Mental Health Glossary & Definitions

Mental Health Language Should Be Easier to Understand

Mental health information can be full of clinical language, shortened terms, service jargon and words that people hear in appointments, articles, support groups or everyday conversation. This page is designed to make those terms clearer without requiring specialist knowledge.

A master glossary, not every specialist glossary at once

This page gives a broad foundation across mental health. More detailed definitions for specific areas such as mood disorders, trauma, medication, neurodiversity or therapies can sit in their own specialist glossaries and feed back into this master page.

That means you can get a useful plain-language overview here without losing the option to go deeper later.

Mental Health Glossary A–Z

Search by word or filter by theme. This master glossary includes the core terminology visitors are most likely to encounter across Mental Health. Definitions stay concise here, while specialist glossaries can provide deeper detail without duplicating the whole system.

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Filter by theme All themes Wellbeing & distress Symptoms & experiences Support & services Therapy & treatment Medication & clinical Safety & risk

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A

A terms

Acute Stress Reaction Symptoms & experiences

A short-term stress response that can occur soon after a frightening or overwhelming event.

Acute Stress Disorder Clinical

A trauma-related diagnosis involving distressing symptoms that begin after a traumatic event and last for a limited period before the one-month point used for PTSD.

Addiction Medication & clinical

A pattern of compulsive substance use or behaviour that continues despite harm or loss of control. Professional definitions vary by the substance or behaviour involved.

Adjustment Disorder Clinical

A diagnosis used when emotional or behavioural symptoms develop in response to an identifiable stressor and cause significant distress or difficulty functioning.

Affect Clinical

A clinical term for the outward expression of emotion that a professional may observe during an assessment.

Agoraphobia Clinical

An anxiety disorder involving marked fear of situations where escape or access to help may feel difficult, such as crowds, public transport or being far from home.

Alexithymia Symptoms & experiences

Difficulty identifying, describing or distinguishing emotions. It can occur in many different people and is not itself a mental-health diagnosis.

Anhedonia Symptoms & experiences

Reduced ability to feel pleasure or interest in activities that would usually be enjoyable.

Antidepressant Medication & clinical

A medication used to treat depression and some other conditions, including certain anxiety disorders. Different classes work in different ways.

Antipsychotic Medication & clinical

A medication used to treat psychosis and some other conditions. Some antipsychotics are also used in mood disorders or for other clinical reasons.

Anxiety Wellbeing & distress

A feeling of worry, fear, tension or unease. Anxiety can be a normal response to stress, but it can also become persistent or overwhelming.

Anxiety Disorder Clinical

A group of diagnoses in which anxiety or fear is persistent, excessive or significantly interferes with daily life.

Assessment Clinical

A process used to understand a person’s experiences, needs, history and possible next steps for support or diagnosis.

Avoidance Symptoms & experiences

Staying away from thoughts, feelings, people, places or situations that feel distressing or threatening. Avoidance can bring short-term relief but may sometimes keep anxiety or trauma responses going.

Advocate / Advocacy Support & services

Helping a person speak up for their rights, needs or choices, or supporting them to do so themselves.

B

B terms

Behavioural Activation Therapy & treatment

A therapy strategy that helps a person gradually reconnect with meaningful or rewarding activities, often used in treatment for depression.

Benzodiazepine Medication & clinical

A class of prescription medicines that can reduce severe anxiety, agitation or insomnia in some situations. They can cause dependence and are usually managed carefully by a prescriber.

Bereavement Wellbeing & distress

The period of grief and adjustment following the death of someone important.

Bipolar Disorder Clinical

A mood disorder involving episodes of depression and episodes of mania or hypomania, depending on the bipolar diagnosis.

Body Image Wellbeing & distress

The thoughts, feelings and beliefs a person has about their body and appearance.

Borderline Personality Disorder (BPD) Clinical

A personality-disorder diagnosis associated with long-term difficulties such as intense emotions, unstable relationships, fear of abandonment or changes in self-image. Experiences vary widely between individuals.

Burnout Symptoms & experiences

Deep physical, emotional or mental exhaustion that can follow prolonged stress, overload or unmet needs.

