Updated January 2023
Although strides have been made to raise awareness and reduce stigma around mental illness, the issue remains shrouded in shame and secrecy.
Research clearly shows that millions of people across the globe are suffering from poor mental health. Yet health care providers and front-line community workers still lack training in how to identify and assist those in need.
And despite the prevalence of mental illness, there is a wide array of poisonous myths regarding the nature of mental health disorders—and the people who are afflicted by them.
Do you have questions about which mental illnesses are most common, their key characteristics, and treatment options?
If you work closely with the public, there is little doubt that you have encountered people suffering from one (or more) of the following five mental health issues.
This list isn't definitive, but it offers a good summary of attributes, statistics, and warning signs associated with these very common mental illnesses.
Depression is one of the most common mental health disorders on the planet.
According to the World Health Organization (WHO), approximately 280 million people suffer from depression worldwide. In the United States alone, 21 million people have a major depressive episode each year.
Depression impacts people of all ages and socioeconomic backgrounds—but adolescents are particularly vulnerable to this mood disorder.
In Canada, the CBC reported that youth aged 15 to 24 had the highest rates of depression of any age group in the country. Suicide is the second-leading cause of death among this demographic, and the WHO reports similar trends on a global scale.
But it's not just young people who are impacted.
The Canadian Institute for Health Information estimates that close to half of all seniors in long-term care suffer from depression (18 per cent of whom have no documented diagnosis or treatment plan).
Depression is a global problem, made worse by stigma, lack of awareness, and limited access to health care services.
Common signs of depression include:
- Loss of interest in daily life
- Withdrawal from social activities
- Impaired functioning at work or school
- Inability to cope with routine tasks
- Major changes in eating and sleeping habits
- Sadness, hopelessness
- Emotional "numbness"
- Difficulty concentrating and remembering things
- Physical aches and pains with no clear cause
With early diagnosis and effective health care, depression is highly treatable. Common approaches include cognitive behavioral therapy and antidepressants.
2. Anxiety Disorders
As a group, anxiety disorders are the most common of all mental illnesses.
In the US, a staggering 40 million adults suffer from anxiety every year. And some experts suggest this number is even higher, since many people don't report their illness or are misdiagnosed. In Canada, anxiety impacts roughly five per cent of the population.
Anxiety disorders include:
- Generalized anxiety disorder (GAD)
- Phobias (such as fear of flying, heights, or specific animals)
- Post-traumatic stress disorder (PTSD)
- Panic disorder
- Obsessive-compulsive disorder (OCD)
- Social anxiety disorder
Each type of anxiety disorder has its own unique symptoms and triggers. But in general, anxiety is characterized by:
- Intense and prolonged feelings of fear and distress that do not align with a real threat or danger
- Avoidance of work, school, and social situations
- Headaches, muscle tension, irritability
Anxiety disorders often start in adolescence or young adulthood and are paired with another mental health problem.
Nearly half of people diagnosed with depression are also diagnosed with an anxiety disorder.
Anxiety is highly treatable, but due to a lack of mental health training , health care providers often miss key signs and symptoms.
Meanwhile, patients typically fear being labelled "weak" or "over-emotional" and avoid discussing their problems with anxiety. Like so many mental health issues, stigma is a major barrier to treatment and recovery.
3. Bipolar Affective Disorder
About 40 million people worldwide suffer from bipolar affective disorder. It is characterized by alternating episodes of depression and mania, separated by periods of normal mood.
Symptoms of manic episodes include:
- Elevated mood, feelings of joy and excitement
- Inflated self-esteem
- Lack of desire for sleep
- Rapid speech
- Racing thoughts
- Very short attention span
- High-risk behaviours
Symptoms of depressive episodes include:
- Extreme sadness
- Little energy but trouble sleeping
- Suicidal thoughts/actions
Bipolar affective disorder can be treated with mood stabilizers, anti-anxiety and antipsychotic medications, and behavioural cognitive therapy.
Schizophrenia is a severe mental illness that affects approximately 24 million people worldwide.
People suffering from schizophrenia often have trouble differentiating between the real and unreal.
Symptoms tend to appear in the early 20s and 30s, and include:
- Hallucinations and paranoid delusions (hearing voices, distorted perceptions and beliefs)
- Difficulty expressing emotions
- Confused thinking and speech
- Bizarre behaviour, abnormal movements
- Decline in memory and concentration (often impacting work/school performance)
There are many harmful myths surrounding schizophrenia. This illness is not the same as split personality or multiple personality disorder.
Nor are sufferers always violent, homeless, or living in hospitals. Many people with schizophrenia live independently, with family, or in group homes.
Although there is no cure for schizophrenia, many patients do well with treatment. Medications and cognitive therapy can help control symptoms and greatly reduce the potential for acute psychotic episodes.
Stress management, social support, and employment programs have been shown to help people suffering from schizophrenia enjoy longer periods of remission.
5. Concurrent Disorders
The term concurrent disorder refers to the combination of addiction with another mental health issue.
A national survey on drug use and health in the US found that 50 per cent of adults with addiction problems had a co-occurring mental illness. That's 10.2 million adults suffering from concurrent disorders.
The story is not so different in Canada, where 282,000 people per year experience substance abuse and mental health issues concurrently.
Addiction is a very common mental health issue in its own right and includes problems with gambling, drugs, and alcohol abuse. However, addiction is often intertwined with other mental health issues, making diagnosis and treatment more complicated.
Some of the most common concurrent disorders include:
- Substance abuse + mood and anxiety disorders
- Substance abuse + personality disorders
- Substance abuse + eating disorders
Typical challenges involved in diagnosing and treating concurrent disorders include:
- People suffering from substance abuse often forget to take prescribed medications.
- Relapse in one area can trigger a crisis in the other.
- Addiction can mimic or hide symptoms of another mental health problem.
- People use drugs and alcohol to self-medicate, which can worsen related mental health symptoms.
Health Canada has identified a serious need for mental health training in this area to better understand the nature of concurrent disorders and how to treat them.
Related: Guide to Concurrent Disorders
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