The metabolic workup in psychiatric patients is broader and more granular than the standard primary care panel. The standard panel — fasting glucose, basic lipid panel, A1c, TSH — catches frank disease but misses the years-to-decades upstream signals that longevity psychiatry needs to act on. The clinical task is to specify a workup that surfaces metabolic dysregulation before it becomes diabetes, cardiovascular disease, or established cognitive decline, and to interpret the results in the context of the patient's psychiatric presentation.
Fasting insulin and HOMA-IR are the most important additions to standard labs. Fasting insulin is not part of routine metabolic panels and must be specifically ordered. HOMA-IR is calculated: (fasting glucose × fasting insulin) / 405, with values above 2.5 generally indicating insulin resistance and values above 4 indicating substantial dysregulation. These measurements often surface the years of insulin resistance that precede frank diabetes by decades — exactly the window where intervention has highest yield. Every patient in the acceleration window benefits from these measurements at baseline.
ApoB is the more accurate cardiovascular and cognitive risk marker than LDL-C in most cases. ApoB measures the number of atherogenic particles, which is the variable that drives risk; LDL-C estimates cholesterol content of particles, which can underestimate risk when particle number is high and particle size is small. ApoB targets for cognitive protection are typically more aggressive than standard cardiology targets — often under 80 mg/dL, sometimes lower depending on individual risk. Lipoprotein(a) should be measured once in a lifetime for every patient — it is inherited, does not change, and identifies an elevated-risk subgroup that benefits from more aggressive intervention.
Inflammatory markers belong in the workup. High-sensitivity CRP at minimum; IL-6 if available and indicated. Elevated CRP without infectious or autoimmune cause is a longevity-psychiatry finding worth addressing — the patient with chronically elevated CRP has a different cardiovascular and cognitive trajectory than the patient with normal CRP, and lifestyle interventions (exercise, sleep, dietary anti-inflammatory patterns, weight management) move the marker meaningfully. Pharmacological intervention for asymptomatic inflammation is on the horizon but not yet standard.
Thyroid workup should be more complete than TSH alone in psychiatric patients. TSH alone misses several relevant patterns: subclinical hypothyroidism in patients on lithium; T3 dysregulation that may affect mood without abnormal TSH; autoimmune thyroid disease that drives both psychiatric and cognitive symptoms. Free T4, free T3, and thyroid antibodies (anti-TPO, anti-thyroglobulin) round out the workup in appropriate patients — particularly those with mood disorders, refractory depression, fatigue with normal TSH, or family history of autoimmune thyroid disease.
Nutritional and hormonal markers complete the longevity-psychiatry panel. B12 and folate (deficiencies frequently produce psychiatric presentations). Vitamin D (relevant to mood, immune function, and possibly cognition; widely deficient in adults). Iron studies including ferritin (relevant to fatigue, restless legs, and cognitive function; women particularly). Testosterone in men with low mood or libido concerns. The full estrogen/progesterone workup in women with mood patterns suggesting hormonal contribution (covered in Stage 19). Magnesium and selenium if clinical suspicion. Homocysteine as an additional cardiovascular and cognitive risk marker, particularly in patients with elevated B-vitamin needs.