C

C terms

Care Plan Support & services

A written or agreed plan describing a person’s needs, goals, treatment, support, responsibilities and follow-up.

CBT Therapy & treatment

Cognitive Behavioural Therapy. A therapy approach that looks at the connection between thoughts, feelings and behaviours.

Chronic Stress Wellbeing & distress

Stress that continues over a long period and may affect mood, sleep, concentration, physical health and day-to-day functioning.

Clinical Psychologist Support & services

A psychologist with advanced clinical training who may provide assessment, formulation and psychological therapy. Registration and scope vary by country.

Co-occurring Conditions Clinical

Two or more conditions or difficulties occurring in the same person at the same time.

Comorbidity Clinical

A clinical term for two or more health or mental-health conditions occurring together. Some people prefer the phrase co-occurring conditions.

Compassion Fatigue Wellbeing & distress

Emotional and physical exhaustion that can affect people repeatedly exposed to others’ distress, especially in caring or helping roles.

Compulsion Symptoms & experiences

A repetitive behaviour or mental act a person feels driven to perform, often to reduce anxiety or prevent a feared outcome.

Confidentiality Support & services

The expectation that personal information shared with a professional or service is kept private, subject to legal and safety-related limits that should be explained.

Consent Support & services

A person’s voluntary agreement to something after having enough information and freedom to decide.

Coping Wellbeing & distress

The ways a person manages stress, emotions or difficult experiences. Some coping strategies are helpful and sustainable, while others may create additional problems.

Counselling / Counseling Support & services

A talking-support approach where a trained professional helps a person explore feelings, difficulties and possible coping strategies.

Crisis Safety & risk

A situation where distress, safety concerns or loss of coping capacity becomes urgent and immediate support may be needed.

Crisis Plan Safety & risk

A plan for what to do, who to contact and what may help if a person’s mental health becomes unsafe or severely distressed.

Cyclothymia Clinical

A mood disorder involving long-term fluctuations between periods of hypomanic symptoms and depressive symptoms that do not always meet full episode criteria.

D

D terms

DBT Therapy & treatment

Dialectical Behaviour Therapy. A therapy approach often focused on emotional regulation, distress tolerance, relationships and mindfulness.

Delusion Symptoms & experiences

A strongly held belief that is not shared by others in the person’s cultural or social context and remains despite clear evidence to the contrary.

Dependence Medication & clinical

A physical or psychological adaptation in which stopping or reducing a substance or medicine may cause withdrawal or strong difficulty stopping. Dependence is not identical to addiction.

Depression Clinical

A mental-health condition involving persistent low mood and/or loss of interest or pleasure, often with changes in sleep, energy, thinking, appetite or functioning.

Depressive Episode Clinical

A period in which a cluster of depressive symptoms is present for long enough and with enough impact to meet clinical criteria.

Diagnosis Clinical

A label given by a qualified professional to describe a health or mental-health condition based on assessment criteria.

Differential Diagnosis Clinical

The process of considering different possible explanations for symptoms and working out which diagnosis or diagnoses best fit.

Dissociation Symptoms & experiences

A sense of feeling disconnected from thoughts, feelings, body, surroundings or memories.

DSM Clinical

The Diagnostic and Statistical Manual of Mental Disorders, a classification system published by the American Psychiatric Association and used in some countries and clinical settings.

Dysthymia / Persistent Depressive Disorder Clinical

A diagnosis involving a long-lasting pattern of depressed mood and related symptoms. The current clinical term in many settings is Persistent Depressive Disorder.

E

E terms

Eating Disorder Clinical

A group of serious mental-health conditions involving eating, food, body image or weight-related thoughts and behaviours that cause distress or health impacts.

Emotional Dysregulation Symptoms & experiences

Difficulty managing the intensity, duration or expression of emotions in a way that feels workable or safe.

Emotional Regulation Wellbeing & distress

The ability to notice, manage, respond to and recover from emotions in ways that feel safe and workable.

Evidence-Based Treatment Therapy & treatment

Treatment supported by research evidence, clinical expertise and consideration of the person’s needs, preferences and context.

