The DSM diagnostic categories — major depressive disorder, generalized anxiety, others — are heterogeneous conditions encompassing patients with different underlying biology and different treatment responses. The precision psychiatry frame engages this heterogeneity by recognizing clinical subtypes within diagnoses and matching treatment to subtype where evidence supports it. The clinical task is to use phenotypic and biomarker information to guide treatment selection beyond the broad diagnostic category.
Depression subtypes with treatment implications. Inflammation-elevated depression (Stage 10.5) — hs-CRP >3 mg/L; responds preferentially to anti-inflammatory augmentation. Melancholic depression — psychomotor symptoms, anhedonia, severity; responds well to ECT (Stage 15.2) and tricyclic antidepressants. Atypical depression — mood reactivity, increased sleep and appetite, leaden paralysis; historically responded to MAOIs particularly. Mixed-features depression — concurrent mild manic symptoms; warrants attention to bipolar spectrum and may respond to specific agents (lurasidone, quetiapine). Anxious distress — concurrent prominent anxiety; warrants attention to both domains. Seasonal patterns — light therapy and timing considerations.
Anxiety subtypes. Generalized anxiety with prominent autonomic symptoms — HRV training (Stage 22.1) and SSRIs/SNRIs as primary. Anxiety with prominent cognitive worry — CBT particularly indicated. Anxiety with prominent somatic symptoms — autonomic and body-based interventions integrated. Panic disorder distinguishes by symptom pattern and benefits from specific treatment. Social anxiety distinguishes and benefits from CBT plus medications. The DSM categories cover real distinctions; the subtyping within each adds precision.
Bipolar spectrum subtyping. Classical bipolar I, bipolar II, cyclothymic disorder, and the broader bipolar spectrum each have different treatment implications. Mixed-features presentations require specific attention. The "soft bipolar" patient with subtle features warrants different treatment than pure unipolar depression. The clinical history matters substantially; family history, treatment response history, episode patterns all inform subtyping.
The clinical practice of subtype-informed care. Detailed history characterizing the specific clinical picture. Biomarker assessment where relevant (hs-CRP, thyroid panel, metabolic panel). Treatment selection informed by subtype — different subtypes get different first-line approaches. Reassessment based on response — non-response to standard treatment may indicate misidentified subtype. The integration of subtype thinking with the broader treatment workflow distinguishes precision psychiatry from generic diagnosis-based care. The discipline is to engage clinical subtyping within DSM categories, match treatment to subtype where evidence supports, and integrate with broader workup and treatment planning.