Two studies published by Poverty Solutions were cited in an article in Vox which stated that "cash transfers in the US, and those studies found the transfers did... very little."
The papers by Ford School professors Brian Jacob, Natasha Pilkauskas, and Luke Shaefer, PhD candidate Katherine Richard, and Elizabeth Rhodes from Open Research, looked at two different rounds of $1,000 cash grants from the charity GiveDirectly, which distributed the money to American households in May 2020 and again in October that year.
The article summarizes, "After surveying recipients, as well as a control group of non-recipients, the researchers found no differences between the two groups on any of the five outcomes they were interested in. The study covering the May 2020 payments did find some reduction in material hardship among very low-income households specifically, and some weak evidence that mental health improved. And in October, there weren’t even those silver linings — even in the subgroups, no significant effects were found."