Fits of periodical depression, familiarly known as "the blues," occur in the experience of practically everyone. In some people they are only slight and passing. In others they last for hours and make the individual quite miserable. In still others, without actually running into melancholia, they produce serious discouragement and continuous discomfort which persists even for days and makes life intolerable. They come and go quite unaccountably. During their occurrence all vitality is lowered, appetite lessened, aches and pains are emphasized, sleep may be disturbed, exercise becomes distasteful, and they usually present an interval when health is at a low ebb. Ordinarily when described as "the blues" they have no definite connection with any known physical cause. They are passing incidents which seem to recur at irregular intervals. When connected with physical ills they are thought of directly as symptoms of these ills. All forms of disease may be associated with such fits of depression and many physical symptoms seem to be due to the fact that during these periods there is a distinct lowering of physical vitality so that the nerve impulses which ordinarily enable functions to be performed without interference are interrupted, or at least are inhibited, to a noteworthy degree. While to a certain extent the condition is a mental disease, it may be modified by the correction of physical derangements, by stimulation and, above all, by suggestion and a change in the point of view.

Serious Pathological Conditions.—Of course, such periodical fits of depression are associated with various serious progressive ailments and then are primarily physical, and are only secondarily psychic. From the standpoint of psychotherapy it is important to remember that certain serious organic lesions may show their first signs in the patient's mental state. It is not unusual, for instance, for the disposition of a patient suffering from kidney disease to change so materially that the attention of friends is called to the change before any physical symptom of the nephritis has been noted. Sometimes for a year there will be a progressive clouding of what had previously been a rather happy disposition. Decisions will be made more slowly than before. The judgment will be impaired. There are some striking examples of this in history, of which the unfortunate Athenian general, Nicias, put to death for incapacity that was undoubtedly pathological, is one. Pleasures will be taken half-heartedly; men who have been bright and jovial will now become saturnine. Men who have been the life of parties will try to hold the place they acquired before, though all around them will perceive how difficult it is for them to maintain the role they have set for themselves. Whenever there is a notable change in disposition, it is well not to attribute it to some passing mental condition and, above all, not to dismiss {642} it as a peculiarity unamenable to treatment, but to look for the underlying pathological basis of the new condition.

In this way physical disease will sometimes be discovered long before it otherwise would be. This must be particularly noted when there have been a series of worries. Occasionally it seems enough to many people to ascribe a change of disposition to the troubles that have come over a patient. If a business man fails or passes through a crisis in his affairs in which failure is very near, or he has many business worries over a prolonged period, these are sometimes thought to be quite enough to explain a change of disposition. They are, but not to the degree that is often noted, for, in excess, melancholic tendencies are always pathological, that is, they have some basis in a serious mental or physical change. If there is an insidious nephritis already at work, its symptoms will be much exaggerated and its progress accelerated by the worries and disquietude of such a time. If a wife loses her husband, or an only son, or a favorite child, the occurrence of a prolonged period of depression should lead to a careful investigation of physical conditions and of the underlying mental state in the hope of guarding against serious developments.

Heart Disease.—Periods of depression are also common in heart disease and are often the first symptom of the beginning of a break in compensation. This effect is not so simple and direct, however, as in the case of the kidneys. Probably the first physical symptom of a break in compensation, where there is real valvular heart disease, is a decrease in the amount of urine. This points to an insufficient elimination of the products of metabolism and to the retention in the circulation of toxic substances. The reason for this is the lessened circulation through the kidneys because of the diseased heart. There is also a lessened circulation through the brain. This impairs the function of the brain and quite naturally leads to mental depression, slowness of decision, and unwillingness to occupy one's self with many things. Besides, because of the lessened function of the kidney the circulating blood not only does not nourish so well but it tends still further to depress the brain cells by the toxic substances that are in it. Depression in such cases is rather to be expected and at the beginning is not continuous but comes in ever longer periods with shortening intervals as the disturbance of the circulation progresses. At first, like other diminutions of function, it is conservative in order to spare the heart work.

Respiratory Affections.—Very curiously an affection of the lungs has exactly the opposite effect and is likely to create in the patient an artificial sense of well-being. Spes phthisica, the characteristic hope of consumptive patients, is well known, and has been described by many a careful observer from Hippocrates and Galen to our own time. A lessened amount of oxygen in the blood produces a certain sleepiness, but this seems to be preceded by a period of slight excitation. The most familiar example of this occurs at the beginning of the inhalation of laughing gas. Practically the only direct physical effect of the inhalation of nitrous-dioxide is to shut off our oxygen and it is a slight period of deoxygenation that produces the anesthesia by this agent. Whether we have not in this the explanation of the feeling of the consumptive, so that often on the day before his death he plans a number of things that he is going to do next year, may require more careful {643} investigation, but the suggestion may serve to show how much disposition, both lively and serious, depends on physical factors as well as on the natural state of mind.