Schizophrenia is a complex and multifactorial mental disorder, and its exact causes are not yet fully understood. However, research suggests that it is likely to be a result of a combination of genetic, environmental, and neurobiological factors.
Genetic factors: There is evidence to suggest that schizophrenia tends to run in families, indicating a genetic component. People with close relatives who have schizophrenia are at a higher risk of developing the condition themselves.
Neurobiological factors: Abnormalities in brain structure and function have been observed in individuals with schizophrenia. Differences in neurotransmitter systems, such as dopamine and glutamate, have also been linked to the disorder.
Environmental factors: Certain environmental factors may contribute to the development of schizophrenia. These factors include exposure to prenatal infections or complications, stress during early development, drug use (especially during adolescence), and adverse life events.
Immunological factors: Recent research has also suggested that immune system dysregulation may play a role in the development of schizophrenia.
As for auditory hallucinations, they are a common symptom of schizophrenia, but not all individuals with schizophrenia experience them. Different individuals may exhibit different symptom patterns, and auditory hallucinations are just one possible manifestation of the disorder. Other symptoms of schizophrenia include delusions, disorganized thinking and speech, diminished emotional expression, and social withdrawal.
It is indeed possible for an adult with schizophrenia to have never experienced auditory hallucinations before being diagnosed. The presence and severity of symptoms can vary widely among individuals with schizophrenia. Some may primarily experience disorganized thinking and delusions, while others may experience a combination of symptoms, including auditory hallucinations. It's important to note that the diagnosis of schizophrenia is based on a constellation of symptoms and not solely on the presence of auditory hallucinations.