Are Psychologists Biased in Criminal Cases?

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Mental health professionals play a crucial role in criminal cases where the defendant is alleged to suffer from a mental health condition.

In the Local Court, for example, evidence that of a “mental condition” can be used to have charges dismissed altogether, provided that the defendant completes a “treatment program” lasting up to 6 months.

In the higher courts, an accused person can be sent to a treatment facility rather than to prison if they are found not guilty by reason of mental illness.

If a person is found guilty, the fact that they suffer from a mental health condition can be used in their favour to receive a lighter penalty.

Defence lawyers that seek these outcomes will often call upon psychologists or psychiatrists to assess clients and provide reports to show that they were suffering from mental health conditions at the time of the alleged offending.

But in one recent case, a psychologist who diagnosed a man with dementia has been accused of ‘cherrypicking’ results to benefit the defendant.

The case has raised concerns that mental health professionals may be biased in favour of the party that engages them in criminal proceedings.

The Role of Mental Health Professionals in Criminal Cases

We have penned several articles about methods by which to achieve positive outcomes for those suffering from mental health conditions.

The role of a psychologist or psychiatrist in these cases depends on the nature of the case itself, the objective to be achieved and whether the case is being heard in the local court or a higher court.

Four situations where a mental health professional may be used are:

1. In assessing whether a defendant is fit to stand trial in a higher court:

In these cases, a psychiatrist may be called upon to provide a report and give evidence before a judge regarding whether the accused person has the mental capacity to stand trial.

2. In support of a ‘section 32’ mental health application in the local court:

A section 32 application is made in the local court in order to have charges dismissed. A successful section 32 application means that there is no conviction, nor is there any finding of guilt against the defendant.

To be successful, a report needs to be obtained from a mental health professional which diagnoses the defendant, supports the proposition that it is more appropriate to deal with the defendant by way of a treatment plan than through punishment, and contains a comprehensive “treatment plan”.

If the charges are dismissed, the defendant will need to complete the proposed treatment plan.

3. Sentencing after a person pleads guilty or is found guilty:

A mental condition, illness or developmental disability may be considered by the courts when imposing a penalty upon person who is guilty of an offence.

The existence of such conditions is one of the factors that can lead to courts imposing a less severe penalty.

4. Mental illness defence:

In some District and Supreme Court trials, a defence of mental illness may be raised where a person was suffering from a condition which meant that they were not responsible for their actions.

If raised successfully, this will result in a finding of ‘not guilty’ being handed down – but the defendant could be held indefinitely in a psychiatric facility.

Psychologist Accused of ‘Cherrypicking’ Results

71-year-old Luigi Costa was recently on trial for killing his neighbour, 89-year-old Terrence Freebody, in Canberra in 2012.

Mr Costa’s criminal lawyers asked the jury to consider a verdict of ‘not guilty by reason of mental impairment,’ arguing that the evidence suggested that he was suffering from dementia at the time of the incident.

They called upon Dr John McMahon, an expert psychologist, to give evidence in court to this effect.

Dr McMahon conducted tests on Mr Costa and gave an opinion that he suffered from severe memory problems, eventually diagnosing him with dementia.

The prosecution challenged that evidence, saying that McMahon had failed to consider ‘built-in tests’ which helped a doctor determine whether a patient was truly suffering from dementia, or whether they were simply exaggerating or fabricating their responses.

The court heard evidence from another psychologist to the effect that it was possible Mr Costa had faked his test results, as he would not otherwise have been able to live as independently as he did.

That psychologist accused Dr McMahon of ‘cherrypicking’ Mr Costa’s test results to diagnose him with dementia.

Are Psychologists Required to Act Independently?

Many criminal defence firms have a list of preferred psychologists and psychologists that they regularly use in their cases. Police and the DPP also regularly call upon the same mental health professionals.

This has led to assertions that particular professionals are biased in favour of the party who is paying for their services. This is despite the fact that professional codes of ethics require psychologists and psychiatrists to act fairly and objectively in their work.

In addition to this, mental health professionals who give testimony in court must – like all other witnesses – take an oath or affirmation that they will tell the truth. Making false statements whilst under oath in court may give rise to charges for perjury, which carries a maximum penalty of 10 years imprisonment.

Are Psychologists Really Impartial?

Despite their ethical and legal obligations, studies suggest that psychologists may inadvertently import a degree of bias in criminal cases depending on whether they are working for the prosecution or the defence.

Research published in the journal Psychological Science found that psychologists who gave evidence on behalf of the prosecution tended to perceive people accused of committing violent sexual offences as having a greater risk of re-offending compared to experts engaged by the defence.

This phenomenon has been dubbed the ‘allegiance effect.’

While the study does not suggest that all mental health professionals will be biased – and indeed acknowledges that most will seek to be as objective as possible – it does indicate that some experts may be inclined to favour the interests of the party who is paying their bills.

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About Ugur Nedim

Ugur Nedim is an Accredited Specialist Criminal Lawyer and Principal at Sydney Criminal Lawyers®, Sydney’s Leading Firm of Criminal & Traffic Defence Lawyers.

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