Parents Pass Down Psychiatric Conditions Due to a General Psychopathology Factor

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Parents with psychiatric disorders have a higher likelihood of passing down psychiatric disorders to their children, according to a new study.¹

According to the World Health Organization, 1 in 8 people (n = 970 million) worldwide have a mental disorder.² Since it was unknown whether parents passing down psychiatric disorders to their offspring is attributed to a broader psychopathology comorbidity or to specific conditions, the study explored this topic.

The study, led by Mengping Zhou, MSc, from the department of medical epidemiology and biostatistics at Karolinska Institutet, aimed to evaluate the associations between the general and specific psychopathology factors in patients, as well as the psychiatric, behavioral, and psychosocial outcomes in their offspring.¹

“Our findings replicate previous smaller children-of-twins studies that observed intergenerational transmission of general psychopathology factors and extend them to nonpsychiatric offspring outcomes and middle adulthood,” the investigators wrote. “Together, these findings suggest that psychiatric and behavioral related parent-offspring associations might be attributable to a general vulnerability toward a broad range of mental health–related phenotypes.”

Zhou and colleagues identified individuals born in Sweden between 1970 – 2000 from the Total Population Register. They looked for 9 psychiatric diagnoses—schizophrenia, schizoaffective disorder, bipolar disorder, alcohol-related disorders, drug-related disorders, depression, anxiety, obsessive-compulsive disorder (OCD), and PTSD. The study included 31 register-based outcomes in the offspring, looking for psychotic-like outcomes, neurodevelopmental outcomes, internalizing outcomes, externalizing outcomes, and psychosocial outcomes.

Psychotic-like outcomes included schizophrenia, bipolar disorder, and the prescription of antipsychotics, lithium, and antiepileptics. Then, neurodevelopmental outcomes included ADHD, tic disorder, autism spectrum disorder, intellectual disability, learning disorders, and prescription of stimulants.

Moreover, internalizing outcomes included anxiety, depression, PTSD, OCD, and prescription of anxiolytics and antidepressants. The externalizing outcomes included alcohol related disorders, drug-related disorders, oppositional defiant disorder, court convictions for violent crimes, and prescription of anti-alcohol and anti-opioid medications.

Lastly, the psychosocial outcomes included low school grade (referring to an individual who ranked the lowest quintile on the standardized junior high school grade measure), high school ineligibility, low cognitive ability, social welfare recipiency, and unemployment.

The investigators found the psychopathology factor in patients was significantly linked to all 31 offspring outcomes (range: odds ratio [OR], 1.08; 95% CI, 1.07 – 1.08 for accidents; OR, 1.40; 95% CI, 1.39 – 1.40 for social welfare recipiency).

Furthermore, the specific psychotic factor in parents was significantly linked to all 5 psychotic-like outcomes (range: OR, 1.05; 95% CI, 1.04 – 1.06 for prescription of antiepileptics; OR, 1.25; 95% CI, 1.23 – 1.28 for schizophrenia).

The specific internalizing factor was linked to all 6 internalizing outcomes and 6 neurodevelopmental outcomes. Then, the specific externalizing factor in patients was linked to 6 externalizing outcomes. Also, the specific externalizing factor in patients was linked with the 6 internalizing outcomes, from obsessive compulsive disorder (OR, 1.01; 95% CI, 1.00 – 1.02) to PTSD (OR, 1.15; 95% CI, 1.00 – 1.02), as well as the 6 neurodevelopmental outcomes, includingautism spectrum disorder (OR, 1.04; 95% CI, 1.03 – 1.05) and ADHD (OR, 1.21; 95% CI, 1.20 – 1.22).

The investigators found similar associations with the psychopathology factors for both male and female offspring. Ultimately, the study significantly demonstrated that a parent with a psychiatric disorder passes down a psychiatric disorder to their offspring.

“Children whose parents scored 1 SD above the mean on the general psychopathology factor had a statistically significant 8 - 40% higher odds of the outcomes,” the investigators wrote.

Because the specific psychotic factor in parents was linked to the psychotic-like outcomes in offspring, the investigators wrote that this association could be attributed to inherited genetics.

“Regardless of the transmission pathway, professionals who work with children (eg, child psychologists, psychiatrists, teachers, and social workers) might benefit from taking the total number of parental psychiatric conditions into account, regardless of type, when forecasting child mental health and social functions,” investigators concluded. “In addition, mental health professionals working with adult patients who have multiple psychiatric conditions might consider a more comprehensive screening and monitoring of their offspring.”

References

1. ^{Zhou M, Larsson H, D'Onofrio BM, Landén M, Lichtenstein P, Pettersson E. Intergenerational Transmission of Psychiatric Conditions and Psychiatric, Behavioral, and Psychosocial Outcomes in Offspring. JAMA Netw Open. 2023;6(12):e2348439. Published 2023 Dec 1. doi:10.1001/jamanetworkopen.2023.48439}
2. ^{Mental Disorders. World Health Organization. June 8, 2022. https://www.who.int/news-room/fact-sheets/detail/mental-disorders. Accessed December 21, 2023.}