Anorexia is the decreased sensation of appetite. While the term in non-scientific publications is often used interchangeably with anorexia nervosa, many possible causes exist for a decreased appetite, some of which may be harmless, while others indicate a serious clinical condition or pose a significant risk.
For example, anorexia of infection is part of the acute phase response (APR) to infection. The APR can be triggered by lipopolysaccharides and peptidoglycans from bacterial cell walls, bacterial DNA, double-stranded viral RNA, and viral glycoproteins, which can trigger production of a variety of proinflammatory cytokines. These can have an indirect effect on appetite by a number of means, including peripheral afferents from their sites of production in the body, by enhancing production of leptin from fat stores. Inflammatory cytokines can also signal to the central nervous system more directly by specialized transport mechanisms through the blood–brain barrier, via circumventricular organs (which are outside the barrier), or by triggering production of eicosanoids in the endothelial cells of the brain vasculature. Ultimately the control of appetite by this mechanism is thought to be mediated by the same factors normally controlling appetite, such as neurotransmitters.
Medical Marijuana Efficacy
Use of marijuana stimulates the body’s metabolism and causes users to experience an increase in appetite. Numerous disease states can cause symptoms of decreased appetite to develop in affected patients. If this occurs, patients often lose significant amounts of weight, which can be detrimental to the disease recovery process. The human body requires energy-in the form of ingested food-to fight infection and heal cell or tissue damage. In patients who experience decreased appetite due to a specific disease, medical marijuana may be helpful in appetite stimulation. Medicinal marijuana can signal a food craving within a patient’s body through the endocannabinoid system, encouraging the patient to eat to provide energy to the body.
An appetite-enhancing effect of THC is observed with daily divided doses totalling 5 mg. When required, the daily dose may be increased to 20 mg. In a long-term study of patients, the appetite-stimulating effects of THC continued for months, confirming the appetite enhancement noted in a shorter six-week study. THC doubled appetite on a visual analogue scale in comparison to placebo. Patients tended to retain a stable body weight over the course of seven months.