What are the causes of insomnia?

Insomnia: Primary or secondary. Examples of secondary are mood disorders, medications, illnesses such as hyperthyroidism, or effect of illicit substances, also effect of environment.

Insomnia: There is acute insomnia or chronic insomnia, acute insomnia is less than 3 months and chronic is more than 3 to 6 months please identify the stressor that caused this, it could be move to a different time zone, financial, relation stress etc. Google sleep hygiene you may need short term meds like ambien cognitive behavior therapy for insomnia works best according to studies.