Fort Meade, Maryland (CNN) -- Army private Bradley Manning, charged in the largest leak of classified material in American history, spoke at length on Thursday about his treatment in military custody, saying he grew distressed and considered suicide.
In a clear voice and often gesturing with his hands at a hearing at Ft. Meade, Maryland, the bespectacled Manning described his experiences publicly for the first time since his arrest more than two years ago.
The hearing was held to consider a defense motion to have his case dismissed on grounds that his confinement so far, especially his time at the brig in Quantico, Virginia, has been harsh and has amounted to enough punishment.
At the very least, his lawyers hope the judge would take his experiences during confinement into account and sharply reduce his sentence should he be convicted at his court-martial, which is set to begin early next year.
The defense has said it plans to have Manning plead guilty to lesser offenses and fight other charges as being too extreme.
The Army intelligence analyst is accused of stealing thousands of classified documents while serving in Iraq. The material was then published online by WikiLeaks. WikiLeaks has never confirmed that Manning was the source of its information.
Counts against Manning include aiding the enemy, wrongfully causing intelligence to be published on the Internet, transmitting national defense information and theft of public property or records.
If he's convicted on all counts, he could face a life sentence.
He discussed his arrest in Iraq and his transfer to Kuwait, where he was held for a nearly two months before being transferred to the brig at Marine Base Quantico in Virginia in July 2010.
He said he once passed out due to the heat. He also said not being allowed to know what was happening to him or in the outside world was distressing.
He contemplated suicide in Kuwait.
"My world just shrunk to Camp Arafjon, to that cage," Manning said. "I thought I was going to die in that cage."
A Navy psychiatrist testified on Wednesday that he believed Manning was a potential suicide risk when he arrived at the Quantico brig, where he was held from July 2010 until April 2011, when he was moved to the military prison at Fort Leavenworth, Kansas.
But Capt. William Hocter said his regular recommendations to ease Manning's heightened confinement status within weeks of his arrival in Virginia were not acted upon by commanders.
"The degree of concern of his safety and security was higher than anything I'd previously seen," Hocter said of Manning's time at Quantico.
The Pentagon has maintained Manning was held in accordance with rules governing all maximum-custody detainees at Quantico, for his protection and the safety of others. His status was called prevention of injury.
Manning said he spent most days at Quantico in his small cell -- at least 21 hours and often more than 23 hours -- with no company. Manning said he was only allowed a mattress, blanket, flip-flops, some clothes and his glasses.
He said he tried to keep moving, because sleeping during the day or even laying down was against the rules.
He was seen dancing by himself in his cell, with no music or playing "peek-a-boo" with himself in the cell mirror. Manning explained that he wasn't acting crazy.
"I'm bored, not a lot going on, not a lot to do," he said.
Manning said he always slept with light from outside his cell in his eyes. If guards could not see his face when he rolled over at night, he said they would wake him to roll back over.
He also began to feel the way he felt in the "cage" in Kuwait, when he contemplated suicide. "I started going back to Kuwait mode, that dark hole," Manning said.
But months passed, over which time Manning and his attorney asked periodically why his status wasn't eased, saying he had not been violent and had not tried to hurt himself.
To show he wasn't a danger, Manning said he told a non-commissioned officer in the brig at one point that he could have used the "waist band of my underwear or my flip flops" to hurt himself, but hadn't done so.
That night he was forced to sleep naked. His underwear, flip flops and glasses were removed from his cell.
The next morning during a head count, he said he was forced to stand naked in front of the guards and other inmates. Contrary to earlier testimony, Manning said he was never given a chance to cover himself with his blanket.
His life changed, he said, upon his arrival at Fort Leavenworth. For the first time in nine months, he could move his arms and legs freely without handcuffs or leg iron restraints.
"I was expecting to be put back in restraints," Manning testified. "I knew they were going to put the hammer down eventually."
Instead, he moved freely among other inmates.
Eight months into his time at the Kansas base, Manning said he heard another inmate talking about him and tried to punch him in "the face and ended up hitting him in the shoulder."
The altercation earned Manning 15 days of disciplinary segregation and 14 days of extra duty. Lt. Col. Dawn Hilton, from Fort Leavenworth, testified by phone earlier Thursday that this December fight was Manning's only problem while there.
Manning was questioned by defense lawyers for about five and a half hours Thursday. Prosecutors will get their chance to query him Friday, and the hearing is scheduled to end the next day.