9. Seek Treatment for Depression

Anything that causes major stress in life, including anxiety or anger, will eventually eat away at the parts of the brain that are responsible for memory. Chief among these stressors is major depression. Depression is often misidentified as a memory problem since one of the main symptoms of the condition is an inability to concentrate. If you can't concentrate on schoolwork or the information needed to complete a task on the job, then you may feel as if you're constantly forgetting things. As it is, you're not even able to concentrate long enough to learn them in the first place.

Depression causes an increase of cortisol levels in the bloodstream, which in turns elevates the amount of cortisol in the brain. With the help of brain imaging devices, doctors have been able to see how that increased cortisol diminishes certain brain areas, chief among them the hippocampus [source: Tan]. One study showed that people who had been depressed, even if it was years ago, had suffered a 12 to 15 percent loss in the hippocampus [source: Victoroff]. Since the hippocampus is the clearing center for short-term memory, prolonged depression demolishes the brain's ability to remember anything new.

Additionally, depression affects the types of things a person is able to remember. While everyone's brain is selective about which memories make it into long-term storage, people with depression seem only able to retain negative memories [source: Crook]. That means there's a neurological reason why a person with depression remains obsessed with the one time a loved one forgot a birthday or anniversary, even if it was remembered every other year.
But happy memories needn't be lost forever to someone battling depression. Medications for depression, including selective serotonin reuptake inhibitors (SSRIs), have been shown to jump-start the process of cell regeneration in the hippocampus [source: Tan].

The next item on our list can help fight depression while it improves memory as well.