Stahl's psychiatric genetics chapter does not treat genes as direct codes for complex behaviour or illness. It discusses intermediate levels between proteins, cellular processes and more complex presentations. Endophenotypes draw attention to those intermediate features. The genotype-phenotype pathway is a simplified, explicitly hypothetical scheme.
The same chapter discusses the diathesis-stress hypothesis through genetic influences and environmental conditions. The Istanbul trauma chapter separates previous functioning, the event, subsequent circumstances and support. The sources do not establish the same mechanism; both work with more than a one-factor explanation.
Similar difficulties in a family do not authorise a learner to calculate relatives' futures. 'Associated with risk', 'may matter under certain conditions' and 'inevitable' are claims of different strength. This lesson does not interpret genetic tests; it practises not turning explanatory models into predictions about individuals.
Apply it: fictional worksheet
Fictional mapping: keep 'a risk variant', 'an information-processing task', 'a recent stressor' and 'change in daily functioning' in four separate boxes. Explain why joining them with one arrow of inevitability is problematic.
Example reasoning and its limit
The cards represent different levels. The nature and evidence for each connection must be shown separately; an intermediate feature does not establish an individual's illness outcome.
Knowledge check
These are original learning questions, not psychiatric scales. Answers are not transmitted.
Concepts and further reading
- Endophenotype
- Biological endophenotype
- Genotype
- Genetic vulnerability
- Diathesis-stress model
- Trauma assessment
- Devre, belirti ve tanı aynı şey değildir (Turkish source-linked essay)
- Beyin değişebilir; fakat plastisite ve nörogenez aynı şey değildir (Turkish source-linked essay)
- Psikosomatik demek “hayalî” demek değildir (Turkish source-linked essay)
Source trail
- Stephen M. Stahl, Stahl’ın Temel Psikofarmakolojisi: Nörobilimsel ve Pratik Uygulamalar. Üçüncü baskı; Türkçe 1. basım 2012. Çeviri editörü: İ. Tayfun Uzbay. | PDF 192, 193, 196 | printed pp. 181, 182, 185
- Psikiyatri. Editörler: Işın B. Kulaksızoğlu, Raşit Tükel, Alp Üçok, İlhan Yargıç, Olcay Yazıcı. İstanbul Üniversitesi İstanbul Tıp Fakültesi, Temmuz 2009. Üniversite yayın no. 4888; fakülte yayın no. 2009/1. | PDF 95 | printed pp. 94