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Sane or Insane: An Insight into Forensic Psychological Assessments

On the 16th and 23rd of December 2020, we had the honour to interview Dr Julia Lam and Dr Derrick Yeo respectively regarding the issue of providing forensic psychological assessments in Singapore.

Dr Julia Lam is an experienced consultant forensic psychologist, with over 16 years of forensic psychology experience, and she holds a Doctorate in Forensic Psychology from the University of Melbourne. She is also the founder of Forensic Psych Services and a council member in the Singapore Psychological Society.

Dr Derrick Yeo is an experienced consultant psychiatrist, with over 15 years of forensic psychiatry experience, and he holds a Master’s degree in Clinical Forensic Psychiatry from King’s College London. He is currently the Deputy Director of Forensic Psychiatry Community Services at the Institute of Mental Health (IMH). Some of the notable cases that he was involved in includes PP vs. BDA and the infamous Woodlands Double Murder.

What are your primary roles as a Forensic Psychologist/Psychiatrist?


Dr Julia Lam: In general, psychologists are involved in assessment, treatment, counselling and psychotherapy. My primary responsibility is in forensic assessments where I conduct interviews, administer assessment tools and write up forensic reports. I also work with a forensic psychiatrist at Novena Medical Centre. He helps me review my patients and prescribe medication when required. As I am mainly involved in assessments, I will usually refer clients who need additional counselling, psychotherapy or treatment to other psychologists in those fields.


Dr Derrick Yeo: Forensic psychiatry is devoted to caring for people who have offended or come into contact with the law while also having a mental illness at the point of time. Forensic psychiatrists serve to interface between the law and mental illness by explaining how medical issues contribute to legal problems. We take a “cradle to grave” approach because we are involved in both the trial and rehabilitative stages. We advise whether a person is at risk of reoffending or is suitable for specific programs such as early release, probation or capability to serve as caretaker for young children. We also conduct follow-ups with those who are allowed back into the community. It’s very all-encompassing and involves a lot of both community and general psychiatry.


I am the Deputy Director of Forensic Psychiatry Community Services, where we look after patients or inmates with mental illnesses released into the community. And we do know that if you just let them go without ensuring that there are follow-up, there may be a chance that they might relapse.


An example of a service we provide is related to the liaison and diversion schemes. In court, psychologists may advise the court whether an individual has a psychiatric issue or not. Intervention by the police may also involve detention on suspicion of being of an unsound mind. In such cases, the individual is not sent to the courts but rather to psychiatric assessment for an expert decision. Another instance could be for inmates at risk of or having mental illnesses. They are referred to psychological services for support, both when they are incarcerated and released.

Who do you usually provide forensic psychological assessment service for?


Dr Julia Lam: As a forensic psychologist, I mainly provide assessment for clients who are involved in criminal, civil or family matters. When the clients are suspected to be suffering from mental disorders, they may be referred by their private lawyer or assigned by the legal aid scheme to seek psychiatric assessments. There are two legal aid schemes in Singapore: Criminal Legal Aid Scheme (CLAS) by the Law Society Pro Bono Services Office and the Legal Assistance Scheme for Capital Offences (LASCO). Most clients under the legal aid scheme are referred to the Institute of Mental Health (IMH) for their assessments. However, for those clients who prefer to seek private help, I will charge lower fees so that they can still afford the assessment service. 


Dr Derrick Yeo: We are usually engaged by the courts, the prosecution, the defense or other government agencies. Our clients include individuals who have yet to be sentenced as well as those who are already inmates. These individuals may or may not be patients with us before the instance. Some individuals are detained because they are unfit to plead in a court of law and others are kept in the system because of the Mental Health (Care and Treatment) Act as they may pose a threat to themselves or others. As such, the individuals to whom we provide this service are those detained due to health and risk issues.

What are the brief processes of a forensic assessment, both during the pre-trial stage and pre-sentencing stage?


Dr Julia Lam: Forensic assessment consists of five stages:

  1. Detailed clinical interview to screen for potential mental disorders by investigating the client’s life and family history.
  2. Administer psychometric tests (E.g., IQ Test) and diagnostic assessment of suspected mental disorders.
  3. Informant interview which may include family members, spouses, colleagues, girl/boyfriend and children
  4. Reviewing past documentations such as past medical reports, current charges, Statement of Facts, criminal history and school reports in younger clients. Information found on social media like Facebook or LinkedIn may also be useful.
  5. Review relevant medical and psychological literature


Clients may be assessed psychologically across various stages in the legal setting. For less severe cases such as drink-driving and upskirt incidents, I may conduct the forensic assessment when the clients are still under police or CNB’s investigation. Although forensic assessment may seem unnecessary in these cases, they can reveal the underlying causes of the clients’ offending behaviours. For instance, a client arrested for taking upskirt pictures may suffer from psychological conditions such as hypersexuality or voyeuristic disorder. However, I may conduct forensic assessments over a longer-term for more severe cases such as drug-related offences as the lawyers prepare for their cases. 


