Joyce (68) has a thick, full mane of brown hair. But what people don't realise is that the locks at her right temple are carefully arranged to cover a huge bald patch, the circumference of a tennis ball.
Joyce suffers from trichotillomania (TTM), commonly known as chronic hair pulling. People with this condition have an irresistible urge to pull out their hair - some, like Joyce, pull out scalp hair, others might pull out eyelashes, facial hair, pubic hair, eyebrows or nose hair.
A disorder of impulse control
The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) classifies TTM as an impulse-control disorder, i.e. as a disorder by itself and not as a variant of obsessive-compulsive disorder or as a symptom of another disorder.
In Joyce's case her hair pulling only started at the age of 61. This is uncommon as the condition typically presents in childhood or early adolescence, with the mean age of onset of hair pulling in males later than that in females.
TMM is more common among women than among men.
"I cannot pinpoint a specific incident which might have triggered it. It started during one of the happiest periods of my life," says Joyce.
"Multiple factors have been identified as possible causal or contributory factors in hair pulling," says Prof Christine Lochner, psychologist and researcher at the Medical Research Council's Anxiety and Stress Disorders Unit in Cape Town.
"For example, onset may in some cases be associated with a stressful or traumatic life event such as illness or injury to self or a family member, parental divorce, or even alienation from friends. In addition, abnormalities in several neurotransmitter systems including the serotonin, dopamine and opiate circuits may also play a role in the aetiology of TTM."
Over the years, Joyce's hair pulling has become more frequent, and is at its worst when she is stressed.
"It is very embarrassing and I'm very ashamed of it. Only my husband and closest friends know about it.
I go to great lengths to hide it from others. I wear my hair in such a way that it isn't noticeable.
I cover that area with my hand on windy days and haven't been to a hairdresser once since I started doing this," says Joyce.
"I'm petrified that others might see the bald patch; I don't want them to think that I have a problem or that something is wrong with me. I don't want them to know my secret."
Joyce says that she prefers to pull out her hair in the dark, in front of the television so that others won't notice it. Another preferred place is when she's in bed.
She says that she sometimes falls asleep with her tweezers in her hand.
"I wish I could stop but I have no control over it. It is an overwhelming urge that I cannot resist. It is definitely stress-related but I also find myself doing it even during holidays.
It isn't painful and once I've done it, I temporarily feel more relaxed and calmer."
Joyce has read a lot about TTM in order to understand it. She once saw a psychologist but the feedback about a cure was pessimistic.
"The development of effective interventions for patients with TTM is still in its infancy. Nevertheless, a combined pharmacotherapy and psychotherapy (i.e. habit reversal training) approach may be helpful in the treatment of impulse-control disorders such as TTM," says Lochner.