Timothy Ray Jones Jr, 32, has also waived his first court appearance in South Carolina.
His lawyer, Aimee Zmroczek, would not elaborate on his mental health problems but said they wanted him evaluated as soon as possible.
In court documents, Jones says appearing in court yesterday would have undermined his ability to receive a fair trial and potentially tainted the jury pool.
Ms Zmroczek said he was being portrayed as a monster but was a scared man trying to deal with the situation. Jones is accused of killing the children, then driving around for days with their decomposing bodies before dumping them in rural Alabama.
The children were Merah, eight; Elias, seven; Nahtahn, six; Gabriel, two and Elaine Marie, one.