Five days were taken to assess and make decisions about treatment, he said.
It was not unusual for police to be the "first port of call", given that the mental health system was "pretty overrun" and under such strain.
"Certainly in Auckland its not unusual for them to carry out that sort of safety check."
Although he said he had a breakdown at the start of the month after being accused of harassment, Ross said last week that he was healthy, most recently on Friday, when he said he was "okay right now".
He pushed back against comments from National leader Simon Bridges and deputy leader Paula Bennett about his mental health, saying his doctor had called them both to say that he was healthy.
Ross wanted to keep his Botany seat and use it to keep criticising the National Party, leading to questions about whether the party might use the waka-jumping law to force Ross out of Parliament.
But that would mean swallowing all of the party's vehement opposition to the law; Bridges himself called it "repugnant to democracy".
Otago University law professor Andrew Geddis said that the party had a case to use the law, but he considered it unlikely.
"No political party is going to force an unwell MP who is undergoing treatment out of Parliament. They just aren't," Geddis wrote on the Pundit blog.
To use the law, Bridges would have to give Ross 21 working day's notice, and then need a two-thirds majority in caucus to support him. He would then notify the Speaker, who would vacate the seat and force a byelection.
Bridges would have to prove that Ross had distorted parliamentary proportionality but, according to Geddis, Bridges would have legal precedent on his side; in 2005, the Supreme Court ruled that Donna Awatere-Huata satisfied this condition when she was expelled from the Act Party.
McDonald said he hoped that Ross was now getting the care he needed.
He said it was sometimes hard to spot signs that people were struggling, and cliches about crazy behaviour were unhelpful.
"The reality is this is about distress, and about people being in a lot of emotional pain that they are failing to manage."
He said it was difficult to make "armchair observations" about whether people should have spotted the signs earlier, given it was a "pretty unprecedented situation" in New Zealand politics.
"The party itself, as his employers, I guess, do have some responsibility in terms of how all of this has played out."
The Mental Health Act says that a compulsory treatment order needs to be heard and determined by a Family Court judge. If an MP is subject to such an order, the Speaker has to be notified under the Electoral Act.
The Speaker then asks the Director-General of Health and a medical practitioner to assess the MP, and they inform the Speaker whether the patient is "mentally disordered".
If so, a further assessment is carried out six months later. If the patient is still mentally disordered, the Speaker informs the House of Representatives and the MP's seat is vacated.
The Mental Health Act defines "mentally disordered" as someone who suffers from "an abnormal state of mind ... characterised by delusions, or by disorders of mood or perception or volition or cognition" that poses a serious health risk or renders that person unable to take care of themselves.
Speaker Trevor Mallard told the Herald he had yet to receive a notice of a compulsory treatment order, and if he did, he would seek advice and weigh up privacy matters, public interest and mental health concerns in deciding whether he should notify the House or the public.
WHERE TO GET HELP:
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call 111.
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
If it is an emergency and you feel like you or someone else is at risk, call 111.
There are lots of places to get support. For others, click here.
