diff --git a/R/add_stan_data.R b/R/add_stan_data.R
index 38aacd8c..fdeee218 100644
--- a/R/add_stan_data.R
+++ b/R/add_stan_data.R
@@ -510,21 +510,30 @@ add_stan_data = function(jags_file, stan_file,
     if(any(grep('## parametric effect priors', jags_file))){
 
       # Get indices of parametric effects
-      min_paras <- as.numeric(sub('.*(?=.$)', '',
-                                  sub("\\:.*", "",
-                                      jags_file[grep('## parametric effect', jags_file) + 1]), perl=T))
-      max_paras <- as.numeric(substr(sub(".*\\:", "",
-                                         jags_file[grep('## parametric effect', jags_file) + 1]),
-                                     1, 1))
-      para_indices <- seq(min_paras, max_paras)
-
-      # Get names of parametric terms
-      int_included <- attr(ss_gam$pterms, 'intercept') == 1L
-      other_pterms <- attr(ss_gam$pterms, 'term.labels')
-      all_paras <- other_pterms
-      if(int_included){
-        all_paras <- c('(Intercept)', all_paras)
-      }
+      smooth_labs <- do.call(rbind, lapply(seq_along(ss_gam$smooth), function(x){
+        data.frame(label = ss_gam$smooth[[x]]$label,
+                   term = paste(ss_gam$smooth[[x]]$term, collapse = ','),
+                   class = class(ss_gam$smooth[[x]])[1])
+      }))
+      lpmat <- predict(ss_gam, type = 'lpmatrix',
+                       exclude = smooth_labs$label)
+      para_indices <- which(apply(lpmat, 2, function(x) !all(x == 0)) == TRUE)
+      all_paras <- names(para_indices)
+      # min_paras <- as.numeric(sub('.*(?=.$)', '',
+      #                             sub("\\:.*", "",
+      #                                 jags_file[grep('## parametric effect', jags_file) + 1]), perl=T))
+      # max_paras <- as.numeric(substr(sub(".*\\:", "",
+      #                                    jags_file[grep('## parametric effect', jags_file) + 1]),
+      #                                1, 1))
+      # para_indices <- seq(min_paras, max_paras)
+      #
+      # # Get names of parametric terms
+      # int_included <- attr(ss_gam$pterms, 'intercept') == 1L
+      # other_pterms <- attr(ss_gam$pterms, 'term.labels')
+      # all_paras <- other_pterms
+      # if(int_included){
+      #   all_paras <- c('(Intercept)', all_paras)
+      # }
 
       # Create prior lines for parametric terms
       para_lines <- vector()
diff --git a/R/stan_utils.R b/R/stan_utils.R
index 7b1427bf..91d78e00 100644
--- a/R/stan_utils.R
+++ b/R/stan_utils.R
@@ -2921,9 +2921,19 @@ add_trend_predictors = function(trend_formula,
         paste0('// dynamic process models\n',
                paste0(paste(plines, collapse = '\n')))
     } else {
-      model_file[grep("// dynamic factor estimates", model_file, fixed = TRUE)] <-
-        paste0('// dynamic process models\n',
-               paste0(paste(plines, collapse = '\n')))
+      if(any(grepl("// dynamic factor estimates", model_file, fixed = TRUE))){
+        model_file[grep("// dynamic factor estimates", model_file, fixed = TRUE)] <-
+          paste0('// dynamic process models\n',
+                 paste0(paste(plines, collapse = '\n')))
+      }
+
+      if(any(grepl("// trend means", model_file, fixed = TRUE))){
+        model_file[grep("// trend means", model_file, fixed = TRUE)] <-
+          paste0('// dynamic process models\n',
+                 paste0(paste(plines, collapse = '\n'),
+                        '// trend means'))
+      }
+
     }
 
   }
diff --git a/src/RcppExports.o b/src/RcppExports.o
index 3738bd53..849c29a4 100644
Binary files a/src/RcppExports.o and b/src/RcppExports.o differ
diff --git a/src/mvgam.dll b/src/mvgam.dll
index 18b55708..4ee6cc2c 100644
Binary files a/src/mvgam.dll and b/src/mvgam.dll differ
diff --git a/src/trend_funs.o b/src/trend_funs.o
index 371ea49f..faf098a5 100644
Binary files a/src/trend_funs.o and b/src/trend_funs.o differ
diff --git a/tests/testthat/Rplots.pdf b/tests/testthat/Rplots.pdf
index 2799ff09..cf2654cc 100644
Binary files a/tests/testthat/Rplots.pdf and b/tests/testthat/Rplots.pdf differ
diff --git a/tests/testthat/test-mvgam.R b/tests/testthat/test-mvgam.R
index 6dae714d..aff31255 100644
--- a/tests/testthat/test-mvgam.R
+++ b/tests/testthat/test-mvgam.R
@@ -225,5 +225,133 @@ test_that("trend_formula setup is working properly", {
 
 })
 
