Mental health disorders: definition, tests & symptoms


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Page last updated: 15/10/2022

Mental health disorders

In this brief guide, we will be discussing the definition of mental illness, how this illness affects a person, the list of mental illness, and the following symptoms of mental illnesses.

Overview of the definition of mental illness

Mental illness is a condition that can influence how a person feels, thinks, and behaves which may be for the worse.

The symptoms of this kind of mental health condition can range from mild to chronic and this condition can cause an affected person’s life to distressing and dysfunctional ways. 

Mental illness is a general term that talks about the disorders that can affect a person’s mental wellbeing.

This kind of mental condition can affect how you can function in your daily life. 

As you’ll soon know, mental illnesses are caused by several factors such as genetics and environmental influences.

This is where mental disorders come in where they affect a person’s behaviours, thoughts, and moods. 

Mental disorders can be a spontaneous moment or they may be chronic.

These kinds of disorders can affect how you treat others and their perceptions of you.

The list of mental illnesses in abnormality

It is sometimes difficult for mental health professionals to pinpoint your mental health disorder since some symptoms tend to overlap with other mental disorders. 

With the information of your diagnosis, you can be able to learn what you need to do about your disorder and helping professionals enlighten you on what your symptoms represent. 

This list of mental illnesses or mental health disorders is based on the evidenced-based standardized psychological disorders found in the Diagnostic and Statistical Manual of Mental Disorders – Fifth Edition (DSM-V) bought on this website.

Without further ado, here are the following mental illnesses or mental conditions recognized in psychological abnormality.

  • Generalized Anxiety Disorder
  • Specific Phobia
  • Selective Mutism
  • Panic Disorder
  • Separation Anxiety Disorder
  • Somatic Symptom Disorder
  • Illness Anxiety Disorder
  • Dissociative Identity Disorder
  • Dissociative Trance
  • Dissociative Fugue
  • Functional Neurological Symptom Disorder
  • Major Depressive Disorder
  • Bipolar I Disorder
  • Bipolar II Disorder
  • Anorexia Nervosa
  • Bulimia Nervosa
  • Binge-eating Disorder
  • Rumination Disorder
  • Insomnia Disorder
  • Hypersomnolence Disorder
  • Circadian Sleep Rhythm Disorder
  • Gender Dysphoria
  • Pedophilic Disorder
  • Tranvestistic Disorder
  • Exhibitionistic Disorder
  • Voyeuristic Disorder
  • Sadistic Disorder
  • Sexual Desire Disorder
  • Premature Ejaculation
  • Tobacco Use Disorder
  • Hallucinogen Use Disorder
  • Alcohol Use Disorder
  • Paranoid Personality Disorder
  • Schizoid Personality Disorder
  • Schizotypal Personality Disorder
  • Antisocial Personality Disorder
  • Borderline Personality Disorder
  • Histrionic Personality Disorder
  • Narcissistic Personality Disorder
  • Dependent Personality Disorder
  • Obsessive-Compulsive Personality Disorder
  • Avoidant Personality Disorder
  • Schizophrenia
  • Schizophreniform Disorder
  • Brief Psychotic Disorder
  • Delusion Disorder
  • Intellectual Disability Disorder
  • Autism Spectrum Disorder
  • Attention Deficit and Hyperactivity Disorder
  • Language Disorder
  • Major Neurocognitive Disorder
  • Delirium
  • Minor Neurocognitive Disorder
Mental health disorders: definition, tests & symptoms

Symptoms and signs of mental health disorders

When other medical disorders have been ruled from the patient, he or she will be referred to a mental health professional where they can get a mental health diagnosis based on the assessment.

The DSM-5 has diagnostic criteria for each mental health disorder to help mental health professionals to figure out what kind of mental condition is the patient going through. 

Some symptoms may not be easily seen by other people or mental health professionals but these symptoms are still distressing, nonetheless, which you can write in a journal that can be bought here.

  • Panic attacks
  • Feeling on edge
  • Fear disproportionate to the circumstance or object
  • Talkative only to family members
  • Focus is on unverified medical symptoms
  • Anxiety over getting a serious medical illness
  • Has many unexpected trips
  • Forgetful with a lot of areas in life
  • Weight is less than the expected weight based on the age and height of the patient
  • Has bloated face due to persistent vomiting
  • Greatly concentrated on the weight
  • Has many binge-eating episodes
  • Feels almost no desire to have sex with a partner
  • Has unusual sexual behaviours and has committed sexual crimes such as statutory rape
  • Has withdrawal symptoms and craving for alcohol and other drugs
  • Isn’t aware that personality is problematic to the people around them
  • Has delusions and hallucinations that impacts every area in life
  • Isn’t able to regulate hygiene on their own.
  • Has a hard time understanding basic topics
  • Tends to disrupt other people’s ongoing conversations
  • Cannot manage their hyperactivity
  • Does not want the routine to be interrupted by any person even loved ones
  • Having issues with memory and reasoning
  • Having hallucinations and delusions after a brain trauma or injury

