Proposed model for reduced heart rate variability (HRV) in patients with major depressive disorder (MDD) and comorbid generalised anxiety disorder (GAD).

<p>These patients typically experience worry and hypervigilance to threat, leading to a chronic withdrawal of the parasympathetic nervous system (PNS) and long-term reductions in HRV, placing these patients at an increased risk for cardiovascular disease (CVD) and sudden cardiac death (SCD).</p

Anxiety Subgroup Characteristics (mean, S.D.).

<p>Anxiety Subgroup Characteristics (mean, S.D.).</p

Group medians of STAI-S scores before and after intervention amongst highly anxious individuals.

<p>Amongst highly anxious individuals, participants in the intervention group showed a reduction in reported state anxiety while those in the control group showed a modest increase. The difference between pre-post difference scores for each group was significant (i.e. a group by time interaction).</p

Participant characteristics.

<p>Participant characteristics.</p

Screen shot of <i>Resilience Builder</i> software training screen and slow breathing pacer.

<p>a) The ball rises for inhalation and falls for exhalation with a longer interval for exhalation. The top graph shows HR, the large amplitude wave indicates slow deep breathing. The lower graph indicates score, which is very high in this case. b) Breathing pacer identical to Resilience Builder yet no feedback is provided.</p

Description of standardized scores for neuropsychological tests.

<p>Description of standardized scores for neuropsychological tests.</p

Flow diagram of participant progress through the study.

<p>Figure depicts progress through the stages of the experiment, including when and why participants were excluded. Conforms to CONSORT guidelines <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0046597#pone.0046597-Schulz1" target="_blank">[89]</a>.</p

DASS-42 scale scores (mean ± standard deviation) for MDD vs CTL (1a) and MDD groupings.

<p>DASS-42 scale scores (mean ± standard deviation) for MDD vs CTL (1a) and MDD groupings.</p

Group differences in HRV comparing intervention to control.

<p>Group means and standard error for HRV measures during anxious anticipation pre and post intervention. Both HF and LF/HF ratio showed significant group by time interactions. a) Participants in the intervention group increased HF after intervention, whereas those in the control group decreased. b) Participant in the intervention group decreased LF/HF ratio whereas those in the control group increased.</p

Time (row 1), frequency (row 2) and non-linear (row 3) domain measures of HRV in unmedicated patients with major depressive disorder (MDD) relative to controls (CTL).

<p>Time (row 1), frequency (row 2) and non-linear (row 3) domain measures of HRV in unmedicated patients with major depressive disorder (MDD) relative to controls (CTL).</p