Key study : Oruc et al Flashcards
what is the study by oruc about? overview
what is the aim in the study by Oruc
-To investigate polymorphism in 5 HTT and 5HTR2c in bipolar disorders.
What is the sample in the study by Oruc
-42 unrelated patients with bipolar disorder type 1
-They were recruited among in and out patients of two psychiatric hospitals in zagreb croatia
-25 female , 17 male
-They had an age range of 31-70 years
-A control sample of 40 subjects matched for age and sex
Describe the procedure in the study by Oruc
all patients were interviewed by one experienced psychiatrist using SADS-L (schedule for affective disorders and schizophrenia, lifetime version).
-All interviews were reviewed by a second experienced senior psychiatrist.
-16 patients had at least one first degree relative with a mania affective disorder
-For the control patients only individuals with no personal or family history of psychiatric disorders were used.
-All patients and controls were of croatian ancestry up to at least the second generation.
-Genomic DNA (full set of DNA in your body) was done for polymorphism in the 5-HTT and the 5HTR2c serotonin genes .These genes were chosen because alterations in them could lead to disturbances in specific pathways with known links to depression. For example serotonin is known to carry signals for appetite so therefore any disturbances in serotonin could lead to known symptoms of depression e.g disturbed sleep.
what are the results in the study by Oruc
1) There was no significant association in the sample i.e there was no significant difference in polymorphism for 5HTT and 5-HTR2c between the patients and the control sample.
2)when data was analysed separately by gender trends for polymorphism for both genes were more common in women with bipolar than women in the control group.
3)those with a family history of mood disorders were no more likely to have polymorphism for both genes than the other patients.
What is the conclusion in the study by Oruc
Polymorphism for 5 HTT and 5HTR2c of serotonin could be responsible for an increased risk of developing bipolar disorder in females only.
Describe the study by Oruč et al. (1997) on association analysis of the genetics of depressive disorder. [6]
Aim – To research the theory that serotonin genes are linked to bipolar disorder.
Sample – 42 patients with bipolar (type 1) from in and out patients of a clinic in Croatia (25 f and 17 m aged 31–70), 40 healthy controls (age and sex matched).
Procedure – Genetic analysis of DNA polymorphisms in the serotonin receptor 2c (5-HTR2c) and serotonin transporter (5-HTT) genes.
Results – No significant associations in polymorphism in the receptor gene (5- HTR2c) were found in the total patient sample. 16 BPI patients had a positive family history as defined by at least one first-degree relative suffering from major affective disorders. When the individuals were divided according to gender, trends for association with both polymorphisms in female
Evaluate the study by Oruč et al., including a discussion about reliability. Evaluation in your answer can include strengths, weaknesses and a discussion of issues and debates.
– Reliability – The study is very reliable as a standardised procedure was followed with objective tests that can be repeated to check for reliability. A matched pairs design can be used in the same way on a future sample. DNA testing is objective and reliable. Family members’ mental health status were checked using similar methods (asking the patient and checking medical records). However, it is possible the reliability of the family members diagnosis could be questioned as the diagnostic criteria applied to each family member could be different, done at different times using different guidelines and possibly interpreted differently by the practitioner.
- Nature versus nurture – Somewhat on nature side of debate as found a genetic association for 16 of the participants as well as the female participants. Suggests nurture could be involved as a strong genetic link was not found for all participants.
- Reductionism versus holism – Reductionist as the focus is just on the DNA analysis and family background of each participant.
- Determinism versus free will – For those participants with a genetic association this suggests the bipolar disorder has been caused by genetics which is outside of the control of the patient. However, many of the participants did not show a genetic association which suggests that there could be other determining factors such as environment. Free will can be involved as the patient may choose to engage with both the manic and the depressive episodes (both thoughts and behaviours)
