Diagnosis of mental illness is the first step in a successful treatment program. Learn how health professionals evaluate symptoms and reach a conclusion.

The National Alliance on Mental Illness (NAMI) reports that in any given year, one in five Americans suffer from some form of mental illness, and for one in 25 Americans, mental illness significantly impairs or limits their life functions.

Many people likely live with an undiagnosed mental health disorder with symptoms that can negatively affect everyday life. Stress management, coping skills, and even substance abuse can be tied to untreated mental illness.

Drug and alcohol abuse can be a way to self-medicate mental illness symptoms. NAMI estimates that half of those with a severe mental illness and one-third of those battling any mental illness will also struggle with substance abuse. Drugs and alcohol only serve to make matters worse, as substance abuse can actually make mental illness symptoms more pronounced and interfere with treatment methods.

Diagnostic Tools

The proper diagnosis of a mental illness is the first step in a successful treatment program. Medical and mental health professionals use a variety of tools to help them properly evaluate symptoms and reach a conclusion.

These tools include:

  • Physical examination
  • Lab testing
  • Neurological imaging
  • Psychological evaluations
  • Physical evidence

Your primary physician will likely perform the initial assessment of your symptoms. He or she will delve into your medical history and may order blood and lab tests to rule out potential physical issues that may be causing your symptoms. There is no specific test for mental illness, but a physical exam and blood work can rule out other ailments or causes for mental illness symptoms, such as psychosis and depression.

Scientific Advances in Neuroimaging

Scientists are making huge leaps in understanding the brain, how it works, and which regions might be responsible for certain personality traits and even mental illness symptoms. The use of neuroimaging, or brain mapping, may be able to identify parts of the brain that could be underdeveloped or damaged, which may indicate mental illness. For instance, certain regions of the brain and some of the connections involved in emotional regulation may be less active in someone suffering from impulse control issues or attention deficit hyperactivity disorder (ADHD), while other areas involved in depressive symptoms may be overactive. These differences may be apparent with magnetic imaging resonance (MRI) scans of the brain.

Bipolar disorder, a mental health condition affecting relationships and mood swings, was successfully identified by brain scans over 70 percent of the time in repeated studies, as published by Pysch Congress. Brain scans are largely used for research purposes to date, and while they can be helpful in detecting a mental health disorder, the National Institute of Mental Health (NIMH) states that they should not to be used on their own in the diagnosis of a mental illness. Professionals still generally rely on a psychological assessment as the optimal method of diagnosing a mental health disorder.

Psychological Assessments

After an initial physical evaluation by your doctor or medical personnel, you may be referred to a mental health professional for a more comprehensive psychological assessment of your symptoms. Mental health professionals, such as psychologist or psychiatrist, will ask you a series of questions related to your symptoms and family history and, they may perform an assessment interview or administer a psychological questionnaire to gather more details about you and your symptoms. Answering all questions honestly is the best way to ensure that you will receive the right diagnosis.

The primary diagnostic tool used to define mental health disorders is the Diagnostic and Statistical Manual of Mental Disorders (DSM) published by the American Psychiatric Association (APA), which is currently on its fifth edition, the DSM-5, and reevaluated every several years.

This manual highlights all of the different mental health disorders and the diagnostic criteria for each of them. The DSM is made up of the diagnostic classification, diagnostic criteria sets, and the descriptive text. The diagnostic classification lists all of the current mental health disorders in the DSM system and all of the diagnostic codes used for insurance and billing purposes associated with them. The diagnostic criteria define what symptoms and how many must be present, the duration of these symptoms, and the conditions that should not be present in order to qualify for a particular diagnosis. These sets of diagnostic criteria outline each specific disorder in order to increase the likelihood of a correct diagnosis. The descriptive text accompanies each disorder in the DSM and contains a more comprehensive account of all of the disorders as related to their diagnosis, prevalence, risk factors, consequences, and more.

Diagnosing Co-Occurring Disorders

Many times, more than one mental health disorder will be present in the same individual at the same time, and when this happens, the disorders are said to be co-occurring. Teams of medical professionals will usually need to work together in order to diagnose and treat co-occurring disorders, as they may be more complex to define than a single disorder. Symptoms may evolve and change during treatment, so regular assessments should be administered to ensure that care plans continue to remain effective.

Highly trained professionals at The Recovery Village are on hand to answer any questions you may have and can assist you in finding dual diagnosis treatment. Call today to learn more.


National Alliance on Mental Illness. “Mental Health By The Numbers.” (n.d.) Accessed May 4, 2019.

Tumolo, Jolynn. “Bipolar Recognizable in Brain Scans.” Psychiatry & Behavioral Health Learning Network. June 11, 2013. Accessed May 4, 2019.

Insel, Thomas. “Post by Former NIMH Director Thomas Insel: Brain Scans – Not Quite Ready for Prime Time.” National Institute of Mental Health. October 7, 2010. Accessed May 4, 2019.

American Psychiatric Association. “Diagnostic and Statistical Manual of Mental Disorders (DSM–5).” (n.d.) Accessed May , 2019.

Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.