More generally, alteration of clock genes (directly or indirectly through sleep problems) might lead to desynchronized and abnormal circadian rhythms (including sleep/wake rhythm but also other circadian rhythms such as neuroendocrine or body temperature rhythms) impairing in turn the synchronization between external and internal rhythms and therefore the adaptation of the individual to his/her internal and external environment with the development of psychiatric disorders. This evidence concerns the gene CLOCK and psychiatric disorder.