6 Reasons Serious Mental Health Issues Are Often Misdiagnosed

In 2022, almost one in four adults in the US (more than 59 million people) had a mental health illness,¹ conditions that impacts thoughts, emotions, and behaviors.² Mental illnesses are considered “severe” if they prevent people from engaging in everyday activities and work.³ This includes conditions such as severe depression and schizophrenia. 

Unfortunately, around 6 in 100 adults (more than 15 million people) in the US have serious mental health conditions, but only two-thirds of these people receive treatment.¹ Diagnosing serious mental health conditions can be highly complex, with rates of mental health misdiagnosis of between 27% and 66%.⁴

An accurate diagnosis is key to recovery – without it, you can be put on the wrong treatment path. At best, this can delay recovery. At worst, it can intensify symptoms and lengthen their duration. This blog will cover 6 main reasons serious mental health issues are diagnosed, and arm you with some tips for preparing for a consultation that might help you avoid this.

What’s the Impact of Misdiagnosis on Treatment Outcomes?

Let’s first look at what happens when you receive a correct diagnosis for a physical condition. You go to your doctor complaining of a rash. They examine the rash and diagnose eczema. They give you a cream, which you use (as directed, of course), and the rash disappears. This is a simplified example, but you get the idea. 

Now imagine that instead of diagnosing eczema, the doctor tells you that you have ringworm. They might look similar, but treatments are different. Using an antifungal cream on your eczema rash will not help and may make it worse.

Mental health conditions are far more difficult to diagnose since they can’t be objectively observed. Misdiagnosing a mental health condition can lead to being prescribed the wrong medication or psychological therapy.⁵

We’ve talked about the problems misdiagnosis can lead to, so let’s explore 6 reasons this might happen for serious mental health conditions.

6 Reasons for Mental Health Misdiagnosis

The following are six common reasons for diagnostic errors in mental health: 

1. Mental Health Disorder Classifications: 

Mental health disorders are categorised using two main systems. These are the Diagnostic and Statistical Manual of Mental Disorders (you may have heard this referred to as the DSM-5, the latest version) and the International Classification of Diseases (or ICD). But having two systems does not make diagnosis simple, far from it. Many conditions share overlapping symptoms (for instance, depression, anxiety, and bipolar disorder), making diagnosis challenging.⁶ Further, individual experiences (for instance, of trauma) affect the development of conditions in different ways.⁶ All of this makes diagnosing these conditions complex, as further shown in point 2 below…

2. Multiple Long-Term Conditions: 

Serious mental health disorders rarely occur in isolation; people often tend to have other mental or physical conditions that can interact with each other in complex ways.⁷ The role of comorbid conditions in misdiagnosis is that symptoms of one condition might mask the symptoms of another, making it even more difficult to diagnose.⁸ To further compound this issue, people with severe mental illness are prone to poor physical health, which can make their mental health symptoms even worse. Plus, sometimes medications for physical conditions can worsen some mental health symptoms⁷ – either as a byproduct of how they work, or if their dose is being reduced (withdrawal). Since consultations are time-limited, talking about other medications might not be at the forefront of a patient’s mind. Which leads to point 3…

3. System Constraints: 

With all areas of healthcare under pressure to reduce wait time, it’s not surprising that consultations need to be quick.⁹ But time limits on consultations can mean a thorough history is not taken, and this prevents a detailed assessment and evaluation. This is especially important for serious mental health conditions to understand the symptom trajectory, and it can influence the diagnosis. On top of this, continuity of care is rare. It is unlikely you will see the same physician each time (unless you are especially lucky), so they will only have a partial view of your history unless very thorough notes are taken. Fast access to specialists is also unlikely, especially when you first seek help. Your first point of call is unlikely to have access to neuropsychological tests, meaning that conditions can be easily mistaken for one another (for instance, anxiety, stress, and depression).

4. Stigma: 

Stigma plays a role in misdiagnosis. It refers to negative beliefs and attitudes towards people, in this context, with mental health conditions. Fear of stigma can lead to delays in seeking help, which can impede any diagnosis and treatment. Stigma influences how people might describe their symptoms to a healthcare professional, perhaps leading to playing down how severe some symptoms are for fear of judgment. Further, someone might overplay what they might construe as more acceptable symptoms (such as anxiety). This might seem harmless, but it can easily lead to misdiagnosis and inappropriate treatment pathways. Further, mental health can be more difficult to claim for under many insurance schemes in the US. 

