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 factors. Biological vulnerability is the tendency to develop problems in a specific area of the bodyâfor example, respiratory system problems such as asthma. Similarly, people can have a biological tendency to develop mental health problems such as depression, bipolar disorder or schizophrenia.