About Dr Daniel Hermens

To guide early identification and intervention approaches for young people at risk of mental health and substance use problems. Furthermore, to reveal the neurobiological underpinnings of stimulant drugs and the spectrum of associated psychiatric disorders: from ADHD to psychosis.

Taken together, my research focuses on brain activity related to stimulants and associated mental health problems. On one hand stimulant medication can be used to treat conditions like ADHD. On the other hand, illicit stimulant misuse can lead to problems like psychosis. That is, despite fundamental similarities, certain stimulants can have profoundly different effects on the human brain. In one situation, stimulant medication can act to balance out certain chemicals in the brain which are thought to be depleted (in ADHD). Whereas, misuse of potent stimulants like methamphetamine (“ice”, “speed”) can lead to an over-production of these chemicals and trigger symptoms that mimic schizophrenia. Stimulant use (whether for medical or illicit purposes) is widespread in our society and therefore understanding the role that they have on mental health and brain function is an important topic that I will continue to work on with much enthusiasm. Currently, I use neurophysiological and neuropsychological measures to assess illicit stimulant use (methamphetamine) and associated mental health problems (psychosis, depression). This work provides a new combination of objective measures in substance use with associated mental health problems, which have previously been explored separately. My research will also provide critical insights into underlying brain mechanisms of psychoses, such as schizophrenia, as I focus on the interplay between neurochemicals and stimulant drugs.

I am head of the neurophysiology laboratory and a research fellow at the Brain & Mind Research Institute (BMRI). I coordinate the youth mental health program at the BMRI, which involves neurobiological studies of young people with early stages of mental health problems, including substance use.  Previously, I coordinated a research program on Attention Deficit Hyperactivity Disorder (ADHD), which included several randomised controlled trials of stimulant and non-stimulant medications. I examined the psychophysiology of ADHD, focusing on the effects of gender, age and medication. Overall, this work on ADHD led to two major career achievements:  (1) Neurophysiological markers in ADHD. I was the first to describe neurophysiological sex differences in adolescents and adults with ADHD. I revealed that males and females with ADHD show opposite patterns, in the central and autonomic nervous systems (CNS and ANS). This work transformed the long standing cortical arousal models of ADHD and  two resulting publications were both in the ‘Top 25 Hottest Articles’ list in their respective journals. This has major implications for the diagnosis and treatment of the disorder: where optimal stimulant versus non-stimulant medication may depend on CNS/ANS function.  (2) Predicting stimulant-medication response. I integrated neurophysiological and cognitive measures to identify which markers best predicted optimal responses to medication in ADHD. I showed that patients with cortical hyper-arousal (hyperactivity) are more likely to respond well to stimulant medication. My work in both profiling ADHD brain function and predicting medication response led to three publications and was taken up by industry, in clinical and pharmaceutical report portfolios.  Having set up a new laboratory at the BMRI, I now have a focus on the neurobiological underpinnings of illicit methamphetamine use and associated mental health problems (depression and psychosis). 

Selected publications

For a comprehensive list of Dr Hermens's publicatons, please visit his Sydney Medical School profile page.