Sweden's National Board of Forensic Medicine (Rättsmedicinalverket) handed the results of its examination of Rakhmat Akilov to Stockholm District Court on Wednesday, in which it concluded that the Uzbek national was not suffering from any mental issues when the attack was carried out.
The same is true of Akilov's condition during the investigation, doctors also concluded. As such there is no reason to consider psychiatric care as part of any eventual sentence, they judged.
According to Akilov's lawyer, the judgement will not impact the investigation.
"This doesn't affect the investigation at all. This is done regularly in cases of a serious nature, as is this one is. It relates only to the issue of sentencing," Johan Eriksson told news agency TT.
On Wednesday, prosecutor Hans Ihrman asked for more time to continue the preliminary investigation into the suspected terror case.
"Substantial investigative matters remain, such as further interviews, analyses, surveys and technical investigations, before the investigation can be completed," Ihrman said in a statement.
The prosecutor has previously said that the investigation could take up to a year to complete.
Five people were killed in the truck attack on Drottninggatan in central Stockholm last April. Akilov, 39, admitted to committing "a terrorist crime" during a remand hearing at Stockholm District Court on April 11th.