Jack was my final patient for the day. I groaned when I saw that he was an inpatient. That meant lugging all my testing equipment up four flights of stairs, then competing with the cacophony of squeaking meal trolleys, patients crying out in pain and beeping medical equipment as I did my assessment. The smell of the hospital wards, with their toxic mix of cleaning liquid, bodily fluids and hospital food, always made me feel queasy.
I checked the referral note again. This handwritten scrawl was more detailed than usual. The medical doctors usually only wrote the name of the patient, their neurological condition and ‘neuropsychology assessment’ – or ‘psychometry’, a term that made me cringe, as it made me feel like a testing machine. This referral had a ‘please’, which was rare. It was also full of acronyms: ‘TBI due to fall from scaffolding. GCS at scene 6. MRI brain R > L frontal damage. Disinhibited. Please assess.’
TBI = Traumatic brain injury, or a brain injury caused by a trauma, in this case a fall.
GCS = Glasgow Coma Scale score. This is a measure of the severity of the brain injury, a score out of 15, with lower scores indicating a more severe injury.
MRI = Magnetic resonance imaging. This is a type of brain scan that gives a detailed image of brain structure.
R > L = Right greater than left.
I found the head nurse on the ward and asked where I could find this ‘disinhibited’ patient. She gestured down the corridor and chuckled. ‘You’ll have fun with him,’ she said in a thick cockney accent as she turned away.
He was lying down staring at the ceiling when I arrived at his bedside. I introduced myself and he tilted his head slightly towards me.
‘Oh, thanks for coming to see me,’ he began. ‘Can you just give me a quick blow job? Just a real quick one. I promise I haven’t been with any other women. I smell fine. Just make it real quick – no one will notice. Go on, I really want you to suck it, real quick. I won’t take long.’
I laughed, blushed and tried to distract him with my tasks, but he was unstoppable. I was curious to see how long he would persist with his sexual requests. I usually spent at least a couple of hours with my patients, checking all their thinking skills including memory, IQ and attention, but his verbal advances were relentless. He had no interest in my cognitive tasks. His mind was fixated on one thing only: sex. I gave up after half an hour. I wondered how his wife was handling this unexpected outcome of his fall.
A decade later, back in my home country on the other side of the world, in the comfort of my private rooms I saw Tessa, an 18-year-old woman who had suffered a traumatic brain injury in a road accident. She had been in the front passenger seat of a car driven by her boyfriend; he had been drunk and speeding after a night out celebrating the end of high school. Tessa had suffered only minor physical injuries, but her mother explained that this was both a blessing and a curse: everyone thought that since Tessa looked the same, she was the same. The invisibility of her brain injury made it difficult for her friends to understand the changes in her behaviour.
Tessa draped herself across the armchair in my room, her model-length legs slung over one arm of the chair, her head resting on her mother’s shoulder. She twisted the ends of her long hair around her fingertips for the entire interview, her other fingers alternating between her lap and her mother’s hand. She let her mother do most of the talking, occasionally contributing in a soft and childish voice. She seemed like a shy eight-year-old girl in a woman’s body.
Her mother gave me her daughter’s history, then hugged her daughter goodbye as she stepped out of the room. Then I asked Tessa to move closer to the desk so we could start the assessment. She swung her legs back over to the front of the chair in a dramatic sweep, flipped her hair back over her shoulder and pulled the chair up to the desk. I asked if there was anything she wanted to discuss now that her mother had gone. She leaned forward and smiled.
‘Actually, there is one thing,’ she said. Her eyes widened and she suddenly appeared more mature and assertive. ‘Since my accident, I feel like I want to fuck every guy I meet.’
I HAVE WORKED AS A CLINICAL NEUROPSYCHOLOGIST for nearly two decades and met thousands of patients with all sorts of brain injuries and diseases. I typically spend a few hours with each of them. The first part is about an hour of getting to know their story – who they were before their brain changed, and how they feel their neurological condition has affected them. This is my favourite part of the assessment process. I have the luxury of time, and the experience for the patient is different from what they go through in other medical appointments where they have a few brief minutes, rather than hours, to share their story. I think this is why I hear things from these patients that they may have never discussed with their other doctors: their secrets, their wishes, their regrets. I then do a couple of hours of cognitive or thinking tasks, to check on their memory and other cognitive functions.