For clients who have been diagnosed with mental disorders, I will usually advise them to seek treatment or counselling before they are even charged or sentenced. This is to ensure that they can present a better side of them in court.


Dr Derrick Yeo: The most important thing is to frame the request appropriately. Firstly, you have to be aware of who is asking, even though we always endeavour to be neutral and objective in Singapore no matter who is making the request and help the court make a better decision. However, there are questions that forensic psychiatrists can answer and also those that we can’t answer. Hence, it is essential to frame the problem in a manner that is answerable and to acknowledge what you cannot determine, such as whether the individual was truthful at a specific point in time. Because of the complexity of certain questions that hold legal weight, the psychiatrist also needs to understand criminal law and work with the requester.


In general, in preparation, we will require charge sheets, statements such as the statement of facts of the case, police statements or the mitigation plea. We also have to determine who would be appropriate to interview in order to get corroborative sources of information. We also consider whether formal assessment tools are necessary, and which are most relevant. We also take a history of the person such as educational level, occupation and functioning to give the judge an idea of what kind of person the individual is. The psychiatrist’s job is to determine what was going through the individual’s mind and his mental state, including any psychiatric illnesses. It would be prudent to advise the court on necessary precautions, such as when the individual is suicidal. When appropriate, we also advise on the risk of reoffending, which involves both formal tools and professional judgment. Nowadays, you have to rely on everything available because some cases are quite complicated and controversial. Hence, you need to be aware of the literature, landmark cases that have occurred, and be open to new information. 


As such, the process is somewhat drawn out. It would help if you were careful with how and why you conduct your assessment. It adds to your credibility and ability in court. Due to limitations, you might have to take less than ideal approaches in some cases. However, it is fine as long as you can logically justify your actions and openly admit the limitations.


It also matters at what stage of the criminal justice system the individual is at. In terms of assessment, we are usually asked to determine 3 or 4 things. We do have a few types of assessments such as the typical forensic type assessment, assessment for things like a mandatory treatment order, or even providing a second opinion on other experts’ reports.

Given the variety of cases you receive, how do you cater your forensic assessments to these cases?


Dr Julia Lam: There are two components of an offence – mens rea and actus rea. I will try to explore both to have a better understanding of the clients. Additionally, although forensic assessments’ overall processes are mostly the same across different cases, the detailed process may differ. After a clinical interview, clients may be suspected of various mental disorders, and diagnostic tests may be administered to confirm their diagnosis. For those who have incentives to “fake good or fake bad”, I will administer tests to screen for malingering. In some cases, I may outsource these testing to other trained practitioners as I may not be qualified to administer forensic assessment for those mental conditions. By outsourcing these testing to other psychologists, I can be more confident of my opinions in the reports generated. Brain scans or blood tests may be ordered if they are deemed relevant (E.g., Previous head injuries, excessive drinking/alcohol consumption, anorexic clients).


Dr Derrick Yeo: In a typical assessment, we are given three weeks to complete it. As I don’t get to choose my cases in my experience, I just put in my best effort for all of them. There are also no fixed questions in terms of the assessment content and it’s essential to approach it with an open mind and adjust according to the situation. Typical assessment will involve fact-finding and taking the history of the individual followed by focusing on the legal issues at hand with subsequent sessions merely a continuation of this.


One difficulty we face is the need to type and interview simultaneously as computers and recorders are not allowed in prison. Hence, a fixed template would be even more problematic in this case, and the use of the template itself would need to be defended. I think in the end, it relies a lot on personal tricks, common sense and the gut feeling that comes from experience.


Ultimately, openness is most important as new information can always arise. You must be able to adjust your opinion based on that further information if appropriate.

As many assessment methods are derived from foreign research, do you think it’s worthwhile to develop assessment methods catered to the local context?


Dr Julia Lam: The development of a localized assessment may be challenging as these are long-term and large-scale projects that may require an institution’s support. In a multiracial population like Singapore, obtaining a representative sample and checking the figures may add to the challenge.


