Parkinson's Disease

🔍 Three Things You Likely Didn’t Know About Parkinson’s Disease

1. Parkinson’s may be a psychiatric disease that eventually becomes a movement disorder. Depression, anxiety, sleep disturbance, constipation, and loss of smell can precede the first tremor by 10 to 20 years. The disease begins silently in brain regions that regulate mood and sleep long before it reaches the motor circuits (Braak et al., 2003).

2. Parkinson’s may start in the gut, not the brain. Early pathological staging work identified alpha-synuclein deposits in the enteric nervous system before they appeared in motor regions of the brain (Braak et al., 2003). More recent work has proposed that Parkinson’s may actually consist of two subtypes: a “body-first” form that begins in the peripheral nervous system and a “brain-first” form that begins centrally, each with distinct prodromal profiles and clinical trajectories (Borghammer & Van Den Berge, 2019).

3. Parkinson’s medications may cause gambling, compulsive shopping, or hypersexuality in up to 1 in 7 patients. The dopamine replacement drugs that treat motor symptoms can trigger impulse control disorders. This is why it is important to screen for these behaviors.

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📋 Overview

Parkinson’s disease is a progressive neurodegenerative disorder defined by certain motor symptoms — resting tremor, rigidity, bradykinesia (slowness of movement), at times bradyphrenia (sluggishness of thoughts), and postural instability — resulting from the loss of dopamine-producing neurons in the substantia nigra pars compacta. But Parkinson’s is increasingly understood as a whole-brain, whole-body condition with prominent neuropsychiatric manifestations that frequently have a greater impact on quality of life than the motor symptoms themselves.

Parkinson’s affects approximately 1-2% of people over 65. Early-onset Parkinson’s (before age 50) accounts for roughly 5-10% of cases.

The pathological hallmark is the accumulation of a protein called alpha-synuclein into clumps called Lewy bodies. While dopamine loss drives the motor symptoms, the underlying pathology is far more widespread — affecting circuits that regulate mood, sleep, cognition, autonomic function, and pain.

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🔀 Subtypes and Presentations

Parkinson’s disease is clinically heterogeneous, and recognizing the predominant pattern has important implications for prognosis and treatment:

• Tremor-dominant Parkinson’s — characterized by prominent resting tremor with relatively less rigidity and bradykinesia. This subtype tends to have a slower progression and a somewhat more favorable cognitive prognosis.
• Akinetic-rigid (postural instability and gait difficulty) subtype — presents with prominent bradykinesia, rigidity, and balance problems with relatively less tremor. This subtype is associated with more rapid motor progression and a higher risk of cognitive decline.
• Mixed presentation — features of both tremor-dominant and akinetic-rigid forms.
• Parkinson’s disease with early cognitive impairment — some patients develop mild cognitive impairment or dementia relatively early in the disease course, suggesting a more aggressive or widespread neurodegenerative process.
• Young-onset Parkinson’s — onset before age 50. Often more slowly progressive but carries a disproportionate psychosocial burden.

The psychiatric profile also varies substantially: some patients experience predominantly depression and anxiety, others struggle primarily with apathy and motivational deficits, and a subset develops psychosis (hallucinations and delusions) — particularly in later stages or with certain medications.

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🩺 Diagnosis

Parkinson’s disease remains primarily a clinical diagnosis, though the diagnostic landscape is evolving. Key elements include:

• Detailed motor examination — assessment of tremor, rigidity, bradykinesia, and postural instability by an experienced clinician. The asymmetric onset of motor symptoms (one side affected more than the other) is a classic feature. In many cases, a psychiatrist will coordinate with a sub-specialist in motor disorders to provide the broadest management possible.
• Non-motor symptom assessment — a thorough inventory of mood, anxiety, sleep quality (particularly REM sleep behavior disorder), cognitive function, autonomic symptoms (constipation, orthostatic hypotension, urinary symptoms), pain, and fatigue. These symptoms are often underreported unless specifically asked about.
• Psychiatric evaluation — formal assessment of depression, anxiety, apathy, psychosis, and impulse control behaviors. Screening for medication-related behavioral changes is essential, particularly in patients on dopamine agonist therapy.
• Cognitive screening and neuropsychological testing — may be necessary to establish a baseline and monitor for progression to Parkinson’s disease dementia, which eventually affects an estimated 50-80% of patients over the long term.
• Neuroimaging — dopamine transporter (DaT) imaging can support the diagnosis by demonstrating reduced dopaminergic uptake in the striatum. Structural MRI helps exclude alternative diagnoses.
• Response to dopaminergic therapy — a robust improvement in motor symptoms with levodopa supports the diagnosis, though this is neither perfectly sensitive nor specific.

