The iBerry Study 4.0 - Research on social, psychological and physical development in youth.

In August 2014, the iBerry Study started the first phase of a longitudinal
study on the development of psychiatric disorders in cooperation with the
Center for Youth and Families in the Rijnmond region (MEC-2014-416). In high
school, adolescents aged 12-14 years were screened on emotional and behavioral
problems as part of standard preventive youth health care. This has resulted in
a selection of adolescents in which adolescents with a problem score in the top
15% scores of emotional and behavioral problems were overrepresented. In the
second phase of the iBerry Study, selected adolescents were invited for their
first visit at the research center as part of the iBerry Study baseline
measurement (MEC-2015-007).
A total of 1022 adolescents enrolled in the study, of which 728 with the
highest problem scores and 294 randomly selected from the other adolescents.
This method generated sufficient power to investigate various biological,
psychological and social factors that contribute to the transition to (adult)
psychiatric disorders.

Selected adolescents and their parents were invited for a first visit, the
baseline measurement, to the iBerry research center in the second phase of the
study (MEC-2015-007). Data on emotional and behavioral problems, physical
health, lifestyle, family functioning, genetic profiles, sociodemographic
background, use of care and cognitive profile were collected by administering
interviews, questionnaires, neuropsychological tasks and physical measurements.
The baseline measurement was completed in 2019, resulting in a total cohort of
1022 adolescents.

The first follow-up measurement started in March 2019 (T1). Part of the
instruments used at the baseline measurement were repeated and additional
age-appropriate instruments were added. Study details are described in the
study protocol, MEC-2018-14472. In total, 807 adolescents participated in this
first follow-up.

The second follow-up measurement started in August 2021 (T2). The measurement
consist of a repetition of some of the previous measurements, as well as the
addition of instruments that are appropriate to the age of the cohort. The
details are described in the research protocol MEC-2021-0330. More than 500
young people have now participated in this second follow-up measurement.

The current research protocol concerns the third follow-up measurement in the
second phase of the iBerry Study (T3). This measurement will take place two to
three years after the second follow-up measurement. The objective is to further
identify key factors in the course of (sub)clinical psychiatric symptoms. By
accurately mapping and monitoring (sub)clinical psychiatric symptoms, the
iBerry Study aims to provide significant insight in the background and course
of psychiatric disorders and to contribute to the development of preventive
interventions.

The iBerry Study has two main study objectives:
1. Descibing long-term prognosis of subclinical symptoms in terms of course
(transition to several psychiatric disorders, chronicity, recurrence,
comorbidiy) and public health consequences (disability, costs)
2. Examining genetic, biological and psychosocial determinants of the
transition from subclinical symtoms to psychiatric disorders.

The iBerry Study is a prospective observational study.

The burden for the young adult consists of measurements using: questionnaires,
interviews and physical measurements (including height, weight, blood pressure,
actigraphy (sleep and movement)). The total time commitment for the visit is up
to a maximum of 2,5 hours. The sleep and exercise study contains a time burden
of 1 hour, spread over 9 days.
The time commitment for completing questionnaire 1 (research center) and
questionnaire 2 (home) is approximately 60 minutes and 40 minutes, respectively.
The time limit for completing the follow-up questionnaire after two years
contains approximately 75 minutes.
The burden on the parent/guardian consists of completing one questionnaire, the
total time burden being 45 minutes.

All measurements are carried out by trained researchers.

There is no direct benefit to participants from participating in the iBerry
Study 4.0, except for the aforementioned gift vouchers for young adults.
Indirectly, participation can lead to early detection of a number of serious
psychiatric disorders for which there is an effective treatment. If
participants are diagnosed with serious psychiatric disorders with a potential
danger to themselves or others, they will be informed and advised to be
referred to specialist mental health care by their GP.