2.7. Time 2 Final SampleA total of 67 individuals received the diagnosis of ASD (autism, atypical autism/PDDNOS, or Asperger syndrome) in 2009, corresponding to total population prevalence for ASD in 15�C24-year-old young adults in the Faroe Islands selleck chem FTY720 of 0.94% [30]. Of these, 24 were ��new cases,�� not found in the study at Time 1. For these, of course, there were no Time 1 assessments, clinical or DISCO algorithm ASD diagnoses available. Only in those individuals who had been assessed both at Time 1 and Time 2 was it possible to study diagnostic stability over time (n = 31 for clinical diagnosis, n = 30 for DISCO algorithm diagnosis).

The source of referral to the study for ASD diagnostic assessment after screening of the 24 new cases at Time 2, who were missed at Time 1, included (a) the Torshavn Hospital Adolescent Psychiatry Outpatient Unit where they had been treated for other mental health problems: anxiety (n = 2), depression (n = 2), ADHD (n = 2), and other (n = 5); (b) adult psychiatrists who had treated them as outpatients for other mental health problems: depression (n = 1), psychosis (n = 1), and other (n = 6); or (c) the Torshavn Hospital Adult Psychiatry Inpatient Unit where they were treated for other psychiatric disorders: depression (n = 4) and OCD (n = 1).The mean age of the DISCO algorithm diagnostic stability study group at followup was 19.5 (SD 3.1) years. There were 5 females (17%) and 25 males (83%). IQ subcategories were defined as follows: IQ 20�C50, n = 9 (30%); 51�C70, n = 3 (10%); 71�C85, n = 7 (23%); >85, n = 11 (37%).

Eleven of the Time 1 sample and 6 of the Time 2 sample of individuals failed to take part in the DISCO-11 assessment, leaving 50 probands at Time 2 for whom there was both a DISCO-11 algorithm diagnosis and an independent clinical diagnosis (including 20 for whom there was no Time 1 diagnosis).2.8. Statistical AnalysisAll statistics were calculated via SPSS 17.0 software on anonymous data, using two-tailed P values. P values < 0.05 were considered statistically significant. An agreement between diagnostic raters at two time points in 2002 and 2009 was quantified by using Kappa statistics. Kappa score was assigned according to Landis and Koch scale [40] using 95% confidence intervals.2.9. EthicsThe study was approved by the Faroe Islands Board for Ethics in Drug_discovery Medicine. All families provided informed consent (parents or, in the case of individuals 18 years or over, by the individuals with a diagnosis of ASD (from Time 1) or with suspected autism spectrum problems (from Time 2) themselves).3. Results3.1. Stability of Clinical DiagnosisWhen combining the AD, AS, and atypical autism/PDDNOS into a collapsed ASD group, 30 of 31 (97%) remained in this overarching clinical diagnostic category.