Inclusion criteria  A) Patients  A diagnosis of idiopathic Parkinson's Disease Age of 18 years or above Current or previous experience of persistent fatigue Able to communicate clearly in English over the telephone/online for over an hour Have access to a working computer and internet connection (required for stage 2 only).  B) Supportive person (partner/family member/caregiver)  Age of 18 years or above A supportive person of an individual with Parkinson's Disease whom has already consented to take part in the research. Supportive individuals cannot take part without an associated individual with Parkinson's Disease having already consented. Has regular contact with and is involved in the care and/or support of an individual diagnosed with Idiopathic Parkinson's Disease. Able to communicate clearly in English over the telephone/online for over an hour Have access to a working computer and internet connection (required for stage 2 only).  C) Healthcare Professionals  Healthcare Professional with at least 2 years experience of Parkinson's disease treatment/management/clinical care and/or an academic currently working in the area of Parkinson's Disease treatment. Have access to a working computer and internet connection (required for stage 2 only).  Exclusion criteria  A) Patients  Reduced cognition that would preclude active involvement and capacity to consent to participate Unable to communicate clearly in English over the telephone/online for over an hour.  B) Partners/Caregivers  Reduced cognition that would preclude active involvement and capacity to consent to participate Unable to communicate clearly in English over the telephone/online for over an hour.  C) Health Care Professional  Less than 2 years' experience in the treatment/management/clinical care of individuals with Parkinson's disease as determined by self-report They have worked in this field but have stopped for two years or more.