Mental health technology funding soared last year, with companies bringing in $5.5 billion globally across 324 deals, according to CBInsights' State of Mental Health Tech 2021 Report.

That amounts to a 139% climb from 2020, when startups scooped up $2.3 billion across 258 deals. 

"As the pandemic continued to exacerbate mental health issues (such as anxiety and depression), there was growth in demand and investor interest in digital tools that enhanced mental healthcare delivery," the report's authors wrote. 

U.S. mental health companies continued to outpace other regions, bringing in $4.5 billion in funding last year. European startups raised $651 million, while Asian companies scored $289 million. 

But the report notes there's still room for growth: Some 68% of last year's deals were early-stage. Some of the largest early deals from the fourth quarter include Alto Neuroscience, Magnus Medical, Dawn Health, Mantra Health, Limbix and firsthand. 

"Notably, early-stage deal share has declined by 9 percentage points since 2019. As the sector matures, and these early-stage companies advance through later stages and find product-market fit, more growth may spur more funding," the authors wrote.

The sector also saw an increase of mega-rounds, funding rounds worth $100 million or more. The report counted 15 mega-rounds compared with only four in 2020. All these huge rounds went to U.S.-based companies in Q4. 

Some of the largest last quarter include BetterUp and Cerebral, which both scored $300 million, Elemy, which brought in $219 million, and Workit Health with $118 million. 

Overall, CBInsights found 43 exits in the mental health space, including 35 M&As, five SPACs and three IPOs. There were only 23 exits in 2020. 

M&A deals, which drove the majority of exits, increased 75% year-over-year.

"This reflected the consolidation trend seen across the broader digital health sector in 2021," the authors wrote. "This trend could continue through 2022 as dominant players emerge in a highly fragmented market."