Final answer:
Chronic medical conditions, isolation, and substance abuse can contribute to the onset of significant depression.
Step-by-step explanation:
The onset of significant depression can be contributed to by a combination of factors. These include chronic medical conditions, isolation, and substance abuse. Studies have shown that each of these factors can play a role in the development of depression.
Chronic medical conditions, such as heart disease or diabetes, can have a negative impact on a person's mental health and increase their risk of experiencing depression. Isolation, or a lack of social support, can also contribute to feelings of loneliness and sadness, which are common symptoms of depression. Additionally, substance abuse, including alcohol or drug addiction, can worsen feelings of depression and increase the risk of developing a depressive disorder.