patient who presents with depressed mood but also reports recurrent periods of decreased need for sleep, unusually high energy, impulsive spending or racing thoughts may fall within the bipolar spectrum rather than having pure unipolar depression. Misclassifying bipolar disorder as major depression is a well-recognized clinical problem and can lead to antidepressant treatments that destabilize mood or delay appropriate mood-stabilizing interventions.
The Role of Medical and Developmental Factors
Figure 1: MERON Diagnostic Algorithm for Primary Care
START Patient Presentation
R-Reality Testing Hallucinations / Delusions?
MERON also emphasizes that psychiatric symptoms do not always arise from primary psychiatric illness. Medical conditions such as thyroid dysfunction, vitamin deficiencies, seizure disorders, neurodegenerative disease and systemic infections can produce symptoms that closely resemble mood or anxiety disorders. Medication side effects and substance use or withdrawal can further cloud the clinical picture.
Psychotic Spectrum Schizophrenia / Psychotic Mood Distord
M- Mood Orientation Depressed / Elevated / Neutral
By explicitly prompting clinicians to consider organic contributors, the framework helps reduce the risk of overlooking treatable medical causes. The final step, neurodevelopmental factors, reminds clinicians to consider whether long-standing cognitive or developmental differences may affect how symptoms are experienced, reported and managed. This is particularly important when interpreting subjective accounts of mood and anxiety or when planning follow-up, psychoeducation and treatment adherence strategies.
A Brief Screening Tool for Clinical Practice
Bipolar Spectrum Mania / Hypomania
Depressive Spectrum Major Depression
E- Energy Level High / Low / Normal
Anxiety / Stress Related Conditions
To operationalize the framework, a brief screening instrument, the 5Switch Diagnostic Screener( 7SDS), was developed. The 7SDS includes 32 yes / no questions that cover seven symptom domains: The 7-SDS is a brief psychometric screener designed to help organize symptom patterns in primary care. Its results are intended to support clinical decision-making and guide further questioning, not to replace a clinician’ s judgment or a full diagnostic evaluation. Instead of producing a single diagnosis, the screener highlights where symptoms may cluster, helping clinicians see whether the overall pattern points more toward depression, bipolar activation, psychosis risk or another concern. The seven system domains are:
» Somatic – mood interface
O- Organic / Medical Causes Thyroid / Infection / Drugs
YES
Investigate Medical Etiology
Treat Medical Cause
NO
N-Neurodevelopmental ID / ASD / Cognitive
Psychiatric Diagnosis
» Eating behavior » Core depressive symptoms » Anxiety symptoms » Alcohol and substance use » Psychosis screening » Bipolar activation symptoms
Completion time is approximately three to five minutes, making it practical for use in primary care. Rather than generating a categorical diagnosis, the instrument provides a probabilistic diagnostic orientation. It highlights where risk is concentrated( for example, toward bipolar activation versus psychosis versus primary depression) and guides the
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ID = Intellicutal Disability ASD = Autism Spectrum Disorder
Figure 1. The MERON diagnostic framework provides a hierarchical approach to psychiatric triage in primary care. The algorithm prioritizes assessment of psychotic symptoms( Reality) followed by mood orientation and energy activation patterns to differentiate bipolar and depressive disorders. Secondary branches evaluate medical contributors and neurodevelopmental conditions.
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