Anxiety disorders
Welcome to Stellenbosch University

Division of Molecular Biology & Human Genetics

​​​​​​​​Anxiety disorders

Neuropsychiatric Genetics R​esearch Group

Loading the Illumina iSeq 100​

Setup for DNA extraction from stool samples

Members of the Neuropsychiatric Genetics team conducting microbiome research in Psychiatric Disorders and
Foetal Alcohol Spectrum Disorder (FASD)​​​

Group leader/head

Sîan Hemmings is an Associate Professor in the Department of Psychiatry. She heads the Neuropsychiatric Genetics research group. She obtained her MSc and PhD from Stellenbosch University, and has been involved in psychiatric research for the past 15 years. Her research interests include investigating the molecular aetiology of PTSD and stress-related disorders, by conducting genetic, epigenetic, transcriptomic and microbiomic studies. She also works on fetal alcohol spectrum disorders (FASD).

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Senior Scientist 

Jacqueline Womersley obtained her PhD in Physiology from the University of Cape Town in 2014.  Jacqueline is currently investigating the role of DNA methylation in a range of projects covering FASD, childhood trauma, aggression, PTSD and anxiety sensitivity.

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Laboratory Manager

Kayleigh Filton is the Laboratory Manager for the Neuropsychiatric Genetics Research G​roup. She is responsible for the day-to-day management of the Neuropsychiatric Genetics laboratory.

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Postdoctoral Research Fel​​lows

Nto JN.jpgNto Johnson Nto obtained his PhD (Anatomy) in 2021. He is currently researching the role of the gut microbiome in PTSD, depression, and anxiety within South African populations.

Nto JN.jpgMatsepo Ramaboli obtained her PhD (Chemistry) from the University of South Carolina. She is currently investigating the role of the gut microbiome in PTSD, depression, anxiety, and substance use disorders within South African populations. 

PhD students

duplessis.jpg Morne Du Plessis is a PhD student using polygenic risk score- and machine learning-based modelling approaches to identify the optimal method through which to predict PTSD status in a South African population.

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duplessis.jpg Carlien Rust is a PhD student investigating the blood and gut microbiome in PTSD, schizophrenia and Parkinson’s disease. Carlien aims to develop a pipeline to investigate the human blood microbiome using RNA-seq data and additionally correlate the blood microbiome composition with that of the gut microbiome as well as with inflammatory cytokine data.

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Aqeedah Roomaney is a PhD student investigating epigenetic profiles relating to neuropsychological function, depression, and structural brain volumes in the context of HIV and childhood trauma.

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Lauren Martin is a PhD student investigating biological influences (particularly the maternal vaginal bacteriome, infant gut microbiome, and maternal and infant DNA methylation profiles) shaping the neurodevelopmental trajectories of infants in cohorts from the Western Cape of South Africa.

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MSc​ students

Catherine Lohrentz is an MSc student whose research investigates virtual reality as a tool for physiological bio-marker exploration in post-traumatic stress disorder in a South African population, with a focus on FKBP5 methylation.

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Kabelo Maloka is an ​MSc student investigating the genetic and epigenetic regulation of ADCYAP1 and BRSK2 in rape exposed women with and without PTSD. This study may provide support for ADCYAP1, ADCYAP1R1 and BRSK2 as potential therapeutic targets and biomarkers of PTSD pathogenesis.

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Leandré van Rooyen is an MSc student whose research examines genomic and microbiome factors in the susceptibility to Long COVID with a focus on neuropsychiatric symptoms.


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Robert Glennon is an MSc student whose research investigates the role of the gut microbiome, host genetic factors and the interplay of the two in the risk and development of PTSD, major depressive disorder, and generalised anxiety disorder in a South African population group.

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BScHons Students

Fatima Chiloane is a BSc Honours student in Molecular Biology and Human Genetics, investigating the host genetic microbiome in common mental disorders in South Africa.

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Claire Kelly is a BSc Honours student in Molecular Biology and Human Genetics, investigating the role of maternal-infant genotype interactions in the development of Foetal Alcohol Spectrum Disorder symptomatology.

