Children who grow up with a mentally ill parent face a substantially elevated risk of developing mental health problems themselves, yet structured support for these families remains scarce. A new randomized controlled trial from Germany and Switzerland has now put one of the most carefully designed family interventions for this group to a rigorous test, and the results are sobering: the program did not outperform usual care on any of its main outcomes.

The trial, published in the journal Child and Adolescent Psychiatry and Mental Health, evaluated the CHIMPS program, a psychodynamic, transdiagnostic family intervention developed at the University Medical Center Hamburg-Eppendorf for children of mentally ill parents, a group the researchers abbreviate as CHIMPS. The study was conducted as a prospective, two-arm, cluster-randomized, controlled, open, multicenter trial with blinded external raters assessing outcomes. Families were recruited at seven sites: the University Medical Center Hamburg-Eppendorf, the University Medical Center Leipzig, Ulm University’s Department of Psychiatry and Psychotherapy II in Ulm-Günzburg, the Medical Center Vitos Clinic in Wiesbaden Rheingau, the LWL Community Hospitals in Gütersloh-Paderborn, Charité in Berlin, and the Center of Social Pediatrics in Winterthur, Switzerland.

The scale of the problem the trial addresses is considerable. Mental illnesses are among the ten most common illnesses worldwide, and in Germany 37.9 percent of people with statutory health insurance were diagnosed with a mental illness in 2022. Many of these patients are parents. An estimated 3.8 million children and adolescents in Germany live with a mentally ill parent. These children often experience shame, guilt, helplessness, insecurity, social isolation, stigmatization, and reluctance to talk about their parent’s illness. They frequently take on responsibilities inappropriate for their age, and parental mental illness is often accompanied by additional psychosocial stressors such as low socioeconomic status, unemployment, and an increased risk of neglect and abuse.

Previous research has suggested that family-oriented interventions can reduce the risk of psychological symptoms in these children by almost 50 percent, and specifically decrease internalizing symptoms. However, most earlier evaluations were limited by small sample sizes and short follow-up periods, and a meta-analysis of randomized trials on preventing depression in offspring of parents with depression found a significant effect only at post-intervention assessments, not at medium or long-term follow-up. The CHIMPS trial was designed to provide the kind of high-quality evaluation that earlier studies lacked.

The intervention itself comprises approximately eight sessions of 60 to 90 minutes each, typically spanning half a year: three sessions with parents only, one per child with children only, and three with the whole family, with additional sessions possible when families need them. Grounded in psychoanalytic family therapy, it aims to bring unconscious conflicts among family members into consciousness using techniques of clarifying, confronting, and interpreting, while also integrating psychoeducation and elements based on behavioral therapy. Therapists address coping with the parental illness, relationships within and outside the family, and family dynamics. The main goals are to provide psychoeducation about the parental illness, improve family communication, strengthen coping and relationships, and reduce social isolation. All therapists received a two-day training based on the treatment manual and ongoing supervision, and sessions were video-recorded for quality control where participants agreed.

In total, 215 families were randomized, 109 to the intervention group and 106 to the control group, which received treatment as usual. Three hundred thirty-eight children and adolescents aged 3 to 19 were included, 171 in the intervention group and 167 in the control group. Families were assessed at baseline and again at 6, 12, and 18 months. The primary outcome was the mental health of children and adolescents who had received an initial psychiatric diagnosis, measured 18 months after baseline using the Schedule for Affective Disorders and Schizophrenia for School-Age Children, Present and Lifetime Version, a semi-structured diagnostic interview administered by blinded external raters. Secondary outcomes included mental health assessed with the parent-rated Child Behavior Checklist and the self-rated Youth Self Report, and health-related quality of life measured with the KIDSCREEN-27 from both parent and self perspectives.

The primary analysis included data from 43 children and adolescents with an initial psychiatric diagnosis in each group. The result was an odds ratio of 0.52 with a 95 percent confidence interval of 0.25 to 1.09, indicating a statistical advantage of the intervention group that fell short of significance. In other words, fewer children in the intervention group retained a confirmed diagnosis at follow-up, but the difference could not be distinguished from chance. At 18 months, 43.6 percent of children who had a psychiatric diagnosis at baseline still had a confirmed diagnosis, while 56.4 percent had moved to a near-diagnosis or no diagnosis. No clinically relevant advantage of the intervention group emerged in any secondary outcome. On the continuous Child Behavior Checklist score, the adjusted mean difference between groups was 0.30 points on a scale where baseline scores averaged 37.7, showing nearly no difference. Sensitivity analyses using per-protocol populations and imputed data supported the primary result, and none of the pre-specified subgroup analyses, covering recruitment center, clinic type, children’s age, and sex, indicated relevant differences.

The researchers point to several possible explanations for the null finding. Notably, for 38.5 percent of families in the intervention group, no therapy sessions were recorded, and only 17.4 percent completed seven or more sessions, suggesting that many families received far less than the intended dose of treatment. The target group proved very difficult to reach and to retain, and the small number of observations at the 18-month main measurement point left the study underpowered, limiting the meaningfulness of the results. The authors also note that both groups improved in most outcomes over time, which could partly reflect a quasi-therapeutic effect of the repeated diagnostic assessments themselves, a phenomenon supported by prior research showing that assessment interviews can enhance participants’ awareness and encourage them to seek support. Alternatively, families who benefited may have been more likely to remain in the study, creating a selective sample. The control condition may also have played a role: families receiving treatment as usual were free to seek psychiatric, psychotherapeutic, and other help, and additional treatments were not systematically recorded.

Despite the negative primary result, the trial carries important implications. About half of the children in the sample had a psychiatric diagnosis at baseline, yet just under one eighth was in treatment at the time, underscoring a clear gap in the German healthcare system, which the authors describe as predominantly individual-centered and lacking family-friendly structures in psychiatric clinics. The research team plans to revise the CHIMPS program to provide families with more needs-based assistance, potentially by tailoring the intervention to families’ situations or extending the number of therapy sessions. They argue that future trials should focus on improving accessibility and adherence, and that interdisciplinary structures enabling low-threshold care for these families must be created. An accompanying cost-utility analysis by project partners found a high probability that the intervention was cost-effective compared with treatment as usual, though with uncertainty that the authors say calls for larger studies. The study thus stands as both a cautionary finding about the limits of a well-intentioned intervention and a detailed roadmap for how to reach, retain, and better serve one of the most vulnerable groups in mental health care.

Subject of Research: A cluster-randomized controlled trial evaluating a psychodynamic family intervention for children of mentally ill parents in Germany and Switzerland

Article Title: Effectiveness of a family-oriented intervention for children of mentally ill parents on children’s mental health and health-related quality of life: a prospective, rater-blinded, cluster-randomized controlled multicenter trial

Article References: Paumen, T., Busmann, M., Daubmann, A., Höller, A., Ozga, A.-K., Kilian, R., Winter, S. M., Lambert, M., Wegscheider, K., Zapf, A., & Wiegand-Grefe, S. (2026). Effectiveness of a family-oriented intervention for children of mentally ill parents on children’s mental health and health-related quality of life: a prospective, rater-blinded, cluster-randomized controlled multicenter trial. Child and Adolescent Psychiatry and Mental Health, 20(1), Article 135. https://doi.org/10.1186/s13034-026-01174-6

Image Credits: AI Generated

DOI: 10.1186/s13034-026-01174-6

Keywords: children of mentally ill parents, family intervention, randomized controlled trial, mental health, health-related quality of life, psychodynamic family therapy, child and adolescent psychiatry, CHIMPS program, cluster-randomized trial, treatment as usual, Germany, psychiatric diagnosis