5. Clinician Bias: 

Everyone has biases, whether they are aware of them or not, and clinicians are no exception. Biases can take many forms, and unfortunately, it can mean diagnoses are not all made equally. For instance, Black people are more likely to be diagnosed with schizophrenia than White people.⁶ Similar biases appear for gender, with women more likely to be diagnosed with depression than men.⁴ Symptoms might be expressed by different cultures in different ways, and clinicians must be sensitive to this when approaching a diagnosis.² Culture might also influence at what stage they seek help – a distrust of the system could mean a late consultation and therefore a delayed diagnosis. Snap judgments made about someone at the start of the consultation can also influence the outcome.

6. Patient Bias: 

Finally, linked with point 5, patients also have biases. Most people will have done some online research into what their symptoms might mean. It’s only natural to try and solve the problem yourself and present a neat case for your physician. But without realizing it, your expectations and unconscious biases can control the narrative you give to the physician. Physicians have extensive training that enables them to make interpretations and spot links between symptoms you might not have noticed.¹⁰ Perhaps you don’t do it this way, and instead do your research after you’ve been given a diagnosis. Still, a diagnosis might cause you to think you have a biological problem, such as a chemical imbalance; this can make many people pessimistic about their chances of recovery, which might influence their outcome.¹¹

AMFM: Professional Support From Assessment to Diagnosis and Treatment 

Serious mental health issues are difficult to manage. Not just for those with a diagnosis, but their families, their employers, and society as a whole. The key is support and understanding. Misdiagnosis is making the problem worse since it’s stopping people from getting the right support at the right time. 

In this blog, we’ve talked about 6 causes of misdiagnosis in mental health. The problem is that misdiagnosis can be caused by one of them, all of them at once, or a mix of several of them.

If you have concerns about your mental health symptoms, try to be as objective and honest as possible about your symptoms to ensure you get the best outcome. Go to consultations prepared with an account of everything you have experienced, regardless of whether you think it is directly relevant. This will help you present your experience in the short time you have, and if you do not feel you have been listened to, get a second opinion. 

The team at A Mission For Michael is here to support you from an initial assessment to an accurate diagnosis and treatment. As specialists in adult mental health diagnosis, if you’re ready to take the next step in protecting your well-being, we can help. Contact us today to learn about the services we offer. 

References

1. The World Data. (September 2025). Mental health statistics in the US 2025 key facts. https://theworlddata.com/mental-health-statistics-in-the-us/. 
2. Chaudhary, R. (n.d.) Understanding the challenges in mental disorder diagnosis. https://labverra.com/articles/understanding-challenges-mental-disorder-diagnosis/. 
3. Public Health England. (2018). Severe mental illness (SMI) and physical health inequalities: briefing. https://www.gov.uk/government/publications/severe-mental-illness-smi-physical-health-inequalities/severe-mental-illness-and-physical-health-inequalities-briefing. 
4. NeuroLaunch. (2025). Consequences of misdiagnosis of mental illness: unraveling the impact on patients and healthcare. https://neurolaunch.com/consequences-of-misdiagnosis-of-mental-illness/. 
5. Bradford, A., Meyer A. N. D., Khan S., Giardina T. D., & Singh H. (2024). Diagnostic error in mental health: a review. BMJ Quality and Safety, 33(10),e016996. https://doi.org/10.1136/bmjqs-2023-016996. 
6. Allsopp K., Read, J., Corcoran, R., Kinderman, P. (2019). Heterogeneity in psychiatric diagnostic classification. Psychiatry Research, 279:15-22. https://doi.org/10.1016/j.psychres.2019.07.005. 
7. Remedy. (January 2026). Why comorbidity matters: treatment, quality of life & misdiagnosis risk. https://remedypsychiatry.com/why-comorbidity-matters-treatment-quality-of-life-misdiagnosis-risk/. 
8. Carter, S. (2024). Understanding psychiatric comorbidities: intersections of mental health disorders. Journal of Clinical Psychiatry and Cognitive Psychology, 8;3:187.
9. Lyzwinski, L., Evéquoz, Y., & Rodondi, P-Y. (2025). Managing consultation duration in primary care: a systematic review with health equity insights. Journal of Family Medicine and Primary Care. 24;14:3132–3158. https://doi.org/10.4103/jfmpc.jfmpc_1594_24. 
10. Cleveland Clinic. (2025). Why self-diagnosis is dangerous (and what to do instead). https://health.clevelandclinic.org/dangers-of-self-diagnosis. 
11. UCL News. (2025) Opinion: are mental health conditions overdiagnosed in the UK? https://www.ucl.ac.uk/news/2025/mar/opinion-are-mental-health-conditions-overdiagnosed-uk.