Biological Causes of APD

Raine et al. (2000) set out to test the accuracy of the hypothesis that APD is caused by problems with the prefrontal cortex. The prefrontal cortex is found in the front part of the brain and is made up of grey matter. This part of the brain helps to control an individual’s social behaviour.

Magnetic resonance imaging (MRI) was used to look at the brain structures of 21 men with APD and 34 men without it. It was discovered that the APD sufferers actually had on average 11 percent less prefrontal grey matter than those without APD.

Conclusions and limitations: It was concluded that a reduction in brain grey matter can be responsible for causing APD. This study, however, did only examine the brain structures of males, all of whom were volunteers. This cross section may not have been large enough to produce a definite conclusion. It might also be possible that abnormalities in one part of the brain are caused by abnormalities elsewhere in the brain.

The amygdala is a small oval shaped formation deep inside the brain which helps us to understand that certain courses of actions lead to negative consequences. It also helps alert us to facial expressions of unhappiness or fear. A damaged amygdala can prevent a person from recognising or responding to stress in others. It is therefore believed that people who suffer from APD have an abnormally developed or damaged amygdale.

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Situational Causes of APD

It has also been suggested that APD is caused by the negative circumstances in which someone grows up. Children from poorer backgrounds who have experienced a lower quality of life are more likely to grow up with APD.

Farrington (1995) This was a longitudinal study in which the antisocial behaviour of males from the poorest parts of inner-city London was monitored. Farrington wanted to know how the background of these 411 men would influence how they would develop as individuals. Their parents and teachers were interviewed and checks with the Criminal Records Office were done to see if participants and their families had ever been convicted of a crime.

Results Forty-one percent went on to commit a minimum of one offence. Farrington found that there was a clear link between poverty, poor parenting, low educational achievement and criminal behaviour.

Limitations Much of the investigation hinged on how parents and teachers responded to questions. These may not have been entirely truthful. The study didn’t take into account how genetics may have played a role in antisocial behaviour.

Elander et al (2000a) Elander and his colleagues studied 225 young twins who had been identified as suffering from behavioural disorders and interviewed them in their adulthood 10-25 years later. He found that behavioural disorders, hyperactivity, low IQ and poor reading skills in childhood are a strong indication that APD and criminal behaviour will follow later.

Limitations Some of the study relied on the adults’ memory of their childhood years, which may not have been accurate. The subjects were all twins and so genetics may have played a role in their behaviour.