PD psychosis, depression, and agonist-related ICD (MEQ)

(i) Formulation and differentials. Leading cluster: PD psychosis (formed visual hallucinations, partial insight, chronic course fitting Ravina-type recurrent phenomena after PD onset) plus dopamine-agonist-related ICD (gambling, hypersexuality temporally linked to pramipexole titration) plus major depression with passive suicidal ideation and cognitive impairment (MoCA 22) raising PDD risk trajectory.^[1][2] Differentials: delirium (less likely without acute medical markers but still consider); primary schizophrenia (atypical age/phenomenology); Charles Bonnet-like pure visual release if severe eye disease; DDS if there is compulsive extra DRT use and craving rather than only behavioural ICD at prescribed doses.^[1][8]

(ii) Psychosis management. Joint neurology: stop/reduce amantadine early; plan pramipexole reduction (also treats ICD); optimise environment and sleep. Avoid haloperidol, high-potency typicals, and high-motor-risk SGAs (risperidone/olanzapine traps).^[3] If psychosis remains after DRT simplification: clozapine start 6.25–12.5 mg oral nocte, slow titration, often under 50 mg/day, with mandatory FBC monitoring; or pimavanserin 34 mg oral daily where available (5-HT2A inverse agonist).^[3][4] Quetiapine low night dose is pragmatic but weaker RCT support. Assess capacity and safety.^[3]

(iii) ICD and depression. Reduce/stop pramipexole with neurology; financial and partner safeguards; document risk. Treat depression: offer CBT; pharmacologically, SAD-PD supports paroxetine or venlafaxine XR (start low, e.g. paroxetine 10 mg oral daily or venlafaxine XR 37.5 mg oral daily, titrate with review). Extreme caution with any MAO-B inhibitor regarding serotonin toxicity; monitor hyponatraemia, suicidality, motor change.^[2][5][6]

(iv) Disposition and risk. Shared PD clinic + psychiatry follow-up; caregiver education; suicide safety plan; discuss that antipsychotics carry an observational mortality association — use lowest effective dose and non-drug measures first, without abandoning treatment of dangerous psychosis.^[7] Driving/work per local law after psychosis and cognitive change.