I've taken Unisom for months...off and on... but not every single night. They help me get to sleep and stay asleep for about 4 hours. My neuro, when told I have this problem and need help getting to sleep, arranged an appt. with the sleep disorder people! She doesn't agree that PD in and of itself causes sleep disturbance. So I'll let you know what develops here...my appt. is in October! Any other comments on sleep disorder clinics will be welcomed as well. Clare Wilson