Tbh, it mainly makes me think in terms of a cocaine binge, which he would feel safe doing given that he had 5 days off work (cocaine clearance in urine is 2-3 days). Hours of driving, prowling, a period of manic activity, but also poor judgement and the mistakes that led to his arrest. The inevitable post-binge crash would account for his extreme agitation in the 72 hours after he was taken into custody.
It's JMO though. As far as I know, there's been no specific evidence of drug misuse mentioned by either LE or MSM.