Paranoid delusions and hallucinations and bright light therapy in Alzheimer's disease.

INTRODUCTION

Bright light therapy (BLT) is becoming increasingly popular as an adjunct in the treatment of non-SAD depression and circadian rhythm disturbances in demented patients. Although the rate of side-effects is low, special attention should be paid when treating new groups of patients. We present the case of an 80-year-old woman suffering from dementia of Alzheimer's type (DAT).

METHOD

Bright light (2.500 lux) was administered two hours daily between 10 and 12 a.m. for 14 days. Changes in delusion or agitation were recorded using the confusion rating scale (CRS).

RESULTS

Out of five patients, three already had delusional symptoms which slightly improved during the course of BLT, one patient never showed delusions before or during BLT, and one patient, which we present here, showed an increase in agitation and developed delusional symptoms. After eight days of treatment, the patient developed conjunctival irritation with marked red eyes and complained about blurred vision. After 12 days of treatment, the patient was disorientated in time and place and after 14 days the patient started to hallucinate and BLT had to be discontinued. The paranoid delusions and hallucinations stopped one day after treatment discontinuation.

CONCLUSION

Looking at all the presented evidence, BLT seems to be a useful treatment supplement in DAT patients, when suffering from delusions or agitation. On the other hand, caution should be used when using BLT in demented patients if agitation develops or increases during BLT.