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Here is a helpful mental health glossary of terms and diagnoses to familiarize yourself with. Please do not use this to self-diagnose.


Acquired Brain Injury

Damage to the brain caused after birth and can result from a traumatic or non-traumatic event. It is not related to a congenital or a degenerative disease and usually affects cognitive, emotional, behavioural or physical functioning. ABI is not to be confused with intellectual disability or with autistic spectrum disorders.

Acute Stress Disorder

An intense, unpleasant, and dysfunctional reaction beginning shortly after an overwhelming traumatic event and lasting less than a month. If symptoms persist longer than a month, people are diagnosed as having posttraumatic stress disorder (PTSD).


Characterized by thoughts and behaviours that include one or more of the following: impaired control over drug use, compulsive use, continued use despite harm and craving. Types of addiction can involve street drugs, prescription drugs, over-the-counter drugs, gambling, video games, exercise, or sex.


Aims to raise the profile and understanding of mental illness among government and non-government organizations, as well as the industry, education, workplace and academic sectors. Advocacy can include a variety of activities, such as: media campaigns, public speaking, commissioning and publishing research, public service announcements, or undertaking a poll


The fear of being alone in public places from which there is no easy escape.

Alzheimer's Disease

A progressive, degenerative disease of the brain, which causes thinking and memory to become seriously impaired. It is the most common form of dementia, a general term for memory loss and other intellectual abilities serious enough to interfere with daily life.


Anxiety is a normal part of life and can even be useful when it alerts us to danger. But for some, symptoms of anxiety are persistent and severe, interfering with daily activities such as work, school and sleep. This type of anxiety can disrupt relationships and enjoyment of life, and can lead to health concerns and other problems over time. In some cases, anxiety is a diagnosable mental health condition requiring treatment. The 6 main categories of anxiety disorders are: phobias, panic disorder, generalized anxiety disorder, OCD, acute stress disorder, and PTSD.

Attention-Deficit/Hyperactivity Disorder (ADHD)

A disorder marked by an ongoing pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development.

Autism Spectrum Disorder (ASD)

A neuro-developmental condition which is usually diagnosed in the first 3 years of life. Generally parents become concerned when their child has delays in speech development, limited social relatedness, and restricted interests and activities.


The right of patients to make decisions about their medical care without their healthcare provider attempting to influence the outcome. Patient autonomy allows healthcare providers to educate the patient, but not to make the decision for the patient.

Bipolar Disorder

Sometimes referred to as manic-depressive illness, is a brain disorder that causes unusual or extreme shifts in mood, energy, activity levels and the ability to carry out daily tasks. Symptoms are severe and sustained, and are different from the usual ups and downs people go through from time to time.

Child Psychiatrist

A physician who specializes in the diagnosis and treatment of disorders of thinking, feeling and behavior affecting children, adolescents and their families.

Child Psychologist

A trained professional who provides treatment to children with mental health issues.

Clinical Social Worker

Provides mental health services for the prevention, diagnosis, and treatment of mental, emotional, and behavioral disorders in individuals, families, and groups.

Cognitive Behavioural Therapy (CBT)

CBT is one of the most commonly practiced forms of psychotherapy in mental health counselling. Its focus is on helping people learn how their thoughts impact and affect their feelings and behaviours. The theory is based on the belief that how individuals think and behave may develop and maintain psychological disorders, and that the resulting symptoms and distress can be reduced if individuals learn coping strategies.

Concurrent Disorders

Concurrent disorders are conditions in which a person experiences both mental illness and a substance abuse disorder. Concurrent disorders can include a wide range of combinations, such as an anxiety disorder and a drinking problem, or schizophrenia and cannabis dependence.

Conduct Disorder

A repetitive and persistent pattern of behavior among teenagers in which they violate the rights of others, or violate norms or rules that are appropriate to their age.


Delusions are false or erroneous beliefs that usually involve a misinterpretation of perceptions or experiences. Delusions are different from hallucinations and paranoia.


Dementia disorders are the most common mental health problem affecting Canadian seniors. Dementia involves loss of memory and cognitive abilities and almost always affects judgment, decision-making and relationships. Alzheimer’s disease is the most common dementia disorder. Other types of dementia include vascular dementia, dementia with Lewi Bodies, and frontotemperal dementia.


