Depression can have multiple causes, but most of the time, it’s a combination of:

• Biological factors.
• Social factors.
• Psychological factors.

The following review showed many determinants at work, such as inflammatory reactions, social and psychological factors, the microbiome, and dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. It indicates that physical issues may be proximal causes of depression, which can cause distal social factors such as social capital, environmental circumstances, and isolation.

The World Health Organization, the Marmot Report, and Compton et al. conclude that people who are most socioeconomically disadvantaged in society face the most discomfort and difficulty. That comes as no surprise to me, seeing as having less money than average means having access to fewer or less-than-adequate resources like proper housing, food, and even clothing. At the end of the day, we all have bills to pay.

This inequality in resources leads to worse outcomes for those who are less privileged.

People who don’t have much social support, no early emotional attachments to others, or access to resources such as water, food, and proper nutrition have a higher chance of contracting a mental disorder such as depression.

And finally, the timing of the events is also critical for our mental health. Early life is the most important because our mental faculties develop when we are young. That’s why experiencing damaging affairs such as stress in our youth can lead us down the path of depression during adulthood or later in life.

This alone will not necessarily cause depression, but combined with a genetic predisposition can greatly increase the risk.

Other risk factors include:

• Genes: Depression regularly runs in families. Thus, a family history of depression can increase the risk of developing it yourself.
• Gender: Women are twice as likely as men to become depressed.
• Older people have a higher chance of getting depressed due to more frequently lacking appropriate social support, being less mobile, and having a higher chance of living alone.
• Frequent conflicts with other people.
• The loss or death of a loved one.
• Personal problems, such as social isolation or other mental disorders.
• Experiencing sexual, emotional, and physical abuse.
• Major life events such as losing your job, retiring, getting divorced, or graduating from school.
• Substance abuse, such as alcoholism.
• Certain medications can increase the risk of becoming depressed.