A Functional and Interdisciplinary Perspective on Mental Health
Understanding Root Causes and Expanding Therapeutic Options
Dr. Kurt Woeller, D.O. | Sunrise Functional Medicine
Depression and anxiety continue to represent a significant and growing burden on individual health and public well-being. Globally, depression affects an estimated 5–6% of adults, and in the United States it is increasingly reported among young adults, adolescents, and women. While these numbers alone are concerning, they do not fully capture the complexity of depression as a condition — nor the lived experience of those navigating it during times of social uncertainty, political strain, and chronic stress.
From a clinical standpoint, depression is not a single disease with a single cause. Rather, it is a multifactorial condition shaped by biological, psychological, environmental, and social influences. This complexity helps explain why a one-size-fits-all treatment approach — particularly one focused solely on medication — often falls short for many patients.
Physicians like Dr. Kurt Woeller, DO, who work within interdisciplinary and functional medicine frameworks, approach depression by asking a different set of questions: Why is this individual experiencing symptoms now? What underlying systems may be contributing? And how can multiple therapeutic strategies work together to support recovery?
Depression: More Than a Neurotransmitter Imbalance
Historically, depression has often been framed as a disorder of neurotransmitter deficiency, particularly involving serotonin. While neurotransmitters are clearly involved in mood regulation, this narrow model does not adequately explain the wide variation in symptoms, treatment responses, or relapse rates seen in clinical practice. Depression is now understood as a condition involving complex interactions between:
- Brain chemistry and neuroplasticity
- Immune and inflammatory signaling
- Hormonal regulation
- Mitochondrial and metabolic function
- Nutritional status
- Genetic predispositions
- Psychosocial stressors
This broader understanding has opened the door to more comprehensive assessment and treatment strategies — especially for individuals who do not respond well to antidepressant medications alone or who experience undesirable side effects.
Limitations of Medication-Only Approaches
Antidepressant medications can be helpful and even life-saving for some patients. However, real-world adherence remains low, and many individuals discontinue treatment due to side effects, limited effectiveness, or feeling emotionally blunted. Research has also raised concerns about long-term impacts of certain medications, including effects on gut health, metabolic balance, and fall risk in older adults.
These challenges have led many clinicians to adopt multimodal treatment models, where medication may be one component of care rather than the sole intervention.
The Functional Medicine Framework
Functional medicine focuses on identifying and addressing root contributors to illness while recognizing that each patient’s experience is biologically unique. In the context of depression, this involves a detailed personal history, timeline-based assessment, and evaluation of interconnected body systems. Rather than asking “Which medication treats this diagnosis?”, the functional approach asks:
- What biological imbalances may be driving symptoms?
- What environmental or lifestyle factors are contributing?
- Where can targeted interventions support resilience and recovery?
This collaborative, patient-centered model allows for personalized treatment strategies that evolve over time.
Key Biological Contributors to Depression
Nutrient Status and Micronutrient Deficiencies
Micronutrients play essential roles in neurotransmitter synthesis, hormone regulation, mitochondrial energy production, and antioxidant defense. Deficiencies in nutrients such as B vitamins, magnesium, vitamin D, zinc, selenium, iron, and omega-3 fatty acids have all been associated with depressive symptoms.
Even mild deficiencies — common in the general population — may influence mood, sleep, energy, and cognitive function. Identifying and correcting these imbalances can be a meaningful component of treatment.
Diet and Inflammation
Dietary patterns influence inflammation, gut microbiota, and metabolic health, all of which affect brain function. Research increasingly supports the role of anti-inflammatory dietary patterns — such as Mediterranean-style or DASH diets — in reducing depressive symptoms and lowering relapse risk.
Rather than rigid rules, the emphasis is on nourishment, blood sugar balance, adequate protein, and reducing inflammatory triggers based on individual tolerance.
Hormonal Influences
Hormonal shifts across the lifespan — including puberty, postpartum periods, perimenopause, and menopause — are well-recognized risk windows for depression. Thyroid dysfunction, adrenal stress responses, and sex hormone imbalances can all influence neurotransmitter sensitivity and emotional regulation. Evaluating hormone patterns can provide valuable insight, particularly when mood symptoms overlap with fatigue, sleep disruption, or metabolic changes.
Mitochondrial and Metabolic Health
Mitochondria play a critical role in brain energy metabolism. Emerging research suggests that impaired mitochondrial function may contribute to depressive disorders, particularly in treatment-resistant cases. Interventions that support mitochondrial health — including targeted nutrients and exercise — are an area of active clinical interest.
Movement, Mind-Body Therapies, and Neuroplasticity
Physical activity is one of the most consistently supported non-pharmacological interventions for mild to moderate depression. Beyond neurotransmitters, exercise improves inflammation, insulin sensitivity, mitochondrial function, and neuroplasticity.
Mind-body practices such as yoga, tai chi, and mindfulness-based meditation further support emotional regulation by influencing autonomic nervous system balance and stress hormone signaling. These approaches are especially valuable because they are low-risk, empowering, and adaptable to individual capacity.
Personalized Testing and Targeted Interventions
Functional medicine assessments may include evaluation of nutrient status, inflammatory markers, hormonal patterns, metabolic function, genetic factors, and — when appropriate — environmental exposures such as heavy metals.
The goal is not excessive testing, but strategic insight — identifying actionable imbalances that inform personalized treatment plans. Interventions may include:
- Nutritional optimization
- Targeted supplementation
- Dietary modification
- Exercise and movement prescriptions
- Stress and sleep support
- Mindfulness-based therapies
- Coordinated use of conventional and integrative treatments
A Collaborative Path Forward
Depression affects how individuals think, feel, relate, and engage with life — but it is also increasingly recognized as a whole-body condition. Addressing it effectively often requires a shift away from isolated solutions toward integrated care. By addressing biological foundations while honoring the emotional and lived experience of depression, this approach offers patients not just symptom management, but a path toward deeper resilience and long-term well-being. Learn more and request a consultation >>