Schizophrenia

Description

Risk Factors

Schizophrenia is the most common psychotic condition. It affects about 1% of the earth's population, including more than 2.7 million people in the US.

Age

Schizophrenia can occur at any age, but it tends to first develop (or at least become evident) between adolescence and young adulthood. Schizophrenia that is recognized in children is likely to be severe. Although the risk of schizophrenia declines with age, there is a lesser peak incidence at around 45 years and another, mostly in women, in the mid-60s. Late-onset schizophrenia that develops in the 40s is most likely to be the paranoid subtype with fewer negative symptoms or learning impairment. Such patients usually have functioned at a near-normal level until structural deficits in the brain break down.

Gender

Although schizophrenia affects both genders, there are some differences:

• Men tend to develop schizophrenia between the ages of 15 and 24. Paranoid schizophrenia, in particular, may be more common in men, and symptoms tend to be more severe.
• The onset in women is usually slightly later, between 25 and 34, and the symptoms tend to be less severe. The earlier a girl starts menstruation, the longer she is protected against schizophrenia. And, in women with schizophrenia, the disease is more severe during the time in their menstrual cycle when estrogen levels are low. Such findings and other evidence suggest that estrogen may have nerve-protecting properties. For example, the higher the estrogen levels in female patients with schizophrenia, the better their mental functions.

Intelligence

Genius is not spared; schizophrenia's victims span the full range of intelligence. In fact, one study reported that a higher than expected number of people who develop schizophrenia had been intellectually gifted children. Research suggests, however, that a decline in IQ scores during childhood may be a harbinger of psychotic symptoms in adults.

Cultural and Geographic Factors

No cultural or geographic group is immune, although the course of the disease seems to be more severe in developed than in developing countries. Also, interestingly, the content of delusions may vary depending on a person's culture. According to one study, for example, European patients were more apt to have delusions of poisoning or religious guilt while in Japan the delusions were most often related to being slandered.

Socioeconomic Factors

The disease occurs twice as often in unmarried and divorced people as in married or widowed individuals. Furthermore, people with schizophrenia are eight times more likely to be in the lowest socioeconomic groups. According to a 2001 study, however, these findings are likely to be a result of schizophrenia rather than a cause. Nevertheless, low income and poverty increases the risk for delayed diagnosis and treatment, and such delays could lead to more severe disease in patients with fewer resources. Poverty may also increase exposure to biologic factors (e.g., infections or toxins) or social stressors that could trigger the illness in susceptible people.

Other Factors Associated with Schizophrenia

Non-Right Handedness. The prevalence of mixed- and left-handedness is significantly higher in patients with schizophrenia than in the general population, suggesting some neurologic pattern that may be responsible for each. (A large minority of the population is non-right handed and very few of these people develop schizophrenia.)

Abnormal Olfactory Bulbs. Studies are reporting impairment in the sense of smell in patients with schizophrenia. One study reported abnormally small olfactory bulbs in patients with schizophrenia. Olfactory bulbs are nerve centers in the brain that regulate the sense of smell.

Obsessive-Compulsive Disorder. Obsessive compulsive disorder (OCD) affects a significant number of schizophrenic patients. OCD is an anxiety disorder marked by obsessions (recurrent or persistent mental images, thoughts, or ideas) that may result in compulsive behaviors, repetitive, rigid, and self-prescribed routines that are intended to prevent the manifestation of the obsession. Some experts believe the behaviors exhibited in the disorder may actually be protective in people with schizophrenia in early stages.

Behavioral and Motor Problems in Childhood. Children who later develop schizophrenia often suffer from the following certain problems, including excessive shyness or minor early physical and motor-control problems. Such problems are so common, however, that their presence without any other risk factors is no cause for concern.

Malnutrition in the Pregnant Mother. Malnutrition in the mother during the first trimester of pregnancy (less than 1,000 calories a day) has been associated with later schizophrenia in the child. Nutritional deficiencies during that time are believed to impair fetal brain growth.

Fathers Age. According to some studies, the older a father is when a child is born, the greater the risk is for schizophrenia in his offspring, perhaps because of a greater chance of genetic mutations in the sperm that can be passed on. In one study, children of fathers who were 50 years old or more or faced a three-fold risk for schizophrenia compared to children of fathers who were 25 or younger.