What the long term data actually shows
This is the part with numbers in it, and they are put here rather than in lesson one on purpose, because starting a parent off with effect sizes is a good way to lose them.
What the research says
Wang MT, Kenny S (2014). Longitudinal links between fathers' and mothers' harsh verbal discipline and adolescents' conduct problems and depressive symptoms. Child Development, 85(3), 908 to 923 doi
Around a thousand two parent families were followed across two years. Harsh verbal discipline by either parent at thirteen predicted increases in both low mood and conduct problems by fourteen. Two details matter more than the headline. The relationship ran both ways, so adolescents with more conduct problems also drew more harsh discipline from their parents. And parental warmth did not cancel the effect, which means the common belief that shouting does not matter as long as the child knows they are loved did not hold in this data. Published sample sizes for this study differ between sources, so no figure is quoted here.