Parkinson disease is now recognized as a multi-system disorder where non-motor symptoms — cognitive dysfunction, mood disturbances, autonomic failure, sleep disorders, sensory abnormalities, and others — often produce more disability than motor symptoms themselves, particularly in advanced disease. Many non-motor symptoms precede motor symptoms by years (anosmia, REM sleep behavior disorder, constipation, depression). Effective non-motor management requires distinct pharmacologic strategies, careful balance with anti-PD therapy, and recognition of treatment-induced versus disease-related symptoms. This page covers the major non-motor symptom categories in PD.

Cognitive Dysfunction

Mild Cognitive Impairment (PD-MCI)

  • Common; ~25% of newly diagnosed PD have cognitive impairment.
  • Address contributors: sleep, mood, medications (anticholinergics, sedatives), comorbidities.
  • Limited evidence for specific pharmacotherapy.

PD Dementia (PDD)

  • Typically >1 year after motor onset.
  • Rivastigmine: FDA-approved (oral and transdermal); modest benefit.
  • Donepezil: off-label; similar evidence.
  • Galantamine: off-label.
  • Memantine: limited data.
  • Cognitive rehabilitation; structured activities.

Dementia with Lewy Bodies (DLB)

  • Dementia within 1 year of motor onset OR before motor onset.
  • Rivastigmine particularly effective.
  • Hallucinations often more prominent.

Psychosis (Hallucinations, Delusions)

Common in Advanced PD

  • Hallucinations: visual most common.
  • Delusions: paranoid.
  • Risk factors: dementia, advanced age, advanced disease, dopaminergic medications.

Stepwise Approach

  1. Investigate triggers: infection, medication, dehydration.
  2. Reduce or eliminate offending PD medications in order: anticholinergics → amantadine → MAO-B inhibitors → COMT inhibitors → dopamine agonists → levodopa (last).
  3. If psychosis remains:
    • Pimavanserin (Nuplazid): FDA-approved for PD psychosis; 5-HT2A inverse agonist; no D2 effect; does not worsen motor; QT prolongation.
    • Quetiapine: 12.5-50 mg at bedtime; off-label; less effective than pimavanserin but cheaper.
    • Clozapine: most effective for refractory psychosis; agranulocytosis risk; REMS monitoring; reserved for severe.
  4. AVOID: haloperidol, risperidone, olanzapine — worsen motor symptoms.

Depression and Anxiety

Depression in PD

  • ~30-50% of PD patients; underrecognized.
  • SSRIs: first-line (sertraline, escitalopram).
  • SNRIs: alternative.
  • TCAs: avoid in elderly (anticholinergic worsens cognition, urinary, GI).
  • Mirtazapine: useful with poor appetite and insomnia.
  • Behavioral therapy: effective adjunct.

Anxiety in PD

  • Often related to off-state (“anxiety when wearing off”).
  • SSRIs/SNRIs: first-line.
  • Buspirone: alternative.
  • Benzodiazepines: short-term; avoid chronic use.
  • Optimize anti-PD medications to address off-state anxiety.

Sleep Disorders

REM Sleep Behavior Disorder (RBD)

  • Common; often precedes motor PD by years.
  • Clonazepam: traditional; effective; sedation, falls in elderly.
  • Melatonin: alternative; less side effects; often preferred in elderly.
  • Address bedroom safety (padding, sleep partner safety).

Insomnia

  • Optimize anti-PD: nighttime levodopa for “off” tremor or off-period dystonia.
  • Sleep hygiene.
  • Melatonin.
  • Trazodone: sedating.
  • Mirtazapine: dual sleep + mood benefit.
  • Doxepin (low-dose).
  • Benzodiazepines: avoid chronic.

Restless Legs / Periodic Limb Movements

  • α2δ ligands (gabapentin, pregabalin): first-line.
  • Dopamine agonists: secondary (augmentation risk).
  • Iron replacement if ferritin low.

Excessive Daytime Sleepiness

  • Dopamine agonists often contributory.
  • Modafinil, armodafinil: stimulant alternatives.
  • Methylphenidate: off-label.
  • Address sleep apnea (common in PD).

Autonomic Dysfunction

Orthostatic Hypotension

  • Non-pharm: head-of-bed elevation, salt, hydration, compression, abdominal binder.
  • Fludrocortisone: 0.1-0.3 mg daily; volume expansion.
  • Midodrine: 2.5-10 mg TID (avoid late in day to prevent supine HTN).
  • Droxidopa (Northera): prodrug of norepinephrine; FDA-approved for neurogenic orthostatic hypotension; 100-600 mg TID.
  • Pyridostigmine: 30-60 mg TID; modest benefit.
  • Avoid: alpha-blockers, hypotensive medications.

Constipation

  • Increase fluid, fiber, exercise.
  • Polyethylene glycol (Miralax): first-line.
  • Lubiprostone: alternative.
  • Prucalopride (Resolor): 5-HT4 agonist; chronic idiopathic constipation.
  • Linaclotide.
  • AVOID: metoclopramide (D2 antagonist → motor worsening); cisapride (cardiac).

Urinary Dysfunction

  • Overactive bladder: mirabegron (β3 agonist) — minimal anticholinergic burden, preferred; alternatives: solifenacin, tolterodine (caution: cognitive).
  • Botulinum toxin to detrusor for refractory.
  • Sacral nerve stimulation for severe.
  • Urinary retention: catheterization; rule out BPH.

Sialorrhea

  • Glycopyrrolate (peripheral; less CNS effect).
  • Botulinum toxin to parotid and submandibular glands (FDA-approved).
  • Scopolamine patches (cognitive trade-off).
  • Sublingual atropine drops.

