It has long been claimed that depression, and other psychiatric illness, might be a manifestation of immune dysregulation involving the Central nervous system. Depression is associated with a significantly increased risk of autoimmune disease compared to those without a history of depression. The increased risk of autoimmune diseases is during the first year following the onset of depression .Conversely, up to 50% of patients with autoimmune diseases show an impairment of health-related quality of life and exhibit depressive symptoms.

The aggregation of depression and some specific autoimmune diseases may demonstrate shared inherited pathogenesis.

The first phase of the study will include patients with the diagnosis of depression. The control group will consist of a healthy population, according to medical records and will be recruited through a recruitment ad and volunteers. In the second phase of the study first and second-degree relatives (parents, siblings, children, grandparents, aunts, uncles and cousins) who are diagnosed with autoimmune disease/s will be recruited. Auto-immune diseases will include - Rheumatoid Arthritis (RA), juvenile idiopathic arthritis JIA), Seronegative spondyloarthropathies (SPA) including inflammatory bowel disease (IBD), psoriatic arthritis (PsA), and ankylosing spondylitis. Other autoimmune diseases: Systemic Lupus Erythematosus, Sjogren' syndrome (SS), systemic sclerosis (SSc), inflammatory myopathies (IIM), any Overlap of the above including mixed connective tissue disease (MCTD), systemic vasculitis (see Chapel Hill classification criteria). All autoimmune diseases will be confirmed by an expert rheumatologist or an internist. Celiac disease, Diabetes Mellitus type I, autoimmune thyroiditis, autoimmune hepatitis will be confirmed by a gastroenterologist, endocrinologist or an internist.

Inclusion Criteria:

• Patients must meet DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) criteria for a diagnosis of depression.
• Sufficient knowledge of the Hebrew language
• A stabled mental state. If hospitalized, patients are scheduled for discharge based on clinical assessment of psychiatric symptoms.

Exclusion Criteria:

• Mental co-morbidity.

The first phase of the study will include patients with the diagnosis of depression. The control group will consist of a healthy population, according to medical records and will be recruited through a recruitment ad and volunteers. In the second phase of the study first and second-degree relatives (parents, siblings, children, grandparents, aunts, uncles and cousins) who are diagnosed with autoimmune disease/s will be recruited.