Globally suicidal behavior is the third most common cause of death among patients with major depressive disorder (MDD). This study presents multi-lag tone-entropy (T-E) analysis of heart rate variability (HRV) as a screening tool for identifying MDD patients with suicidal ideation. Sixty-one ECG recordings (10 min) were acquired and analyzed from control subjects (29 CONT), 16 MDD subjects with (MDDSI+) and 16 without suicidal ideation (MDDSI-). After ECG preprocessing, tone and entropy values were calculated for multiple lags (m: 1-10). The MDDSI+ group was found to have a higher mean tone value compared to that of the MDDSI- group for lags 1-8, whereas the mean entropy value was lower in MDDSI+ than that in CONT group at all lags (1-10). Leave-one-out cross-validation tests, using a classification and regression tree (CART), obtained 94.83 % accuracy in predicting MDDSI+ subjects by using a combination of tone and entropy values at all lags and including demographic factors (age, BMI and waist circumference) compared to results with time and frequency domain HRV analysis. The results of this pilot study demonstrate the usefulness of multi-lag T-E analysis in identifying MDD patients with suicidal ideation and highlight the change in autonomic nervous system modulation of the heart rate associated with depression and suicidal ideation.

Physiological and psychological underpinnings of suicidal behavior remain ill-defined and lessen timely diagnostic identification of this subgroup of patients. Arterial stiffness is associated with autonomic dysregulation and may be linked to major depressive disorder (MDD). The aim of this study was to investigate the association between arterial stiffness by photo-plethysmogram (PPG) in MDD with and without suicidal ideation (SI) by applying multiscale tone entropy (T-E) variability analysis. Sixty-one 10-min PPG recordings were analyzed from 29 control, 16 MDD patients with (MDDSI+) and 16 patients without SI (MDDSI−). MDD was based on a psychiatric evaluation and the Mini-International Neuropsychiatric Interview (MINI). Severity of depression was assessed using the Hamilton Depression Rating Scale (HAM-D). PPG features included peak (systole), trough (diastole), pulse wave amplitude (PWA), pulse transit time (PTT) and pulse wave velocity (PWV). Tone (Diastole) at all lags and Tone (PWA) at lags 8, 9, and 10 were found to be significantly different between the MDDSI+ and MDDSI− group. However, Tone (PWA) at all lags and Tone (PTT) at scales 3–10 were also significantly different between the MDDSI+ and CONT group. In contrast, Entropy (Systole), Entropy (Diastole) and Tone (Diastole) were significantly different between MDDSI− and CONT groups. The suicidal score was also positively correlated (r = 0.39 ~ 0.47; p < 0.05) with systolic and diastolic entropy values at lags 2–10. Multivariate logistic regression analysis and leave-one-out cross-validation were performed to study the effectiveness of multi-lag T–E features in predicting SI risk. The accuracy of predicting SI was 93.33% in classifying MDDSI+ and MDDSI− with diastolic T-E and lag between 2 and 10. After including anthropometric variables (Age, body mass index, and Waist Circumference), that accuracy increased to 96.67% for MDDSI+/− classification. Our findings suggest that tone-entropy based PPG variability can be used as an additional accurate diagnostic tool for patients with depression to identify SI.

Major Depressive Disorder (MDD) is a serious mental disorder that if untreated not only affects physical health but also has a high risk of suicide. While the neurophysiological phenomena that contribute to the formation of Suicidal Ideation (SI) are still ill-defined, clear links between MDD and cardiovascular disease have been reported. The aim of this study is to extract suitable features from arterial pulse signals with a view to predicting SI within MDD and control groups. Sixteen unmedicated MDD patients with a history of SI (MDDSI+), sixteen without SI (MDDSI-) and twenty-nine healthy subjects (CONT) were recruited at a psychiatric clinic in the UAE. Depression severity and SI were assessed using the Hamilton Depression Rating Scale and Beck Depression Inventory. Pulse Wave Amplitude (PWA) was calculated as the difference between the peak (Systole) and the valley (Diastole) of the arterial pulse within each cardiac cycle. Then, 2D Tone-Entropy (TE) features were extracted from the Systole, Diastole and PWA time series. The TE features extracted from Diastole were the best markers for predicting MDDSI+. The overall classification accuracies of Classification and Regression Tree (CART) model by using TE features of Systole, Diastole and PWA were 88.52%, 90.2% and 88.52% respectively. When all TE features were combined, accuracy increased up to 93.44% in identifying MDDSI+/MDDSI-/Control groups.

is a centrally acting antihypertensive agent with alpha-2 adrenergic receptor agonist properties. Several open reports noted beneficial effects of guanfacine in treating symptoms of attention deficit hyperactivity disorder (Hunt et al. 1995;Chappell et al. 1995). Side effects commonly reported with guanfacine include dry mouth, somnolence, fatigue, constipation, asthenia, dizziness, headache, and insomnia (Physicians' Desk Reference 1999). Recently, there was a case report of symptoms resembling a manic episode in five children on guanfacine (Horrigan and Barnhill 1998). To date, psychotic symptoms associated with guanfacine use in children have not been reported. The following case describes a youngster who developed visual hallucinations on treatment with guanfacine.A 10-year-old African-American boy was admitted to the psychiatric service for fighting and disruptive behavior. He had a diagnosis of attention deficit hyperactivity disorder and conduct disorder for which he had been treated with 45 mg/day of dextroamphetamine in divided doses for 6 weeks. Prior to hospitalization, he had been partially compliant with his medication. Oral dextroamphetamine 20 mg at 9 a.m., 15 mg at noon, and 10 mg at 4 p.m. was started on admission. On the third night on this dose, he woke up fearful, complaining of visual hallucinations of snakes and frogs crawling everywhere in his room. The hallucinations persisted during the day and at night while he was awake. Dextroamphetamine was discontinued, and his visual hallucinations stopped within 48 h except for one brief hypnopompic event of seeing snakes, 4 days later. The patient was rechallenged with dextroamphetamine 5 mg at noon 1 week later, and he reported hypnopompic hallucinations after snakes and frogs for two successive nights. There were no further reports of hallucinations after stopping the dextroamphetamine.The patient remained hyperactive and disruptive and was started on guanfacine 0.5 mg/day. The dose was gradually increased over the next 2 weeks without difficulties. Two nights after the dose was increased to 2 mg/day, the patient woke up with visual hallucinations of snakes and frogs. He did not respond to reassurance by the staff and was awake the remainder of the night. No visual hallucinations were reported in the daytime. Due to decrease in his blood pressure, the patient was given 1.0-1.5 mg of guanfacine daily over the next 2 days and was free of hallucinations. The daily dose of guanfacine was increased to 2.5 mg, and the patient again complained of visual hallucinations of snakes at night; he was visibly afraid but fell asleep a couple of hours later with no more report of hallucinations. Due to decrease in blood pressure over the next 3 days, the patient was given 1.0-1.5 mg of guanfacine daily and reported no hallucinations. Subsequently, the daily dose of guanfacine was gradually increased to 3.0 mg, and the patient was able to tolerate it without any adverse effects. There was no report of hallucinations on this dose for the remaining 3 weeks of hosp...

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