Several causes of mental health disorders in psychological abnormality

Mental health disorders are elicited by several influences such as the following:

  • Inherited or inner traits. Mental health disorders are typical in people with close relatives who have these kinds of disorders as well. Some genes have been found to make some people susceptible to having this kind of disorder.
  • Environmental exposures before childbirth. If the child is exposed to environmental stressors, toxins, inflammatory disorders, alcohol or drugs while in the womb can sometimes be associated with mental health disorders.
  • Brain chemistry. Brain chemicals in the brain are called neurotransmitters which pass messages from the brain to the other nerves in the body. When these neurotransmitters may become less or more in the nervous system, this may lead to mental health disorders.

Diagnosis of mental health disorders

To make a diagnosis of a mental health disorder, the doctor will first make you take these kinds of tests which are the following:

  • A physical test. This kind of test will help the doctor to take note if there are physical disorders that may be causing your mental health symptoms.
  • Lab or blood tests. These kinds of tests can include checking for alcohol or drug use before mental health symptoms started.
  • A psychological assessment. A mental health professional will inquire about your components of mental wellbeing such as thoughts, emotions, and behaviours. You may also be asked to take a psychological test to answer these inquiries.

Determining which mental illness you have

As mentioned before, it is hard to find a diagnosis of a mental health disorder based on your symptoms.

In taking the effort and time to make a precise diagnosis, it would lead the patient to the right treatment. 

With enough information, you and your mental health professional will work on the understanding of your symptoms.

The symptoms of each mental health disorder are categorized into diagnostic criteria in the manual of mental disorders which is the DSM-5. 

This manual is useful for mental health professionals to help them figure out the mental health disorder of a patient and proceed to treatment immediately.

You can learn more about how mental health professionals diagnose people with these disorders by buying this book on this website.

Psychological tests for mental health disorders

As mentioned before, medical professionals will let you go through a series of tests to know your mental health disorder.

These kinds of tests could include a physical examination, a mental health questionnaire, and blood or laboratory examinations. 

A series and patterns of questions help doctors understand your thoughts, feelings, and reactions to events and scenarios.

Psychological tests that are meant to find symptoms of mental health disorders on clients are very prominent in psychological clinical assessments which you can learn more by buying this book on this website.

Here are some tests that can help diagnose people who are suspected of having a mental health disorder 

  • 3 Minute Depression Test
  • Cork ADHD Quiz
  • Psych Central Personality Disorders Test
  • Achenbach System of Empirically Based Assessment
  • Minnesota Multiphasic Personality Inventory (MMPI)

A diagnosis will be made after going through other opinions of mental health professionals about a person’s mental health disorder.

The medical background of the patient with their recent life situations will also be taken into account in the evaluation. 

Loved ones can also help pinpoint the symptoms of the patient that can imply a mental health disorder.

The following are diagnostic tests for people who may have this kind of disorder:

  • Online OCD Test
  • Online Bipolar Test
  • Online Anxiety Test
  • Online Depression Test
  • Online Anorexia Nervosa Test
  • Personality Disorders Test
  • psychology Today Mental Health Assessment
  • NHS Mood self-assessment
  • Minnesota Multiphasic Personality Inventory
  • Free Post Traumatic Stress Disorder Test

Treatment of mental health disorders

If you leave the symptoms of mental health disorders untreated, these kinds of symptoms will only get worse over time.

This is why you need to immediately call for psychological help to minimize the person’s potential in getting endangered. 

If you’re not sure where to start looking, you can ask your primary care doctor.

This kind of professional can help with the diagnosis of a mental health disorder and refer the patient immediately to a psychiatrist.


Psychological medications don’t really heal the mental health disorder but they can help minimize the symptoms of the disorder.

These kinds of medications are also helpful in assisting the benefits of psychotherapy. 

Your mental health symptoms will be the keys to helping the mental health professional find the best psychological interventions for you.

Some of the most famous medications in this class are the following:

  • Antidepressants. As stated in the name, antidepressants are used to treat depression and other mental health conditions as well. These medications can help reduce the symptoms fo depression such as anhedonia or lack of pleasure in doing pleasurable activities and heaviness which causes lack of energy. These medications do not cause addiction or tolerance in the patient.
  • Anti-anxiety medications. As stated in the name, these medications are used to cure anxiety symptoms in disorders. These medications have also been used to minimize insomnia and agitation. Long-term medications of this class are antidepressant medications that can help anxiety. Fast-acting anti-anxiety drugs help with short-term relief but they also have the susceptibility to cause tolerance so ideally they’d be used short term for patients.
  • Mood-stabilizing medications. Mood stabilizers are most typically used to treat bipolar disorders which are mood disorders that involve switching episodes of mania or hypomania and depression. Sometimes these medications are used with antidepressant medications to treat depressive disorders.
  • Antipsychotic medications. These medications are used to stabilize the psychotic symptoms in psychotic symptoms such as schizophrenia. Since these medications can help in stabilizing psychotic symptoms, they have been used to cure psychotic symptoms in some mental health disorders such as bipolar disorder and depression.