In my experience thus far, I am not aware of any assessment methods that are developed and used locally. However, institutions such as the Institute of Mental Health (IMH) and the Ministry of Social and Family Development (MSF) may have translated some assessment tools such as IQ tests for internal usage. That being said, I have seen experienced psychologists verbally translate assessment tools into other languages or dialects such as Hokkien and Mandarin when they are administering them. In these cases, psychologists may include a clause to highlight the use of verbally translated assessment tools, and the court must exercise caution during interpretations of such findings.


In my practice, I use assessment tools as a reference as I rely more on thorough clinical interviews to understand what was happening in the client’s life. This is because psychometric benchmarks such as IQ may not accurately explain or reflect the client’s intention when committing the crime.


Dr Derrick Yeo: Yes. Tools and assessments are always better when it’s validated in the local context. That being said, getting funding for such research is usually quite tricky unless you have access to massive registries or prison information. 


Furthermore, in Asia, we balance between deterrence and rehabilitation. So we do not have as strong a focus on rehabilitation as in the West due to the element of “Punishment” which translates into less emphasis on developing therapeutics. However, even with interest, randomized control trials are difficult to run due to ethical concerns such as denying a subset of individuals treatment. For myself, in the few papers I have written, the majority have been retrospective studies. Another ethical issue lies with consent as in the prison setting. Individuals may give consent under duress as they may fear being “marked” or disliked due to their refusal to participate.


Currently, we use methods from Canada, America and the UK, and we send our experts overseas for training, but as our department grows, we hope to be able to train our own experts. This will require time and for more individuals who are appropriately motivated to come forward.

What are some considerations that you will take into account when assessing the mental states of the patients referred to you?


Dr Julia Lam: There are two time-points of a client’s mental state – at the time of the offence commission and during the assessment interview. One of the considerations I have is the client’s presentation which includes his/her appearance, eye contact, speech, tone and volume, personal hygiene, restlessness, unusual thinking or beliefs, and unusual perceptions. Talking to an informant will also be useful when assessing the client’s mental state.


Another consideration I have is the circumstances when the incident happened. The availability of informants and relevant documents would be helpful to corroborate and verify information. For instance, in a love scam, the offender could have been a victim herself but was used by the scammer to engage in money laundering activities. In my experience, I have seen cases where the victim married a Nigerian and helped to transport money to Malaysia a couple of times. Due to her circumstances, she only received a warning/fine and was able to keep her job. Victims of love scam often share similar circumstances such as the lack of social support from family and friends, lack of an intimate relationship and lack of hobbies. This made them socially isolated individuals that may turn to the internet for friendships. Before individuals fell victim into love scams, they usually post about themselves online, which provided materials for the scammers to learn about their vulnerabilities and pretended to understand them well.


Dr Derrick Yeo: There are many things to consider. You have to pay attention to symptoms that may not amount to any clearly defined disorder. The more widely read the psychiatrist and the more general knowledge he or she has and the better the command of English, the better equipped they will be. This is important as if you are not familiar with something, you will need to look it up to verify it. You have to be open to the things the individual tells you because you always have to verify it. In this sense, your opinion is based on the information you receive, so it’s important to gather as much as is appropriate.


Do you think the insanity defence or abnormality of mind defence will pose a concern for you as a psychologist/psychiatrist, especially when assessing accused persons’ mental states?


Dr Julia Lam: Insanity defence is a legal term. For psychologists and psychiatrists, we assessed whether an individual suffered from any mental conditions or had any abnormality of mind at the time of the offence. Sometimes it can be challenging as it is very much a retrospective assessment. Prosecution psychiatrists may interview the accused shortly after the arrest. For defence psychiatrists or psychologists, the assessment may only take place 2 to 3 years after the arrest when the accused is assigned to a pro bono lawyer. Prison medical records or information like prison staff’s observation may also not be readily available to private practitioners. The delay in timing of assessment by defence psychiatrists or psychologists may affect the quality and credibility of the (retrospective) assessment, as they are denied first-hand involvement in the process like prosecution psychiatrists.


However, in most cases, experienced lawyers may refer their clients to forensic assessment if they suspect that their clients may have certain mental conditions or have given a false confession. Hence, these lawyers will request me to assess if their clients are suffering from any mental disorders.