It’s impossible to remember every patient, but some are hard to forget. It’s not part of my routine practice to ask about people’s sex lives, but sometimes patients or their partners will spontaneously raise the subject. And sometimes, as in the case of the two patients I just described, it is the most memorable feature of their presentation.
Jack and Tessa both had traumatic brain injuries and experienced hypersexuality. Why? In both cases it was a result of where their injuries had damaged their brains. Traumatic brain injuries typically occur in motor vehicle accidents. People hit their heads on the windscreen or, even worse, are flung through it headfirst. The frontal and temporal lobes of their brains are the most vulnerable regions, given their positions in the brain, and these two regions are critical parts of the sexual neural network (see Chapter 1). Any type of brain injury or disease that affects these brain regions or specific structures within them, such as the amygdala, can alter the functioning of the sexual neural network and cause changes in sex drive and behaviour. This is typically an unexpected surprise, especially for the person’s partner.
Traumatic brain injuries are not the only type of neurological condition that can cause hypersexuality. Certain types of dementia can also give rise to this sexual change, as in the case of Terence. He was a highly successful lawyer, a partner in a big law firm. Polite and introverted, he loved his job and planned to work until he was too frail to walk up the two flights of stairs to his office. But his retirement came much earlier than expected. In his mid-fifties, over the course of a year, he transformed into someone who his colleagues, clients and family did not recognise. He put on ten kilograms after suddenly developing a sweet tooth; the cleaning staff at his office would find lolly wrappers scattered under his desk and bags of sweets protruding from his filing cabinet drawers. He became impulsive and careless in his work, and rude to clients. He made inappropriate jokes to his colleagues and showed no insight into how his behaviour was affecting others.
After numerous complaints from his secretary, and clients requesting to change lawyers, his old high school friend and partner in the firm ended up calling Terence’s wife. She burst into tears and said that he was ‘no longer the man I married’. She confided that he was demanding sex multiple times a day, and if she didn’t comply he became verbally aggressive or stormed off to his study to watch porn for hours. After that phone call, Terence’s wife insisted that Terence visit his GP with her, and it didn’t take long for him to be referred to a neurologist. He was eventually diagnosed with behavioural-variant frontotemporal dementia.
Frontotemporal dementia is a rarer form of dementia than Alzheimer’s dementia, and has a younger age of onset. There are different subtypes; some mainly affect language functions, resulting in difficulties with verbal expression, while the behavioural variant primarily affects a person’s personality and behaviour. This is unlike Alzheimer’s dementia, in which the main symptom is memory difficulties. The behavioural changes are often first noticed in social situations when a person shows a lack of empathy, or may become disinhibited and inappropriate. As the name suggests, this type of dementia affects the frontal and temporal lobes of the brain. Your left and right frontal lobes sit behind your forehead. They are the last parts of the brain to mature, and are the largest of all four lobes of the brain. They are extensively connected with other cortical (top surface) and subcortical (inner, deeper) parts of the brain. The frontal lobes comprise three major regions: (1) the primary motor cortex; (2) the premotor and supplementary motor cortices – both these regions are involved in controlling voluntary movement and integrating sensory and motor information to perform actions – and (3) the prefrontal cortex. This prefrontal area can be further subdivided into numerous regions, including the superior medial cortex, controlling ‘energisation’ or the initiation and sustaining of behaviours; the orbitofrontal cortex, mediating social and emotional behaviours; and the dorsolateral prefrontal cortex, involved in task setting and monitoring, among other functions.
The frontal lobes are often referred to as the ‘executive’ or ‘conductor’ of the brain, as they control many social, behavioural, emotional and cognitive functions that are considered to be the very ‘essence’ of what makes us human. To name a few, they enable us to plan, organise, make decisions and act on things. They help us regulate and control our emotions, are involved in motivation and reward processes, and control an array of cognitive functions including attention, memory, problem solving and language. They make us who we are in that they play a role in personality and complex social and emotional behaviours, such as empathy, humour, deception and creativity. Entire books and PhD theses have been written on frontal lobe function, so it would be impossible to cover it all here. For our purposes, the frontal lobe’s critical role in human sexual behaviours is most relevant. Everything sexual that humans do involves a complex interplay of motor, social, cognitive and emotional functions, so it makes sense that the frontal lobes play a critical role in the sexual neural network. For example, in the broadest sense, our frontal lobes (specifically the regions that mediate motor function) control the movements we need to make to have sex, inhibit us from having or seeking sexual responses at socially inappropriate times, and are involved in the myriad social and emotional functions that accompany sex, such as the ability to empathise with our partner.
