There is a critical need for treatments that address depression and barriers to mental health care in Parkinson's disease (PD). This randomized-controlled trial will evaluate a 10-session telephone-guided cognitive behavioral self-help program (TH-CBT) for depression in PD (dPD). 72 people with dPD (and their caregivers) will receive either TH-CBT plus enhanced usual care (INTERVENTION GROUP) or enhanced usual care only (CONTROL GROUP). Groups will be compared at baseline, midpoint, endpoint, and 1 and 6 months post-treatment. Participants assigned to the control group with have the opportunity to receive the experimental intervention (TH-CBT) after the data collection period (e.g., after the 6-month follow-up evaluation). Given the public health impact of improved depression treatment in PD, the knowledge to be gained may be significant and the project could directly impact clinical practice.

All study procedures, including the initial evaluation, study treatment sessions, and follow-up study assessments, take place over the phone and no travel is required. All PWP across the USA may participate.

All participants will continue to receive their routine medical treatment under the supervision of their personal doctors (e.g., neurologists, psychiatrists, primary care physicians, therapists) while participating in the study. In addition to usual care, half of the participants in the study will receive the experimental telehealth treatment (TH-CBT; intervention group), immediately after enrolling in the research program. The other half will only receive usual care (control group) and will have the option to receive TH-CBT, after completing all study related assessments (9 months after the initial evaluation). Group assignment will be decided randomly (i.e., by chance).

Study eligibility will be determined by a qualified professional. Those who qualify for participation will be randomly assigned (e.g., flip of a coin) to either the intervention (TH-CBT) or the control group (enhanced usual care).

Participants assigned to the TH-CBT group will receive a 10-chapter CBT self-help treatment workbook, tailored to the unique needs of people with PD, immediately following enrollment. Participants will read and complete one treatment module per week (approximately 60 minutes per module plus practice exercises throughout the week). The treatment materials will review different coping skills for the effective management of depression. Study therapists will call participants to review the treatment material over the phone every week (after every chapter) or every other week (after ever 2 chapters), based on participant needs. These telephone-based counseling sessions will last 60 minutes. It will take approximately 10 weeks to complete the study treatment materials.

A family member or friend (carepartner) will also be asked to participate in 3-4 separate educational sessions (30-60 minutes each), evenly dispersed throughout the 10 week TH-CBT treatment period. The study treatment provided to the care-partner will teach the care-partner how to best support the participant with PD as he/she tries to incorporate the information learned during the study treatment, in day-to-day life.

Participants will be re-evaluated 6, 11, 15, and 35 weeks after the initial evaluation.

Inclusion Criteria:

1. Confirmed diagnosis of Parkinson's disease.
2. Clinically significant depressive symptoms (e.g., symptoms are pervasive, distressing, and make life harder). The presence of a formal depressive disorder will be determined by study staff based on standardized criteria (e.g., SCID).
3. 35-85 years old
4. Stable medication regimen ≥ 6 weeks
5. No change in mental health treatment in the past 2 months
6. Family member or friend willing to participate
7. Access to a telephone
8. Live in the United States of America (USA)

Exclusion Criteria:

1. Suicidal plans or intent
2. Probable Dementia or Significant Cognitive Impairment
3. Significant motor fluctuations (i.e., ≥ 50% of the day)
4. Unstable medical conditions
5. Bipolar, Psychotic Spectrum, or Substance Abuse Disorders