The Scottish Strategy for Autism

Scottish Strategy for Autism to ensure that progress is made across Scotland in delivering quality services for people with autism and their families.


Annex 2: Prevalence and incidence

The prevalence estimates in the Public Health Institute of Scotland's ( PHIS) ASD Needs Assessment Report suggested 60 in every 10,000 people are affected by ASD. More recent studies suggest that a rate of around 1 in 100 is currently the best estimate of the prevalence in children and adults. [51] [52]

Diagnosis for school age children is vastly improved both in its sophistication and in its consistency. This has led to benefits for some adults in the extended family of those recently diagnosed children whereby they have come forward to ask for their own diagnosis as they recognise similar behavioural patterns within themselves. There is no one single explanation of why more people appear to be diagnosed with the condition. It is probable that a mix of factors is coming into play including increasing public and professional awareness, improved diagnosis, wider diagnostic criteria or a combination of all the above.

As part of its acceptance of the PHIS recommendations, the then Scottish Executive undertook an audit of services for people with ASD in 2004 [53] . Its remit was to provide information for service commissioners on the best available knowledge about ASD and current service provision in Scotland, and guidance on how these services might better meet the needs of both children and adults with ASD in the future. The intention was to assess the extent to which national prevalence rates could be regarded as a sound basis on which to plan services. It was also the first time that social and health care planners for both children and adult services attempted to quantify the incidence of ASD in their locality. Whilst the ultimate analysis carried a number of reservations about the reliability of the findings, acknowledging its patchiness and the likelihood of underestimation, it did provide a much clearer picture than had existed up until that point. It meant that many planners did take the opportunity to discuss the findings together and to plan appropriate interventions at local level.

The overall picture that emerged was that 35 children per 10,000 were diagnosed with ASD, making a total 3,400 children and young people. Within this, the highest rate was for the 5-10 age group where there were 49 children diagnosed per 10,000 population. Incidence figures have varied across Health Boards from 16 in Forth Valley to 102 in Highland and 299 in Orkney. For the 11-15 age group, there were 27 children and young people diagnosed per 10,000 population which drops to 16 per 10,000 population for the 16-18 age group.

The higher rates for the 5-10 and preschool age groups was thought to have been due to a combination of better reporting procedures and improved diagnosis in recent years. The rate per 10,000 population for preschool children at 42 was less than the rate for 5-10 year olds. It could have been expected that the pre-school data should have been of equal or better quality than the 5-10 age group because of improved reports but much diagnosis takes place after the age of 3 because the behaviours associated with the condition may not be displayed before then. Other significant findings were that 20% of children with ASD were reported as having learning disabilities with two thirds of diagnosed primary school children attending mainstream schools. Around one third of children with ASD were specifically diagnosed with Asperger's syndrome.

Moving to adults, 645 adults were identified in the audit, 1 in 7 of whom was described as having Asperger's. The data here was less robust. Eight of the 15 NHS Boards were able to provide complete information but 4 could not do so. NHS Lothian conducted a file review so that its data was possibly the most accurate. Given these limitations, we see that 24% of people were in the 18-24 bracket, 63% were aged 25-29 and 12% were over 50 years of age. The rate was highest for the 18-24 age group where for Scotland there were 5.1 people diagnosed per 10,000 population. This changes to 3.2 for the 25-49 age group and again to 0.6 for the 50 plus age group. As before, these lower rates probably reflect a combination of better reporting procedures and improved diagnosis over the years. As with the children's data, the rates of diagnosis vary considerably between NHS Board areas from 0.8 per 10,000 population in Lanarkshire to 8.7 people diagnosed per 10,000 population in Orkney.

Overall, more than half (55%) of the adults with ASD that were known to partnerships also had learning disabilities. In addition, nearly one third of these adults had other behavioural or biomedical conditions, 10% had both a learning disability and a physical impairment and 3% had mental health problems.

Since the time the survey was conducted, some authorities have built on this data to continue local planning. The Scottish Government now collects data on the number of school children with autism. The Pupils in Scotland 2010 publication and the Independent School census (September 2008) record the number of children for reason of support of autism spectrum disorder as being 6,506 which is closer to 1 in 100.

The prevalence figures outlined in Table 2 are estimates of the total number of people with autism spectrum disorder by local authority area, based on the prevalence rate of 90 in 10,000 people from the Office of National Statistics survey of the mental health of children and young people in Britain (2005). The ratio of males to females was found to be 4:1. Not all of this population will need formal community care services. Many will need life time support. However, it is clear from the figures that wider community services, such as housing, transport, sport and leisure, should be taking account of the range of needs of this population.

