Violence and delusional jealousy in Parkinson’s disease

Abstract

Psychosis in Parkinson’s disease (PD) can have a hugely detrimental effect on patient outcomes and quality of life. It can be a feature of PD itself, or can be exacerbated by the very pharmacological agents that are prescribed to treat the motor symptoms of the disease. The treatment of psychosis in PD is often complex, with clinicians having to balance the debilitating physical symptoms of PD against the risk of exacerbating the psychosis. We describe the case of an octogenarian who presented with violence motivated by delusional jealousy in the context of PD, who was treated in a specialist psychiatric inpatient environment.

Background

Parkinson’s disease (PD) exerts a huge burden on global health services, with cases predicted to exceed 9.3 million by 2030.¹ The disease process spans a wide range of symptoms classically including unilateral resting tremor progressing to bradykinesia, rigidity, postural instability, falls, hypomimia, dysphonia and dysphagia. These symptoms adversely affect the independence and quality of life of sufferers and are thought to be characterised by dopamine depletion in the substantia nigra.^{2 3}

Additionally, PD is often accompanied by neuropsychiatric symptoms including sleep disorders, depression, dementia and autonomic symptoms such as bladder and erectile dysfunction.² Psychosis is also common with up to 50% of people with PD experiencing visual hallucinations.⁴ Although efforts have been made to create a standardised diagnostic tool for the identification of cases of PD psychosis,⁵ it remains a clinical diagnosis which is frequently made by geriatricians, neurologists and psychiatrists.⁶

Dopamine agonists such as pramipexole are used to treat the motor symptoms of PD.⁷ They reduce motor fluctuations and postpone the commencement of levodopa therapy.⁸ Unfortunately, these agents are associated with a number of adverse effects including oedema, constipation, dizziness and nausea. They are also associated with neuropsychological sequelae including somnolence and psychosis.⁹ With particular relevance to this case, dopamine agonist use in PD has been implicated in delusional jealousy,¹⁰ hypersexuality¹¹ and impulse control disorders.^{12 13} Delusional jealousy has an estimated prevalence of 1.1%–7.2% in PD.^{10 14–16} In systematic reviews of case reports and cross-sectional studies, the majority of patients with delusional jealousy were males in the early-middle stages of the disease and had relatively preserved cognition.^{15 17} Although further studies are needed to determine the absolute risk increase of developing delusional jealousy after taking a dopamine agonist, treatment with these medications may be a risk factor for developing the disorder. This is supported by the findings that delusional jealousy occurs at an increased rate (5%) in patients with PD who are prescribed dopamine agonists,¹⁰ and that 64%–100% of patients with PD with delusional jealousy have been treated with a dopamine agonist.^{15 16} It has been postulated that the behavioural side effects of dopamine agonists such as aggression and psychosis are mediated by D2-receptor agonism; these receptors are implicated in reward and reinforcement neural pathways, and it is via antagonism of these receptors that antipsychotic drugs exert their effects.⁸ However, there must be other important patient factors since the disorder is also found in patients who are not treated with dopamine agonists. There are several theories that seek to explain this apparent contradiction, that low levels of dopamine predispose patients with PD to develop psychosis, as well as elevated levels of dopamine brought about by dopamine agonists.¹⁵ It has been suggested that overstimulation or sensitisation of dopaminergic receptors in the mesolimbic system can increase risk of psychosis in patients with PD who have a premorbid predisposition to develop the condition.¹⁸ There may also be a role played by acetylcholine in development of psychosis in patients with PD, as demonstrated by the beneficial effects of cholinesterase inhibitors in treating visual hallucinations in PD.¹⁹ Concurrent serotonergic dysfunction has also been implicated.¹⁵ It has also been suggested that an imbalance between dopamine and norepinephrine may affect the forebrain and hypothalamic response to stress which may lead to abnormal behaviours and delusions although this theory has not been thoroughly researched to date.¹⁵ Finally, sexual dysfunction is common in PD and this has been associated with delusions of infidelity²⁰ and intimate partner violence.²¹

The psychosis improves in most patients with the withdrawal of dopamine agonists and treatment with antipsychotic medications such as quetiapine or clozapine. Clozapine is often favoured as it causes less deterioration in motor symptoms,²² and the associated sedation can be beneficial by reducing behavioural symptoms at night.²³ Where pharmacological therapies have failed to treat drug-induced psychosis in PD, there is some evidence that electroconvulsive therapy can be beneficial although there is an absence of large randomised controlled trials in this field.^{24 25}

Clinicians, patients and their loved ones face a challenging balance between preserving motor function, managing risks and controlling the symptoms of psychosis which may be hugely disruptive to the patients’ life. We report the case of a patient with PD who developed delusional jealousy while taking a dopamine agonist and was treated successfully with clozapine.

Case presentation

A man in his 80s was brought to the emergency department after an altercation with his partner. He woke up early in the morning to ask his partner for sex. When they declined, he used a multitool to stab them 14 times in the chest and ear and proceeded to strangle them. They managed to break free to call an ambulance and were admitted briefly to hospital for treatment of their wounds. The man was detained under section 2 of the Mental Health Act and admitted to the local psychiatric hospital for further assessment.