Dr Derrick Yeo: It is appropriate to have an abnormality of mind defense, and it is usually only used for diminished responsibility defences. This occurs in very high impact cases trialled in the high court, so there will be greater scrutiny and pressure. Psychiatrists can take it in their stride as it is a legal term and essentially you are again just providing an opinion as per usual. And even if the person was not charged with such a severe offence as homicide, it will still be important to draw links or associations between symptoms, signs and the offence.


It is more important to point out when there is no mental disorder as there is a risk of people medicalizing all their problems. This takes a brave psychiatrist as there is always the trap of wanting to help the person, but the psychiatrist must remain objective and neutral. The forensic psychiatrist seeks to help not the accused but rather the courts in making a good decision. Such a psychiatrist requires three values, namely honesty, truthfulness and equality of treatment.

Following the assessment, I understand that you may have to provide your opinions in court. How was your experience as an expert witness in general? Were there any memorable experiences?


Dr Julia Lam: As the court usually accepts my report with no issues or the lawyers decide to not use the report, I did not appear in court many times. However, when the client pleads not guilty, it is a trial and I will have to go to court to serve as an expert witness.


One of my more memorable experiences was when there was a Newton hearing for a case of shoplifting where I suspected that the client was suffering from Impulse Control Disorder. Newton hearings will happen if the experts’ opinions on both sides differ significantly, and the court will require the expert witness to go to court to explain their findings. In some instances, when the experts’ opinions differ, email correspondence is sufficient. In these cases, the prosecution’s witness may disagree and pose some questions after reading my report and send those questions to me via the DPP and defense lawyer. I will then try my best to answer those questions and reply to the prosecution’s witness through email and if necessary, a supplemental report. The defense lawyer may also require me to look through the prosecution’s psychiatric report and see if I agree or disagree with the findings. If both experts cannot settle disagreements via email, it will be escalated to a Newton hearing. Escalating the case to a Newton hearing is not ideal as the client will have to pay me for attending court. Newton hearings are typically very stressful as it behaves like a trial, and I will have to defend my opinions.


Dr Derrick Yeo: Most do not enjoy going to court, but I do enjoy it as I do not fluster under pressure. This is because you can prepare only so much for questions, and the other side definitely won’t share their questions with you. So above board, I do a good job and write the best report I can. As such I’m not unduly worried and I consider it like a friendly chat.


Perhaps the memorable ones would be Newton hearings where the judge has to decide which expert to believe. In one of the cases I handled, I had to prove my opinions to the court. In the end, the judge was more persuaded by my opinions. However, it is not a matter of who wins but instead of doing due diligence, and the judge will be able to appreciate it. This is important as reports may be scrutinized at any time. But what struck me in the cases is that the accused did not blame me even though my opinion was not favourable.

What are some challenges that you have faced as an expert witness in court? How did you deal with these challenges?


Dr Julia Lam: Some of the challenges that I have faced were doubts casted on my credentials and my profession as a psychologist. I am usually required to establish my credibility, which included questions regarding my qualifications, specialization, training, and the number of times I have testified in court. In some cases, the DPP may doubt my credibility as I did not have many experiences testifying in court. However, my limited experience was due to other circumstances, such as accepting my report by the court. Hence, it was unfair for such questions to be asked to challenge my credibility.


Additionally, as Singapore’s courts value a psychiatrist’s opinions more, I am often questioned about my intention to include the signature of a psychiatrist who has assisted in reviewing my patients. Hence, the lack of regard for the status of a psychologist also poses a challenge for me. As far as I know, I am also the only psychologist with a doctorate in forensic psychology working in the private sector in Singapore.


Dr Derrick Yeo: I think being an expert witness, one must be mindful not to fall into situations where you say things that are unsupported because there is a tendency of some people to use their experience or quote some research article and say that “because of this finding, I feel that this is possible”. I think that’s relatively weak evidence and you must always come across as a balanced view. The way to learn how to be a good expert witness is always to acknowledge your limitations. You show a balanced opinion when you agree with certain points made by your opponent.

To what extent do you think that the court should consider these assessments when deciding the accused’s responsibilities?


Dr Julia Lam: I think it depends on the mental condition being assessed and whether the accused/defendant can adapt to the prison culture. If I find that my client may not be able to adapt to the prison culture or have the potential to be bullied, I will highlight it in my report. For instance, if the accused is a young offender caught for taking upskirt pictures, I may want to highlight the psychosocial and developmental issues that the accused might face if they were sent to prison as these are considerations that should be taken into account. This can affect the sentence being given, but it also depends on how the lawyer presents their case.


