"In fact, it is possible that insomnia represents a significant risk for the development of a subsequent psychiatric disorder." Insomnia occurs in between 60% and 80% of people with depression. This may partly be due to treatment used for depression.Determination of causation is not necessary for a diagnosis. DSM-5 criteria
The DSM-5 criteria for insomnia include the following:Predominant complaint of dissatisfaction with sleep quantity or quality, associated with one (or more) of the following symptoms:

Difficulty initiating sleep. (In children, this may manifest as difficulty initiating sleep without caregiver intervention.) Difficulty maintaining sleep, characterized by frequent awakenings or problems returning to sleep after awakenings. (In children, this may manifest as difficulty returning to sleep without caregiver intervention.) Early-morning awakening with inability to return to sleep.In addition:

The sleep disturbance causes clinically significant distress or impairment in social, occupational, educational, academic, behavioral, or other important areas of functioning. The sleep difficulty occurs at least 3 nights per week. The sleep difficulty is present for at least 3 months. The sleep difficulty occurs despite adequate opportunity for sleep. The insomnia is not better explained by and does not occur exclusively during the course of another sleep-wake disorder (e.g., narcolepsy, a breathing-related sleep disorder, a circadian rhythm sleep-wake disorder, a parasomnia). The insomnia is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication). Coexisting mental disorders and medical conditions do not adequately explain the predominant complaint of insomnia. Types
Insomnia can be classified as transient, acute, or chronic. Transient insomnia lasts for less than a week.
Schizencephaly (from Greek  skhizein to split, and  enkephalos brain) is a rare birth defect characterized by abnormal clefts lined with grey matter that form the ependyma of the cerebral ventricles to the pia mater. These clefts can occur bilaterally or unilaterally. Common clinical features of this malformation include epilepsy, motor deficits, and psychomotor retardation. Presentation
Schizencephaly can be distinguished from porencephaly by the fact that in schizencephaly, the fluid-filled component is entirely lined by heterotopic grey matter, while a porencephalic cyst is lined mostly by white matter. Individuals with clefts in both hemispheres, or bilateral clefts, are often developmentally delayed and have delayed speech and language skills and corticospinal dysfunction. Individuals with smaller, unilateral clefts (clefts in one hemisphere) may be weak or paralyzed on one side of the body and may have average or near-average intelligence. Patients with schizencephaly may also have varying degrees of microcephaly, Cognitive impairment, hemiparesis (weakness or paralysis affecting one side of the body), or quadriparesis (weakness or paralysis affecting all four extremities), and may have reduced muscle tone (hypotonia). Most patients have seizures, and some may have hydrocephalus. Causes
In schizencephaly, the neurons border the edge of the cleft, implying a very early disruption of the usual grey matter migration during embryogenesis. The cause of the disruption is not known, but likely the cause may be either genetic or a physical insult, such as infection, infarction, hemorrhage, in utero stroke, exposure to a toxin, or mutation.