The type of disorder described is a mood disorder , which is a mental illness that causes serious changes in how people feel.

Quick Scoop

Mood disorders are a group of mental illnesses where a person’s emotional state is persistently disturbed, often for weeks or months at a time, not just for a day or two. These disorders affect feelings, energy, motivation, sleep, appetite, and how someone functions at work, school, and in relationships.

Common mood disorders include:

  • Major depressive disorder (long-lasting sadness, loss of interest, low energy).
  • Bipolar disorder (periods of depression and periods of unusually high or irritable mood).

A simple way to remember it: if the main problem is big, ongoing shifts in mood and feelings, you are usually talking about a mood disorder.

Mini Breakdown

What the question is asking

The question: “Which type of disorder is a mental illness that causes serious changes in how people feel?” is pointing to a category of mental illness, not one single diagnosis. That category is mood disorders, because they are defined by significant, lasting changes in emotional state.

Tiny illustrative example

Imagine someone who:

  • Feels deeply sad most of the day for weeks.
  • Loses interest in things they used to enjoy.
  • Has big swings from feeling extremely “up” and energetic to very “down” and hopeless.

Those kinds of serious, ongoing changes in feelings are typical of mood disorders , such as depression or bipolar disorder.

Information gathered from public forums or data available on the internet and portrayed here.