The hard way – look for unusual behaviors and try to get the person to admit he is behaving irrationally.
The easy way – the other drivers of health, so visible to everyone, even the person suffering from psychological ills – drop off when psychological ailments lay a person low and a person’s psychological health deteriorates faster and more thoroughly because of these second winds. It is common medical practice to treat mental illness and none of these other factors – naïve to the point of ludicrousness.
As an example, think of Nietzsche’s lifestyle in the decade before he went insane. His “insanity” was an intermittent medical condition, with all kinds of warning signs, long before it was diagnosed as a mental illness. Of course nothing was done about it; medicine does not know what to make of intermittent medical conditions. It was likely that paresis was a driver and the negative lifestyle variables accelerators of the development of outright insanity.
Those drivers of overall health that contribute to psychological health (a driver of overall health as well) and that fall off during the decline in psychological health and accelerate and aggravate the process of mental illness:
1. Quality/quantity of sleep – people with psychological ills are almost all taking drugs to help them sleep and even then the quality is poor, the side effects noxious, and they live in a stupor.
2. Quality/quantity of exercise – people with psychological ills rarely even go for walks. When someone used to enjoy a good stroll and no longer derives enough pleasure to continue to do so, something is wrong.
3. Quality of diet – catch as catch can, virtually no effort made in this area when psychological ills take over. May be accompanied by significant weight loss as well as outright nutrient deficiencies. When the person used to take great joy in preparing and enjoying delicious and nutritious meals, and no longer makes any effort or seeks the same thing in good restaurants, something is wrong.
4. Daily fasting – the vast majority of even psychologically healthy people do not do this; this counts only if the person used to fast or at least calorie restrict. Lack of fasting -lack of effort is the common denominator in mental illness- is easily concealed by the weight loss due to irregular eating habits that may look like an effort is being made to control food intake and weight gain. No – next to no effort is a hallmark of mental illness.