A new study is suggesting that premature babies are more likely to develop serious medical disorders like depression and bipolar disorder. The researchers found that babies who were born after less than 32 weeks of gestation were at least three times more likely to have to be hospitalized because of psychiatric issues at the age of 16 or older than babies who were born later.

Researchers of this study believe that the increased risk might be caused by small but critical differences in the child’s brain development due to having been born early. While the risk varied with each condition, it turns out that psychosis was two and a half times more likely in premature babies, depression was three times more likely, and bipolar disorder was 7.4 times more likely for preemies.

“Since we considered only the most severe cases that resulted in hospitalization, it may be that in real terms this link is even stronger,” said Chiara Nosarti from the Institute of Psychiatry at King’s College London, who was the lead researcher of the study.

For the study, scientists at the Karolinska Institute in Sweden monitored information collected from 1.3 million medical records between 1973 and 1985.

“The strongest association we found was to mental health disorders known to have a strong biological basis, such as bipolar disorder,” Nosarti said.

Bipolar disorder and depression are treated with a variety of medications, including antidepressants like Paxil and Effexor. These antidepressant have been known to cause serious side effects, which can include violent and suicidal thoughts and behavior and birth defects (PPHN, cleft palate and heart, lung and brain defects) in babies whose mothers take the drugs while pregnant. It turns out that the treatment for these two conditions may end up causing more problems for the offspring of those premature babies later on in life. In this case, the risk-to-benefit ratio just doesn’t seem worth it.