pan>

<span class="co"># import cleaned survey data ------------------------</span>
<span class="kw">load</span>(<span class="st">&quot;data/cleaned/t0.Rda&quot;</span>)
<span class="kw">load</span>(<span class="st">&quot;data/cleaned/t1.Rda&quot;</span>)

<span class="co"># add PHQ-9 sum scores ---------------------------------------</span>
t0<span class="op">$</span>phq9 &lt;-<span class="st"> </span><span class="kw">rowSums</span>(t0[<span class="kw">paste0</span>(<span class="st">&quot;phq&quot;</span>,