Key facts
- These definitions are written in plain language for general understanding, not clinical diagnosis.
- Terms are grouped alphabetically so you can scan to what you need.
- Many entries link to a fuller guide on that condition or topic.
- If a term about your own care is unclear, ask the professional who used it.
A
Antidepressant — a type of medication used to treat depression and other conditions by adjusting brain chemicals that affect mood. See antidepressants.
Anxiety — a feeling of worry, fear, or unease. When it is persistent and interferes with daily life, it may be an anxiety disorder. See anxiety.
ADHD — attention-deficit/hyperactivity disorder, a condition involving ongoing patterns of inattention, hyperactivity, or impulsivity. See ADHD.
Assessment — the process a professional uses to gather information, through interviews and questionnaires, to understand a person's mental health.
B
Bipolar disorder — a mood disorder with shifts between depressive episodes and periods of elevated mood (mania or hypomania). See bipolar disorder.
Burnout — a state of physical and emotional exhaustion, often caused by prolonged stress, especially at work.
C
CBT (cognitive behavioral therapy) — a widely used, evidence-based talk therapy that helps people change unhelpful thoughts and behaviors.
Cognitive distortion — an inaccurate or exaggerated thought pattern, such as all-or-nothing thinking, that can fuel anxiety or low mood.
Comorbidity — the presence of two or more conditions at the same time, such as depression and an anxiety disorder.
Compulsion — a repeated behavior or mental act a person feels driven to perform, often to ease anxiety. See OCD.
D
DSM-5 — the Diagnostic and Statistical Manual of Mental Disorders, fifth edition, a reference clinicians use to define and diagnose mental health conditions.
Dual diagnosis — having a mental health condition and a substance use disorder at the same time. See dual diagnosis.
Dysthymia — an older name for persistent depressive disorder, a long-lasting, lower-grade form of depression. See depression.
E
Eating disorder — a serious condition involving a disturbed relationship with food, eating, and body image. See eating disorders.
Episode — a distinct period during which symptoms of a condition, such as depression or mania, are present.
G
Grief — the natural response to loss, which can include sadness, longing, and changes in sleep and appetite. See grief and bereavement.
I
Intrusive thought — an unwanted thought, image, or urge that enters the mind. Intrusive thoughts are common and do not reflect a person's character.
M
Mania — a period of abnormally high energy, mood, or activity, a key feature of bipolar disorder. See bipolar disorder.
Mood disorder — a group of conditions, including depression and bipolar disorder, that primarily affect a person's emotional state.
N
Neurotransmitter — a chemical messenger, such as serotonin or dopamine, that carries signals between brain cells and influences mood and behavior.
O
Obsession — a recurring, unwanted thought or urge that causes distress, a core feature of OCD. See OCD.
P
Panic attack — a sudden surge of intense fear with physical symptoms such as a racing heart and shortness of breath. See panic disorder.
Phobia — an intense, persistent fear of a specific object or situation that is out of proportion to the actual danger. See phobias.
Psychiatrist — a medical doctor who specializes in mental health and can prescribe medication.
Psychologist — a professional trained in psychology who provides therapy and assessment but, in most settings, does not prescribe medication.
Psychotherapy — talk therapy, a treatment that uses conversation with a trained professional to improve mental health.
PTSD — post-traumatic stress disorder, a condition that can develop after a frightening or traumatic event. See PTSD.
R
Relapse — the return of symptoms after a period of improvement or recovery.
Remission — a period during which symptoms are reduced or absent.
Resilience — the ability to adapt and recover in the face of stress, adversity, or trauma. Resilience can be strengthened over time.
S
Schizophrenia — a serious mental health condition that affects how a person thinks, feels, and perceives reality. See schizophrenia.
Seasonal affective disorder — depression that follows a seasonal pattern, often in winter. See seasonal affective disorder.
SSRI — selective serotonin reuptake inhibitor, a common class of antidepressant. See antidepressants.
Stigma — negative attitudes or beliefs about mental health that can lead to discrimination and discourage people from seeking help.
Substance use disorder — a condition in which the use of alcohol or drugs causes significant harm or loss of control.
T
Therapist — a general term for a trained professional who provides talk therapy.
Trauma — the lasting emotional response to a deeply distressing or disturbing event. See PTSD.
Trigger — something that sets off a strong emotional reaction or the return of symptoms.
Frequently asked questions
What is the difference between a psychiatrist and a psychologist?
A psychiatrist is a medical doctor who can prescribe medication, while a psychologist provides therapy and assessment and, in most settings, does not prescribe. Many people work with both.
Is this glossary a substitute for a diagnosis?
No. These plain-language definitions are for general understanding. Only a qualified professional can diagnose a mental health condition.
Where can I learn more about a specific condition?
Many entries link to a full guide. You can also browse all of our conditions for detailed, evidence-based information.