Prioritizing mental health is important at every stage of life, from childhood all the way through adulthood. Poor mental health can affect your mood, behaviours, and thinking, and negatively impact your relationships and physical health. This link also works in the other direction – your relationships, physical well-being, and habits can all affect your mental health. The impact of mental health on physical health and quality of life – and vice versa – is why mental health is so important.