Executive Function Symptoms & experiences

Mental processes involved in planning, starting tasks, organising, remembering, shifting attention and regulating behaviour. Difficulties can interact with stress and mental health.

Exposure Therapy Therapy & treatment

A structured therapy approach that helps a person gradually and safely face feared thoughts, feelings or situations instead of avoiding them.

F

F terms

Fawn Response Symptoms & experiences

A term sometimes used for a stress response involving appeasing or pleasing others to reduce perceived threat. It is not a formal diagnosis.

Fatigue Symptoms & experiences

More than ordinary tiredness. Fatigue can involve low energy, physical exhaustion, mental exhaustion or reduced capacity.

Fight / Flight / Freeze Symptoms & experiences

Common terms for automatic threat responses in which the body prepares to confront danger, escape it or become still and less responsive.

Flashback Symptoms & experiences

An intense re-experiencing of a past traumatic event that can feel as though it is happening again in the present.

Formulation Clinical

A shared explanation of how a person’s difficulties may have developed and what keeps them going, used to guide support or therapy.

Functional Impairment Clinical

Difficulty carrying out everyday activities, roles or responsibilities because of symptoms or health-related challenges.

G

G terms

Generalised Anxiety Disorder (GAD) Clinical

An anxiety disorder involving persistent and hard-to-control worry across several areas of life, often with physical or cognitive symptoms.

GP Support & services

General Practitioner. A family doctor who may be a first point of contact for mental-health concerns, referrals and medication support.

Grief Wellbeing & distress

A natural response to loss. Grief may affect emotions, thoughts, body, behaviour, identity and relationships.

Grounding Wellbeing & distress

Techniques that help a person feel more present, steady or connected when distressed, dissociated or overwhelmed.

Group Therapy Therapy & treatment

Therapy delivered to several people together by one or more trained professionals, usually around shared goals or treatment approaches.

H

H terms

Hallucination Symptoms & experiences

A sensory experience that feels real but occurs without an external source, such as hearing a voice or seeing something others do not perceive.

Helpline Support & services

A phone, text, chat or online service that offers listening, guidance, crisis support or information.

Hopelessness Wellbeing & distress

A feeling that things will not improve or that there is no positive future. It can be an important sign that extra support may be needed.

Hyperarousal Symptoms & experiences

A state of increased alertness or nervous-system activation that can involve irritability, tension, sleep difficulty, startle responses or feeling constantly on guard.

Hypomania Clinical

A period of elevated, expansive or irritable mood with increased energy and other changes that is less severe than mania but still represents a noticeable change from usual functioning.

I

I terms

ICD Clinical

The International Classification of Diseases, a World Health Organization classification system that includes mental-health diagnoses.

Informed Consent Support & services

Consent given after a person receives understandable information about what is being offered, including relevant benefits, risks and alternatives.

Inpatient Care Support & services

Mental-health treatment or support provided while a person stays in a hospital or specialist facility.

Insomnia Symptoms & experiences

Ongoing difficulty falling asleep, staying asleep or getting sleep that feels refreshing enough.

Intake Support & services

An initial stage of entering a service, often involving information gathering, screening or deciding what support may be appropriate.

Intrusive Thoughts Symptoms & experiences

Unwanted thoughts, images or urges that can feel distressing, repetitive or difficult to dismiss.

J

J terms

Jargon Support & services

Specialist language that may be familiar to professionals but confusing or inaccessible to other people unless it is explained clearly.

Journaling Wellbeing & distress

Writing thoughts, feelings or experiences down as a reflection or coping tool. It can be helpful for some people but is not a replacement for professional support when that is needed.

K

K terms

Ketamine Treatment Medication & clinical

A medical treatment using ketamine or related medicines in specialist settings for certain mental-health conditions, including some cases of treatment-resistant depression. Availability and regulation vary by country.

Kindness / Self-Compassion Wellbeing & distress

Treating yourself or others with care and understanding, especially during difficulty, mistakes or distress.

L

L terms

Licensed / Registered Professional Support & services

A professional who meets the legal or regulatory requirements of their country or region to practise in a particular role.

Lived Experience Support & services

Knowledge gained through personally experiencing mental-health difficulties, support systems, recovery or related life circumstances.

