What is mental illness?

Theresa Nguyen, LCSW, Mental Health America

Mental Illnesses are brain-based conditions that affect thinking, emotions, and behaviors. Since we all have brains – having some kind of mental health problem during your life is really common.

For people who have mental illnesses, their brains have changed in a way in which they are unable to think, feel, or act in ways they want to. For some, this means experiencing extreme and unexpected changes in mood – like feeling more sad or worried than normal.  For others, it means not being able to think clearly, not being able to communicate with someone who is talking to them, or having bizarre thoughts to help explain weird feelings they are having. 

Unlike other general physical illness, mental illnesses are related to problems that start in the brain. The brain is an organ. Just like any other organs in our body, it can experience changes based on life experiences like stress, trauma, lack of sleep, and nutrition. Generally, when someone has a mental illness, something has changed in such a way that their brain and the way that it works has also changed.

Having negative feelings and thoughts does not mean you have a mental illness.  To be diagnosed with a mental illness, the negative changes in thinking and emotions must be:

  1. Pervasive, meaning they seriously affect your ability to do things you want to do; and
  2. Persistent – which means they stick around for longer than normally expected. 

    Negative feelings can come from life changes, like moving to college, losing friends, or grief.  These changes in mood are not mental illness – this is just dealing with life circumstances.  For some people, extreme life circumstances (like trauma or significant stress) that are not addressed can develop in a more serious problem – a mental illness.

Getting Better

No matter what kind of mental health problem someone is facing, it is always possible to get better.  If you think you’re experiencing a mental illness, try to find any kind of support earlier than later. Like other illness, treating mental illnesses early can help you get better faster.

Treatment & Resources