Recently, attention has been paid to youth suicides in Japan. Statistically the number of suicides under 19 years old is decreasing (peaked in 1950's). The suicide rate of this age group is very low in comparison with other age groups. Whilst, the suicide rate of over 15 years-old in Japan is the highest in the Group of Seven major industrialized countries.

Generally, adolescents tend to have suicidal ideations but a low proportion of them perform suicidal behaviors. And history of suicide attempts is the most important risk factor of further completed suicide in adolescents,as well as in other age groups. Nonsuicidal self-injury (NSSI), which is prevalent in youth, also increases the possibility of suicide in the future.

Clusters of adolescent suicides happen in Japan under the influence of media, and cybersuicide has emerged from the late 1990's. “Cyberbullying” is the universal topic, related to adolescent suicides.

As adolescent suicide is few in phenomena, it is difficult to establish the way to prevent adolescents from suicide. Follow-up studies of those outcomes of completed suicide are few. Treatments and strategies of suicide prevention for adolescents are complicated under the conditions of uncertainty of psychiatric diagnoses in these ages, psychological and physical changes, and social environments. However, suicide prevention of adolescents has become the strong demand of society today. Hence, we need to establish more evidence in the future.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an autosomal dominant hereditary disease characterized by subcortical infarctions and leukoencephalopathy as its neurological manifestations. Patients with CADASIL sometimes visit psychiatrists because this disease is often accompanied by depression which occurs as a psychiatric symptom. We herein report a 40-year-old woman with CADASIL who complained of memory disturbance. She was initially diagnosed with postpartum depression. However,magnetic resonance imaging revealed subcortical ischemic changes in the bilateral temporal lobes. Her family history of stroke and the genetic diagnosis of CADASIL in her mother confirmed the diagnosis of CADASIL in this patient. A genetic analysis of the Notch 3 mutation and a skin/muscle biopsy may have also helped in making a definitive diagnosis of CADASIL.

Hyperostosis frontalis interna (HFI) is characterized by the bilateral thickening of the frontal bone of the skull. Although most patients with HFI show no clinical symptoms, a few have been reported to show diverse and non-specific symptoms, including－but not limited to－cognitive decline, epileptic seizure, and endocrine disorder. We experienced the case of an 80-year-old woman with cognitive decline, in whom HFI was discovered on MRI and CT. Neurophychiatric examinations revealed frontal lobe dysfunction. HFI was therefore suggested to be one of the causes of frontal lobe dysfunction.

Iizuka Hospital is an acute general hospital in the Chikuho area of Fukuoka Prefecture where psychiatric consultations take place for inpatients. We analyzed the achievements of the liaison team activity over the past year, as a Department of Liaison Psychiatry was established at our hospital in 2016.

We received 613 consultations, and the most frequent psychiatric diagnosis was delirium (N=292). We consulted on 59 suicide attempts.

We must educate the staff on selecting the appropriate psychotropic drugs, as benzodiazepine-type drugs are often used to treat delirium patients. Regular follow-up after a suicide attempt is extremely important, and we must establish a system for adequately following up such patients.