 1991). "The incidence of operationally defined schizophrenia in Camberwell, 1965-84". The British Journal of Psychiatry. 159 (6): 790–794. doi:10.1192/bjp.159.6.790. PMID 1790446. S2CID 41661565.
  9. ^ Diagnostic and statistical manual of mental disorders : DSM-5 (5th ed.). American Psychiatric Association. 2013. pp. 99-105. ISBN 978-0-89042-555-8.
  10. ^ Da Fonseca D, Fourneret P (December 2018). "[Very early onset schizophrenia]". L'Encéphale. 44 (6S): S8–S11. doi:10.1016/S0013-7006(19)30071-5. PMID 30935493. S2CID 150798223.
  11. ^ Murante T, Cohen CI (January 2017). "Cognitive Functioning in Older Adults With Schizophrenia". Focus. 15 (1): 26–34. doi:10.1176/appi.focus.20160032. PMC 6519630. PMID 31975837.
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  13. ^ Castle D, Sham P, Murray R (October 1998). "Differences in distribution of ages of onset in males and females with schizophrenia". Schizophrenia Research. 33 (3): 179–183. doi:10.1016/s0920-9964(98)00070-x. PMID 9789910. S2CID 22355423.
  14. ^ a b Kulkarni J, Riedel A, de Castella AR, Fitzgerald PB, Rolfe TJ, Taffe J, Burger H (March 2001). "Estrogen - a potential treatment for schizophrenia". Schizophrenia Research. 48 (1): 137–144. doi:10.1016/s0920-9964(00)00088-8. PMID 11278160. S2CID 42146691.
  15. ^ a b Ayuso-Mateos JL. "Global burden of schizophrenia in the year 2000" (PDF). World Health Organization. Retrieved February 27, 2013.
  16. ^ "Age-standardized DALYs per 100,000 by cause, and Member State, 2004". Global burden of disease: 2004 update. World Health Organization (WHO). 2004. Retrieved 2011-04-01.
  17. ^ Elixhauser A, Steiner C. Readmissions to U.S. Hospitals by Diagnosis, 2010. HCUP Statistical Brief #153. Agency for Healthcare Research and Quality. April 2013.
  18. ^ a b c Bresnahan M, Begg MD, Brown A, Schaefer C, Sohler N, Insel B, et al. (August 2007). "Race and risk of schizophrenia in a US birth cohort: another example of health disparity?". International Journal of Epidemiology. 36 (4): 751–758. doi:10.1093/ije/dym041. PMID 17440031.
  19. ^ a b Bae SW, Brekke JS (2002-01-01). "Characteristics of Korean-Americans with schizophrenia: a cross-ethnic comparison with African-Americans, Latinos, and Euro-Americans". Schizophrenia Bulletin. 28 (4): 703–717. doi:10.1093/oxfordjournals.schbul.a006974. PMID 12795500.
  20. ^ Brown AS, Susser ES (November 2008). "Prenatal nutritional deficiency and risk of adult schizophrenia". Schizophrenia Bulletin. 34 (6): 1054–1063. doi:10.1093/schbul/sbn096. PMC 2632499. PMID 18682377.
  21. ^ Johnson EC, Hatoum AS, Deak JD, Polimanti R, Murray RM, Edenberg HJ, et al. (November 2021). "The relationship between cannabis and schizophrenia: a genetically informed perspective". Addiction. 116 (11): 3227–3234. doi:10.1111/add.15534. PMC 8492483. PMID 33950550.

Further readingEdit