He may or may not have been an insomniac as we understand the term today – but he certainly saw not sleeping at night as an option for drawing closer to God – as is borne out by several of his Psalms.
“When I remember You on my bed, I meditate on You in the night watches.” Psalm 63:6
“My eyes anticipate the night watches, that I may meditate on Your Word.” Psalm 119:148
David certainly was a mystic in the sense that He loved the presence of the Lord – and this love drove His heart after God. David was so remarkable in this aspect – that his son Solomon – and all the rest of his descendants – were measured against him and found wanting. This comparison starts with Solomon (1 Kings 11:4) and continues through David’s line until it fades into the exile. King after king the Bible records their devotion as being “not like his father David.”
It’s not just David who heard the voice of the Lord during the silent hours. Samuel’s famously unique experience is a favorite Bible story among children and gives adults pause for good reason.
Do you anticipate laying awake on your bed in the night watches meditating on the Lord? It sounds great on paper … It sounds like an utterly different proposition the fourth, fifth, or the twentieth night in a row. When you’re reduced to existing on 3 hours or so a night – and insomnia frequently means you cannot “catch up” on sleep via naps, or going to bed early, or … anything … until one night you finally just sleep again. Anticipating – with true eagerness – another night of meditating on the Lord requires a leap of faith that surpasses and surpasses again the exhaustion. It requires an abiding faith that He will sustain you – and letting go of such a basic level of control – over one’s own sleep.
The thing is: He will sustain you. You may find that sustenance in a level of leaning on Him that you’d previously been dodging.