Genetics of obsessive-compulsive disorder
(MRC Unit on Anxiety and Stress Disorders, Dept Psychiatry, University of Stellenbosch)

Introduction
For many years, obsessive-compulsive disorder (OCD) was thought of as a relatively rare disorder, caused by unconscious conflict, and very difficult to treat. OCD is now viewed as one of the most common psychiatric disorders (the fourth most common in one important study) and one of the most disabling of all medical disorders. Indeed, a study of the most disabling medical conditions (including such diseases as heart disease, cancer, and infectious diseases) indicates that OCD is the 10th most important cause of disability worldwide. Furthermore, there is growing evidence that specific brain circuits mediate OCD, and that certain medications and cognitive-behavior therapy result in a decrease in symptoms and in normalization of dysfunctional activity on brain imaging. Despite this paradigm shift, OCD still remains under-diagnosed and under-treated.

What is Obsessive-Compulsive Disorder?
People with OCD suffer from obsessions (repetitive thoughts or images that the person finds intrusive and inappropriate, and that increase levels of anxiety) and/or compulsions (repetitive rituals to counter obsessions and lower anxiety), which cause marked distress and are time-consuming, or significantly interfere with an individual's social, academic or occupational functioning. For example, a person with obsessions about contamination may wash their hands repetitively, or a person with obsessions about possible harm may check repeatedly.

Who gets Obsessive-Compulsive Disorder and why?
Around 2-3% of people will develop OCD during the course of their lifetime. It is equally common in males and females, and appears to occur at similar rates throughout the world. OCD often begins in childhood, perhaps particularly in males. In females, another common age of onset is at the time of pregnancy or giving birth; hormonal interactions with brain chemicals are likely to play an important role in such cases. One subtype of OCD begins after certain infections, typically after a streptococcal throat infection. On occasion, OCD is seen in people with various other neurological conditions, typically those that involve basal ganglia lesions. Various neurochemical systems are thought to be important in mediating OCD symptoms; these include the serotonin and dopamine systems. Genetic influences have been hypothesized, and indeed OCD is somewhat more common in relatives of people with OCD or Tourette's disorder than in the general population. This is a rapidly advancing area of research, and several candidate genes for OCD have already been proposed (e.g. catechol-O-methyl transferase).

Research participation
The MRC Unit on Anxiety and Stress Disorders, in collaboration with the OCD Association of SA, the MRC/US Centre for Molecular and Cellular Biology, as well as the Genealogical Institute of SA, has been involved in studies of the neurochemistry and genetics of OCD. We are currently focusing on a range of serotonergic and dopaminergic genes in OCD, and welcome South African patients with OCD to participate in our genetics research project.

For more information on OCD, research participation or the research protocol, please contact Christine Lochner at 021 - 938 9179 or email: cl2@sun.ac.za. All information will be regarded as confidential.

Genetika van obsessief-kompulsiewe steuring
(MNR Eenheid vir Angs- en Stressteurings, Dept. Psigiatrie, Universiteit van Stellenbosch)

Inleidend
Vir baie jare is daar aan obsessief-kompulsiewe steuring (OKS) gedink as 'n relatief seldsame geestesiekte, veroorsaak deur onbewuste intrapsigiese konflik, en baie moeilik om te behandel. OKS word egter tans beskou as een van die mees algemene psigiatriese steurings (as die vierde mees algemene toestand in een belangrike studie bevind) en een van die mees inperkende mediese toestande. 'n Studie van die mees inperkende siektes (insluitend siektes soos hartsiekte, kanker, en infektiewe siektes) dui inderdaad daarop dat OKS die 10de mees belangrike oorsaak van inperking is - wêreldwyd. Verder is daar toenemend bewyse dat spesifieke impulsbane in die brein OKS meebring, en dat sekere medikasies en kognitiewe gedragsterapie 'n afname in simptome meebring en tot die normalisering van disfunksionele aktiwiteit by brein-beelding kan bydra. Ten spyte van hierdie paradigma-skuif, word OKS steeds te min gediagnoseer en te min behandel.

Wat is Obsessief-Kompulsiewe Steuring?
Mense met OKS ly aan obsessies (herhalende gedagtebeelde wat die persoon as inperkend en ontoepaslik ervaar, en wat die angsvlakke beduidend verhoog) en/of kompulsies (herhaaldelike rituele om die obsessies teen te werk en angs te verlaag), wat redelike ongemak veroorsaak, tydrowend is, en/of beduidend inmeng met die persoon se sosiale, akademiese of beroepsfunksionering. So byvoorbeeld sal 'n persoon met obsessies oor besmetting sy/haar hande herhaaldelik skrop, of 'n persoon met obsessies oor moontlike besering/skade sal herhaaldelik sekermaak of alles in die haak is ("checking").

Wie kry Obsessief-Kompulsiewe Steuring en waarom?
2-3% van die bevolking sal OKS gedurende hulle lewensverloop ontwikkel. Dit kom ewe dikwels by mans en vrouens, en wel wêreldwyd voor. OKS begin dikwels tydens die kinderjare, veral by seuns. By vrouens ontwikkel OKS dikwels tydens swangerskap of kindergeboorte; hormonale interaksies met brein-chemikalieë blyk om 'n belangrike rol by hierdie gevalle te speel. Een subtipe van OKS begin na sekere infeksies (tipies na 'n streptokokkale keel-infeksie). By geleentheid word OKS gesien by mense met ander neurologiese toestande, en veral daardie toestande waar basale ganglia letsels voorkom. Verskeie neurochemiese sisteme word belangrik beskou by die meebring van OKS simptome; hierdie sluit die serotonien- en dopamiensisteme in. Genetiese invloede word ook ondersoek, en dit is 'n feit dat OKS meer dikwels by familielede van mense met OKS of Tourette se steuring as in die algemene bevolking voorkom. Dit is 'n snelgroeiende navorsingsgebied, en verskeie kandidaatgene vir OKS is reeds voorgestel (bv. katekol-O-metieltransferase).

Navorsingsdeelname
Die MNR Eenheid vir Angs- en Stressteurings, in samewerking met die OKS Assosiasie van Suid-Afrika, die MNR/US Sentrum vir Molekulêre en Sellulêre Biologie, sowel as die Genealogiese Instituut van SA, is betrokke by studies van die neurochemie en genetika van OKS. Ons fokus tans op 'n reeks van serotonergiese en dopaminergiese gene in OKS, en verwelkom Suid-Afrikaanse pasiënte met OKS om deel te neem aan ons genetika navorsingsprojek.

Vir meer inligting oor OKS, navorsingsdeelname of oor die navorsingsprotokol, kan u Christine Lochner by 021 - 938 9179 of email: cl2@sun.ac.za kontak. Alle inligting sal vertroulik hanteer word.