Location Population Estimated 0 to 4 5 to 9 10 to 14 15 to 19 20 to 29 30 to 65
ASD
(Caps -city status) 2006 90/10,000 M F Total M F Total M F Total M F Total M F Total M F Total
Aberdeen 206880 1862 90 23 113 94 24 118 97 24 121 95 24 119 197 49 246 696 174 870
Aberdeenshire 236260 2126 103 26 129 108 27 135 110 28 138 109 27 136 225 56 281 794 199 993
Angus 109320 984 48 12 60 50 13 63 51 13 64 50 13 63 104 26 130 368 92 460
Argyll & Bute 91390 823 40 10 50 42 10 52 43 11 54 42 11 53 87 22 109 307 77 384
Clackmannanshire 48900 440 21 5 27 22 6 28 23 6 29 23 6 29 46 12 58 164 41 205
Dumfries & Galloway 148030 1332 64 16 81 68 17 85 69 17 86 68 17 85 141 35 176 498 124 622
Dundee 142170 1280 62 15 77 65 16 81 66 17 83 66 16 82 135 34 169 478 120 598
East Ayrshire 119290 1074 52 13 65 55 14 68 56 14 70 55 14 69 113 28 141 401 100 501
East Dunbartonshire 105460 949 46 11 57 48 12 60 49 12 61 49 12 61 100 25 125 355 89 444
East Lothian 92830 835 40 10 51 43 11 53 43 11 54 43 11 53 88 22 110 312 78 390
East Renfrewshire 89290 804 39 10 49 41 10 51 42 10 52 41 10 51 85 21 106 300 75 375
Edinburgh 463510 4172 202 50 252 212 53 265 216 54 270 214 53 267 441 110 551 1559 390 1949
Falkirk 149680 1347 65 16 82 69 17 86 70 17 87 69 17 86 142 36 178 503 126 629
Fife 358930 3230 156 39 195 164 41 205 167 42 209 165 41 206 341 85 426 1207 302 1509
Glasgow 580690 5226 253 63 316 266 66 332 271 68 339 268 67 335 552 138 690 1953 488 2441
Highland 215310 1938 94 23 117 99 25 124 100 25 125 99 25 124 205 51 256 724 181 905
Inverclyde 81540 734 36 9 44 37 9 46 38 10 48 38 9 47 77 19 96 274 69 343
Midlothian 79290 714 35 9 43 36 9 45 37 9 46 37 9 46 75 19 94 267 67 334
Moray 86750 781 38 9 47 40 10 50 40 10 50 40 10 50 82 21 103 292 73 365
North Ayrshire 135490 1219 59 15 74 62 16 78 63 16 79 62 16 78 129 32 161 456 114 570
North Lanarkshire 323780 2914 141 35 176 148 37 185 151 38 189 149 37 186 308 77 385 1089 272 1361
Orkney 19770 178 9 2 11 9 2 11 9 2 11 9 2 11 19 5 24 66 17 83
Perth & Kinross 140190 1262 61 15 76 64 16 80 65 16 81 65 16 81 133 33 166 471 118 589
Renfrewshire 169590 1526 74 18 92 78 19 97 79 20 99 78 20 98 161 40 201 570 143 713
Scottish Borders 110240 992 48 12 60 50 13 63 51 13 64 51 13 64 105 26 131 371 93 464
Shetland 21880 197 10 2 12 10 3 13 10 3 13 10 3 13 21 5 26 74 18 92
South Ayrshire 111670 1005 49 12 61 51 13 64 52 13 65 51 13 64 106 27 133 375 94 469
South Lanarkshire 307670 2769 134 34 168 141 35 176 144 36 180 142 35 176 292 73 365 1035 259 1294
Stirling 87810 790 38 10 48 40 10 50 41 10 51 40 10 50 83 21 104 295 74 369
West Dunbartonshire 91240 821 40 10 50 42 10 52 43 11 54 42 11 53 87 22 109 307 77 384
West Lothian 165700 1491 72 18 90 76 19 95 77 19 96 76 19 95 157 39 196 557 139 696
Western Isles 26350 237 11 3 14 12 3 15 12 3 15 12 3 15 25 6 31 89 22 111
Total 5116900 46052 2229 557 2787 2342 586 2926 2387 597 2983 2358 589 2827 4863 1216 6077 17205 4301 21512
Back to top