Misdiagnosis is not uncommon, particularly early in the disease course. Conditions that can mimic classic Parkinson’s include essential tremor, drug-induced parkinsonism, Lewy body dementia, among various “Parkinson plus” syndromes such as multiple system atrophy, progressive supranuclear palsy, and vascular parkinsonism. An experienced clinician can usually distinguish these over time.

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💊 Treatment Approach

The psychiatric management of Parkinson’s disease requires specialized expertise — because standard psychiatric medications can worsen motor symptoms, and standard Parkinson’s medications can cause or exacerbate psychiatric symptoms. This bidirectional complexity is precisely why Parkinson’s patients benefit from a psychiatrist with specific experience in neurodegenerative disease.

Psychotherapy and Behavioral Approaches

Acceptance and Commitment Therapy (ACT) — which helps patients build psychological flexibility in the face of progressive illness rather than fighting to control uncontrollable symptoms — is particularly well suited to the emotional challenges of Parkinson’s. Behavioral activation strategies, tailored to fluctuating motor capacity, address the motivational deficits driven by dopamine loss. Mindfulness-based cognitive therapy (MBCT) and other mindfulness-based interventions have shown promise for anxiety, stress, and quality of life. CBT adapted for Parkinson’s — incorporating psychoeducation about the neurological basis of mood symptoms and cognitive techniques for catastrophic thinking — provides an additional evidence-based option.

Caregiver-focused interventions are equally important, as Parkinson’s caregivers face not only progressive physical demands but the emotional challenge of personality and behavioral changes that can feel like losing the person while they are still present.

Medication and Neuromodulation

The pharmacological management of psychiatric symptoms in Parkinson’s requires navigating a complex pharmacological landscape. Depression in Parkinson’s involves not only serotonergic deficits but noradrenergic and dopaminergic losses, which means that certain classes of antidepressants may address the underlying neurochemistry more precisely than others. The choice of antidepressant must also account for potential interactions with anti-parkinsonian medications, particularly monoamine oxidase inhibitors used in Parkinson’s motor treatment.

Psychosis in Parkinson’s disease — hallucinations, delusions, and paranoia — presents a particularly delicate challenge because most conventional antipsychotic medications block dopamine receptors and can catastrophically worsen motor symptoms. Managing Parkinson’s psychosis requires agents that address psychotic symptoms without exacerbating parkinsonism — a narrow therapeutic window that demands specialized knowledge.

Impulse control disorders triggered by dopaminergic therapy may require careful dose adjustments, strategic deprescribing, or medication substitutions in collaboration with the patient’s neurologist. Apathy — one of the most functionally devastating symptoms — may respond to specific pharmacological strategies targeting dopaminergic and noradrenergic circuits.

Neuromodulation approaches, including transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), are being investigated for both motor and non-motor symptoms of Parkinson’s disease. While not yet standard of care for Parkinson’s-related depression, emerging evidence suggests potential utility, particularly for patients who cannot tolerate or have not responded to pharmacotherapy.

Integrative and Lifestyle Approaches

Exercise is the single most important non-pharmacological intervention in Parkinson’s disease, with robust evidence supporting its neuroprotective effects and benefits for both motor and non-motor symptoms. Beyond general physical activity, specific interventions targeting the gut microbiome, neuroinflammatory pathways, sleep architecture, and metabolic health are areas of active research with intriguing early results.

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🌱 Outlook

Parkinson’s disease is progressive, and the trajectory varies considerably. Some individuals maintain a high quality of life for many years with appropriate treatment. What is consistent is that the psychiatric dimensions — depression, anxiety, apathy, sleep disruption, cognitive changes, and psychosis — are highly amenable to treatment, and managing them well can profoundly influence overall functioning and quality of life.