The man denied hurting his partner and claimed that the couple had been ‘frolicking’ in bed when the partner had an accident. He had a 16-year history of idiopathic PD, which caused significant bradykinesia. Over the months prior to admission, he had been experiencing visual hallucinations of children, soldiers and animals in his house but recognised these as abnormal experiences. He had also been increasingly obsessed with watching and buying pornography and most things triggered sexual thoughts in him when he was with his partner. Although he had always been interested in gambling, this had escalated and he had lost a significant amount of money. When his partner left the house to visit their friends, he frequently became upset and was convinced that they had gone to have sex with others. He refused to accept reassurances regarding this.

The man had previously suffered a myocardial infarction but had no history of psychiatric illness. There was no family history of neurological or psychiatric disorders. He was a retired civil servant who lived in a house together with his partner and was independent with mobility and activities of daily living. Premorbidly, the couple had consensual sex on most days and there was no history of domestic violence. He was a non-smoker, drank minimal alcohol and had no history of illicit drug use.

On admission, his medications included aspirin 75 mg, atorvastatin 80 mg, bisacodyl 10 mg, macrogol two sachets, co-beneldopa (25 mg/100 mg) two capsules four times daily, lansoprazole 15 mg, pramipexole 880 μg daily and rivastigmine 1.5 mg two times per day. None of the medications had been recently changed.

On examination, he was a frail and thin man with no signs of self-neglect. He had significant bradykinesia but was pleasant in his demeanour. His speech was slow, with low pitch and volume. His mood was euthymic with a flat affect and hypomimia. There was no formal thought disorder present. The patient was convinced that his partner was a ‘sex worker’ and a ‘swinger’ and was suspicious of other patients in the ward whom he believed were fake and had been placed there to spy on him. He claimed to hear sounds of his partner having sex with other men in the ward and on one occasion dismantled some of his furniture to make weapons. Furthermore, he described a feeling that his room was part of a carriage on a moving train which he could control by moving his door handle and could also see writing appearing on the floor in his room. These multimodal hallucinations were present during night-time but largely absent during the day. His orientation and attention were intact, but he had no insight into some of his beliefs being part of his mental illness or being responsible for the assault of his partner. This was evident as he threatened to strangle his partner while they were on a supervised visit in the hospital grounds.

Investigations

A CT head scan showed patchy deep white matter hypoattenuation with age-related brain volume loss, but no acute intracranial lesions. He completed Addenbrooke’s cognitive examination III and scored 84/100 while psychotic, and 92/100 months after the psychosis had resolved.

Differential diagnosis

Psychosis in PD.

Treatment

Although he had limited insight into some of his symptoms, the patient retained capacity to make decisions about changes to his medications, hoping that his partner would allow him to return home. His pramipexole was reduced and he was started on 200 mg of quetiapine. The hallucinations improved but he remained fixed about the infidelity of his partner and suspicious of the ward team. His pramipexole was subsequently stopped and he was switched to clozapine which was titrated to 25 mg. This resulted in an almost complete resolution of his psychotic symptoms, although he still harboured some beliefs that his partner had previously had affairs. Unfortunately, the new treatment regimen led to a significant worsening of his mobility and urinary incontinence, and he required care for most activities of daily living.

Outcome and follow-up

The police and his partner decided not to press charges as he was deemed to lack capacity at the time of the incident. His section expired after a month, and the patient agreed to continue his treatment and stay as an informal patient on the ward for a further 4 months. He was adamant that he wanted to return home rather than move to a care home. Although his partner still loved him and frequently visited him at the hospital, they were concerned about the risk of recurring violence and did not want him to live in their shared home. This view was supported by an independent forensic psychiatrist. His partner was granted an occupation and non-molestation order, which meant that he was unable to return home for a period of 12 months. The patient reluctantly accepted this, and he was discharged to a care home. Over the following 6 months, the patient became increasingly frail, with worsening mobility, falls, weight loss, constipation, sleepiness and postural hypotension. He stopped eating and drinking and passed away peacefully around 12 months after his initial admission to hospital.

Discussion

This case illustrates the risk associated with delusional jealousy in PD and the challenges when planning a safe discharge from hospital. There are several previous case reports of patients with PD who developed delusional jealousy, usually linked to a change in treatment with dopamine agonists.^{15 26–36} It also frequently occurs in combination with the development of impulse control disorders such as hypersexuality, pathological gambling or compulsive behaviour.15 26–28 30 Although these symptoms are associated with treatment with dopamine agonists, there are no previous reports of violence towards others. There is one case report in the literature, which describes a man with PD stabbing his partner.³⁷ This was thought to be a non-insane automatism related to misuse of a dopamine agonist causing an acute confusional state. Our case is clearly different and illustrates a significant episode of violence, with ongoing threats towards the patient’s partner. Furthermore, our patient had been stable on his treatment regime for some time prior to the onset of the impulse control disorder and delusional jealousy, suggesting that internal patient-specific factors other than medications were important for the episode of violence. The inevitable progression of PD made it difficult to predict whether he would suffer a relapse of psychosis, at which point there would be a significant risk of further violence. Since he retained capacity to make decisions about where to live after discharge, there were limited legal options, apart from a temporary occupation order, to support his partner and the mental health team to manage this risk. This highlights the risk and challenges in treating delusional jealousy and impulse control disorders in PD.

Learning points.

• Delusional jealousy is an uncommon feature of psychosis in Parkinson’s disease which can have serious consequences, including episodes of violence.

• Treatment includes the withdrawal of the contributing medications and the use of quetiapine or clozapine.

• Managing the risks associated with relapse can be challenging. Discussion with a forensic team to explore legal options to manage the risk may be helpful.

Ethics statements

Patient consent for publication

Consent obtained from next of kin.