But how do we know this? The development of brain imaging techniques has enabled major advances in the scientific study of the neurological control of human sexual arousal. As well as structural brain imaging methods that reveal the structure of the brain, there are now ‘functional’ methodologies too. These measure the function of the brain through blood flow (such as fMRI – functional magnetic resonance imaging) and glucose metabolism (such as PET – positron emission tomography). What we do know so far about what happens in healthy brains during sexual arousal has primarily come from studies in which people look at both sexual images and non-sexual images while their brains are scanned. A review and meta-analysis of these studies found that various frontal regions (premotor cortex, orbitofrontal, medial prefrontal and anterior cingulate regions) are consistently activated, along with other brain regions such as the famous amygdala, the hypothalamus, the thalamus and the substantia nigra – all of which will appear later in this book. Heterosexual and gay men showed similar patterns of brain activation, as did women and men. The topic of how the healthy brain controls sexual arousal and behaviour warrants its own book, but for our purposes the message is clear: the research confirms that the sexual neural network consists of many different regions spread throughout the brain. Disruption of any of them in brain injury or disease can result in an altered sex life.
So: back to the frontal lobe and its role in the sexual neural network. In rare cases of behavioural-variant frontotemporal dementia – like Terence’s – hypersexuality can be the first or ‘presenting’ symptom. However, the typical sexual change in this type of dementia is not hypersexuality but hyposexuality, or a lack of interest in sex. People with this condition will fail to initiate any form of sexual behaviour, even simple affectionate gestures such as holding hands or offering a hug. If their partners try to initiate these gestures, they are likely to hear, ‘Not tonight, darling’. A person with frontotemporal dementia will typically be oblivious to the impact of their hyposexuality on their relationship.
This obliviousness to a sexual change has also been observed in people with acquired brain injury. Sally had been complaining of blurry vision, but she and her husband just thought she needed glasses and joked that she was ‘past her prime’ now that she had hit her mid-forties. Her GP sent her for a brain scan, just to exclude anything ‘sinister’. A mandarin-sized tumour was discovered deep within her brain. It had to come out, and she was immediately admitted to a neurosurgical ward. During her surgery, Sally had a stroke that affected a crucial brain structure called the thalamus, which has rich interconnections with all the brain regions – in particular the frontal lobes.
When she emerged from the intense fatigue that engulfed her in the first six months after the stroke, only her closest friends and immediate family realised that she was different. Everyone else commented how lucky Sally’s husband was to have Sally back – alive, walking, talking. She looked normal, but they had no idea that she was not the wife he knew. ‘My wife went into surgery and never came back,’ Sally’s husband said. ‘It is like having another child.’ Sally had always been witty, but now her jokes were childish. She kept referring to farts and poo. She made loud comments about ‘fat’ and ‘ugly’ people while out in public. She threw food around the dinner table while their three children watched, wide-eyed, unsure whether to laugh and join in or tell her to stop. When she caught a glimpse of her husband in the shower one morning, Sally pointed and started giggling: ‘I saw your doodle!’ They were never intimate again. Sally had no interest in sex, and neither did her husband now that he had suddenly become a carer rather than a partner.
It was a similar story for Rita, whose husband of more than 30 years had enjoyed a few too many beers one evening and tumbled headfirst down the stairs at the pub. When Rita arrived at the hospital she was expecting to see a broken leg, and was shocked to find her husband unconscious. The doctors asked her to sit down and looked serious as they pointed to dark patches on his brain scan that glowed on the computer screen. The only words she heard and remembered were ‘frontal lobes’ and ‘severe’. She couldn’t comprehend how a fall down some stairs could be so dramatic and cause so much damage. When I met them several years later, Rita had gotten used to her new husband, who exploded over minor irritations, repeated himself in conversation and couldn’t stand her talking to him if he was doing something else. She spontaneously referred to their sex life and said, ‘I’ve tried and there’s nothing. He’s not interested since his fall. That’s OK. It doesn’t bother me. At least he’s not aggressive.’ Then she shrugged and changed the subject.
