Genetic Explanation for Schizophrenia

Evidence from: family studies, twin studies, adoption studies

1. EVIDENCE FROM FAMILY STUDIES:

• 1st degree relatives - share around 50% of genes
• 2nd degree relatives - share around 25% of genes

*KENDLER ET AL (1985) - 1st degree relatives of those with schiz = 18x more at risk

--> fam studies - often inconclusive because conducted retrospectively (comparing cross section of ppl already diagnosed)

--> longitudinal study = reliable data, showing comparisons before and after illness

higher concordance rate of other one getting schiz.

2. EVIDENCE FROM TWIN STUDIES:

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