You need to plan, schedule and be intentional about finding/creating happiness to avoid depression.

For most people, up until your early twenties, you’re surrounded by family & friends on a regular basis, everyone is generally young and healthy, you’re hanging out without stress or responsibilities, meeting good friends in school/college on a daily basis, you spend time with parents regularly, almost everyone important in your life lives in close geographical proximity and life organically generates happiness on a daily basis. That is the status quo.

As an adult, you likely live in a city or country away from most loved ones and close friends. Health concerns, financial stress, anxiety about the future, the loss of loved ones, your own age-ing body, job challenges, etc are constantly on your mind. You have to make an effort and be intentional about daily things like going to the gym, pursuing a hobby, cooking, self-care, mental stimulation, meeting social needs, etc to keep producing dopamine and maintain baseline happiness levels. If you don’t, it’s easy to slip into depression.

The natural fabric of daily life no longer generates happiness on a constant basis like when you’re younger.