HYPOSEXUALITY CAN ALSO OCCUR IN PEOPLE WITH temporal lobe epilepsy. Their lack of interest in sex develops gradually over time as frequent seizures disrupt the temporal lobe and sexual neural network. As I had learned in my research, neurosurgery that removed the temporal lobe causing the seizures could result in a dramatic increase in sex drive, and in some people this had occurred after a decades-long absence of libido. Hypersexuality in the context of temporal lobe epilepsy can be associated with other striking changes in sexual behaviour, as noted earlier – such as a change in sexual preference, or even the development of a ‘paraphilia’ or sexual disorder, such as paedophilia (see Chapter 7). In some cases, this has led to criminal behaviour and legal dilemmas (see Chapter 10).
Temporal lobe seizures can be triggered by an orgasm, or even cause orgasms. Seizures that are induced by orgasm are rare but they can be frightening for partners and have a significant impact on a person’s sex life. They can lead to a life spent avoiding sex and fear of orgasm, which can have a devastating effect on relationships. In one case, the husband of a woman who experienced orgasm-induced seizures was so frustrated by their sex life that he threatened divorce if surgery to cure her seizures was not successful. (See Chapter 3 for a related discussion on the sexual side effects of seizure surgery.) Orgasm-induced seizures occur much more commonly in women than men and are usually associated with a right temporal lobe seizure focus. Brain imaging studies of healthy men and women have found that orgasm, and its lead-up, is predominantly associated with activation (and, in some earlier studies, deactivation) in the temporal and frontal brain regions, including the amygdala and orbitofrontal cortex; other regions involved in sensory, motor and reward processes are also implicated. It appears that if the neurons (the nerve cells) in those very brain regions are highly sensitive, perhaps due to scar tissue or other causes of seizures, such as hippocampal sclerosis (discussed in the next chapter), then a seizure can be triggered by the activation or stimulation of those exact regions that occurs during orgasm. One brain imaging study of women suggests that just imagining or thinking about genital stimulation can activate the same sensory and reward brain regions that actual genital stimulation and orgasms do.
In contrast to orgasm-induced seizures, seizures that result in orgasms may be savoured by those who experience them. Orgasmic ‘auras’ (a feeling or ‘warning sign’ that a seizure is about to happen) linked to seizures are also more common in women and typically arise from the right temporal lobe. Spontaneous orgasms might sound like fun, but these sexual seizures can occur suddenly and in unexpected situations. Imagine travelling on a bus during peak hour on your way to work, standing in the aisle jammed in between other passengers, and suddenly feeling a wave of tingling. You know what is coming, and you know that you are about to experience it in front of an audience. Case studies of women who experience these pleasurable seizures have found that they often keep them a secret from their doctors – for decades in some cases – even when they are undergoing investigations for epilepsy and know that orgasmic auras are part of their seizures. Despite the fact that the pleasure progresses into a seizure, some people have refused to have surgery to cure their seizures out of fear of losing these unexpected orgasms.
Apart from orgasm, there are other sexual behaviours that can occur during a seizure. Sexual ‘automatisms’ (automatic behaviours that the person later has no memory of) include writhing, thrusting, rhythmic movement of the pelvis and legs, and rhythmic handling of genitals or masturbation. These are rare and occur relatively equally in men and women who experience frontal lobe seizures. Sexual ‘ictal’ manifestations (that is, those that occur during a seizure) have also been reported, such as erotic feelings, genital sensations and sexual desire; these have been found to occur most commonly in women with right temporal lobe seizures. So there are many different types of sexual behaviours that can be associated with seizures, and these occur when the seizure focus is in the temporal (typically right-sided) or the frontal lobes.
