Aim: How many adopted children of BIO mothers with SZ would go on to develop SZ themselves. If Sig number sis be powerful evidence of genes in SZ.
Procedure: Experimental sample born between 1915 & 45 to SZ mothers in Oregon state psychiatric hospital (47). Children adopted at birth, Fathers believed not to be hospital patients. Matched group of 50 adoptees who’s mothers mentally healthy. Matched on sex, eventual placement, length of time in child care.
Subjects contacted by letter to participate in interview (standardized) structured as general medical & environmental questionnaire exploring important psychosocial dimensions in depth. Conducted in homes of subjects adding to observations. Short from of MMPI (Minnesota multiphasic personality inventory) given after.
Adults interviewed to see if developed SZ.
Information on subjects excluded genetic & institutional information was blindly & indepdently evaluated by 2 psychiatrists. Final evaluation by another researcher by numerical score 100-0 with psycho-social disability assigned to each subject (based from MHSRS).
Previously established risk of developing SZ if one parent had it was 10%. We would expect none or 1 of ppt with bio mothers getting SZ. Control group to eliminate adoption alone as a factor of SZ.
Results: Of 47 interviewed with Mom of SZ, 5 hospitalised with SZ, 3 chronically ill. 10% developed SZ what we would have expected if brought up by BIO Mom. None of control group got SZ.
Diagnosis of SZ based on generally accepted standards. Unanimous opinion of three raters, subjects similarly diagnosed in psychiatric hospitals
Comparisons of other psychiatric diagnosis, some discharged from armed forces for psychiatric or behavioural reasons, sig excess of psycho-social disability in 1 half of ppl in experimental group.
Conclusion: Provided powerful evidence for role of genes in SZ. No evidence emerged of any environmental factors.
| Strengths | Weaknesses |
| R – interviews were standardized meaning questioning of ppts were consistent of psycho-social dimensions (general medical & environmental questionnaire) – easier to replicate for consistencies.
A – SZ due to genetics may help reduce stigma & blame associated with the disorder – not responsible for the way they behave as they were born that way & could help develop bio methods to reduce symptoms. V – study used independent measures where ppts in control & experimental groups matched on health, sex, type of placement & being adopted – adds to validity of results as more meaningful comparisons & rules out adopted as factor. V – data gathered qualitative from range of sources observations of homes, interviews, questionnaires – rich & indepth allowing to look at more detail of human behaviour (SZ) |
G – opportunity sample as used children born in Oregon state psychiatric hospital between 1915-1945. With mothers of SZ – meaning used those who are available, this could be a biased sample & therefore not represent the whole population.
V – Qualitative data through interviews of patients of general medical & environmental questionnaire looking at psycho-social dimensions –element of demand characteristics of what the researcher wants to hear or socially desirable answers based on mental health. Ethics – Nature of research may have caused some distress to ppts – the testing & interviewing of ppts may cause distress at aim of developing SZ If bio mom has it. |