Tightly connected symptom networks have previously been linked to treatment resistance, but most findings come from small-sample studies comparing single responder v. non-responder networks. We aimed to estimate the association between baseline network connectivity and treatment response in a large sample and benchmark its prognostic value against baseline symptom severity and variance.

N = 40 518 patients receiving treatment for depression in routine care in England from 2015–2020 were analysed. Cross-sectional networks were constructed using the Patient Health Questionnaire-9 (PHQ-9) for responders and non-responders (N = 20 259 each). To conduct parametric tests investigating the contribution of PHQ-9 sum score mean and variance to connectivity differences, networks were constructed for 160 independent subsamples of responders and non-responders (80 each, n = 250 per sample).

The baseline non-responder network was more connected than responders (3.15 v. 2.70, S = 0.44, p < 0.001), but effects were small, requiring n = 750 per group to have 85% power. Parametric analyses revealed baseline network connectivity, PHQ-9 sum score mean, and PHQ-9 sum score variance were correlated (r = 0.20–0.58, all p < 0.001). Both PHQ-9 sum score mean (β = −1.79, s.e. = 0.07, p < 0.001), and PHQ-9 sum score variance (β = −1.67, s.e. = 0.09, p < 0.001) had larger effect sizes for predicting response than connectivity (β = −1.35, s.e. = 0.12, p < 0.001). The association between connectivity and response disappeared when PHQ-9 sum score variance was accounted for (β = −0.28, s.e. = 0.19, p = 0.14). We replicated these results in patients completing longer treatment (8–12 weeks, N = 22 952) and using anxiety symptom networks (N = 70 620).

The association between baseline network connectivity and treatment response may be largely due to differences in baseline score variance.

Rapid diagnosis of dementia is essential to ensure optimum patient care. This study used real-world data to quantify the dementia diagnostic pathway in Australia.

A real-world, cross-sectional survey of physicians and patients.

Clinical practice.

Primary care or specialist physicians managing patients with cognitive impairment (CI).

Descriptive analyses focused on key events in the diagnostic pathway. Regression modeling compared the duration between first consultation and formal diagnosis with various factors.

Data for 600 patients were provided by 60 physicians. Mean time from initial symptoms to first consultation was 6.1 ± 4.4 months; 20% of patients had moderate or severe CI at first consultation. Mean time from first consultation to formal diagnosis was 4.0 ± 7.4 months (1.2 ± 3.6 months if not referred to a secondary physician, and 5.3 ± 8.3 months if referred). Time from first consultation to diagnosis was significantly associated with CI severity at first consultation; time was shorter with more severe CI. There was no association of disease severity and referral to a secondary physician; 69.5% of patients were referred, the majority (57.1%) to a geriatrician. The highest proportion of patients were diagnosed by geriatricians (47.4%). Some form of test or scale was used to aid diagnosis in 98.8% of patients.

A substantial number of Australians experience cognitive decline and behavioral changes some time before consulting a physician or being diagnosed with dementia. Increasing public awareness of the importance of early diagnosis is essential to improve the proportion of patients receiving comprehensive support prior to disease progression.