The Czech, who won the Wimbledon title in 2023, said the incident in December occurred because she had "reached a breaking point after months of physical and mental stress".
In December, Vondrousova described a "serious intrusion into my privacy" from a doping control officer who arrived demanding an immediate test.
"It is very tough for me to talk about this, but I want to be transparent with you about my mental health," Vondrousova, 26, wrote on Instagram.
"For a long time, I've been dealing with injury, constant pressure and ongoing sleep issues that left me feeling exhausted and fragile. It slowly wore me down more than I probably realised at the time.
"Years of hateful messages and threats have affected how safe I feel in my own space. When someone rang my door late at night without properly identifying themselves or following protocol - I reacted as a person who felt scared.
"In that moment, it was about feeling safe, not about avoiding anything."
The International Tennis Integrity Agency (ITIA) said they were aware of Vondrousova's comments and confirmed that she was not serving a mandatory provisional suspension.
"We can confirm that an investigation is underway and the player has been charged with refusing a test," the agency said.
"At this stage, we are not able to comment any further on the specifics."
Vondrousova has not played a tournament since the Adelaide International in January and withdrew from the Australian Open citing a shoulder injury. She is on the entry list for the Madrid Open starting on Tuesday.
She revealed that experts confirmed she suffered an acute stress reaction and generalised anxiety disorder.
"In that moment, fear clouded my judgment and I just couldn't process the situation rationally," she said.
Vondrousova referred to twice Wimbledon champion and compatriot Petra Kvitova, who suffered severe wounds to her left hand in a struggle with a knife-wielding intruder at her home.
"After what happened to Petra, we don't take strangers at our door lightly," Vondrousova added.
"I'm trying to slowly find my way back - both on and off the court ... I'm still working to clear my name, but at the same time I need to take care of myself."
Elsewhere, French Open champion Coco Gauff's claycourt season got off to a shaky start as she lost 6-3 5-7 6-3 to Karolina Muchova at the Stuttgart Open.
Mirra Andreeva overpowered four-times Roland Garros winner Iga Swiatek 3-6 6-4 6-3 in her quarter-final tie.
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