Poison ivy and other poison plant rashes canât be spread from person to person. But it is possible to pick up the rash from plant oil that may have stuck to clothing, pets, garden tools, and other items that have come in contact with these plants.
Biological Causes. Some individuals are more vulnerable to depression than others due to their own unique biological factors, such as presence of depression-triggering genes. This means that depression is hereditary; hence it tends to run in families, notes the Black Dog Institute.nother biological trigger of depression is abnormal brain structure and chemistry. The report released by the National Institute for Mental health notes that the brain structure of an individual with depression is slightly different from the rest of individuals who do not have the disorder.
Biological depression is thought to be triggered by changes in the body with no contribution from external events. Periods of stress or trauma â a result of events such as losing a job or a loved one â are the most commonly cited triggers for the onset of depression in individuals.