Disease-modifying therapies targeting alpha-synuclein, neuroinflammation, and mitochondrial dysfunction are in clinical trials. The gut-brain axis is being explored as both a biomarker pathway and a therapeutic target. Gene therapies and advanced neuromodulation techniques are progressing through development pipelines and may represent options for patients and families who want to explore alternatives.

For patients and families navigating Parkinson’s today, the most impactful decision is assembling a care team that addresses the full breadth of the disease — motor and non-motor, neurological and psychiatric — with the depth of expertise each dimension demands.

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🏥 How to Get Better

At our practice, we have extensive experience treating various types of dementia and neurodegenerative disease, including Parkinson’s. The psychiatric symptoms of Parkinson’s — depression, anxiety, psychosis, impulse control changes, and cognitive decline — require specialized knowledge, and we bring an evidence-based approach that draws on medication management, psychotherapy, neuromodulation, supplements, and lifestyle strategies tailored to each patient. We also find that psychoeducation and supportive conversations with the family can shift the home environment in ways that meaningfully reduce mood, anxiety, sleep, and energy symptoms.

Ready to get started? Schedule an intake appointment — a thorough evaluation where we clarify your diagnosis, map out your treatment plan, and get everything moving: medication orders, therapy, supplements, and nutrition. Your care begins the same day, not weeks later.

Schedule Your Intake

We offer statewide telehealth services in California and Florida, with in-person appointments available in Los Angeles and Miami. We also regularly assist international patients due to our fluency in Portuguese, Spanish, and Farsi.

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📚 References

1. Postuma, R. B., Aarsland, D., Barone, P., et al. (2012). Identifying prodromal Parkinson’s disease: pre-motor disorders in Parkinson’s disease. Movement Disorders, 27(5), 617-626.
2. Braak, H., Del Tredici, K., Rub, U., de Vos, R. A., Jansen Steur, E. N., & Braak, E. (2003). Staging of brain pathology related to sporadic Parkinson’s disease. Neurobiology of Aging, 24(2), 197-211.
3. Weintraub, D., Koester, J., Potenza, M. N., et al. (2010). Impulse control disorders in Parkinson disease: a cross-sectional study of 3090 patients. Archives of Neurology, 67(5), 589-595.
4. Aarsland, D., Batzu, L., Halliday, G. M., et al. (2021). Parkinson disease-associated cognitive impairment. Nature Reviews Disease Primers, 7(1), 47.
5. Seppi, K., Ray Chaudhuri, K., Coelho, M., et al. (2019). Update on treatments for nonmotor symptoms of Parkinson’s disease — an evidence-based medicine review. Movement Disorders, 34(2), 180-198.
6. Schapira, A. H. V., Chaudhuri, K. R., & Jenner, P. (2017). Non-motor features of Parkinson disease. Nature Reviews Neuroscience, 18(7), 435-450.
7. Bloem, B. R., Okun, M. S., & Klein, C. (2021). Parkinson’s disease. The Lancet, 397(10291), 2284-2303.
8. Dobkin, R. D., Menza, M., Allen, L. A., et al. (2011). Cognitive-behavioral therapy for depression in Parkinson’s disease: a randomized, controlled trial. American Journal of Psychiatry, 168(10), 1066-1074.
9. Chou, K. L., Stacy, M., Simuni, T., et al. (2018). The spectrum of “off” in Parkinson’s disease: what have we learned over 40 years? Parkinsonism & Related Disorders, 51, 9-16.
10. Schrag, A., Horsfall, L., Walters, K., Noyce, A., & Petersen, I. (2015). Prediagnostic presentations of Parkinson’s disease in primary care: a case-control study. The Lancet Neurology, 14(1), 57-64.
11. Heinzel, S., Berg, D., Gasser, T., Chen, H., Yao, C., & Postuma, R. B. (2019). Update of the MDS research criteria for prodromal Parkinson’s disease. Movement Disorders, 34(10), 1464-1470.
12. Borghammer, P., & Van Den Berge, N. (2019). Brain-first versus gut-first Parkinson’s disease: a hypothesis. Journal of Parkinson’s Disease, 9(s2), S281-S295.