Causes

The exact cause of persistent depressive disorder isn't known. As with major depression, it may involve more than one cause, such as:

• Biological differences. People with persistent depressive disorder may have physical changes in their brains. The significance of these changes is still uncertain, but they may eventually help pinpoint causes.
• Brain chemistry. Neurotransmitters are naturally occurring brain chemicals that likely play a role in depression. Recent research indicates that changes in the function and effect of these neurotransmitters and how they interact with neurocircuits involved in maintaining mood stability may play a significant role in depression and its treatment.
• Inherited traits. Persistent depressive disorder appears to be more common in people whose blood relatives also have the condition. Researchers are trying to find genes that may be involved in causing depression.
• Life events. As with major depression, traumatic events such as the loss of a loved one, financial problems or a high level of stress can trigger persistent depressive disorder in some people