Loneliness Wellbeing & distress

A distressing feeling of not having the amount or quality of connection a person wants, even when other people may be physically present.

Low Mood Wellbeing & distress

A period of feeling down, sad, flat or less able to enjoy things. Low mood can happen for many reasons and may be short- or longer-term.

M

M terms

Major Depressive Disorder (MDD) Clinical

A depressive-disorder diagnosis involving one or more major depressive episodes that significantly affect mood, interest, functioning or daily life.

Mania Clinical

A period of markedly elevated, expansive or irritable mood with increased energy and other changes that cause major impairment, may require hospital care or can include psychotic symptoms.

Mental Health Wellbeing & distress

A person’s emotional, psychological and social wellbeing. Everyone has mental health, whether they have a diagnosed condition or not.

Mental Health Condition Clinical

A broad phrase for a diagnosable mental-health disorder or condition. People may prefer different language for their own experience.

Mental Health Professional Support & services

A trained professional working in mental-health care or support, such as a psychologist, psychiatrist, counsellor, psychotherapist, mental-health nurse or social worker.

Mental Illness Clinical

A broad term for diagnosable mental-health conditions that significantly affect thoughts, emotions, behaviour or functioning.

Mental Status Examination (MSE) Clinical

A structured clinical observation of areas such as appearance, behaviour, speech, mood, thinking, perception, cognition, insight and judgement.

Mindfulness Therapy & treatment

A practice of paying attention to the present moment with awareness and as little judgement as possible.

Mood Wellbeing & distress

A person’s emotional state over a period of time, such as feeling calm, low, irritable or elevated.

Mood Disorder Clinical

A broad clinical category involving significant disturbances in mood, including depressive disorders and bipolar-related disorders.

Mood Stabiliser / Mood Stabilizer Medication & clinical

A term for medicines used to help prevent or reduce extreme mood changes, particularly in bipolar disorder. Different medicines may be used for different purposes.

Motivational Interviewing Therapy & treatment

A collaborative counselling approach designed to help people explore mixed feelings about change and strengthen their own reasons for taking action.

N

N terms

Nervous System Symptoms & experiences

The body system involved in sensing, responding and regulating. Stress, trauma and overload can affect how the nervous system responds.

Non-Suicidal Self-Injury (NSSI) Safety & risk

Intentional self-injury without the intent to die. It is a form of self-harm and still deserves compassionate support and safety assessment.

Needs Support & services

What a person requires to feel safe, supported or able to function, such as emotional support, rest, therapy, medication, housing or accommodations.

O

O terms

Obsessions Symptoms & experiences

Repetitive, intrusive thoughts, images or urges that can create significant anxiety or distress.

Obsessive-Compulsive Disorder (OCD) Clinical

A disorder involving obsessions, compulsions or both, which can be time-consuming, distressing or interfere with daily life.

Outpatient Care Support & services

Mental-health treatment or support received without staying overnight in a hospital or residential facility.

Overwhelm Wellbeing & distress

A state where thoughts, emotions, demands or sensations feel too much to manage at once.

P

P terms

Panic Attack Symptoms & experiences

A sudden surge of intense fear or distress, often with physical symptoms such as racing heart, dizziness, shaking or shortness of breath.

Panic Disorder Clinical

An anxiety disorder involving recurrent unexpected panic attacks and ongoing concern or behaviour changes related to having more attacks.

Peer Support Support & services

Support provided by people with shared or similar lived experience. Peer support is different from professional therapy, although both may be useful.

Person-Centred Care Support & services

Support that puts the person’s goals, preferences, values and circumstances at the centre of decisions about care.

Personality Disorder Clinical

A group of diagnoses describing long-term patterns of thinking, feeling, behaviour or relationships that cause significant distress or difficulty. The label can be experienced differently by different people.

Phobia Clinical

An intense and persistent fear of a particular object, situation or activity that leads to distress or avoidance.

Prescriber Support & services

A qualified health professional legally authorised to prescribe medicines in their jurisdiction.

Protective Factors Wellbeing & distress

Things that support wellbeing or reduce harm, such as safe relationships, support, community, coping skills, housing or access to care.