A type of mood disorder characterized by low or irritable mood or loss of interest or pleasure in almost all activities over a period of time.

Developmental Disabilities

A disability of a person which results in impairment of intellectual functioning or adaptive behavior.

Dialectical Behavioural Therapy (DBT)

This is a specific blend of cognitive and behavioural therapies developed to share acceptance-based strategies. It is usually used in the treatment of Borderline Personality Disorder and is also used to treat individuals with eating disorders, addictions, anger problems and other impulsive behaviours.

Disruptive Mood Dysregulation Disorder

A childhood condition of extreme irritability, anger, and frequent, intense temper outbursts. DMDD symptoms go beyond a being a “moody” child—children with DMDD experience severe impairment that requires clinical attention.

Dual Diagnosis

Dual diagnosis is a term used to describe mental health issues experienced by people with a developmental disability. Sometimes, dual diagnosis identifies issues that are usually referred to as concurrent disorders, that is, psychiatric illness and addiction.

Eating Disorders

Unhealthy pattern of eating characterized by preoccupation with food and distorted body image.

Gender Dysphoria

Psychological distress that results from an incongruence between one's sex assigned at birth and one's gender identity.

Generalized Anxiety Disorder

Ongoing anxiety that isn’t related to a particular event or situation. It also can be anxiety that isn’t “normal” about a situation. For instance, a person who has GAD may constantly worry about something that’s unlikely to happen. These worries interfere with your day-to-day life.


Hallucinations are false or distorted sensory experiences that appear to be real perceptions. When you hallucinate, you are hearing, seeing, smelling or feeling things that do not actually exist. The most common hallucinations are auditory – people will hear voices talking about them or to them. Although these experiences are not real, they seem as vivid and real as any other experience.

Huntington Disease

Huntington disease (HD) is a progressive, degenerative brain disorder that causes nerve cells in specific parts of the brain to waste away and die. Signs and symptoms of this inherited disease typically develop in middle age.

Major Depressive Disorder

Characterized by a persistently depressed mood and long-term loss of pleasure or interest in life, often with other symptoms such as disturbed sleep, feelings of guilt or inadequacy, and suicidal thoughts.

Mental Illness

Health conditions involving changes in emotion, thinking or behavior (or a combination of these). Mental illnesses are associated with distress and/or problems functioning in social, work or family activities.

Obsessive Compulsive Disorder (OCD)

A disorder in which people have recurring, unwanted thoughts, ideas or sensations (obsessions) that make them feel driven to do something repetitively (compulsions).

Oppositional Defiant Disorder (ODD)

A type of behavior disorder. It is mostly diagnosed in childhood. Children with ODD are uncooperative, defiant, and hostile toward peers, parents, teachers, and other authority figures.

Panic Disorder

A type of anxiety disorder. It causes panic attacks, which are sudden feelings of terror when there is no real danger. You may feel as if you are losing control.


Paranoia is a groundless or exaggerated distrust of others. Someone experiencing paranoia, for example, may suspect the motives of those around them. They may believe that some people are trying to harm them or that something dreadful is about to happen. But unlike being suspicious or fearful about the future, someone experiencing paranoia may not recognize that their fears are unfounded. In extreme forms, paranoia may reach delusional proportions, with the person unable to distinguish between realty and fantasy.

Personality Disorder

Personality disorders are often diagnosed when particular elements of a person's behaviours, reactions and perceptions of the world are extreme and cause distress to the person experiencing them, as well as to other people in their lives.


An extreme or irrational fear of or aversion to something.

Post Traumatic Stress Disorder (PTSD)

Post-Traumatic Stress Disorder (PTSD) is an anxiety disorder triggered by a traumatic event that caused intense fear, helplessness or horror. It can result from a trauma an individual experienced personally, such as rape, war, natural disaster, abuse, serious accident and captivity. Individuals can also develop PTSD after witnessing or learning of a violent or tragic event.


The treatment of mental disorder by psychological rather than medical means.

Reactive Attachment Disorder (RAD)

A rare but serious condition in which an infant or young child doesn't establish healthy attachments with parents or caregivers.


These are just some of the mental health related terms and diagnoses that exist.

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