Clinical depression is thought to be caused by a combination of biological, psychological and social factors. There are certain risk factors that may make you more vulnerable. Learning what the risk factors are and making lifestyle changes might help reduce the risk of developing depression.

• Genetics. If you have family members who have suffered from depression, you may have a greater risk of developing depression yourself, although there is currently no direct gene that has been found to cause depression.
• Early childhood trauma or abuse. Emotional trauma and abuse has a powerful effect on the psyche. If you had traumatic early life experiences, you may be more at risk to develop depression during or after a stressful life event. 
• Loneliness and lack of social support. A key risk factor for depression is isolation and loneliness. Lack of support, whether it is family, friends or colleagues, makes coping with stress all the more difficult. Having marital and relationship problems can also make you feel alone and frustrated.
• Recent stressful or traumatic life experiences.  Some events, like losing a loved one, are clearly stressful and cause enormous disruption and strain in our lives. However, anything that causes change can be a stressful life experience, even if it is normally considered a happy event such as a big work promotion, a wedding or childbirth.
• Alcohol and drugs. Alcohol and drugs can cause strong depression symptoms on their own. They can also make you more vulnerable to depression even if you decide to stop using them. Some people try to treat themselves with alcohol and drugs to self medicate, but this only worsens the problem.
• Finances and employment. Financial strain can be an enormous stressor. Struggling to pay the bills or mortgage, or suddenly becoming unemployed, is a very stressful life event. Being unemployed can be a blow to self confidence and can be a very difficult adjustment, especially for men.
• Health problems or chronic pain. Health problems and chronic pain may reduce your mobility, your ability to work or your spare time. They can chip away at supportive relationships and make you feel hopeless and frustrated.