Psychiatrist Support & services

A medical doctor specialising in mental health, including assessment, diagnosis and medication management.

Psychologist Support & services

A professional trained in psychology who may provide assessment, psychological therapy, research or other services depending on their registration and role.

Psychosis Clinical

A state in which a person has significant difficulty distinguishing shared reality from their own perceptions or beliefs. It can include hallucinations, delusions or disorganised thinking.

Psychotherapy Therapy & treatment

A broad term for structured psychological treatment that uses conversation and therapeutic techniques to address mental-health or emotional difficulties.

Psychoeducation Therapy & treatment

Education about mental health, symptoms, treatment, coping and recovery, often used as part of therapy or support.

PTSD Clinical

Post-Traumatic Stress Disorder. A trauma-related diagnosis involving symptoms such as re-experiencing, avoidance, negative changes in mood or thinking, and heightened threat responses after trauma.

Q

Q terms

Quality of Life Wellbeing & distress

A broad measure of how a person experiences their physical, emotional, social and everyday life, including functioning, relationships, safety and satisfaction.

Questions to Ask a Service Support & services

Useful questions may include what support is offered, wait times, costs, confidentiality, accessibility, professional qualifications and whether online options are available.

R

R terms

Recovery Wellbeing & distress

A personal process of healing, adapting, living with or moving forward from mental-health difficulties. Recovery does not always mean symptoms disappear completely.

Referral Support & services

When one service or professional directs a person to another service, clinician or type of support.

Relapse Wellbeing & distress

The return or worsening of symptoms after a period of improvement or recovery.

Remission Clinical

A period in which symptoms are greatly reduced or no longer meet the threshold for a condition, even though ongoing support may still be useful.

Resilience Wellbeing & distress

The capacity to cope, adapt or recover after challenge. Resilience is not about never struggling; it is also shaped by support and circumstances.

Risk Assessment Safety & risk

A structured process for understanding possible risks to a person’s safety or wellbeing and deciding what support or action may be needed.

Risk Factors Safety & risk

Things that may increase the likelihood of mental-health difficulties or harm, such as trauma, isolation, major stress or lack of support.

S

S terms

Safety Plan Safety & risk

A practical plan listing warning signs, coping steps, supportive people, professional contacts and ways to reduce danger during a crisis.

Schizoaffective Disorder Clinical

A diagnosis involving symptoms of psychosis together with significant mood episodes, with particular timing requirements used in diagnosis.

Schizophrenia Clinical

A long-term mental-health condition that can involve psychosis, changes in thinking, motivation, emotional expression and functioning. Experiences vary greatly.

Screening Clinical

A brief process, often using questions or checklists, to identify whether further assessment may be helpful. Screening alone does not usually provide a diagnosis.

Self-Esteem Wellbeing & distress

A person’s overall sense of their own worth or value.

Self-Harm Safety & risk

Intentionally hurting oneself. People may self-harm for many reasons, and it is important to respond with support rather than judgement.

Side Effect Medication & clinical

An unintended effect that can occur alongside the intended effect of a medicine or treatment.

Sleep Hygiene Wellbeing & distress

Habits and environmental practices intended to support healthier sleep, such as consistent routines, light exposure and a suitable sleep environment.

SNRI Medication & clinical

Serotonin-Norepinephrine Reuptake Inhibitor. A class of antidepressant medicines used for depression and some anxiety or pain conditions.

Social Anxiety Disorder Clinical

An anxiety disorder involving intense fear of being judged, embarrassed or negatively evaluated in social or performance situations.

Somatic Symptoms Symptoms & experiences

Physical symptoms or sensations that are experienced in the body. They may have physical, psychological or mixed influences and still deserve appropriate assessment.

SSRI Medication & clinical

Selective Serotonin Reuptake Inhibitor. A commonly used class of antidepressant medicines for depression and several anxiety-related conditions.

Stigma Wellbeing & distress

Negative stereotypes, prejudice or discrimination attached to a condition, identity or experience.

Stress Wellbeing & distress

The body and mind’s response to demands or pressures. Stress can be short-term and manageable or become harmful when severe or prolonged.