Epilepsy, however, is not the only neurological condition that can be associated with sexual changes. Parkinson’s disease is another that will come up repeatedly throughout this book. Parkinson’s is caused by the death of neurons that produce a neurotransmitter – a chemical that communicates information between neurons – called dopamine. These neurons are found deep in the brain, in a region called the substantia nigra, which is part of the basal ganglia. This region has extensive connections to the frontal brain regions, which as we know are integral parts of the sexual neural network. Dopamine is crucial in the regulation of movement, but is also involved in many other functions including emotion and reward processing. (The ‘reward system’ is a group of brain structures and neural pathways that are activated by rewarding or reinforcing things, such as addictive drugs and sex.) Therefore a lack of dopamine can cause problems in these areas, such as depression, addiction and, in the case of Parkinson’s disease, movement difficulties. The treatments for Parkinson’s disease are drugs that increase dopamine production.
The first thing Steven noticed years before he developed a trembling hand and shuffling feet was that his voice became husky and soft. He struggled to sing in his church choir and couldn’t talk as loudly as he used to. At his daughter’s wedding the microphone cut out during his father-of-the-bride speech, and he could not project his voice beyond the front row of tables. A month later his legs started to feel heavy, and they wouldn’t move as quickly as he wanted them to. It was when his right hand started trembling that he decided it was time to talk to his doctor. He didn’t want to worry his wife or daughters, and reassured himself that since none of them had made any comments they probably hadn’t noticed anything. But when his GP mentioned the words ‘Parkinson’s disease’, he suddenly wished someone was there with him.
Reduced levels of dopamine in the brain cause many symptoms. The classic symptoms of Parkinson’s are the motor ones, including limb tremors, a shuffling gait and slow movements. There are also many ‘non-motor’ symptoms that can occur, including depression and anxiety, and the striking ‘impulse control disorders’. These include compulsive gambling, shopping and eating, and hypersexuality; these can manifest as part of the disease’s progression or in response to treatments. Drugs that boost dopamine levels in the brain, and the neurosurgical treatment of deep brain stimulation that is used in more severe cases, are highly effective at easing the motor symptoms but can trigger compulsive behaviours that cause financial and personal havoc for patients and their families (see Chapter 4). Dopamine drug therapy is the first port of call to treat the motor symptoms of Parkinson’s disease, but it requires a careful juggling of timing and dosage that can take months to sort out.
Steven started dopamine treatment and was surprised at how quickly his legs and hand responded; the shaking and shuffling subsided and he regained his smooth stride. He was relieved that his body was working in a predictable way again, but there was a catch. An unusual side effect had appeared in the first week he had started the medication: he craved sex. Previously satisfied with the once-a-week routine that he and his wife had fallen into after decades of marriage, Steven quickly found that this didn’t cut it anymore. He needed sex – absolutely had to have it – multiple times a day. If his wife didn’t oblige he would disappear into his study and masturbate. If that didn’t ease the craving, he’d google porn websites. Even more surprising to him was that he was now getting aroused by men, a novel experience for him. He started frequenting gay beats. When his wife discovered a flyer for a gay bar in one of his trouser pockets, she started googling two things: the link between Parkinson’s and sex, and how to get a divorce. She was shocked to find similar stories online about the sexual side effects of the drug Steven was taking. She raced upstairs to find his medication and searched the fine print for warnings, but there was nothing. She followed up her googling with two phone calls: one to their doctor, and one to a lawyer.
In December 2014, the pharmaceutical company Pfizer agreed to settle a class action brought by 160 Australian patients who had suddenly developed hypersexuality or pathological gambling after taking the drug Cabaser, a dopamine treatment for Parkinson’s disease. Steven’s compulsive sexual behaviour was devastating for his wife, but when she heard that a man who developed similar side effects had ended up on the sex offenders register and had to ask permission to visit his grandchildren, she was grateful that his desires had remained with adults. This is not always the case. Disruptions to the sexual neural network can result in a change to sexual preferences, not just from heterosexual to homosexual desire or vice versa, but from adult to child – with devastating consequences for everyone (see Chapter 10).
The people described here manifested extreme changes in their sexual behaviours – that is, hyposexuality or hypersexuality – after a brain injury or disease. Others can experience such changes as side effects of neurosurgery, which is where the next two chapters will take us.