When we cannot stop our thinking mind, there is burning, the burning of body, the burning of mind. The mind is full of suffering every day because thoughts torture us. The thought of drowning or taking drugs in order to commit suicide is caused by continuous thought. All this is suffering.
More thinking causes more suffering. When we cannot escape from our own thought processes, we wish to rise above them. How can we rise above them when we fail to concentrate or meditate? So we would rather die in order to stop thinking without realizing that it is impossible to stop thoughts just like that.
Only Dhamma will eliminate the unwholesome state of mind that is full of bad and excessive thinking. We must destroy the root cause of them. By doing so we will encounter happiness in our lives.