Past Students

Natasha Kitchin obtained her PhD (Psychiatry) in 2024. Her research investigated the role that the maternal and infant gut microbiome, and the maternal vaginal microbiome, played in Foetal Alcohol Spectrum Disorders (FASD).​

Michaela O’Hare  was an MSc student whose research investigated the gut microbial composition of individuals with self-reported symptoms of depression, anxiety and PTSD compared to matched healthy controls.

Lianna Kapp  was an MSc student whose research investigated the associations between PACAP plasma levels and methylation in relation to PTSD symptom scores over 12 months.

Daniélle Jansen van Rensburg was an MSc student whose research investigated the association between microRNAs in blood and anxiety proneness in a cohort of South African adolescents with exposure to childhood trauma.​

Thomas Rust was an MSc student whose research examined the influence of childhood trauma and epigenetic variation in the oxytocin receptor (OXTR) gene on anxiety proneness and structural and functional neuroimaging measures. 


Leah Chifamba was an MSc student whose research examined the influence of childhood trauma and epigenetic variation in brain-derived neurotrophic factor (BDNF) on anxiety sensitivity. 

Philippa Taitz was a BSc Honours student whose research investigated​​ the influence of maternal DNA methylation markers on the development of Foetal Alcohol Spectrum Disorders (FASD). 

Rachel Ince was a BSc Honours student who was researching the genetic contributions to anxiety sensitivity in the context of childhood trauma. 

Allegra Moodley was an MSc student investigating pro-inflammatory cytokines as markers of inflammation in PTSD, Parkinson’s disease and Schizophrenia patients.

Sylvanus Toikumo
 obtained his PhD (Psychiatry) in 2020. His research focused on identifying shared epigenetic markers associated with the development of PTSD and metabolic syndrome.



Allan Kalungi
 was a Ph.D. student jointly registered at Stellenbosch University and Makerere University in Uganda. He obtained his PhD (Psychiatry) in 2020. His research focused on investigating the association between acute stress and internalising mental disorders and factors that mediate this relationship, among HIV+ children and adolescents in Uganda.

Chané Bain
 obtained her MSc (Human Genetics) in 2020. Her research investigated Foetal Alcohol Spectrum Disorder (FASD), focusing on mothers of the Robertson and Wellington area with hazardous drinking.


Stefanie Malan-Müller obtained her PhD (Psychiatry) from Stellenbosch University in 2014. Her research investigated the gut microbiome profiles of PTSD patients to gain insight into how these microbes affect mental health and behaviour. 

Khethelo Xulu obtained his PhD (Psychiatry) in 2018.  His research focused on the molecular aetiology of PTSD and aggressive beh​aviour, investigating DNA methylation amongst young former offenders from Cape Town townships.



 BMRI open day 2023.jpg

On the 15th of April 2023, members of the SU Neuropsychiatric Genetics Research Group participated in the Biomedical Research Institute (BMRI) Open Day on SU Tygerberg Campus by interacting with the public through science-themed games and sharing information on our current research projects.

On the 14th of February 2023, the SU Neuropsychiatric Genetics Research Group moved to a brand-new laboratory facility located within the BMRI, overlooking the Tygerberg Hospital.​


On the 16th and 17th of September 2022, members of the SU Neuropsychiatric Genetics Research Group presented their research at the 2022 Biological Psychiatry Congress at the Century City Conference Centre, Cape Town, South Africa.



 The SA Medical Research Council piloted the Generation S (Gen S) Job Shadow Programme that took place in June and October 2022, in which the SU Neuropsychiatric Genetics Research Group assisted in exposing Grade 10 and 11 learners to various laboratory experiments. The aim of the initiative was to provide high school learners with opportunities to gain insight into the work undertaken by the MRC and affiliated organisations.


On the 3rd of June 2022, the SU Neuropsychiatric Genetics Research Group posted pictures of their colourful socks on their Instagram page (@suneuropsychgen) in support of the annual Crazysocks4docs campaign, to raise awareness regarding the mental health of health professionals.​