International NGO Save the Children said around 800,000 young people in Gaza have "never known life without the blockade".
Four out of five children in Gaza suffer from emotional distress, Save the Children has said, 15 years after Israel slapped a crippling blockade on the Palestinian enclave.
In Wednesday's report called "Trapped", Britain-based Save the Children said the mental health of Gazan children has continued to deteriorate.
Since 2018, symptoms of "depression, grief and fear," have risen from 55 percent to 80 percent, the report said.
Save the Children's director for the occupied Palestinian territories, Jason Lee said: "The children we spoke to for this report described living in a perpetual state of fear, worry, sadness and grief, waiting for the next round of violence to erupt and feeling unable to sleep or concentrate".
"The physical evidence of their distress - bedwetting, loss of ability to speak or to complete basic tasks - is shocking and should serve as a wakeup call to the international community," he added.
Children make up nearly half of Gaza's population of 2.1 million. Around 800,000 young people in the territory who have "never known life without the blockade," Save the Children said.
Israel and the United States have led an international economic and political boycott of Gaza since 2007 after the resistance movement Hamas was elected to govern the densely populated enclave.
Israel also imposed a land, sea and air blockade since 2007, disabling the entire population from leaving or entering Gaza and choking the import and export of goods.
Gaza has seen four Israeli assaults since 2007, most recently in May 2021 when over 260 Palestinians were killed under Israeli fire.
In a statement marking the anniversary of the blockade, Human Rights Watch said that Israel has turned Gaza into an open-air prison.
In July 2020 UN human rights expert Michael Lynk urged Israel to end its blockade on Gaza and accused Israel of the crime of collective punishment.
HRW's director for Israel and Palestine, Omar Shakir, said: "Young people face the brunt of (the blockade) because they don't know of a Gaza before the closure".