IGF1 and depressive disorder: In military personnel diagnosed with insomnia or comorbid insomnia with OSA receiving four to eight biweekly sessions of cognitive behavioral therapy for insomnia (CBT) and CPAP for their OSA, improvements in sleep quality were associated with significant declines in depression and posttraumatic arousal symptoms, and a significant increase in plasma concentrations of IGF-1, the growth hormone dependent factor implicated in memory processes [7,116].