A new study has shown that offspring of parents with schizophrenia or bipolar disorder are more likely to develop the same illness or another psychiatric condition than those with only one parent with psychiatric illness.
For the study, Irving I. Gottesman, of the University of Minnesota Medical School, Minneapolis, and colleagues examined a population-based cohort of 2.7 million individuals born in Denmark.
The researchers matched records in a general registry of the population with a database of psychiatric admissions.
They identified individuals whose parents had both been admitted to psychiatric facilities for schizophrenia and bipolar disorder, and compared the rate of psychiatric admissions for these individuals to those of offspring with one or no parents admitted to psychiatric facilities.
Rates of schizophrenia were highest among offspring of two parents with schizophrenia. Of the 196 couples who both had schizophrenia, 27.3 percent of their 270 children were admitted to a psychiatric facility, increasing to 39.2 percent when schizophrenia-related disorders were included.
This compared with a rate of 7 percent among 13,878 offspring of 8,006 couples in which one parent had schizophrenia and 0.86 percent in 2.2 million offspring of 1 million couples in which neither parent was admitted for schizophrenia.
Similarly, the risk of bipolar disorder was 24.9 percent in 146 offspring of 83 parent couples who were both admitted for bipolar disorder (increasing to 36 percent when unipolar depressive disorder was also included).
This compared to a risk of 4.4 percent among 23,152 offspring of 11,995 couples with only one parent ever admitted for bipolar disorder and 0.48 percent in 2.2 million children of 1 million couples with neither parent ever admitted.
When one parent had bipolar disorder and the other had schizophrenia, offspring had a 15.6 percent risk of schizophrenia and an 11.7 percent risk of bipolar disorder.
The study has been published in the March issue of Archives of General Psychiatry, one of the JAMA/Archives journals. (ANI)