+# Check that parametric effect priors are properly incorporated in the
+# model for a wide variety of model forms
+test_that("parametric effect priors correctly incorporated in models", {
+  mod_data <- mvgam:::mvgam_examp_dat
+  mod_data$data_train$x1 <-
+    rnorm(NROW(mod_data$data_train))
+  mod_data$data_train$x2 <-
+    rnorm(NROW(mod_data$data_train))
+  mod_data$data_train$x3 <-
+    rnorm(NROW(mod_data$data_train))
 
+  # Observation formula; no trend
+  mod <- mvgam(y ~ s(season) + series:x1 +
+                 series:x2 + series:x3,
+               trend_model = 'None',
+               data = mod_data$data_train,
+               family = gaussian(),
+               run_model = FALSE)
+
+  expect_true(any(grepl('// prior for seriesseries_3:x1...',
+                        mod$model_file, fixed = TRUE)))
+  expect_true(any(grepl('// prior for (Intercept)...',
+                        mod$model_file, fixed = TRUE)))
+
+  para_names <- paste0(paste0('// prior for seriesseries_', 1:3,
+                              paste0(':x', 1:3, '...')))
+  for(i in seq_along(para_names)){
+    expect_true(any(grepl(para_names[i],
+                          mod$model_file, fixed = TRUE)))
+  }
+
+  priors <- get_mvgam_priors(y ~ s(season) + series:x1 +
+                               series:x2 + series:x3,
+                             trend_model = 'None',
+                             data = mod_data$data_train,
+                             family = gaussian())
+  expect_true(any(grepl('seriesseries_1:x2',
+                        priors$param_name)))
+  expect_true(any(grepl('seriesseries_2:x3',
+                        priors$param_name)))
+
+
+  # Observation formula; complex trend
+  mod <- mvgam(y ~ s(season) + series:x1 + series:x2 + series:x3,
+               trend_model = 'VARMA',
+               data = mod_data$data_train,
+               family = gaussian(),
+               run_model = FALSE)
+
+  expect_true(any(grepl('// prior for seriesseries_3:x1...',
+                        mod$model_file, fixed = TRUE)))
+  expect_true(any(grepl('// prior for (Intercept)...',
+                        mod$model_file, fixed = TRUE)))
+
+  para_names <- paste0(paste0('// prior for seriesseries_', 1:3,
+                              paste0(':x', 1:3, '...')))
+  for(i in seq_along(para_names)){
+    expect_true(any(grepl(para_names[i],
+                          mod$model_file, fixed = TRUE)))
+  }
+
+  priors <- get_mvgam_priors(y ~ s(season) + series:x1 +
+                               series:x2 + series:x3,
+                             trend_model = 'VARMA',
+                             data = mod_data$data_train,
+                             family = gaussian())
+  expect_true(any(grepl('seriesseries_1:x2',
+                        priors$param_name)))
+  expect_true(any(grepl('seriesseries_2:x3',
+                        priors$param_name)))
+
+  # Trend formula; RW
+  mod <- mvgam(y ~ 1,
+               trend_formula = ~ s(season) + trend:x1 +
+                 trend:x2 + trend:x3,
+               trend_model = 'RW',
+               data = mod_data$data_train,
+               family = gaussian(),
+               run_model = FALSE)
+
+  expect_true(any(grepl('// prior for (Intercept)...',
+                        mod$model_file, fixed = TRUE)))
+
+  para_names <- paste0(paste0('// prior for trendtrend', 1:3,
+                              paste0(':x', 1:3, '_trend...')))
+  for(i in seq_along(para_names)){
+    expect_true(any(grepl(para_names[i],
+                          mod$model_file, fixed = TRUE)))
+  }
+
+  priors <- get_mvgam_priors(y ~ 1,
+                             trend_formula = ~ s(season) + trend:x1 +
+                               trend:x2 + trend:x3,
+                             trend_model = 'RW',
+                             data = mod_data$data_train,
+                             family = gaussian())
+  expect_true(any(grepl('trendtrend1:x1_trend',
+                        priors$param_name)))
+  expect_true(any(grepl('trendtrend2:x3_trend',
+                        priors$param_name)))
+
+  # Trend formula; VARMA
+  mod <- mvgam(y ~ 1,
+               trend_formula = ~ s(season) + trend:x1 + trend:x2 + trend:x3,
+               trend_model = 'VARMA',
+               data = mod_data$data_train,
+               family = gaussian(),
+               run_model = FALSE)
+
+  expect_true(any(grepl('// prior for (Intercept)...',
+                        mod$model_file, fixed = TRUE)))
+
+  para_names <- paste0(paste0('// prior for trendtrend', 1:3,
+                              paste0(':x', 1:3, '_trend...')))
+  for(i in seq_along(para_names)){
+    expect_true(any(grepl(para_names[i],
+                          mod$model_file, fixed = TRUE)))
+  }
+
+  priors <- get_mvgam_priors(y ~ 1,
+                             trend_formula = ~ s(season) + trend:x1 + trend:x2 + trend:x3,
+                             trend_model = 'RW',
+                             data = mod_data$data_train,
+                             family = gaussian())
+  expect_true(any(grepl('trendtrend1:x1_trend',
+                        priors$param_name)))
+  expect_true(any(grepl('trendtrend2:x3_trend',
+                        priors$param_name)))
+})