Minor hallucinations occur in drug-naive Parkinson's disease patients, even from the premotor phase

Further characterising the cognitive/psychiatric phenomena which are now not only recognised to be present in late stages of parkinson's disease but often even before motor symptoms.  42% of patients in this newly diagnosed cohort of PD patients reported minor hallucinations in the preceeding 3 months - significantly less than healthy control subjects, with a third of these occurring before motor symptoms. 

Follow up of these patients was interesting: L-dopa equivalent doses did not differ between PD patients with and without hallucinations in an average of 4.4 years follow up. Only 3 of 21 patients went on to develop dementia over this time course. So, no evidence here to suggest that these patients experience a more severe disease course. 

A correlation with REM sleep behaviour disorder may well be significant; further characterisation of this group prospectively, from premotor to end stage disease is certainly worthwhile.

Mov Disord. 2015 Sep 26. doi: 10.1002/mds.26432. [Epub ahead of print] Pagonabarraga J, Martinez-Horta S, Fernandez de Bobadilla R, et al.

http://www.ncbi.nlm.nih.gov/pubmed/26408291

OBJECTIVES:

The description of minor hallucinatory phenomena (presence, passage hallucinations) has widened the spectrum of psychosis in Parkinson's disease (PD). Minor hallucinatory phenomena seem to antedate the development of more severe hallucinations. Early detection of minor hallucinations may be useful for screening patients with more severe endophenotypes. Motivated by the observation of "de novo," drug-naive PD patients reporting minor hallucinations, we aimed to prospectively identify "de novo" untreated PD patients experiencing hallucinatory phenomena, and to compare their clinico-demographic characteristics with those of untreated PD patients without hallucinations and healthy controls.

METHODS:

Screening and description of psychosis was assessed by the Movement Disorders Society Unified Parkinson's Disease Rating Scale-Part I and a structured interview covering all types of psychotic phenomena reported in PD. Clinical, neuropsychological, and demographic data of PD patients with and without psychotic phenomena were compared with those of age- and education-matched healthy controls.

RESULTS:

Fifty drug-naive, "de novo" PD patients and 100 controls were prospectively included. Minor hallucinations were experienced in 42% (21 of 50) PD patients and 5% controls (P < 0.0001). Coexistence of passage and presence hallucinations was the most common finding. Unexpectedly, 33.3% of patients with minor hallucinations manifested these as a pre-motor symptom, starting 7 months to 8 years before first parkinsonian motor symptoms. The presence of minor hallucinations was significantly associated with presence of rapid eye movement sleep behavior disorder.

CONCLUSIONS:

In this first study to prospectively analyze the frequency of minor hallucinatory phenomena in incident, untreated PD patients, hallucinations appeared as a frequent early non-motor symptom that may even predate the onset of parkinsonism. © 2015 International Parkinson and Movement Disorder Society.