Cognitive Effects of Roflumilast in (a)MCI and Mild Dementia Patients

Inclusion Criteria: * 50 to 90 years of age * Willingness (including the informal caregiver) to sign an informed consent * Body mass index (BMI) between 18.5 and 35 * MMSE of 20 or higher * Clinical (amnestic)MCI or mild dementia diagnosis * Memory performance on the delayed recall in the clinically relevant 15 words VLT of 1 or more SD below the average * Clinical dementia rating (CDR) scale total score of 0.5 or 1 * Fazekas of 2 or lower Exclusion Criteria: * Normal Pressure Hydrocephalus (NPH) * Fazekas of 3 or higher * Morbus Huntington * Parkinson's disease * HIV/AIDS * Hepatitis C \& B * Recent Transient Ischemic Attack (TIA) (\< 2 years) * Cerebrovascular Accident (CVA) (\< 2 years) * TIA/CVA followed by cognitive decline (within 3 months) * Chronic Obstructive Pulmonary Disease (COPD) gold criteria 3 or 4 and severe asthma * History of schizophrenia, bipolar disorder or psychotic symptoms not otherwise specified or previous treatment for these diseases (lifetime) * Current radiotherapy * Current affective disorder (i.e. anxiety or major depression) * Cognitive problems due to alcohol abuse, brain tumor, epilepsy, encephalitis or lack of capacity to consent to participation. * Current treatment with (or illicit use of) cannabis, opiates, benzodiazepines, MDMA and cocaine * Patients with moderate or major liver impairments will be excluded (e.g. Child-Pugh B and C). * Use of medication showing strong inhibition of either CYP3A4 or CYP1A2 * Patients with rare hereditary problems of galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption * Patients participating in other drug studies * If patient does not have the possibility to be accompanied by the same informal caregiver during all test days