# Study design The High Risk Cohort Study for the Development of Childhood Psychiatric Disorders (HRC) was designed for the purpose of understanding developmental trajectories of psychopathology and mental disorders. It is an ongoing multicentric follow up study of 2511 children and adolescents who were born between the years of 1998 and 2004, and who live in the cities of Porto Alegre and São Paulo (Brazil). Up to this date, assessments have already been made in three different phases: screening (2010), baseline (wave 0; 2010/2011), and 3-year-follow up (wave 1; 2013/2014). The 6-year (wave 2) and 9-year-follow-ups (wave 3) are predicted, respectively, for the years 2017/2018 and 2021/2022. ### Screening The screening phase was conducted in 57 public schools (22 in Porto Alegre and 35 in São Paulo) with more than 1000 students within the age of interest during early school year registry days. Eligible subjects for the study were those who (1) were being registered by a biological parent that was a primary caregiver, (2) were 6-12 years old at enrollment. All parents of children fulfilling the mentioned requirements were invited to participate and those who agreed were interviewed in loco, or later, by telephone, with a modified version of the Family History Screen (FHS) (Weissman et al., 2000). In total, we were able to interview 9937 children (from 8012 families) and collect information about 45.394 family members. ![location_index][1] *The Family History Screen (FHS)* The FHS is an interview used to screen all members of a family for DSM-IV mental disorder symptoms based on information provided by one family member. For this study, the instrument was adapted to allow the collection of information about the index child, his/her biological parents, biological sibling, and half-siblings, instead of asking about family members of the informant. The version used is one of 48 items, 29 main questions accompanied by 19 conditional questions. The questions evaluate symptoms of depression, mania, specific phobia, social phobia, generalized anxiety disorder, panic disorder, agoraphobia, obsessive-compulsive disorder, psychotic experiences, alcohol use and problems due to alcohol and drug use, attention deficit hyperactive disorder, separation anxiety, oppositional defiant disorder, conduct disorder and inhibited behavior towards unfamiliar people. Based on the information collected with the FHS, a family load index was computed for each of the 9937 potential eligible children. This index expresses the percentage of family members, adjusted for relatedness, who screened positively for any of ADHD, anxiety disorders, OCD, psychotic experiences, and learning disorders. ![screening][2] Among the 9937 eligible children, 1500 were randomly selected to compose the random study sample, and among the remaining children, those who had screened positively for any of the five disorders were ranked according to percentage of members in their families presenting symptoms of the same disorder. High-risk subjects were invited until a fixed number of 2511 individuals was achieved. ![selection][3] ![design_image][4] ### Wave 0 - Baseline A total of 2511 subjects selected through the earlier mentioned procedures were comprehensively studied during Wave 0. Participants were assessed through a parent interview (household interview) and a child interview and testing (school evaluation). Molecular genetic information was collected through the children and their parents saliva, and a sub-sample of 750 subjects were assessed using neuroimaging and blood biomarkers. *Household parent interview* The parent interview consisted of: (1) a detailed evaluation of general risk factors for mental disorders (demographical, prenatal and perinatal, and early life stressors); (2) an assessment of the child’s psychiatric diagnosis (using the Development and Well-being Assessment (DAWBA, Good- man et al., 2000a); (3) an assessment of parental diagnosis (using the Mini International Psychiatric Interview (MINI) and the MINI Plus (Amorim et al., 1998; Sheehan et al., 1998); (4) questions about the child’s treatment history and service use. *Child Interview and Testing (school evaluation)* The child interview and testing comprised of (1) a detailed child evaluation regarding psychosis and psychotic experiences (using the Community Assessment of Psychotic Experiences [CAPE, Konings et al., 2006], the Comprehensive Assessment of At-risk Mental States [CAARMS, Yung et al., 2003], and the K-SADS-PL [Kiddie–Sads – Present and Lifetime Version; Kaufman et al., 1997]), anxiety (using the Screen for Children Anxiety Related Emotional Disorders [SCARED, Isolan et al., 2011]) and temperament (using the Early Adolescent Temperament Questionnaire – revised version [EATQ-R, Ellis and Rothbart, 2001]); (2) specific neurocognitive tests (go/no-go task, conflict control task, long dot-probe task, two-choice task delay, reaction task and duration discrimination task); and (3) an evaluation of literacy (using the The School Performance Test [Teste de Desempenho Escolar, TDE; Stein, 1998]) and phonological awareness (using The Simplified Assessment of Auditory Processing [Pereira and Schochat, 1997], the CONFIAS [Consciência fonológica instrumento de avaliação sequencial] Phonological Awareness Instru- ment [Moojen et al., 2003], and The Phonology Test, part of the ABFW Test [Teste de linguagem infantil nas áreas de fonologia, vocabulário, fluência e pragmatic; Wertzner, 2000]). ![neurop_tasks][5] *Molecular genetic evaluation* Saliva was collected from the child and both parents using an Oragene© salivary kit. If saliva from one of the biological parents was not available, the brother with the closest age to the child was chosen to provide a saliva sample. *Neuroimaging and peripheral biomarkers* A sub-sample of approximately 750 subjects was selected to participate in a neuroimaging and blood biomarkers study. Brain magnetic resonance imaging (MRI) was acquired in two centers using a 1.5T General Electric Scanner. The sequences acquired were: (a) high-resolution tridimensional T1-weighted; (b) diffusion tensor imaging (DTI); (c) intrinsic connectivity fMRI; (d) MT ON/OFF. **More details about the sample and the methodological procedures and mental disorders prevalences for screening and wave 0 can be found in Salum et al (2015) (attached in files section).** ---------- **References**: Salum G. A., Gadelha A., Pan P. M., Moriyama T. S., Graeff-Martins A. S., Tamanaha A. C., Alvarenga P., Krieger F. V., Fleitlich-Bilyk B., Jackowski A., Sato J. R., Brietzke E., Polanczyk G. V., Brentani H., Mari J. d. J., Do Rosário M. C., Manfro G. G., Bressan R. A., Mercadante M. T., Miguel E. C., and Rohde L. A. (2015) *High risk cohort study for psychiatric disorders in childhood: rationale, design, methods and preliminary results*, Int. J. Methods Psychiatr. Res., 24, pages 58–73. [doi: 10.1002/mpr.1459][6] [1]: https://mfr.osf.io/export?url=https://osf.io/3zbvn/?action=download&direct&mode=render&initialWidth=848&childId=mfrIframe&format=1200x1200.jpeg [2]: https://mfr.osf.io/export?url=https://osf.io/w5mpc/?action=download&direct&mode=render&initialWidth=848&childId=mfrIframe&format=1200x1200.jpeg [3]: https://mfr.osf.io/export?url=https://osf.io/vp27a/?action=download&mode=render&direct&public_file=False&initialWidth=848&childId=mfrIframe&format=1200x1200.jpeg [4]: https://mfr.osf.io/export?url=https://osf.io/m7kr4/?action=download&direct&mode=render&initialWidth=848&childId=mfrIframe&format=1200x1200.jpeg [5]: https://mfr.osf.io/export?url=https://osf.io/hzyxg/?action=download%26mode=render%26direct%26public_file=False&initialWidth=848&childId=mfrIframe&format=1200x1200.jpeg [6]: http://onlinelibrary.wiley.com/doi/10.1002/mpr.1459/abstract