Anxiety disorders
Welcome to Stellenbosch University

Division of Molecular Biology & Human Genetics


​Anxiety disorders

Psychiatric Genetics Group

Our Research Team

Group leader/head

Prof Sîan Hemmings is a Senior Research Scientist in the Department of Psychiatry. She heads the Psychiatric 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, transciptomic and microbiomic studies. She also works on fetal alcohol spectrum disorders (FASD).

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Laboratory Manager

Jessica Theron is a Department of Psychiatry laboratory research assistant.  She assists with departmental research projects including managing databases, and performing DNA extractions. Jessica obtained her BSc. Hons in Molecular Biology and Human Genetics from Stellenbosch University in 2016.




Postdoctoral fellows

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

Her other research interest is coding and non-coding RNAs and their interactions and functions in fear extinction in a PTSD animal model.

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» NIH Biosketch




Jacqueline Womersley obtained her Ph.D in Physiology from the University of Cape Town in 2014.  Her research project focusses on the effects of major depression, telomere length and the expression of telomere-related genes on the development of HIV-associated neurocognitive disorders in the context of early childhood trauma.  

Her other research interests include electrophysiology and the role of S-glutathionylation, a redox-sensitive post-translational cysteinyl modification, on drug-induced neuroplasticity.

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PhD students

Khethelo Xulu is a Ph.D. student whose research focusses on the molecular aetiology of posttraumatic stress disorder and aggressive behaviour.  His study investigates DNA methylation amongst young former offenders from Cape Town townships and seeks to discover diagnostic and treatment outcomes biomarkers.

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Allan Kalungi
is a Ph.D. student jointly registered at Stellenbosch University and Makerere University in Uganda.  His research will focus on investigating the association between acute stress and internalising mental disorders and factors that mediate this relationship, among HIV+ children and adolescents in Uganda.






M.Sc students

Keren de Buys is a first year Masters student investigating relevant novel markers of and the association of leukocyte telomere length to cardio-metabolic risk in the Black population of Cape Town. Her project forms part of the SAMRC funded Cardiovascular Risk in Black South Africans (CRIBSA), in collaboration with Dr Nasheeta Peer and Dr Andre Kengne.



Chané Bain is a M.Sc. student currently completing her studies in the field of Human Genetics. She is investigating Fetal Alcohol Spectrum Disorder, focusing on mothers of the Robertson and Wellington area with hazardous drinking.

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Laetitia Dicks is a second year M.Sc. student working on a gene expression project investigating susceptibility to the development of post-traumatic stress disorder following trauma exposure. The study forms part of the Flagship Shared Roots study focusing on Neuropsychiatric Disorders and Cardiovascular Disease.

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Helène Herholdt is a first year MSc student who will be investigating gene expression signatures as shared aetiologies for PTSD and metabolic syndrome. The study forms part of the Flagship Shared Roots study focusing on Neuropsychiatric Disorders and Cardiovascular Disease.

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BSc Honours students​

erin.jpg Erin Manolas obtained her undergraduate BSc degree in Human Life Sciences (majoring in Genetics & Physiology) at Stellenbosch University, in 2016. She is currently completing her Honours degree in Human Genetics. Her research project involves using telomere length as a biomarker of ageing, for the investigation of the role of childhood trauma on cellular ageing (through telomere erosion) and the development of anxiety disorders.  She aims to start an M.Sc with the psychiatric genetics group in 2018 with a research project focussing on the role of the infant gut microbiome and DNA methylation in Fetal Alcohol Spectral Disorder (FASD) symptomatology. 

Past members​


Rolanda Londt was a Department of Psychiatry laboratory research assistant responsible for the management of the psychiatric genetics laboratory.  She assisted with departmental research projects including managing databases, and performed DNA extractions and genetic analyses. Rolanda obtained her M. Phil. in Biomedical Forensic Science from the University of Cape Town in 2014.


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Lyndon Zass completed his M.Sc. in the Hemmings lab.  His thesis investigated the epigenetic underpinnings of anxiety disorders by investigating DNA methylation in an anxiety sensitivity study.

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On Monday, 10 October 2016 The Neuropsychiatric Genetics group celebrated World Mental Health Day 2016 by spreading awareness about mental health. This year’s theme was "Take 10 Together", the #WMHD campaign called on everyone to reach out to someone – a friend, a family member, a colleague – and have a meaningful 10-minute conversation with them to start talking about their mental health and wellbeing.

"Never give up on someone with a mental illness. When "I" is replaced by "We", illness becomes wellness."