Several studies indicate that the incidence of schizophrenia is higher in men. Most of the studies found the age of onset to be earlier in men than in women. Findings on symptoms are less conclusive, with some authors suggesting that men suffer more negative symptoms while women have more affective symptoms.
Men show an earlier age at onset, higher propensity to negative symptoms, lower social functioning, and co-morbid substance abuse than that is women, whereas women display relatively late onset of the disease with more affective symptoms.
There is no disparity in the occurrence and prevalence of schizophrenia between men and women, though schizophrenia is more closely associated with younger men. This may be due to the fact that women are more likely to experience the onset of schizophrenia later than men.
Past studies have reported that offspring of affected mothers have a higher risk of schizophrenia than the offspring of affected fathers; however, other studies found no such maternal effect [Gottesman and Shields, 1976].
The exact causes of schizophrenia are unknown. Research suggests a combination of physical, genetic, psychological and environmental factors can make a person more likely to develop the condition. Some people may be prone to schizophrenia, and a stressful or emotional life event might trigger a psychotic episode.
11 The heritability of schizophrenia in this study was estimated to be 79%. However, the relatively low rate (33%) of concordance in identical twins indicates that other factors besides genetics are at play in schizophrenia development.
Risk factors
Having a family history of schizophrenia. Some pregnancy and birth complications, such as malnutrition or exposure to toxins or viruses that may impact brain development. Taking mind-altering (psychoactive or psychotropic) drugs during teen years and young adulthood.
Men and women are equally likely to get this brain disorder, but guys tend to get it slightly earlier. On average, men are diagnosed in their late teens to early 20s. Women tend to get diagnosed in their late 20s to early 30s. People rarely develop schizophrenia before they're 12 or after they're 40.
Although schizophrenia can occur at any age, the average age of onset tends to be in the late teens to the early 20s for men, and the late 20s to early 30s for women. It is uncommon for schizophrenia to be diagnosed in a person younger than 12 or older than 40.
Most studies, but not all, report an almost equal gender ratio in the prevalence of bipolar disorder but the majority of studies do report an increased risk in women of bipolar II/hypomania, rapid cycling and mixed episodes. Important gender distinctions are also found in patterns of co-morbidity.
The peak age of onset of schizophrenia is 15 – 25 years in men and 20 – 30 years in women. It is often preceded by a prodromal phase of vague symptoms, some odd behaviours and a decline in functioning at school or work and interpersonally.
In most people with schizophrenia, symptoms generally start in the mid- to late 20s, though it can start later, up to the mid-30s. Schizophrenia is considered early onset when it starts before the age of 18. Onset of schizophrenia in children younger than age 13 is extremely rare.
Schizophrenia usually involves delusions (false beliefs), hallucinations (seeing or hearing things that don't exist), unusual physical behavior, and disorganized thinking and speech. It is common for people with schizophrenia to have paranoid thoughts or hear voices.
Having a first degree relative (FDR) with schizophrenia is one of the greatest risks for the disorder. While the risk is 1 percent in the general population, having an FDR such as a parent or sibling with schizophrenia increases the risk to 10 percent.
A large Danish study of twins found that schizophrenia is about 79% heritable. In other words, 79% of the risk of developing schizophrenia is due to genetic factors. But that doesn't mean you have a 79% chance of developing the disorder if you have a close relative who has it.
Schizophrenia affects approximately 24 million people or 1 in 300 people (0.32%) worldwide. This rate is 1 in 222 people (0.45%) among adults (2). It is not as common as many other mental disorders.
However, the impact of schizophrenia tends to be highest in Oceania, the Middle East, and East Asia, while the nations of Australia, Japan, the United States, and most of Europe typically have low impact.
The risk for schizophrenia has been found to be somewhat higher in men than in women, with the incidence risk ratio being 1.3–1.4. Schizophrenia tends to develop later in women, but there do not appear to be any differences between men and women in the earliest symptoms and signs during the prodromal phase.
Genetic studies suggest multiple genes and/or genomic regions, each making a small contribution to the risk of schizophrenia. The accumulation of genetic susceptibility factors plus other environmental, developmental and epigenetic factors lead to disease.
Schizophrenia is a chronic, devastating mental disorder with complex genetic components. Given the advancements in the molecular genetic research of schizophrenia in recent years, there is still a lack of genetic tests that can be used in clinical settings.
Genetic factors are believed to play an important role in the causation of schizophrenia. While the lifetime risk in the general population is just below 1%, it is 6.5% in first-degree relatives of patients[1] and it rises to more than 40% in monozygotic twins of affected people.
Having schizophrenia could affect your ability to drive. If you've had or currently suffer from a medical condition or disability that may affect your driving you must tell the Driver & Vehicle Agency (DVA).