What are natural frequencies?

Background Suicide is common in the context of depression and bipolar disorders, but there remains a lack of understanding as to how suicide ideation, a common symptom of mood disorders, progresses to suicidal behaviour. Irritability, a feature of some types of depression, is thought to contribute to the development of suicidal behaviour, but these associations are not well established. Objective To examine the relationship between irritability and suicide ideation according to the subtype of depression expressed in patients with mood disorder. Methods 75 patients with mood disorders seen at the CADE (Clinical Assessment Diagnostic Evaluation) Clinic underwent clinical assessment for suicidal ideation (Paykel Suicide Scale), symptom severity (Young Mania Rating Scale (YMRS), Hamilton Rating Scale for Depression (HAM-D) (anxious depression), Montgomery-Åsberg Depression Rating Scale (MADRS) (melancholic depression)) and irritability (item 5 of the YMRS). Findings Interestingly, irritability correlated with mania (r=0.734, p0.05). Conclusions The nature of the relationship between irritability and suicidal ideation is determined by the emotional context within which irritability operates. Clinical implications Findings suggest that rather than examining irritability alone, consideration of the subtype of depression, especially that of anxious depression, should be paramount in assessing suicide risk.