Symptoms are often deliberately produced or feigned, and may relate to either symptoms in the individual or in someone close to them, particularly people they care for. There are attempts to introduce a category of relational disorder, where the diagnosis is of a relationship rather than on any one individual in that relationship. The relationship may be between children and their parents, between couples, or others. There already exists, under the category of psychosis, a diagnosis of shared psychotic disorder where two or more individuals share a particular delusion because of their close relationship with each other. There are a number of uncommon psychiatric syndromes, which are often named after the person who first described them, such as Capgras syndrome, De Clerambault syndrome, Othello syndrome, Ganser syndrome, Cotard delusion, and Ekbom syndrome, and additional disorders such as the Couvade syndrome and Geschwind syndrome. Signs and symptoms
Course
The onset of psychiatric disorders usually occurs from childhood to early adulthood. Impulse-control disorders and a few anxiety disorders tend to appear in childhood. Some other anxiety disorders, substance disorders, and mood disorders emerge later in the mid-teens. Symptoms of schizophrenia typically manifest from late adolescence to early twenties.The likely course and outcome of mental disorders vary and are dependent on numerous factors related to the disorder itself, the individual as a whole, and the social environment. Some disorders may last a brief period of time, while others may be long-term in nature. All disorders can have a varied course.
Pathophysiology
The symptoms of CAP are the result of lung infection by microorganisms and the response of the immune system to the infection. Mechanisms of infection are different for viruses and other microorganisms. Viruses
Up to 20 percent of CAP cases can be attributed to viruses. The most common viral causes are influenza, parainfluenza, human respiratory syncytial virus, human metapneumovirus and adenovirus. Less common viruses which may cause serious illness include chickenpox, SARS, avian flu and hantavirus.Typically, a virus enters the lungs through the inhalation of water droplets and invades the cells lining the airways and the alveoli. This leads to cell death; the cells are killed by the virus or they self-destruct. Further lung damage occurs when the immune system responds to the infection. White blood cells, particularly lymphocytes, activate chemicals known as cytokines which cause fluid to leak into the alveoli. The combination of cell destruction and fluid-filled alveoli interrupts the transportation of oxygen into the bloodstream. In addition to their effects on the lungs, many viruses affect other organs. Viral infections weaken the immune system, making the body more susceptible to bacterial infection, including bacterial pneumonia. Bacteria and fungi
Although most cases of bacterial pneumonia are caused by Streptococcus pneumoniae, infections by atypical bacteria such as Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila can also cause CAP. Enteric gram-negative bacteria, such as Escherichia coli and Klebsiella pneumoniae, are a group of bacteria that typically live in the large intestine; contamination of food and water by these bacteria can result in outbreaks of pneumonia.