Yes. They are. During pmo, frequency of dreams and how vivid they are seem to slowly reduce over years and reach a point where you no longer have any dreams. Once you are abstinent they gradually come back. It can only be inferred that recovery is happening.
Because I measured sleep once with a watch to measure sleep when I was watching porn and I got no REM phase and a small percentage of the deep phase.
Am not sure if you could completely skip a sleep stage during addicition phase. But any sort of substance addicition severely affects REM sleep and overall sleep but not completely skip a stage. Say,if an healthy brain gets 20% REM, addicts brain would get half or even less than that but completely 0. Am really not sure. Likewise, when addicts were in recovery, in the early days all the sleep stages were severely decreased. The following is a study done on opiate addicits during abstinence: "Several studies have reported changes in patterns of sleep with progressive abstinence from opiates. At around 5–7 days of acute abstinence from chronic heroin use, Howe et al. reported decreased total sleep time, slow-wave sleep, REM, and stage 2 sleep and increased sleep latency, wake after sleep onset, and REM latency compared to healthy sleepers [101] (Table 2). During the first 3 weeks of abstinence, prolonged sleep latency, decreased sleep efficiency, decreased TST, increased arousal index, increased stage 1 and 2, and decreased slow-wave sleep (SWS) were prominent compared to healthy sleepers [17] (Table 2). After 6 weeks and up to 6 months of abstinence from methadone, there is a rebound increase in SWS and REM time to a higher level than baseline"
