Lightment itself speaks about how the Darkness supress. There are several studied effects of the Darkness that we shall list here:

1. Hallucinations

Human tends to create different kind of hallucination such as seeing light, hearing footsteps, imaging different animals or horror creatures.

2. Hatred

We all tend to love living during night time, where we mostly do meet different invididuals and have more likely feelings of hatred. This has been used by militaries trough out the time.

3. Depression

When staying in darkness it is more than likely to build depression. Depression affects personality, different spychological ilnesses are more likelly to come. The cells in brains that control emotions like pleasure as well as cognition are also the brain regions that tend to be underactive that means maybe without any exposure to light, it may be nearly impossible to feel happy. More here.

4. Skin regression

The skin loses vitality, color and body cells lose strenght.

5. Lies

Human more likely lies in darkness than in lightment. Studies have shown that even adding some amount of the Spirit to the room increases persons truth telling.