INSANITY is one of the few songs that are mistakenly attributed to Dir En Grey, despite being from another band, namely Vasalla.
At one concert during Dir En Grey's early days, they covered this song. More specifically, this happened on September 15, 1997, on the last date of the Dir en grey presents MAZOHYST OF DECADENCE SHOW tour at Meguro Rockmaykan. At the same concert, they also covered 親愛なるDEATHMASK by 黒夢 (Kuroyume) and X by X Japan, both with Vasalla. A live recording of Dir En Grey's INSANITY cover exists, but it's only available to tereko traders. However, you can listen to Vasalla's original version here.
Dir En Grey would later provide background vocals for Vasalla's 月神~Artemis~.
Jirijiri to nijimi yoru kussetsu Mōsō Nigerarenai
Miugoki mo torezu ni aseri Hamukaeba surudoi itami
Hana o tsuku fushū wa atsukute Miminari wa atama o tokasu
Furisosogu itami no naka de Hohoemeba raku ni nareru
Fukkireta karada wa karuku Nagaredeta gyōketsu matoi
Itami sae kaikan ni kawari Afurederu yokubō mitase
Kurue Sakebe Omou ga mama ni
Warai Korose Mushikera no yō ni
Yugamu toki no hazama no naka de Naeta karada Chi o motomete iru
The distortion slowly blurs, drawing near Delusion Can't run from it
Being unable to move I become impatient
When it bites back there's a sharp pain
The pungent rotten smell is hot The ringing in my ears melts my head
Inside the pain that pours down on me I can be more at ease when I smile
My cut up body is light Clad in blood clots that came leaking out
Even the pain changes into pleasure Satisfy the overflowing desire
Go mad Scream To your heart's content
Laugh Kill Like a worm
Inside the warping intervals of time My weakened body Wants blood
These lyrics don't have an official translation. The fan-translation was taken from here.