>Genetic loci shared between major depression and intelligence with mixed directions of effect[0]
>Although intelligence conferred no consistent independent effects on depression, it did increase the risk for depression across samples once neuroticism was adjusted for.[1]
>Those with high IQ had higher risk for psychological disorders (RR 1.20 - 223.08). High IQ was associated with higher risk for physiological diseases (RR 1.84 - 4.33).[2]
I guess one way to look at this is that it's risky having a higher-performance brain. Kind of like how a sports car breaks down more often than a basic sedan or wagon.
It's not. Intelligence is negatively correlated to both anxiety and depression.