Harvard Health Content API

Research suggests that depression is not simply a chemical imbalance. It doesn't spring from simply having too much or too little of certain brain chemicals. Rather, there are many possible causes of depression, including faulty mood regulation by the brain, genetic vulnerability, and stressful life events. It's believed that several of these forces interact to bring on depression.

To be sure, chemicals are involved in this process, but it is not a simple matter of one chemical being too low and another too high. Rather, many chemicals are involved, working both inside and outside nerve cells. There are millions, even billions, of chemical reactions that make up the dynamic system that is responsible for your mood, perceptions, and how you experience life.

Hypoxemia is the medical term for a low blood oxygen level. There are many causes but by far most of them are caused by a lung or heart problem. The primary symptom is shortness of breath, but people with hypoxemia will also have less exercise tolerance, feel weak and tire easily. They often have a rapid breathing rate and accelerated heart rate.

Smell disorders are often classified as one of the following:
•    anosmia: complete loss of the ability to detect odors
•    hyposmia: decreased sense of smell with some ability to detect odors
•    dysosmia: distorted sense of smell.
Hyposmia commonly happens as we age. Other causes of loss of smell or distorted smell include:
•    COVID-19 or a cold or sinus infection
•    hay fever (allergic rhinitis)
•    nasal polyps
•    a medication, such as the cholesterol-lowering drug atorvastatin (Lipitor), the blood pressure drug amlodipine or the antibiotic erythromycin
•    a side effect of general anesthesia.

The best remedy for headaches is the one that works best for you. It could be just lying down in dark, quiet room. For people with migraine, taking preventive medicine daily can be very effective. If you do use medication, take it as soon as your feel the headache about to come on. An inexpensive over-the-counter product that contains aspirin, acetaminophen and caffeine works well for many people.

Five symptoms of myalgic encephalomyelitis/chronic fatigue syndrome include:
1.    A substantial reduction or impairment in the ability to engage in pre-illness levels of occupational, educational, social or personal activities for longer than 6 months
2.    Post-exertional malaise (PEM), which is a worsening of symptoms following physical, mental, or emotional exertion that would not have caused a problem before the illness.
3.    Unrefreshing sleep that leaves not feeling better or perhaps even feeling worse after a full night’s sleep and no other reason for poor sleep quality.
4.    Cognitive impairment, such as problems with thinking, memory, attention, organization skills, and information processing. 
5.    Orthostatic intolerance, which is a worsening of symptoms upon assuming and maintaining upright posture.