Study of the Transition From Child Psychiatry to Adult Psychiatry in Nice Within a Population of 17-year-old Adolescents

Overview

Transitional psychiatry addresses the complex process through which individuals move from adolescence to adulthood, both in terms of developmental stage and mental healthcare systems. This transition includes the shift from pediatric to adult psychiatric services, as well as the evolution from vague or subclinical symptoms to established psychiatric disorders that may become chronic without early intervention. Psychiatric disorders often emerge early in life: approximately 50% before age 15 and 75% before age 25. Early detection and intervention are therefore crucial to improving long-term mental health outcomes, functional independence, and social integration. However, current healthcare systems frequently fail to meet the needs of adolescents and young adults during this critical transition phase. Organizational discontinuities and clinical complexity lead to several risks: * Difficulties in accessing appropriate psychiatric care for adolescents presenting with emerging symptoms, * High rates of service disengagement for patients already receiving pediatric mental health care who do not successfully transition to adult services. Studies have shown that nearly half (48%) of young people drop out of psychiatric follow-up for at least three months after reaching adulthood. This interruption increases the likelihood of relapse and involuntary psychiatric admissions. Despite numerous publications over the past decade emphasizing the need for dedicated transitional care models, services remain fragmented in many systems. One of the largest recent studies in this area, the European MILESTONE longitudinal study, followed 763 patients (mean age 17.5) over two years in eight countries. It found that 11% of participants discontinued care entirely, 41% experienced discontinuity, and only 21% successfully transitioned to adult psychiatry. Continued care was more likely among patients with severe psychiatric disorders who had already accepted treatment. In contrast, those with mood disorders or poorly defined symptoms-despite being at high risk-were less likely to receive ongoing support. Transitional psychiatry therefore aims to establish integrated practices and systems that ensure the continuity of mental healthcare for youth aged approximately 16 to 25. The main objectives of such services are to: * Prevent care disruptions at the age of majority, * Maintain appropriate and developmentally sensitive treatment for young adults, * Promote patient autonomy in managing their care, * Ensure coordination and collaboration between child/adolescent and adult psychiatric teams. Despite growing recognition of these needs, no consensus exists in the literature regarding a fixed duration that defines a true care discontinuity, and practices vary significantly between regions and systems. In this context, the Odyssée 3 project was launched in Nice, France, as a prospective epidemiological study focusing specifically on the real-life transition from child and adolescent psychiatry to adult psychiatry. The study targets a cohort of 17-year-olds who are currently receiving mental health care and will soon face the shift to adult services. The project is part of the CNR Santé Mentale territorial initiative, supported by the Regional Health Agency (ARS 06). It is co-led by the University Department of Child and Adolescent Psychiatry (SUPEA) at Lenval Pediatric University Hospital and the Department of Psychiatry at the Nice University Hospital (CHU de Nice). Odyssey 3 has three primary goals: * To assess the care pathways and clinical outcomes of adolescents undergoing transition to adult psychiatry; * To identify patient profiles, trajectories, and risk factors associated with successful or failed care continuity; * To generate data that will inform the creation of a dedicated transitional psychiatry team and pathway in the Nice area. Ultimately, this study aims to strengthen the healthcare system's ability to detect early warning signs, intervene proactively in emerging psychiatric conditions, and ensure that adolescents already engaged in care do not experience service discontinuities. Its findings will serve as a foundation for building a specialized, coordinated, and sustainable transitional psychiatry structure in Nice, aligned with best practices and international recommendations.

Interventions

• Behavioral Group of 17-year-old patients living in Nice and receiving psychiatric care
  Prospective study aiming to determine the annual prevalence of 17-year-old patients living in Nice who attend hospital-based child and adolescent psychiatry services. Secondary objectives include: estimating prevalence among under-18 psychiatric patients; describing clinical and sociodemographic profiles (sample of 100 patients); mapping 1-year care trajectories; evaluating clinical outcomes; assessing transition preparedness (to adult psychiatry); and identifying factors associated with psychia

Primary outcome measures

• Annual prevalence of 17-year-old patients living in Nice who consulted hospital-based child and adolescent psychiatry services, calculated against the total number of 17-year-olds in the general population of Nice. [Time frame: one year]

Secondary outcome measures (9)

• Annual Prevalence of 17-Year-Old Adolescents Consulting Child and Adolescent Psychiatric Services in Nice [Time frame: One year following the first psychiatric consultation during the study period.]
• Baseline Description of Patient Profiles in a Child and Adolescent Psychiatric Population [Time frame: Baseline]
• One-Year Psychiatric Care Trajectories in Adolescents [Time frame: 12 months after study inclusion]
• Clinical Evolution [Time frame: Baseline (M0), 6 months (M6), and 12 months (M12).]
• Readiness for Transition to Adult Psychiatric Care [Time frame: Baseline (M0) and 6 months (M6).]
• Continuity of Psychiatric Care at 12 Months [Time frame: 12 months (M12).]
• WHOQOL-BREF Quality of Life Score [Time frame: Baseline (M0), 6 months (M6), and 12 months (M12).]
• Psychosocial Functioning (Health of the Nation Outcome Scales for Children and Adolescents [HoNOSCA] Total Score [Time frame: Baseline (M0), 6 months (M6), and 12 months (M12).]
• Outcome of Transition to Adult Psychiatric Care (Transition Related Outcome Measure [TROM] Total Score) [Time frame: 12 months (M12).]

Eligibility criteria

Inclusion criteria

Participants must meet all of the following criteria:

• Age ≥17 and <18 years at inclusion.
• Receiving care (outpatient, inpatient, or emergency) within the Child and Adolescent Psychiatry Department at Lenval University Children's Hospital.
• Presence of a psychiatric disorder according to DSM-5 criteria, irrespective of diagnostic category.
• Considered to be in a potential transition situation to adult mental health services within the following 12 months.
• Living in the municipality of Nice (postal codes 06000, 06100, 06200, 06300).
• Able to provide written informed consent, together with at least one parent or legal guardian.

Exclusion criteria

Participants meeting any of the following criteria will be excluded:

• Insufficient command of French preventing comprehension of study information or completion of questionnaires.
• Cognitive or sensory impairments (e.g. moderate-to-severe intellectual disability, major visual impairment, severe reading difficulties) preventing valid completion of assessments.
• Legal incapacity (e.g. guardianship) preventing independent consent.
• Acute or unstable clinical condition requiring urgent or intensive care incompatible with research participation (e.g. severe psychiatric decompensation, immediate suicidal crisis).
• Refusal to participate by the adolescent or the parent(s)/legal representative(s).
• Any situation judged by the investigator as incompatible with one-year follow-up (e.g. imminent transfer to another region).

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Observational model

Cohort

Study locations

France · 1 center

• Fondation Lenval Hôpitaux pédiatrique Nice CHU Lenval — Nice

Identifiers

NCT: NCT07068945 · 25-HPNCL-04 Odysee3

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