Adolescence and the intergenerational transmission of mental illness and self-harming

Article

According to the World Health Organization (WHO), adolescence is the phase of life following childhood, spanning roughly from the first to the second decade of life. This stage is crucial for healthy physical and psychological development into adulthood. It is marked by rapid physical growth and significant body changes due to puberty, alongside cognitive and psychosocial evolution, including decision-making skills. Adolescence and young adulthood are peak times for the onset of adult mental illnesses, with three-quarters of adults with mental health issues showing their first symptoms by age 24 ¹. The onset of mental illness during this critical period can hinder personal achievements, leading to long-term disadvantages such as school failure, job instability, and poor social functioning ². In fact, the onset of mental illness during adolescence may contribute to several negative outcomes, impacting many aspects of an individual’s life. Among those adverse outcomes, it is possible to enlist potential academic challenges, since adolescents with mental health issues often struggle with poor academic performance, absenteeism, and school dropout rates, leading to consequent employment instability due to difficulties in securing and maintaining stable employment, which may result in financial instability in adulthood. Above all, adolescents with mental illness may experience delays in achieving key developmental milestones, affecting their ability to function independently as adults. The cumulative effect of these challenges often limits personal and professional opportunities, affecting the individual’s long-term potential and success. Furthermore, social and family relationships can be compromised since mental illness may impair an adolescent’s ability to form and maintain healthy social and family relationships, leading to social isolation and familial conflicts. Lastly, mental health issues can negatively affect physical health due to poor self-care, engagement in risky behaviors like substance abuse or self-harm, and a higher risk of chronic illnesses and a higher likelihood of chronic mental health issues, reducing overall quality of life.

Accordingly, the negative outcomes of mental illness in adolescence underscore the importance of early intervention and support to mitigate these effects and promote healthier developmental trajectories.

Mental disorders typically result from a combination of genetic and environmental factors. Parental psychopathology is a significant risk factor for offspring psychopathology, due to both genetic transmission and environmental influences. Children of parents with severe psychopathology have a 2.5 times higher risk of developing mental illness compared to the general population, with even higher risks if both parents are affected. Maternal psychopathology has a greater impact than paternal psychopathology ^3-5. Transmission mechanisms include both biological and behavioral pathways, where information is consciously or unconsciously transferred through parental behavior.

Furthermore, suicide is a leading cause of death among young people, with heritability estimated between 15% and 45%. Studies of twins and adoptive siblings underscore this genetic component, though comorbid psychopathology often complicates findings ^6-10. Research indicates higher suicide rates among relatives of individuals who attempt suicide. Children exposed to parental suicide or alarming behaviors face adverse neurodevelopmental outcomes. A large study in The Lancet links suicide risk to completed sibling or parental suicide, family psychopathology, and familial suicidal behavior as independent risk factors ^11-14.

Our study, conducted on 963 adolescents and young adults (ages 17-25) support such evidence and offer possible new insights. They were recruited on a voluntary basis from high schools and universities in the district of Monza, aiming at analyzing a possible intergenerational transmission of self-harming. We assessed participants’ personal and family histories using charts, the Mini-International Neuropsychiatric Interview for self-harming, and the Childhood Trauma Questionnaire. Half of the participants showed no psychiatric diagnosis, 25% anxiety and/or depressive disorders and 25% diagnoses belonged to cluster B of personality issues. Subjects with a personal psychiatric diagnosis were at higher risk of self-harming, but the risk was detected even among those without a psychiatric diagnosis (OR = 5.4). We found a strong correlation between family suicide and increased suicide risk (χ2 = 10.898, p < 0.001; OR = 2.945, p = 0.002), with no significant differences between parental and grandparental suicides. A family history of psychopathology also increased suicide risk (OR = 1.813; p = 0.008), especially in high-risk individuals (OR = 2.064; p = 0.003). Maternal psychiatric history was significantly linked to offspring self-harming (OR = 2.508; p = 0.0123).

Childhood trauma significantly predicted suicide risk, except for sexual abuse. Multivariate analysis confirmed family history’s significance, but childhood trauma emerged as the most significant predictor. The study highlighted a doubled risk of suicide among those with family psychiatric disorders, with maternal psychiatric issues posing a higher risk due to potential neglect from primary caregivers. Future analysis should clarify the mediation of a personal psychiatric diagnosis, but the aim of these preliminary results confirmed the role of family transmission independently from each subject’s psychiatric history.

In conclusion adolescence is a crucial time frame for both physical and psychological development. Unfortunately, the onset of many adult mental illnesses occur in this sensitive period. As highlighted by the WHO, the changes experienced during this time –ranging from rapid physical growth to cognitive and psychosocial evolution – are foundational for healthy adulthood. However, the onset of mental illness during adolescence can have profound and lasting negative effects.

Our study highlights the role of the hereditary nature of mental illness since its association with familial psychopathology were evident in our findings. The study demonstrated higher suicide risks among those with a family history of suicide or psychopathology. Specifically, maternal psychiatric issues were linked to a higher risk of self-harming behaviors in offspring, possibly due to emotional neglect from primary caregivers.

Remarkably, childhood trauma emerged as the most significant predictor of suicide risk, overshadowing even family history. This finding highlights the crucial role of early traumatic experiences in shaping mental health outcomes.

Our analysis underlines two main conclusions:

First of all, treating parents’ mental issues should be mandatory to reduce an intergenerational transmission of mental illness and should include a special attention to a patient’s offspring’s wellbeing.

Secondly, addressing mental health issues during adolescence through timely and effective intervention is vital to mitigating these negative outcomes and promoting healthier developmental trajectories. Further research into the underlying mechanisms and potential mediators of these effects is essential to develop more person-tailored prevention and intervention strategies.