The Genetics Behind Anxiety, ADHD, Autism, OCD, and Anorexia

Why These Conditions Overlap—and Why Diagnosis Isn’t Always the Point

At Metta Vita Health, we rarely see anxiety, ADHD, autism spectrum disorder (ASD), obsessive-compulsive disorder (OCD), or anorexia nervosa occur in isolation. Patients and families often come in asking which diagnosis is the “real one.”

Modern genetics gives us a clearer—and more useful—answer: these conditions are biologically connected.

What looks like “comorbidity” in the clinic is often the result of shared genetic and neurodevelopmental pathways, not multiple unrelated disorders.

Psychiatric Diagnoses Share Genetic Roots

Large-scale genome-wide association studies (GWAS), led by the Psychiatric Genomics Consortium (PGC), have fundamentally changed how we understand mental health conditions.

A landmark Nature study analyzed genetic data from over one million individuals across 14 psychiatric disorders. Rather than identifying disorder-specific genes, researchers found shared genetic factors that cut across diagnoses.

Two of these factors are especially relevant to the patients we see at MVH:

• Neurodevelopmental genetic factor

  Includes ADHD and autism, reflecting shared genetic influences on brain development, executive function, attention regulation, and sensory processing.

• Compulsive genetic factor

  Includes OCD and anorexia nervosa, reflecting shared vulnerability related to rigidity, compulsivity, perfectionism, and intolerance of uncertainty.

Anxiety disorders cluster within an internalizing genetic factor, which overlaps strongly with depression and trauma-related conditions.

Bottom line: these diagnoses are not separate silos. They are overlapping expressions of how a nervous system develops and responds to stress.

One Set of Genes, Multiple Presentations

Another critical concept in psychiatric genetics is pleiotropy—the idea that the same genes can influence multiple conditions.

A major Cell publication from the PGC identified over 100 shared genetic loci across disorders including ADHD, ASD, OCD, and anorexia nervosa. These genes are involved in:

• Brain development

• Neuronal signaling

• Synaptic plasticity

• Emotional and behavioral regulation

  
  

This helps explain why someone may present with anxiety in childhood, ADHD in adolescence, and OCD or eating disorder symptoms later on—without anything being “missed” along the way.

“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, and genetic studies consistently show overlap in risk variants.

Clinically, this often shows up as:

• Anxiety driven by executive dysfunction and overwhelm

• Sensory sensitivities mislabeled as “behavioral issues”

• Perfectionism and masking, especially in girls and high-achieving individuals

  
  

When ADHD or autism goes unrecognized, anxiety frequently becomes the presenting diagnosis—while the underlying drivers remain unaddressed.

OCD and Anorexia: The Genetics of Compulsivity and Control

Although OCD and anorexia nervosa appear very different on the surface, genetics tells a different story.

Both conditions involve:

• High rigidity and rule-based behavior

• Intolerance of uncertainty

• Anxiety relief through repetitive or compulsive actions

  
  

Genetic studies consistently show overlap between OCD and anorexia, supporting what we see clinically: eating behaviors often function as anxiety regulation strategies, not simply issues of food or body image.

Anxiety Is Often the Messenger—Not the Root Cause

Genetically, anxiety disorders overlap strongly with other internalizing conditions. But when anxiety co-occurs with ADHD, autism, OCD, or anorexia, it is often secondary—a response to overwhelm, unpredictability, or loss of control.

Treating anxiety alone, without addressing the broader neurodevelopmental or compulsive picture, often leads to partial improvement and recurring symptoms.

At MVH, we view anxiety as an important signal—not the full story.

Why We Focus on Symptoms and Functional Impact—Not Just Diagnoses

This is why, at Metta Vita Health, we focus less on chasing a single diagnosis and more on identifying clusters of symptoms that are actually impacting daily functioning.

“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 are descriptive frameworks, not biological truths. Genetics makes this clear: the same underlying vulnerabilities can show up as anxiety, ADHD, autism traits, OCD patterns, eating disorder behaviors—or some combination of all of the above.

What matters most clinically is:

• Which symptoms are present

• How they interact

• Where functioning is breaking down (school, work, relationships, health)

  
  

When we treat symptom clusters—such as executive dysfunction, sensory overload, compulsivity, emotional dysregulation, or anxiety-driven avoidance—we are treating the nervous system more directly.

This approach allows us to:

• Avoid over-labeling and mislabeling

• Reduce unnecessary polypharmacy

• Individualize care across therapy, medication, neurofeedback, and integrative supports

• Adapt treatment as symptoms evolve over time

  
  

A diagnosis can be useful—but it is never the goal.

Our goal is improved function, regulation, and quality of life, guided by how each individual nervous system actually operates—not by forcing symptoms into rigid categories.

Final Thought

The question is rarely “Which diagnosis is correct?” The more useful question is “What is this nervous system struggling with—and how can we support it?”

Genetics doesn’t determine destiny. But it gives us a clearer map—and a much better place to start.

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