Biological Explanations

BIOLOGICAL EXPLANATIONS OF SCHIZOPHRENIA

Genetic Factors

• Schizophrenia has a strong heritability, suggesting a significant role of genetic factors.
• Research shows higher concordance rates of schizophrenia in identical twins compared to non-identical twins.
• Ventura et al. indicated that first degree relatives of schizophrenics have a 10% risk of developing the condition, significantly higher than the general population.

Biochemical Factors

• The dopamine hypothesis suggests that schizophrenia is associated with excessive dopamine activity in the brain.
• Post-mortem studies have found elevated dopamine levels and increased numbers of dopamine receptors in the brains of individuals diagnosed with schizophrenia.
• Antipsychotic medication, which reduces dopamine activity, can alleviate positive symptoms of schizophrenia, further supporting this hypothesis.

Neuroanatomical Factors

• Abnormal brain structures are often observed in individuals with schizophrenia. This includes an enlargement of ventricular systems and a reduction in the size of certain brain regions such as the hippocampus and amygdala.
• Advanced imaging technology like MRI has provided evidence of these structural differences.

Neurodevelopmental Hypothesis

• The neurodevelopmental hypothesis suggests that schizophrenia originates from early disruptions to the normal development of the brain.
• It proposes that adverse events during pregnancy or birth like infections, malnutrition, and complications can lead to these disruptions.

Genes and Environment

• Gottesman’s model, suggests that a combination of genetic susceptibility and environmental stress factors can precipitate the onset of schizophrenia.
• Certain environmental factors such as sociocultural deprivation, family stress, and drug abuse can trigger schizophrenic symptoms in genetically predisposed individuals.