New research suggests that certain mental health conditions share genetic similarities, which may explain why certain conditions can overlap. Experts grouped conditions into five main groups based on these similarities. It is anticipated that this discovery could lead to faster and more accurate polydiagnosis for multiple mental health conditions, increasing the effectiveness of care from an early stage.
The overlap of mental health conditions
Mental health conditions are often diagnosed based on their distinct individual symptoms. However, many people experience symptoms of multiple conditions simultaneously, making diagnosis difficult. Understanding the root cause of overlapping mental health conditions has been an important subject of research for years, since new data helps enhance diagnosis and treatment. When providers can accurately identify (and even predict) mental health concerns, this improves access to care for all.
Mental health and genetics
Mental health providers encounter unique challenges when diagnosing patients. One such example is the lack of any known laboratory tests to offer definitive evidence of a certain diagnosis. As a result, professionals in this specialty almost exclusively depend on a patient’s signs and symptoms when completing an evaluation.
To ease this process, researchers aimed to create a greater understanding of the genetic link between various conditions. Researchers did this by performing a genomic analysis of 14 mental health conditions – including those that began in childhood and those starting in adulthood. After pinpointing commonalities among these conditions, they found five main factors accounted for the majority of mental health diagnoses. [1]
Conditions that share the most genetic similarities
Researchers grouped conditions into five categories based on their genetic similarities: [1]
- Neurodevelopmental disorders: The main conditions were attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). There was also a link, though a weaker one, to Tourette's disorder.
- Internalizing disorders: Anxiety disorders, post-traumatic stress disorder (PTSD), and major depressive disorder (MDD) had the most similarities, with a 90% shared risk among them.
- Substance use disorders: A link was found between nicotine dependence, opioid use disorder (OUD), alcohol use disorder (AUD), and cannabis use disorder (CUD).
- Compulsive disorders: There are commonalities between anorexia nervosa (AN) and obsessive-compulsive disorder (OCD). There was also a link, though a weaker one, to anxiety disorders and Tourette's disorder.
- Bipolar disorder and schizophrenia: There is an overlap of around 66% of genetic markers between these conditions.
In addition to genetic risk, there were often biological similarities between these conditions. For example, the study showed a strong link among bipolar disorder, schizophrenia, and nerve cells that stimulate other brain cells (called excitatory neurons).
Diagnosing multiple mental health conditions
Previous evidence shows that many people diagnosed with one mental health condition go on to meet criteria for others. [2] However, experts now know which other conditions someone might be at risk of and why. This information can serve as an invaluable guide for providers as they complete evaluations with individuals who already have mental health conditions or those with a strong family history of psychiatric conditions.
Limitations of diagnostic tools
Mental health experts have critiqued the Diagnostic and Statistical Manual of Mental Disorders (DSM) and other measures for years. Many feel the DSM does not account for subjectivity or bias within reporting. In addition, professionals have reported the inability to test for biological factors as one of the biggest limitations of existing diagnostic processes. [3] This new data can potentially improve current diagnostic tools and even enhance the creation of new measures.
Risks of multiple mental health conditions
Individuals with more than one mental health condition are at risk of several complications: [4][5][6][7][8]
- A higher level of functional impairments.
- Decreased health-related quality of life.
- Less robust responses to treatment.
- Increased treatment complexity.
- More severe symptoms.
- An increased risk of physical health concerns, such as chronic pain, diabetes, stroke, and heart disease.
Suicidal ideation
Several mental health conditions, including depression, substance use disorders, and psychotic disorders, can raise someone’s risk of experiencing suicidal ideation. If someone experiences more than one of these conditions, they are at an even greater risk of suicide. [9] Therefore, proper treatment is essential to preventing and managing suicidal ideation.
Anyone in the United States who is experiencing suicidal ideation or other mental health emergencies should call or text the crisis helpline at 988. Individuals who need immediate assistance can use this helpline, which is available 24/7.
Treatment implications
Experts already know how essential early intervention is to a patient’s long-term treatment outcomes. With this information, providers can enhance the timeliness and accuracy of the diagnostic process, thereby improving these outcomes.
In addition, the results of this study help providers understand just how nuanced the role of genetics in mental health risk is. Mental health professionals can use this data to inform their screening efforts by observing patients for warning signs of other conditions in the same category.
