Biological factors consist of anything physical that can cause adverse effects on a person’s mental health. This includes genetics, prenatal damage, infection & aberrant post-infection immune reposes, exposure to toxins, epilepsy, concussions or TBI, physiochemical imbalances, and substance abuse. As we seek a genetic understanding we should consider the concept of endophenotype – which gives us some tools to discern the various illnesses that create apparently similar symptoms (depressive suffering can be caused by any number of illnesses like depression, bipolar depression, epilepsy, early dementia, paraneoplastic syndromes, fever).
Experienced events that evoke feelings of loss or of (impending) damage are most likely to cause a mental disorder to develop in an individual. Some examples include abuse, trauma, violence or neglect, social isolation, loneliness or discrimination, bereavement, stress, economic instability, and psychosocial failure. In some cases, temperament or social influences can alter the way that an experience can lead to illness – sometimes this is related to resilience.
The brain is a highly changeable organ. It can respond in fruitful and also dysfunctional ways to outside influence. The “right amount of stress” can facilitate maturation and healthy strength. On the other hand, “early life stress” can harm the tissue of the brain in a way that creates epilepsy within the limbic system. The epigenetic phenomenon might be a missing link in the analysis of how biological and experiential influences collide to create illness.