Sexual Dysfunction

  • PDE5 inhibitors (sildenafil, tadalafil) for ED.
  • Lubricants for women.
  • Address relationship aspects.

Sweating Disturbances

  • Excessive sweating: address dopaminergic dosing; clonidine.
  • Decreased sweating: hyperthermia risk; counsel.

Sensory Disturbances

Anosmia / Hyposmia

  • Common early PD; no effective treatment.
  • Counsel about kitchen safety.

Pain Syndromes

  • Musculoskeletal pain: standard analgesics, PT.
  • Off-period pain: optimize levodopa schedule.
  • Central pain: gabapentinoids, SNRIs.
  • Dystonic pain: botulinum toxin for focal.
  • Shoulder pain: common early; PT.

Fatigue

  • Methylphenidate, modafinil: off-label.
  • Optimize PD medications.
  • Address depression, sleep.

Drooling-Specific Treatment

  • Botulinum toxin to salivary glands: FDA-approved (incobotulinumtoxinA, rimabotulinumtoxinB).
  • Glycopyrrolate: peripheral antimuscarinic.
  • Sublingual atropine: very low absorption.

Impulse Control Disorders

  • ~14-17% on dopamine agonists.
  • Counseling at every visit; QUIP-RS screening tool.
  • If develops: reduce or eliminate dopamine agonist; convert to levodopa.
  • Naltrexone: emerging evidence for ICD reduction.
  • Cognitive behavioral therapy.

Dopamine Dysregulation Syndrome

  • Compulsive use of dopaminergic medications.
  • Often patient-driven dose escalation.
  • Treatment: structured medication management; reduce dopamine agonist exposure; CBT.

Punding

  • Stereotyped repetitive behaviors (sorting, taking things apart, organizing).
  • Treatment: reduce dopaminergic exposure.

Specific Drug Avoidance List in PD

  • AVOID for nausea: metoclopramide, prochlorperazine (D2 antagonists).
  • Use instead: ondansetron, domperidone (where available).
  • AVOID for psychosis: haloperidol, risperidone, olanzapine.
  • Use instead: pimavanserin, low-dose quetiapine, clozapine if needed.
  • AVOID as anti-emetic for vertigo: prochlorperazine.
  • Use instead: meclizine, ondansetron.

🔍 Did You Know?

The recognition that REM sleep behavior disorder (RBD) is a prodromal marker of Parkinson disease and other α-synucleinopathies has transformed how we think about the early stages of neurodegeneration. Patients with idiopathic RBD have approximately 90% risk of developing a defined neurodegenerative synucleinopathy within 14 years — predominantly Parkinson disease, dementia with Lewy bodies, or multiple system atrophy. This is one of the strongest prognostic markers in all of neurology. The clinical implications are profound: RBD identifies patients who would be ideal candidates for disease-modifying therapy — if such therapy existed. The current focus on early α-synuclein-targeted therapies (e.g., prasinezumab — anti-α-synuclein monoclonal antibody in trials) makes the early identification of RBD patients particularly important. For practicing neurologists, the lessons: (1) any patient reporting “acting out dreams” deserves polysomnography to confirm RBD, (2) RBD patients should receive comprehensive baseline neurological evaluation to detect prodromal motor or cognitive features, (3) discussions about long-term prognosis should be balanced with current absence of preventive therapy, (4) annual follow-up to monitor for emerging features. The lesson generalizes: prodromal neurodegeneration is becoming an increasingly identifiable target for disease-modifying therapy, and biomarker-driven early intervention will likely transform the field once effective therapies emerge.

Pitfalls and Pearls

  • PDD/DLB: rivastigmine FDA-approved; donepezil alternative.
  • PD psychosis stepwise: reduce PD meds first; then pimavanserin or quetiapine.
  • AVOID: haloperidol, risperidone, olanzapine, metoclopramide, prochlorperazine.
  • Depression: SSRIs first-line.
  • RBD: clonazepam or melatonin; prodromal synucleinopathy marker.
  • Orthostasis: fludrocortisone, midodrine, droxidopa, pyridostigmine; supine HTN risk.
  • Constipation: PEG, lubiprostone, prucalopride; AVOID metoclopramide.
  • OAB: mirabegron preferred over anticholinergics.
  • Sialorrhea: glycopyrrolate or botulinum toxin.
  • ICDs: counsel + screen on dopamine agonists.
  • RBD prodromal: 90% develop synucleinopathy in 14 years.
  • Sleep disorders: address; common.
  • Fatigue: methylphenidate, modafinil; optimize PD meds.
  • Pain in PD: type-specific approach.
  • Non-motor symptoms often most disabling in advanced disease.

References

  1. Schapira AHV, Chaudhuri KR, Jenner P. Non-motor features of Parkinson disease. Nat Rev Neurosci. 2017;18(7):435-450.
  2. Postuma RB, Iranzo A, Hu M, et al. Risk and predictors of dementia and parkinsonism in idiopathic REM sleep behaviour disorder: a multicentre study. Brain. 2019;142(3):744-759.
  3. Cummings J, Isaacson S, Mills R, et al. Pimavanserin for patients with Parkinson’s disease psychosis. Lancet. 2014;383(9916):533-540.
  4. Emre M, Aarsland D, Albanese A, et al. Rivastigmine for dementia associated with Parkinson’s disease. N Engl J Med. 2004;351(24):2509-2518.
  5. Kaufmann H, Norcliffe-Kaufmann L, Palma JA. Droxidopa in neurogenic orthostatic hypotension. Expert Rev Cardiovasc Ther. 2015;13(8):875-891.
  6. Bloem BR, Okun MS, Klein C. Parkinson’s disease. Lancet. 2021;397(10291):2284-2303.