A randomized crossover trial (n=80) showed that cognitive behavioral therapy for insomnia (CBT-I) combined with melatonin treatment increased sleep efficiency by 25% (p < 0.001) and reduced plasma phosphorylated tau (p-tau181) levels by 18% compared to the control group (p = 0.03) (Clynes et al., 2019). Here, MAPT is linked to insomnia.