A 32-year-old patient has a history of symmetrical joint swelling and morning stiffness. What is the most likely diagnosis?

In the context of the presented symptoms—symmetrical joint swelling and morning stiffness—the most likely diagnosis is rheumatoid arthritis. This condition is characterized by persistent joint symptoms, including swelling and stiffness, which typically worsen in the morning or after periods of inactivity. The symmetrical nature of the joint involvement is also a hallmark of rheumatoid arthritis, distinguishing it from other forms of arthritis.

Osteoarthritis, in contrast, usually presents with joint pain that worsens with activity rather than stiffness, and it commonly affects joints asymmetrically. Gouty arthritis is marked by acute attacks of pain and swelling in a single joint, often identified by a sudden onset and the presence of tophi. Psoriatic arthritis can involve joint swelling but often accompanies psoriasis and can manifest with asymmetric joint symptoms. Given the combination of the patient’s history and presenting symptoms, rheumatoid arthritis stands out as the most appropriate diagnosis.