How chronic diseases can affect personality?

Thyroid Disease

The thyroid makes hormones that tell your body how fast or slow to work. If it makes too much of those, it can feel like someone stomped on the gas pedal. You might be irritable, anxious, and have big mood swings. If you don't make enough of those hormones, your personality may seem flat. You may be forgetful and have a hard time thinking things through. It can have long-lasting effects on your brain if it's not treated.