Theory

• Low serotonin levels in the blood are linked to depression. Also, medications that block reuptake or increase serotonin levels through another mechanism alleviate depressive symptoms in many cases.
  
  

Insomnia

• Poor sleeping habits can lead to decreased serotonin levels. If you are experiencing depression, try to follow a set sleep schedule, or talk to your physician about a sleep aid.
  
  

Lack of Exercise

• Depression is linked to low motivation and a decrease in activity. Chronic fatigue may be experienced. However, forcing yourself to follow a set exercise routine may help alleviate your depression and increase serotonin levels.
  
  

Poor Diet

• A diet that lacks carbohydrates or includes a lot of junk food can lead to a decrease in serotonin levels. Consider healthy carbohydrates and also foods that contain tryptophan, such as almonds, pumpkin or sesame seeds, whole grains and beans.
  
  

Lack of Sunlight

• Inadequate exposure to sunlight may lead to low serotonin levels. Some forms of artificial light can help raise serotonin levels. Light therapy has been suggested as a possible treatment for depression for this reason.
  
  

Stress

• Poorly managed stress can decrease serotonin levels, leading to depression. Finding ways to adequately cope with stress can help alleviate depression, improve physical health and increase serotonin levels.