  The burden of depression and anxiety in the world is rising. Identification
of individuals at increased risk of developing these conditions would help to
target them for prevention and ultimately reduce the healthcare burden. We
developed a 10-year predictive algorithm for depression and anxiety using the
full cohort of over 400,000 UK Biobank (UKB) participants without pre-existing
depression or anxiety using digitally obtainable information. From the initial
204 variables selected from UKB, processed into > 520 features, iterative
backward elimination using Cox proportional hazards model was performed to
select predictors which account for the majority of its predictive capability.
Baseline and reduced models were then trained for depression and anxiety using
both Cox and DeepSurv, a deep neural network approach to survival analysis. The
baseline Cox model achieved concordance of 0.813 and 0.778 on the validation
dataset for depression and anxiety, respectively. For the DeepSurv model,
respective concordance indices were 0.805 and 0.774. After feature selection,
the depression model contained 43 predictors and the concordance index was
0.801 for both Cox and DeepSurv. The reduced anxiety model, with 27 predictors,
achieved concordance of 0.770 in both models. The final models showed good
discrimination and calibration in the test datasets.We developed predictive
risk scores with high discrimination for depression and anxiety using the UKB
cohort, incorporating predictors which are easily obtainable via smartphone. If
deployed in a digital solution, it would allow individuals to track their risk,
as well as provide some pointers to how to decrease it through lifestyle
changes.