The court may also consider the assessment tools used in evaluating the accused’s mental conditions, such as whether they are reliable, valid or well-known, before taking the assessment results into account. In most situations, I will look through the literature and include a bibliography list in my report to support my opinions. However, in some cases, the conditions may not be generalizable, and it may differ on a case by case basis.


Dr Derrick Yeo: Apparently, the chief justice said that they would get the opinion, but it will not be the only thing under consideration. They will also take into opinion the facts of the case. So even though you are an expert, you must make sense. You have to convince the judge. So, don’t think too highly of your capability and come up with opinions which are not substantiated.


The court is robust with checks and balances. They have an appeal process, and our objective is to aid the court to make a decision. And even if the judge makes an opinion against your own expert opinion, you should not take it personally.

What are some areas that you think can be further improved in the forensic mental health sector?


Dr Julia Lam: I think that psychiatrists and psychologists could be more updated with the literature. In one of the cases I assessed, the opposing psychiatrist concluded that the literature I cited was laymen even though the author’s opinion is worth considering.


Additionally, there were also cases when non-forensically trained psychologists or psychiatrists were involved in assessing forensic patients even though they are not qualified. This resulted in a lack of substance in their forensic reports and is a concern for me. I think more experienced psychologists and psychiatrists could have been tasked instead.


Dr Derrick Yeo: I think the most important thing is for psychologists to get registered more formally. Psychology is always evolving with new tools coming out every year, and there is not enough consistency in terms of skills. So, I think it is important to avoid putting the profession into suspicion of amateurism by ensuing everyone who is recognized as experts to have a certain level of training. I believe that in the future, forensic psychiatrists are moving forward to form a professional organization itself under the Academy of Medicine. I’m happy to report that we will even start a section of forensic psychiatry next year. Membership will be determined by established people in the profession, from both the private and public sector. The court would be more confident that the people who practice are recognized and would have a greater dependability level on expert witnesses. So, moving forward, we have to become more professional.

How do you think the forensic mental health scene will change in Singapore in the next 10 to 15 years?


Dr Julia Lam: In recent years, I have seen many courses on forensic mental health taught online. However, forensic mental health differs from forensic psychiatry and forensic psychology. Forensic mental health is more about mental illness. It touches a bit on different treatments, with a little bit about the law and legislation such as false confession and eyewitness testimony. But it depends on how rigorous the programme is, with the danger that these individuals engage in forensic work even when they did not possess a psychology degree. When I was doing my master’s degree, I have seen people who are occupational therapists that work with offenders in my forensic psychology classes. They cannot do forensic psychological assessments as they are not trained in this. Hence, in future, people could misrepresent themselves and do forensic psychiatric or psychological work even though they only studied forensic mental health. Thus, in the future, I can foresee that more people with such qualifications are insufficient for formulating opinions in reports to be used in court.


I have also heard that there might be a local course on the Master of Science in Forensic Psychology that will be launched in Singapore. I do see some potential in the course. That being said, the course should be rigorous with a supervised practicum to train professionals who can present their opinions in court. As we have the setting and institutions like MSF in place, there is enough potential for such courses to be developed locally.


Dr Derrick Yeo: I think moving forward, society would rely more on experts in the field. With the explosion of the internet, access to information is easy. However, it still takes an expert to decipher the papers and establish relevance to the case or situation. It will also be important to learn from each other as there will be cases and situations that you have not encountered personally. Having someone to guide you and give you first-hand information will be necessary. There will also be greater collaboration on individual cases such as between a psychiatrist and neurologist due to the required assessment. Such groups will then have to reconcile their different opinions and come to a consensus.



The interviews that we have conducted with Dr Julia Lam and Dr Derrick Yeo gave us some insights into forensic psychological assessments and psychological/psychiatric opinions in court. Additionally, they even provided some advice for aspiring forensic psychologists and psychiatrists who wish to become expert witnesses in court. All in all, they have provided us with invaluable insights and experiences that will motivate us to continue our exploration in the field of clinical forensic psychology.

*The views and opinions expressed in this article do not constitute legal advice and solely belong to the author and do not reflect the opinions and beliefs of the NUS Criminal Justice Club or its affiliates.

Author’s Bibliography

Xin Hui is a Year 4 undergraduate student majoring in Psychology, with a minor in Forensic Science. As the project manager for Forensic Psychology in CJC-F, she is in charge of coordinating, advising and working together with her team to spread awareness of the use of forensic psychology in the legal setting. Intrigued by the marriage between her two academic backgrounds, she is interested in exploring the use of psychology in legal settings and seeks to champion its importance.