Brunner et al Flashcards
what was the aim?
Brunner and his colleagues wanted to explain the behaviour of a large family in the Neth-erlands where the males are affected by a syndrome of borderline mental retardation and abnormal violent behaviour. These included impulsive aggression, arson, attempted rape and exhibitionism.
what was the method used ?
Quasi experiment.
How many pp’s ?
and the nature of the pp’s
The study was based on five affected males from the family.
what was the procedure ?
Data were collected from analysis of urine samples over a 24-hour period.
What were the the findings??
The tests showed disturbed monoamine metabolism associated with a deficit of the en-zyme monoamine oxidase A (MAOA). In each of the five males a point mutation was identified in the X chromosome of the gene responsible for production of MAOA.
Conclusion: MAOA is involved in serotonin metabolism.
what conclusions were drawn up?
The defect in the gene leading to impaired serotonin metabolism is likely to be responsi-ble for the mental retardation in the family and this in turn may account for the violent behaviour (serotonin is a neurotransmitter which is believed to inhibit aggression, appe-tite, moods, sexuality and anger).
Brunner concluded that the MAOA deficiency in this family was associated with a recog-nisable behavioural phenotype that accounted for their inability to regulate their aggres-sion. However, not all the males in the family were affected by the violent behaviour even when they suffered the mental retardation. In addition, this is an extremely rare condition and even if it were true that it was responsible for the criminal behaviour it is not yet pos-sible to generalise this very far.
