If parasites are present in the body, they produce toxins inside the body. These toxins are in the blood. The toxic blood can affect the heart. They can also affect the central nervous system.
Toxic blood flows across the myelin sheath that covers the brain, this irritates and triggers the central nervous system. CNS problems include depression, anxiety, mood swings, brain fog, etc.
Removing the parasites removes the source of the toxins that might be causing the symptoms.
You do not have to purchase anything, but more information can be found at http://www.humaworm.com