Table 2.

The summary of the lesions and atrophy in the brains of ketamine addicts in term of years of addiction.

Years of abuse	Cerebellum or cerebella	Holes/degenerative patches in white matter	Cortex	Limbic system (Uncus or entorhinal)	Internal capsule	Capsule striatum	Diencephalon	Brainstem	Atrophy of cortex (frontal/partial/occipital)	Severity of brain damage#
0.5	−	+	+Δ	−	−	−	−	−	+	Light
1	+	+	−	−	+	−	−	−	−	Light
2	+	+	−	−	+	−	−	−	+	Moderate
3	+	+	+ΔΔ	−	+	−	−	−	+	Moderate
4	+	+	+	−	+	−	+	+*	+	Severe
5	+	+	+	+	+	−	+	+	+	Severe
6	+	+	+	+	+	+	+	+	+	Severe
7	+	+	+	+	+	+	+	+**	+	Severe
10	+	+	+	+	+	+	+	+	+	Severe
12	+	+	+	+	+	+	+	+	+	Severe

+, stands for the positive lesion; −, stands for the negative lesion;

^ΔThis is a patient on three types of abusive drug including ketamine and who had early lesions;

^ΔΔThis is a patient that had 3 g per day of ketamine;

^*Lesion firstly appeared in pons by 4 years of addiction.

^**Lesion in the midbrain appeared by 7 years of addiction;

#Light damage meants two or less regions affected in the brain, moderate indicates three to four brain regions affected, and severe meants five or more brain regions affected.