Understanding the Overlap of Mental Health Conditions: A Comprehensive Approach
Updated: Aug 18
The Interconnectedness of Mental Health Disorders
At Metta Vita Health, we frequently observe that conditions such as anxiety, ADHD, autism spectrum disorder (ASD), obsessive-compulsive disorder (OCD), and anorexia nervosa do not exist in isolation. Patients and families often inquire about which diagnosis is the "real one."
Modern genetics provides a clearer—and more insightful—answer: these conditions are biologically interconnected.
What may appear as “comorbidity” in a clinical setting often results from shared genetic and neurodevelopmental pathways, rather than multiple unrelated disorders.
The Genetic Basis of Psychiatric Diagnoses
Large-scale genome-wide association studies (GWAS), spearheaded by the Psychiatric Genomics Consortium (PGC), have fundamentally altered our understanding of mental health conditions.
A landmark study published in Nature analyzed genetic data from over one million individuals across 14 psychiatric disorders. Instead of identifying disorder-specific genes, researchers discovered shared genetic factors that span multiple diagnoses.
Two of these factors are particularly relevant to the patients we encounter at MVH:
Neurodevelopmental Genetic Factor
This includes ADHD and autism, reflecting shared genetic influences on brain development, executive function, attention regulation, and sensory processing.
Compulsive Genetic Factor
This encompasses OCD and anorexia nervosa, highlighting shared vulnerabilities related to rigidity, compulsivity, perfectionism, and intolerance of uncertainty.
Anxiety disorders cluster within an internalizing genetic factor, which has a strong overlap with depression and trauma-related conditions.
In summary: these diagnoses do not function as separate entities. They represent overlapping manifestations of how a nervous system develops and responds to stress.
One Set of Genes, Multiple Presentations
Another essential concept in psychiatric genetics is pleiotropy—the notion that the same genes can influence multiple conditions.
A significant publication in Cell from the PGC identified over 100 shared genetic loci across disorders such as ADHD, ASD, OCD, and anorexia nervosa. These genes are involved in:
Brain development
Neuronal signaling
Synaptic plasticity
Emotional and behavioral regulation
This genetic overlap helps explain why an individual may exhibit anxiety in childhood, ADHD in adolescence, and OCD or eating disorder symptoms later in life—without any critical issues being overlooked.
“People are dimensional." — Lindsey Bauman CPNP-PC, PMHNP-BC
ADHD and Autism: A Shared Neurodevelopmental Foundation
ADHD and autism are both highly heritable neurodevelopmental conditions. Genetic studies consistently reveal overlap in risk variants.
Clinically, this often manifests as:
Anxiety driven by executive dysfunction and feelings of overwhelm
Sensory sensitivities misidentified as “behavioral issues”
Perfectionism and masking, particularly in girls and high-achieving individuals
When ADHD or autism goes unrecognized, anxiety frequently becomes the primary diagnosis—while the underlying drivers remain unaddressed.
OCD and Anorexia: The Genetics of Compulsivity and Control
Although OCD and anorexia nervosa may appear distinct at first glance, genetics reveals a different narrative.
Both conditions share characteristics such as:
High rigidity and rule-based behavior
Intolerance of uncertainty
Anxiety relief achieved through repetitive or compulsive actions
Genetic studies consistently demonstrate overlap between OCD and anorexia, supporting clinical observations: eating behaviors often serve as anxiety regulation strategies, rather than merely issues of food or body image.
Anxiety as a Messenger: Understanding Its Role
Genetically, anxiety disorders exhibit a strong overlap with other internalizing conditions. However, when anxiety co-occurs with ADHD, autism, OCD, or anorexia, it is often secondary—a response to feelings of overwhelm, unpredictability, or loss of control.
Treating anxiety in isolation, without addressing the broader neurodevelopmental or compulsive context, often results in partial improvement and recurring symptoms.
At MVH, we regard anxiety as an important signal—not the complete narrative.
Focusing on Symptoms and Functional Impact
This perspective is why, at Metta Vita Health, we prioritize identifying clusters of symptoms that significantly impact daily functioning over pursuing a singular diagnosis.
“While we aim to accurately document diagnoses, our main focus is understanding which symptoms are interfering with functioning and addressing those in a practical, individualized way.” — Lindsey Bauman CPNP-PC, PMHNP-BC
Psychiatric diagnoses serve as descriptive frameworks, not biological certainties. Genetics clarifies this: the same underlying vulnerabilities can manifest as anxiety, ADHD, autism traits, OCD patterns, eating disorder behaviors, or a combination of these.
What is clinically significant includes:
The symptoms present
Their interactions
Areas where functioning is compromised (school, work, relationships, health)
When we treat symptom clusters—such as executive dysfunction, sensory overload, compulsivity, emotional dysregulation, or anxiety-driven avoidance—we are addressing the nervous system more directly.
This approach enables us to:
Avoid over-labeling and mislabeling
Minimize unnecessary polypharmacy
Individualize care across therapy, medication, neurofeedback, and integrative supports
Adapt treatment as symptoms evolve over time
While a diagnosis can be beneficial, it is never the ultimate goal.
Our objective is enhanced function, regulation, and quality of life, guided by how each individual’s nervous system operates—not by forcing symptoms into rigid categories.
Final Thoughts
The inquiry is rarely “Which diagnosis is correct?” A more constructive question is “What challenges is this nervous system facing—and how can we provide support?”
Genetics does not dictate destiny. However, it offers a clearer map—and a much more effective starting point.
References
Grotzinger AD et al. Nature — Cross-disorder genetic architecture
Cross-Disorder Group, Psychiatric Genomics Consortium. Cell
Cortese S et al. Neuroscience & Biobehavioral Reviews
Psychiatric Genomics Consortium Eating Disorders Working Group. The Lancet Psychiatry
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