The Department of Biomedicine

Children of two parents with ADHD have the highest risk of getting the diagnosis themselves

Research conducted by ADHD researcher Berit Skretting Solberg shows a strong connection between ADHD in children and parents. The sons had the highest absolute risk, but the daughters had the highest relative risk.

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ADHD has been shown to have a strong hereditary component, but the relationship between parents' gender, their diagnosis and the child's diagnosis is little known. Little is also known about other psychiatric diagnoses in parents, such as bipolar disorder, schizophrenia, autism spectrum diagnoses or depression affecting children's risk of developing ADHD.

In her doctoral degree, Berit Skretting Solberg at the Department of Biomedicine has looked in particular at gender differences in ADHD. Among other things, she has found that women with ADHD have other additional diagnoses than men with the diagnosis. How are their children?

Greatest heredity from mother

Using various Norwegian registeries, such as the Birth Registry, the Prescription Registry and the Patient Registry, she linked data from parents and children from the 1960s to the present day. Solberg found a clear connection between the parents' ADHD diagnosis and the children's diagnoses, which confirms previous findings. Absolutely most at risk were sons with parents who were both diagnosed with ADHD:

- 40 percent of these boys are themselves diagnosed with the condition, says Solberg.

The greatest inheritance was from the mother to the children. Compared with if only the father had ADHD, there was a higher risk of getting the diagnosis if only the mother had the diagnosis.

- A hypothesis is that an ADHD diagnosis in the mother can affect the upbringing environment to a greater extent than an ADHD diagnosis in the father, says Solberg.

Possible hypothesis:

Mothers receive the diagnosis after the daughters have been diagnosed
There was also a gender difference among the children:

- If only the mother has ADHD, there was a higher risk that the daughters would get ADHD than the sons, says Solberg

In fact, daughters of parents with ADHD had the greatest relative risk. If the mother had ADHD, the daughter's risk of being diagnosed was ten times as high as if neither parent had ADHD. The reason for this is complex, Solberg believes:

- In general, there are fewer girls than boys who are diagnosed with ADHD. One hypothesis is that more risk genes from mother must be transferred to daughter in order for her to be diagnosed, ie that it takes more for a girl to be diagnosed with the condition, says Solberg

Another hypothesis is that the mother, to a greater extent than the father, sees a doctor herself after the daughter has been diagnosed, because they themselves suspect that they have the diagnosis:

- Women generally have a lower threshold for seeking medical help than men. It may be that women, while examining their children for the diagnosis, recognize the traits of their daughters in themselves, Solberg explains.

Doubled risk in other psychiatric diagnoses
Solberg was surprised by the strong correlation between gender and ADHD.

Another thing she was surprised by was that the risk of getting ADHD in the child was doubled if the parents had other psychiatric diagnoses, such as bipolar disorder, autism spectrum diagnosis, schizophrenia, or depression. These parents were not even diagnosed with ADHD:

- We have reason to believe that there is a common genetic starting point, together with possible common environmental factors, which can explain the connection between these diagnoses and ADHD in children, Solberg explains.

Read the article here: https://acamh.onlinelibrary.wiley.com/doi/full/10.1111/jcpp.13368

Read also about it in Bergens Tidende (subscription required): https://www.bt.no/btmagasinet/i/gWp6P5/tonje-og-begge-doetrene-har-adhd-...