Substance Use Disorder Clinical

A diagnosis involving a problematic pattern of alcohol or drug use that causes significant impairment or distress.

Suicidal Thoughts / Suicidal Ideation Safety & risk

Thoughts about dying, wanting to be dead or suicide. These thoughts should be taken seriously and can be a sign that urgent support is needed.

Suicide Attempt Safety & risk

A self-injurious act carried out with at least some intent to die. It requires compassionate, urgent safety-focused support.

Support Group Support & services

A group where people connect around shared experiences or needs. Some are peer-led and some are professionally facilitated. A support group is not automatically the same as group therapy.

Symptom Clinical

A sign, feeling, behaviour or experience associated with a condition or difficulty.

T

T terms

Telehealth Support & services

Health or support services delivered remotely through phone, video or other secure digital communication.

Therapist Support & services

A broad term for a professional who provides therapy. Training, registration and legal use of the title vary between countries.

Therapy Therapy & treatment

A structured support approach provided by a trained professional to help with emotions, thoughts, behaviour or mental-health difficulties.

Treatment Plan Therapy & treatment

A plan for support or care that may include therapy, medication, lifestyle steps, practical support or follow-up appointments.

Treatment-Resistant Depression Clinical

A term used when depression has not improved enough after adequate trials of standard treatments. Exact definitions vary in clinical settings.

Trauma Wellbeing & distress

The impact of deeply distressing or overwhelming experiences. Trauma can affect emotions, body, relationships, sense of safety and daily life.

Trauma-Informed Care Therapy & treatment

An approach that recognises trauma may affect people in different ways and aims to increase safety, choice, trust, collaboration and control.

Trigger Wellbeing & distress

Something that activates distress, strong emotion, memory or a stress response.

U

U terms

Uncertainty Wellbeing & distress

Not knowing what will happen next. Uncertainty can increase stress, anxiety or difficulty coping for some people.

Unipolar Depression Clinical

An older or informal term sometimes used for depressive disorders that do not include episodes of mania or hypomania.

Urgent Support Safety & risk

Support needed quickly because of immediate distress, escalating risk or concern for safety.

V

V terms

Validation Wellbeing & distress

Responding in a way that shows a person’s feelings or experiences make sense in context, even if you do not agree with every conclusion or action.

Voluntary Admission Support & services

Entering inpatient mental-health care by agreement rather than under compulsory legal powers. Exact rules vary by jurisdiction.

Vulnerability Wellbeing & distress

Being more open to harm, stress or difficulty because of personal, social, health or environmental factors.

W

W terms

Waitlist / Waiting List Support & services

A delay period before a person can access a service, assessment, appointment or treatment.

Warning Signs Safety & risk

Changes that may suggest a person’s mental health is worsening or that extra support may be needed. Warning signs are individual and context-dependent.

Wellbeing Wellbeing & distress

A broad term covering how a person is doing emotionally, mentally, socially and sometimes physically or spiritually.

Window / Zone of Tolerance Wellbeing & distress

A concept used to describe the range in which a person can cope, think and respond relatively effectively without becoming overwhelmed or shut down.

Withdrawal Medication & clinical

Physical or psychological symptoms that can occur when a substance or some medicines are reduced or stopped, especially after regular use. Medication changes should be discussed with an appropriate prescriber.

Wraparound Support Support & services

A more holistic approach to support that may include practical help, family involvement, education, housing, health or community-based support.

X

X terms

X-Factor Language Note Support & services

There are very few standard mental-health glossary terms beginning with X. If a service uses an unfamiliar X-term or acronym, ask for a plain-language explanation.

Y

Y terms

Youth Mental Health Support & services

Mental-health information, support or services designed for children, teenagers or young adults.

Youth Service Support & services

A service designed specifically for children, teenagers or young adults. Age ranges, eligibility and types of support vary between organisations.

Z

Z terms

Zone / Window of Tolerance Wellbeing & distress

A concept used to describe the range in which a person can cope, think and respond relatively effectively without becoming overwhelmed or shut down.

Language & Respectful Terminology

Specialist Glossaries

This page is the master glossary. Specialist glossaries can expand on specific areas without overloading the main page.

Related Mental Health Pathways