Psychotherapy is called the talking cure where individuals will talk about their mental health symptoms.

In this therapy, you will learn about your mental health disorder and your moods, thoughts, emotions, and behaviour. 

By understanding your mental health disorder, you will be able to learn how to cope with this disorder.

Many forms of psychotherapy exist with different strategies that can help improve your mental wellbeing. 

Psychotherapy can be effective even if you only took it for a few weeks but some of these therapies will be a lifetime occurrence due to the severity of the symptoms.

These therapies can be in two forms such as individual where you will be speaking to the therapist or group therapy where you will be speaking with a group or your family.

It is also important that you choose the right therapist for you since you have to make sure that he or she is willing to listen.

It is also important that you choose a therapist who specializes in your mental health disorder so that you are confident that he or she knows what to do.

Brain-stimulation treatments

Brain-stimulation interventions are used for people who have depression or erratic disorders.

These interventions are only used when other forms of treatment have not shown any effects. 

Brain-stimulation interventions include electroconvulsive therapy, deep brain stimulation, transcranial magnetic stimulation and vagus nerve stimulation.

You should be able to understand the risks and benefits of these treatments before getting yourself involved with this treatment.

Hospital and residential treatment programs

People with severe mental health disorders are tended to in psychiatric hospitals.

This is recommended to people who can’t take care of themselves or may have a risk for danger to themselves or others.

Depending on the severity of symptoms that needs immediate psychological intervention, your program options will include 24-hour inpatient care, residential treatment or day hospitalization which provides a temporary supportive place to live.

Another program option is an intensive outpatient intervention for patients who are assessed to be somewhat able enough to still live a normal life despite their mental health disorders.

Substance misuse psychological treatment

Substance abuse tends to become comorbid with other mental health disorders.

This symptom can minimize the effects of other forms of treatment. 

If you can’t avoid your drug addiction, it is time that you seek psychological help.

You need to speak to your doctor about interventions for substance abuse

Participating in your own care or self-help

Working with your mental health professional can help you find the best psychological intervention available for you depending on your symptoms and preferences.

In some situations, a loved one may be asked to assist you in your treatment to guide you towards mental wellbeing.

It’s important to know that you can still have a full and happy life with a mental health disorder.

Collaborating with your mental health professionals and loved ones can help you find the treatment options that can help you. 

Some of these interventions are combined to help you get the best out of psychological interventions.

An example is a patient with schizophrenia who is being designated to early psychological intervention after the initial manifestation of premature signs and symptoms which you can read in this book available here.


In this brief guide, we have discussed the definition of mental illness, how this illness affects a person, the list of mental illness, and the following symptoms of mental illnesses.

If you have any questions about mental health disorders, please let us know and the team will gladly answer your queries.

FAQs: Mental health disorders: definition, tests, symptoms

What are the five most common mental disorders?

The five most common mental disorders are anxiety disorders, psychotic disorders, mood disorders, neurocognitive disorders, and eating disorders.

These disorders are usually found in people between adolescence towards early adulthood.

What is the most difficult mental illness to live with?

The most difficult mental illness to live with is a borderline personality disorder because people with this disorder aren’t even aware that they have this disorder.

They also tend to have unstable relationships due to this disorder and may have co-occurring disorders associated with this disorder such as substance abuse.

What is the deadliest mental health disorder?

The deadliest mental health disorder is anorexia nervosa due to the great control of weight loss leading to an extreme loss of weight which always leads to the death of the patient.

This is also deadly since most patients with this disorder will receive the diagnosis after a majority of their weight has been diminished.

How can you tell if someone is mentally sick?

You can tell if someone is mentally sick when he/she has these signs and symptoms such as confused thinking patterns, frequent feelings of extreme ups and downs, long-term sadness or irritability, excessive fears and worries, significant changes in sleeping or eating habits, social avoidance, extreme expressions of anger, and delusional thinking patterns.

How long can a psychiatric hospital keep you in?

A psychiatric hospital can keep you admitted as determined by the court hearing if you are considered a danger to yourself or others and the court can keep you in this kind of hospital for 90 days.

You can be released once you are psychologically evaluated to be secure to society and to yourself.

List of mentions and citations

Mayo Clinic Staff. (2019). Mental illness. Retrieved from here.

MedicineNet. (n. d.). Mental Illness Basics. Retrieved from here.

MedlinePlus. (n. d.). Mental Disorders. Retrieved from here.

MedlinePlus. (n. d.). Mental Health Screening. Retrieved from here.

Mind Wise. (n. d.). HOW IS MENTAL ILLNESS DIAGNOSED?. Retrieved from here.

NAMI. (n. d.). Understanding Your Diagnosis. Retrieved from here.

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