What can drive someone to insanity? Certainly, insanity is commonly understood (or misunderstood) and it usually carries some sort of stigma in the popular consciousness. If you believe in modern psychology and psychiatry, there are thousands of forms of insanity that a person can end up to develop over a lifetime. Some of them, like depression, are temporary, while others, like social anxiety, require more work for a person to get through. However, there appears to be some commonality of what actually brings about most forms of insanity that people go through. This brings the question to bear: is there a common, underlying trigger that deteriorates the stability of a person's mental health?
Often cited are factors like stress and anxiety as most of the common (and several uncommon) mental health issues are triggered by one of the two. Continued exposure to stress can eventually push someone beyond their “breaking point," and external factors will affect this form of insanity afterward. This is often a long, strenuous process because most people have some level of resistance to such things, allowing them to at least survive the stressful period with their sanity intact. Additionally, the process may not even really result in insanity, with most of the population serving as proof of this theory. Prolonged stress can affect a person's behavior and outlook, but it is also known that several other factors can increase or reduce the impact of this. In some cases, stress and anxiety can even have the opposite effect, depending on the person's outlook.
Emotions are also said to play a critical role in driving or pushing people into insanity as it is so closely tied to mental health. A person's emotional state can often be a reflection of a person's relative mental stability, but may also become an outcome of fractured sanity. There is no doubt that emotions can disrupt and affect a person's thought process, making one do things that one would not normally do. It has also been noted that extremely emotional situations and heavy emotional trauma can permanently affect a person's mind, often resulting in a condition that requires a therapy to overcome. However, it is rather arguable that emotions are merely augmenting the effects of stress and pressure, not causing them.
Trauma is also frequently regarded as having drastic effects on a person's sanity, particularly if it occurs during the formative years. The extreme psychological and emotional impact of trauma can force people to go past their breaking point, having permanent effects on mental health. However, it should be noted that trauma tends to be little more than a combination of stressful and emotional factors, usually mixed with extreme circumstances. The vulnerability of the person's psyche plays a larger role here than in other potential causes of insanity. This explains why trauma encountered later on in life does not have the same general effect as similar events encountered during childhood do.
Ultimately, insanity is something that, like sanity, must be defined on an individual basis. What is sane for one person in a given society may not be considered such by a different person within the same society. Insanity is a matter of context in this case - an assumption that some psychological texts make.