The Most Common Mental Illnesses

Mental diseases are conditions that affect your thinking, mood, or behavior. It is estimated that throughout our life, almost fifty percent of us will be diagnosed with a mental illness at some point. Mental illness is not always a permanent condition. For example, depression can be seasonal, chronic, or once in a lifetime. 

Considering that fifty percent of us will be diagnosed with a mental illness at some point during our life, it can be said that we all know someone that is currently dealing with a mental illness. The best way to support them is to better understand the condition. We can only do this if we educate ourselves on mental illness.

Top 5 Most Common Mental Diseases

The following six conditions are the most common types of mental illness. This is a good starting point in your research of mental diseases. Let’s take a look at the top six most common mental diseases as well as the symptoms and treatment options.


Autism, or autism spectrum disorder, is a condition characterized by difficulty with social skills, verbal and nonverbal communication, and repetitive behaviors. The condition is believed to impact one in fifty-four children across the United States. Boys are four-hundred percent more likely to be affected than girls. In terms of a diagnosis, the earlier it is made the better. Early intervention encourages better development.


Children with autism are more likely to be bullied because the condition is stigmatized. But, children with this condition simply think differently. There are a few symptoms that can be easily recognized. The presence of these symptoms is what encourages a diagnosis. There is no medical test available for autism.

  • Unusual arrangements of the body
  • Unusual facial expressions
  • Poor, or absent, eye contact
  • Disturbances in behavior
  • Delay in speech
  • Speech is monotone or flat
  • Does not engage, or conversate with peers
  • Learning disability present
  • Struggles to understand feelings and social cues
  • Repetitive words, sayings, and behaviors


There is no known treatment for autism. But, many interventions have been found and prove helpful. The treatment plan is designed around the child. Each child with autism is different. Their symptoms, functioning, and interests vary dramatically. 

The treatment plan is designed to assist the child in daily living activities, social development, and cognitive ability. Treatment should help reduce the symptoms of autism. Unfortunately, there is not one option for every child dealing with this condition. Each child will be treated differently. 

Mood Disorders 

There are two main types of mood disorders, depression, and bipolar disorder. These two mood disorders are the two most commonly diagnosed mental illnesses. Both depression and bipolar disorder are characterized by the effect they have on the individual’s mood and energy levels. Both of these disorders involve depressive episodes. The difference between these two disorders is that bipolar disorder involves both depressive and manic episodes


The majority of the symptoms related to mood disorders involve feelings. The condition is primarily diagnosed based on the severity of these feelings and whether there seems to be a pattern. Take a look at the symptoms below. 

  • Feelings of hopelessness or worthlessness
  • Low self-esteem
  • Feeling empty or believing that the world is empty
  • Loss of interest
  • Lack of focus
  • Change is sleeping or eating habits
  • Irritability
  • Displays of anger or aggression
  • Thoughts or threats of suicide


Mood disorders are primarily treated through therapy and medications. Antidepressants or mood-stabilizing medications are used to help alleviate the symptoms of the mood disorder. Talk therapy or family therapy is necessary to learn how to cope with the disorder. A therapist can teach you new coping mechanisms and help you manage the symptoms. 

Anxiety Disorders 

Anxiety Disorders is an umbrella that encompasses quite a few conditions. Generalized anxiety disorder, social anxiety disorder, separation anxiety disorder, and panic disorder are just a few conditions found under this umbrella. The umbrella also covers a specific phobia and agoraphobia. Essentially, any condition that is characterized by anxiety, or feelings of anxiousness, is an anxiety disorder.


The following symptoms are associated with anxiety and are the primary symptoms used to diagnose an anxiety disorder.

  • Feelings of nervousness or restlessness
  • Thoughts of impending doom, panic, or danger
  • Increased heart rate and shallow breathing
  • Feelings of weakness or exhaustion
  • Trembling, sweating, and stomach aches
  • Difficulty sleeping and controlling worry


Anxiety disorders are typically treated with talk therapy. This talk therapy is often in addition to medication. Antidepressants seem to help individuals struggling with anxiety, but are unlikely to help those affected by specific phobia or agoraphobia. Unfortunately, the only treatment available for phobias is therapy. 

Eating Disorders 

Anyone can be affected by an eating disorder, but girls, especially teenage girls are more likely to be affected. An eating disorder is characterized by abrupt and significant changes in eating habits. Unfortunately, too many people view eating disorders as a choice, but in reality, they are an illness. Common eating disorders include anorexia nervosa, bulimia nervosa, and binge eating disorder.


Because there are different types of eating disorders, the symptoms vary. But, here are a few symptoms to watch for.

  • Changes in eating patterns
  • Obsession with weight
  • Low self-esteem
  • Guilt or negative feelings associated with food or eating


Eating disorders are serious. They can lead to health problems and even death. A distorted body image and low self-esteem often accompany eating disorders. This poor self-image places those suffering from an eating disorder at a higher risk of committing suicide. 

It is vital that you seek treatment early for an eating disorder. Treatment consists of talk therapy and learning to see yourself in a different light. Medical intervention may be necessary depending on the progression of the disorder.

Personality Disorders 

Personality disorder covers a wide range of mental illnesses. These disorders are characterized by unhealthy patterns of thinking and behaving. These disorders typically rear their head in the teenage years or early twenties. 

When you suffer from a personality disorder, you may have a hard time relating to other people and situations. Usually, those who suffer from a personality disorder do not realize that they have one. This is because their thought process is natural for them and they see nothing wrong with it. 


There are three clusters of personality disorders, A, B, and C. The symptoms of a personality disorder vary from illness to illness, but each cluster shares a few unique characteristics.

Cluster A 

  • Odd or eccentric thinking and behavior
  • Intense and unwarranted suspicion
  • Cold and angry behavior
  • Discomfort in social settings and relationships

Cluster B 

  • Impulsive actions and decision-making
  • Anger, aggression, and violence
  • Big emotions
  • Strong and unwavering opinions

Cluster C

  • Submissive thinking and behavior
  • Anxiety regarding decision making
  • Lack of self-confidence
  • Intense fear of disapproval and failure


Psychotherapy and medication are the primary treatment options for personality disorders. The key to managing personality disorders is learning to control your impulses and coping with stress. In addition to psychotherapy, your doctor may recommend social skills training. This training will assist you in building healthier, more satisfying relationships. In severe cases, hospitalization may be necessary.

Published by alswartz

I am an aspiring novelist working on my first book. I have an interest in mental health and each of my works is related to mental health in some way.

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