2.1 Participants
The current study is part of larger project aimed to investigate sex differences in the neurocognitive mechanisms underlying CUD. While the main objective of this project was to investigate sex differences in the neural correlates of (negative) emotional and cocaine cue-reactivity, two more exploratory studies to investigate sex differences in the neural correlates of working memory and cortical morphometry of the insula, have already been published elsewhere(Cousijn et al. , 2021; Abdel Malek et al. , 2022). The total sample (n = 111) aged 18 to 43 years consisted of regular CUs (n = 57, 45.6% females) and matched non-CUs (n = 54, 48.1% females). All participants were free from any MRI contraindications. General exclusion criteria were potential post-traumatic stress disorder (PTSD) (≥ 2 on the Jellinek-PTSD screening questionnaire)(van Dam et al. , 2013), an age outside the range of 18 to 45, and contraindications for MRI scanning. For the non-CU group, individuals were excluded if they smoked cigarettes, had a score higher than 12 on the Alcohol Use Disorders Identification Test (AUDIT)(Saunders et al. , 1993) or used other drugs or cocaine no more than five times in the past six months or year, respectively. Individuals were included in the CU group when they used cocaine (intranasally) at least four times per month. Participants provided informed consent and received a monetary compensation for participation. The current study was approved by the Ethics Review Board of the Faculty of Social and Behavioral Sciences, University of Amsterdam (ERB number: 2019-DP-9964).