Green’s Dictionary of Slang

1. (US drugs) withdrawal symptoms from cocaine addiction.

1922		E. Murphy Black Candle 51: When on the verge of suicide for need of the drug, they are said to have ‘the cocaine leaps’.
1934		F. Tuohy Inside Dope 195: ‘Helldust’, ‘coke’, ‘the needles’, ‘honeymoon stage’, ‘Having an edge’, ‘bull horrors’, ‘the leaps’ [...] all are of American origin.
1938		D. Maurer ‘Lang. of the Und. Narcotic Addict’ Pt 2 in Lang. Und. (1981) 105/1: leaps. A state approximating delirium tremens resulting from excessive and continued use of cocaine; these hallucinations range from the unspeakably horrible to the whimsical and harmless. Some addicts contentedly dig gold out of the floors [...] one informant always has the same kind of leaps – an endless procession of white rats which come popping backward through the keyhole.

2. (US Und.) nerves, tension.

1950		Goldin et al. DAUL 123/1: Leaps. Jumpy nerves, especially after the tension of having been on a risky criminal venture.
1965		T. Capote In Cold Blood 109: No wonder you got leaps.