Depression can affect people at any life stage. An individual suffering from depression can experience a variety of symptoms that may include fatigue, difficulty concentrating, change in appetite, irritability, agitation, withdrawal, insomnia or excessive sleeping, and in some cases, thoughts of death. The causes of depression are still unknown, but it is thought that imbalances in neurotransmitters or chemicals in the brain contribute to symptoms. Several pharmaceutical agents can be used to treat depression; however, many of them have unwanted, negative side effects. Fish oil, and more specifically EPA, has been extensively researched for the role it can play for the treatment of major depression and postpartum depression, as well as potentially for bipolar disorder.