Common genetic variants play a role in an individual's risk of bipolar disorder and schizophrenia, scientists say.
These conditions, experienced by many using assisted living, in part result from genetics, according to an international study published online in two papers in journal Nature Genetics.
Eleven regions are strongly linked to these diseases, including six of which were previously unidentified.
Professor Philip Mitchell, of the University of New South Wales, said that the research confirmed gene CACNA1C is involved in causing bipolar disorder, while gene ODZ4 was implicated in cell surface signalling.
"Both findings were highly statistically significant and the research indicates new targets for the development of improved treatments for this severe and disabling condition," he said.
Furthermore, upon combining bipolar and schizophrenia, evidence indicated CACNA1C is involved in both conditions, suggesting some genetic overlap.
This comes after research from Taiwan linked schizophrenia with epilepsy.
Research published in journal Epilepsia revealed that patients with the condition were almost eight times as likely to develop schizophrenia.
Those with schizophrenia were also almost six times as likely to get epilepsy.
Read about support and personalised care at Barchester care homes for anyone with mental health concerns.