Children of parents with mental disorders are at greater risk of suffering from both the same and other types of mental disorders. For example, children of a father or mother with psychosis are 5.8 times more likely to develop this disease, but their chances of having disruptive disorders are also multiplied by 3.
These are conclusions from the largest meta-analysis carried out to date on the specific risk that the child of a person with a mental disorder has of acquiring a psychological problem. The study, carried out by the Clínic research institute, Idibaps, together with the University of Dalhouse (Canada) and King's College London, integrates the results of 211 previous studies, with 3.2 million children of parents with the disorder and 20 million descendants of people without disorders.
There was previously proven evidence that pathologies such as psychosis or depression are transmitted with certain regularity between generations. In other diseases, the risk was poorly defined and it was not very clear whether it affected only the parents' illness or the mental spectrum in general.
“It cannot be said that it surprised us, but the risk of transdiagnosis is significant, that the child of a person with a disorder has a greater risk of developing a wide range of other disorders,” explains Joaquim Raduà, co-author of the work and head of the research group on Imaging of disorders related to depression of the Idibaps.
What's more, the most probable 'inheritance' of various pathologies from the parents is not the same. Thus, the son or daughter of a person with a depressive disorder is 2.3 times more likely to develop depression than the offspring of a person without this disorder. But, at the same time, their chances of suffering from obsessive-compulsive disorder are multiplied by 3.2 and those of eating disorders are multiplied by 3.9.
The offspring of a parent affected by drug use has a 2.8 times greater risk of suffering from the same disease, but 11.4 times greater risk of suffering from bipolar disorder. This (from consumption to bipolarity) is the most likely transmission of all those established.
“The risks that we determine are those that are observed on average. The individual factor can be different because it depends on environmental factors, such as the consumption of toxic substances, physical exercise or diet, or social factors, such as work stress or suffering from attacks, bullying or racism,” says Raduà.
The psychiatrist rejects that the study has a fatalistic reading. On the contrary: "It helps us to better understand the risks in order to adjust prevention, which always has to be appropriate to the risk." On the other hand, he highlights that the average risk of transmission of disorders stipulated in the analysis can be significantly reduced if environmental risk factors are controlled and preventive interventions are carried out.
The information provided by the study may be useful in deciding preventive interventions. “Professionals should get used to exploring the mental health of patients' children to detect symptoms and be able to offer interventions before the disorder develops or treat it as soon as possible in order to improve its evolution.” “Knowing the risk can improve prevention strategies,” explains Raduà, in whose opinion mental health specialists should not only intervene in the disorder of their patients but also in that of their children.
“We have to take into account that up to 55% of children of people with mental disorders will develop one throughout their lives,” says researcher Lydia Fortea, co-author of the work: “That is why it is so important to make a complete synthesis of the risks that help us improve prevention techniques.”
The individual studies carried out until now have focused mainly on depressive, bipolar or psychotic disorders. The meta-analysis, published in 'World Psychiatry, the journal with the greatest impact in the world of psychiatry, has included disorders such as attention deficit and hyperactivity, anxiety, substance use disorders, eating disorders, obsessive compulsive disorder or borderline personality disorder.
The work calculates the possibilities of transmission in the case of a single affected parent. “There is not enough data to estimate whether having two parents with a disorder increases the chances, but it seems that they do,” Raduà clarifies. On the other hand, given the lack of trials with sex discrimination, the authors have preferred to look for strong evidence and not differentiate between men and women.
