Ms Holz said she lived with depression for most of her life but had been "in recovery" for three years.
"I was diagnosed with depression and anxiety at 22, although Id had it since I was about 12," she said.
The 29-year-old psychology student said she joined public speaking group Toastmasters in January this year to build professional connections.
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READ NOW"At university, we do lots of speeches and that was one of the reasons I joined, because I did a speech about three years ago and I just froze," Ms Holz said.
"I can see the contrast of what I used to be and it's like looking at a different person, but that's how depression affects your confidence and self worth."
The Plain Speakers, a group of 15 people "from all walks of life", met in East Perth each week to present structured presentations and improve their public speaking skills.
Ms Holz shared her journey at the annual Men in Black Ball in June to raise awareness of men's mental health
"Going from not being able to speak in front of a class to speaking in front of 300 people shows how much I've grown," she said.
Ms Holz said public speaking and her study had helped her mental health.
"Having knowledge of psychology has been the cornerstone to my recovery in understanding the basics of depression," she said.
Ms Holz said she had also judged the Speak with Confidence awards, a primary school public speaking competition held by the City of South Perth in June this year.