People who survived the Holocaust faced a significantly greater risk for developing schizophrenia compared to those who were indirectly affected, according to a new comprehensive study conducted at the University of Haifa in Israel. Among all survivors, the highest rates of schizophrenia were found in those who had been born into the Holocaust.
“The exposure to protracted multiple maximal physical, social, and psychological adversities of the Holocaust increased the risk of survivors developing schizophrenia,” said researcher Stephen Levine, Ph.D.
Holocaust researchers have long documented how survivors were at greater risk of emotional distress and various psychiatric disorders, such as sleeping disorders. However, until now no study has examined the effect of Holocaust exposure on the risk of developing schizophrenia.
For the study, the researchers examined comprehensive population-based data on 113,932 European Jews from nations where the Holocaust occurred. The population was split into two groups.
The first group included those who were indirectly exposed to the Holocaust. Although they had immigrated to Israel before the Holocaust began in their country of origin, they still had relatives, friends, or colleagues who were exposed to it.
The second group included those who were directly exposed to the Holocaust. These individuals did not immigrate to Israel until after the end of the Second World War.
The findings reveal that individuals with direct exposure to the Holocaust had a 27 percent higher chance of developing schizophrenia than those who were not directly exposed to it.
Furthermore, within the directly exposed group, people with the highest risk of developing schizophrenia were those born during the Holocaust and who continued to experience it afterward. This group’s risk of developing schizophrenia was 41 percent higher than the group with indirect Holocaust exposure.
The researchers note that the disruption of normal neurological development in childhood most likely increased the risk of developing schizophrenia. This would support the hypothesis that neurological development in young children is a critical period for subsequent development later in life.
“The study results are not entirely intuitive, as scholars disagree as to the consequences of Holocaust exposure,” Levine said. “Some researchers claim that Holocaust survivors were stronger and healthier. Selective mortality induced by the Nazis systematically murdered more vulnerable people, leaving the fittest to survive. This school of thought would anticipate that survivors would be at a reduced risk of developing schizophrenia.
“Conversely, other scholars have argued that irrespective of the fact that the strongest survived, protracted exposure to extreme trauma made Holocaust survivors vulnerable to developing schizophrenia. This study is consistent with the latter argument.”