We intend to conduct a phase III b trial to verify Oxcarbazepine's effect in agitation and aggression in patients with dementia. We designed the study as a randomized, double-blind, placebo-controlled multi center trial. Hundred patients will be included. The treatment period will be eight weeks, with a further follow up of four weeks.

The primary outcome measure will be the reduction in aggression and agitation as measured by means of NPI-NH-subscale agitation / aggression (Neuropsychiatric Inventory, Nursing Home Version). Secondary outcomes are reduction in aggression as measured by BARS (Behavior Agitation Rating Scale)and reduction in the burden to health-care personnel as measured by NPI-NH.

Inclusion criteria: Patients of either gender, 55 years of age or older, living in a nursing home diagnosed with or a strong suspicion of dementia of Alzheimer's type or vascular origin, and BPSD in form of agitation / aggression as measured by subscale of NPI-NH and BARS.

Exclusion criteria: Patients that have any other kind of dementia as FTD, PD or LBD; patients with hepatic or renal failure, or diseases that make it impossible to follow the study schedule; patients on antiepileptics or antipsychotics.

Inclusion Criteria:

• Alzheimer's dementia, vascular dementia or mixed forms of both according to ICD10 (F00, F01) criteria.
• The patient is 55 years of age or older.
• Residents at a nursing home and who have been there for at least 4 weeks prior to inclusion.
• Signed informed consent by the patient or the relatives signed agreement that they have no reservations against patient's participation in the study.
• At least one week history of agitation or aggression, score 6 or more in NPI-NH-subscale agitation/aggression.

Exclusion Criteria:

• Previous intolerability or known hypersensitivity to Oxcarbazepine or its equivalents
• Low sodium serum levels <135 mmol/L
• Severe impaired renal function (creatinine clearance <30 ml/min, calculated with Cockroft + Gault's formula)
• Hepatic failure (transaminases (g-GT and ALAT > 3 times upper normal limit).
• Patients with AV-block II and III and all kinds of arrhythmia necessitating a treatment.
• Severe somatic diseases that afford a change of medication and will compromise the attendance to the study.
• Patients on cyclosporine.
• Patients in need of strong analgesics like opioids as codeines
• Patients taking carisoprodol
• Alcohol or drug abuse during the last 12 months (used a higher dosage than prescribed)
• The patient has been on ChEIs or memantine for less than 3 months or any change in the dosage during the last 2 weeks.
• The patient is taking antiepileptics or antipsychotics (may be included two weeks after the use of antipsychotics has been ended).
• The patient is taking MAOI or lithium
• The patient with a dementia of type PDD, FTD or DLB
• The patients with a severe or acute neurological disease (e.g. epilepsy, acute CVE, severe Parkinson's disease, acute confusion) or a severe psychiatric disorder like bipolar disorder, schizophrenia...
• The patients who have participated in another clinical trial during the last 3 months.
• The patients who have been randomized to the same study before.