Substantial changes were made to the study protocol and a new ethics application will be submitted.

This study seeks to determine the feasibility and efficacy of a Problem Solving Therapy intervention for the treatment of late life depression (LLD). Participants diagnosed with LLD will participate in six sessions of Problem Solving Therapy, a form of talk-therapy, over a period of eight weeks. A Case Manager (CM) will lead the PST. The primary outcome measure is depression severity and will be measured throughout the study at weeks 0, 4, and 8. the secondary outcome measure is quality of life and will be measured at week 0 (pre-intervention) and week 12.

In the elderly (i.e. individuals 60 years of age or older) major depressive disorder (MDD) is common occurring in 2-3% of the population and known as late life depression (LLD). LLD is both disabling and associated with a high mortality rate. Response to treatment of LLD using at least one antidepressant trial of adequate dose and duration is around 30-40%. Due to these suboptimal response rates, additional interventions should be tested and implemented to further alleviate the symptoms and severity of LLD.

It is common for individuals referred to geriatric psychiatry programs to live alone and have impaired independent mobility, which makes them more susceptible to depression as they are at a higher risk for social isolation. Best practice guidelines recommend using psychosocial therapies, which are effective in reducing symptoms of LLD, as the standard treatment for mild to moderate depression, either alone or in combination with medications. PST can be delivered to patients close to their homes making it ideal for treating seniors with limited mobility. The elderly are more likely to suffer from co-morbid conditions and be treated with multiple medications. Antidepressants are associated with serious adverse events, making psychosocial treatments especially important to the elderly who take more medications and are more likely to suffer comorbid conditions.

Problem-solving therapy (PST) is an established psychosocial therapy shown to be effective in treating depression and other mental disorders in adults of all ages. PST involves seven stages of problem resolution including a)identifying and clarifying the problem b)setting clear achievable goals c) brain-storming to generate solutions d) selecting a preferred solution and f) evaluation. Studies of PST in older adults have shown the treatment to be effective in reducing depression. PST has been successfully adapted to meet the needs of seniors with comorbid conditions and those with early dementia or cognitive impairment.

Despite the importance of psychotherapy interventions for older adults with MDD there is limited access to these treatments for seniors. At present, nurse case managers and social work case managers (CM) do not receive formal training in problem solving therapy. Since they often provide treatment for geriatric mental health outpatients, this limits access to treatments like PST. However, if CM's have formal training in PST, this treatment option can be made available to seniors that could benefit from such programs. To the best of the investigators' knowledge no study has evaluated the effects of CM trained to deliver PST for individuals with LLD in Canada, as such, this is the aim of the current investigation.

Inclusion Criteria:

• Are of either gender and greater than 60 years of age.
• Reside in a community setting (either independent living environment or retirement home).
• Meet diagnostic criteria for major depressive disorder (MDD) according to the Diagnostic and Statistical Manual of Mental Disorders-V (DSM-V) criteria.
• Have a Hamilton Depression Rating Scale (HAMD) 17-item total score of >= 8 and < 24 at baseline.
• Have a Mini Mental Status Exam score of >= 20.
• Have adequate hearing and vision to be able to participate in Problem Solving Therapy.

Exclusion Criteria:

• Have suicidal ideation requiring inpatient admission to hospital for stabilization.
• Have an unstable medical condition requiring hospital admission.
• Have a life expectancy of less than 6 months or are currently receiving palliative care.
• Have psychotic symptoms.
• Have a lifetime history of bipolar disorder or schizophrenia.
• Are currently alcohol dependent or have another substance dependence.
• Are diagnosed with moderate to severe dementia.
• Are planning admission to a long-term care facility within next 6 months.