"Is this man healthy in a general sense?" Breivik`s lawyer Oystein Storrvik asked in his final remarks to an Oslo appeals court. "His mental health doesn`t seem good, in my opinion."

The 37-year-old, who killed 77 people in twin attacks in 2011, is serving a 21-year prison sentence handed down in 2012, which can be extended indefinitely as long as he is considered a threat.

Last year, an Oslo district court stunned victims` families when it found the Norwegian state guilty of treating Breivik "inhumanely" and in "degrading" fashion, in breach of Article 3 of the European Convention on Human Rights.

It noted the main reason was his prolonged isolation. Breivik has been held apart from other inmates since 2011 for security reasons.

The state appealed that ruling.

The killer has complained of headaches and told the appeals court last week his isolation has radicalised him further.

In July 2011 Breivik, disguised as a police officer, tracked and gunned down 69 people, most of them teenagers, at a Labour Party youth camp on the island of Utoya, shortly after killing eight people in a bombing outside a government building in Oslo.

He said he killed his victims because they worked for multiculturalism.

`A VIP inmate`

While the state`s lawyers have painted a picture of an inmate in strong physical and psychological health, Storrvik said he had doubts about Breivik`s mental health, citing among other things the inappropriate content of his correspondence and his persistent insensitivity over his crimes.

"It is because of these elements ... that, at least to me as a lawyer, he can in no way be considered as being in good health as defined by the European Court of Human Rights," he said.

At his side, Breivik, who sees himself as an ideological leader, listened to the remarks motionless with his eyes cast downward.

Storrvik also noted that the length of his client`s isolation "is soon approaching six years."

"That`s a bigger problem for every day that passes."

The state has however argued that Breivik has not been isolated, noting his multiple contacts with guards, with whom he plays backgammon, a prison visitor, his lawyers and pastors.

He also studies by correspondence and engages in various activities in his cell to compensate for being detained alone.

On Tuesday, Attorney General Fredrik Sejersted told the court Breivik was "a VIP inmate" who enjoyed "cosy" conditions, including three cells, some of which have views of nature outdoors, where he can play video games and watch television.

He also has a computer without internet access, gym machines, books and newspapers.

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