A quick guide to assessing an expert’s assessment of mental health.
Many legal cases involve making assumptions about the mental state of a person, which often means relying on a psychology expert. Consider a case involving workers compensation. A valid diagnosis is needed to determine any psychological injuries in order to establish someone’s mental state, which usually includes an external assessment. This can be undertaken by a range of mental health professionals such as psychiatrists, psychologists, social workers, occupational therapists or psychiatric nurses. How can you, a non-expert, assess the expert’s assessment? Does the worker suffer from depression or trauma? If the depression is caused by someone’s biology, the legal liability is different than if it is trauma due to an event at work.
As a lawyer, you may need answers to questions such as:
- Does the person have a mental illness which explains their mental state?
- Are they mentally sound enough to stand trial?
- Does their mental illness prevent them from understanding right from wrong?
Surprisingly, there is no formal system in Australia to evaluate the quality of the advice, which can range from little more than anecdotal to nearly 100 per cent certainty. Therefore, determining the quality of the response is an issue.
The good, the bad and the ugly
Fortunately, current research principles and practices can provide a viable path to providing the information needed.
The graphic above is designed to filter the veracity of psychological assessments and help determine the mental capacity of clients. It stratifies the assessment according to levels of evidence, similar to medical science practices. At the top end, results are based on multi-site, randomised control trials and meta-analyses, which are accurate, valid and reliable. At the other end of the scale you have the “lean over the fence and have a chat” type of assessment, which isn’t supported by evidence.
An accurate assessment involves a detailed testing process. Many clinical decisions come up short as this requires serious time commitments – both for professional training and administering of tests – and a willingness of the subject to undertake the process. Unfortunately, decisions are often made on the lowest end of the scale. Common assessment elements and terms frequently used in evaluation include:
The interview: The standard health professional interview is only 12 minutes long. It often includes no testing or uses tests that don’t follow standard diagnostic systems, such as Diagnostic and Statistics Manual (DSM) or International Classification of Disease (ICD).
Recognised diagnostic systems: DSM or ICD are the only internationally accepted systems of classifying mental illnesses and are required for many insurance and legal claims.
The gold standard test: An internationally recognised method of establishing a diagnosis.
A standard specialist assessment level, which relates to Tier 4 in the graphic, involves a clinical interview plus some testing. For example, the person may present with what the clinician thinks is post traumatic stress disorder, so a special validity test, such as the Post Traumatic Check List (PCL), is administered, based on the interview. In other words, the person presented with what looked like X so was only tested for X, but not other possibilities.
The best option
As noted in the graphic, a Tier 1 assessment tops the list. This involves extensive testing for more than 40 assumptions, including the subject’s understanding and exaggeration capacity, along with information gathered by other experts. The level of accuracy approaches 100 per cent. In short, when you request an assessment by a psychologist, consider how accurate a result you need. If you can live with a 30 per cent accuracy rate, go for the lowest level or flip a coin. If you really need to know, which is more likely, request a Tier 1 standard. This is the only level that conforms to the handbooks of differential diagnosis and the Black Dog Institute’s guidelines.