Cross-over Study on the Influence of Fampridine on Working Memory in Mild to Moderate Depression

Inclusion Criteria: * Male or female * Major depressive episode confirmed by the Mini-DIPS. Currently mild to moderate (MADRS: 7-30). * Normotensive (BP: 90/60mmHg - 140/90mmHg). Sufficiently treated hypertensive subjects will be included. * BMI: 19 - 34,9 kg/m2 * Age: 18 - 55 years * Fluent in German * IC as documented by signature Exclusion Criteria: * Contraindications to the class of drugs under study, e.g. known hypersensitivity or allergy to 4-aminopyridine * Use of potassium channel blockers within the last 3 months * Treatment with OCT 2 inhibitors and -substrates (e.g. cimetidine, propranolol) * Treatment with antidepressants or antipsychotics within the last 3 months and throughout the study period * Current intake of psychoactive drugs (e.g. benzodiazepines, antidepressants, neuroleptics). * Other acute or chronic psychiatric disorder (e.g. psychosis, somatoform disorder, alcohol or drug abuse disorder) * Cognitive impairment (MoCA score \< 25) * MADRS item 10 \> 1 (suicidal tendency) * Risk of lowered seizure threshold (due to e.g. sleep deprivation, withdrawal of alcohol after alcohol abuse, hyponatraemia) * History of seizures * Acute cerebrovascular condition * Acute renal failure or severe renal insufficiency (creatinine clearance \< 30 ml/min per 1.73 m2) * Bradycardia \< 50/min during clinical examination. * History of malignant cancers * Walking problems (e.g. due to dizziness) * Other clinically significant concomitant disease states (e.g. hepatic dysfunction, cardiovascular disease, diabetes, asthma) * Clinically significant laboratory or ECG abnormality that could be a safety issue in the study * Severe somatic or neurological comorbidities * Smoking including all nicotine containing smoking systems and devices (\>10 cigarettes/units per day). Failure to withstand a test day without craving, due to regular consummation patterns. * Pregnancy or breast feeding. Intention to become pregnant during the study participation. * Known or suspected non-compliance * Inability to follow the procedures of the study, e.g. due to language or psychological problems of the participant * Participation in another study with an investigational drug within the 30 days preceding and during the present study * Enrolment of the investigator, his/her family members, employees and other dependent persons