Hostages freed by Hamas are experiencing cycles of euphoria followed by crashes, families say.

Family members who were captured during the Hamas-led terrorist attacks on Oct. 7 who have now been freed are experiencing bursts of euphoria followed by emotional crashes as they emerge from weeks of paralyzing fear in captivity, according to Israelis who spoke to journalists at the Israeli Embassy in London on Tuesday.

“Everything is just so fragile,” said Limor Sella-Broyde, 40, whose cousins Judith Raanan, 59, and Natalie Raanan, 17, were freed on Oct. 20.

She said the mother and daughter were in difficult psychological states as they recovered. “It’s an adrenaline rush and then a crash,” Ms. Sella-Broyde said. “They try to speak and then they get really tired.”

Three of Ms. Sella-Broyde’s relatives were killed by Hamas during the cross-border attacks on Oct. 7, while seven others were taken hostage from Kibbutz Be’eri.

Judith and Natalie Raanan, who are dual citizens of Israel and the United States, were the first hostages to be freed from captivity after negotiations involving the United States, Qatar and other nations. But for their family, any sense of relief remains out of reach because so many other members remain captive, and because the life they knew in the kibbutz has been shattered.

Ms. Sella-Broyde was part of a small group of Israelis brought to London this week to speak about their experiences related to the Oct. 7 attacks and to raise the profiles of the many other hostages who remain in captivity.

The event, sponsored by an Israeli charity, appeared designed in part to refocus public attention on Oct. 7, at a time when much of that attention has shifted to Israeli airstrikes and military operations in Gaza that have caused thousands of civilian deaths.

But the Israelis who spoke on Tuesday were reluctant to give details of the ordeals their family members had gone through in Gaza or describe their medical conditions after being released, citing a desire to protect their privacy.

Ms. Sella-Broyde said that she was nervous about broaching difficult topics with Judith and Natalie Raanan. “They are broken,” she said.

Another member of the group who spoke, Shahar Mor, 52, said that four of his family members had been kidnapped on Oct. 7. Three of them, including Ohad Munder Zichri, 9, have since been released, but the family’s patriarch, Avraham Munder, 78, has not.

Mr. Mor said that when his relatives were first freed, the family members simply hugged one another. But he added that he was dogged by a feeling of horror at the events of Oct. 7 and by worry for Mr. Munder.

In captivity, Mr. Mor said, his relatives had subsisted mainly on pita bread, which became more scarce as the weeks went by, and they ate with their guards. One guard gave them a pack of cards, which helped to pass the time, he said.

Mr. Mor downplayed the significance of the gesture, arguing that one humane act by a Hamas guard should not be a distraction from the group’s ruthlessness.

“Some of the captors are nicer; some are less nice,” he said. “It makes no difference.”