There are many characteristics which Mary Shelley allots to Victor which can support his defining as a "mad scientist" in the novel Frankenstein.
The following definitions of mad, in correlation with Victor's interest (or obsession) in science, define Victor as mad.
1. One who is "completely unrestrained by reason and judgement." When applying this definition to Victor, one can support that Victor is, indeed, mad. His obsession with the reanimation of life leads him to ignore friends, family, and his own health. Therefore, Victor's desire to animate life leads him to ignore all reasonable thought and judgement.
2. One who is "carried away with enthusiasm or desire." Like the previous definition, Victor's behavior speaks to the fact that his enthusiasm, or desire, to reanimate life is one which outweighs all other things of importance.
3. One who is "marked by intense, and often chaotic, activity." Victor, after each trauma that he faces, is so excited by what is going on that he falls ill. These illnesses are so intense that one may expect Victor to die. He often acts without thinking things completely through (for example, when he tears the monster's mate to pieces, throws the body into the lake, and falls asleep only to find he is about to be charged with the murder of Clerval).
Victor can also be paralleled to the stock character (one who is easily recognized based upon stereotypes) of the mad scientist. The typical "mad scientist," completes unimaginable experiments which tend to go horribly wrong.