General introduction and definitions.- Neurotransmitter systems..- Regulatory mechanisms..- The neuron..- Biological decompensations caused by individual neurotransmitters..- Sites of action of psychoactive drugs and treatment strategies.- Principal groups..- Pain..- Sleep..- The balance between energy consumption and energy production..- Sleep-disturbing factors and possibilities of treatment..- Pathological sleep conditions..- Climatic conditions..- Parkinson's disease..- The motor disturbances in Parkinson's disease..- Autonomic disturbances in Parkinson's disease..- The treatment of Parkinson's disease..- A synopsis of treatment for Parkinson's disease..- Depression..- Autonomic-affective dysfunctions..- Treatment..- Emaciation and obesity..- Neuroses..- Psychopathic disorders..- Neurotransmitters in old age..- The significance of neurotransmitters for human behaviour..- Epilogue..- Reading list..- Subject Index..