Changes in a person's energy level, sleep patterns, self-esteem, concentration, drug or alcohol use can be signs of an oncoming<unk>  disorder. Many different things might trigger<unk> s, from unhealthy diet or lifestyle to drug abuse or hormonal imbalance. Other major causes of<unk> s (besides bipolar disorder and major depression) include diseases/disorders which interfere with nervous system function. Attention deficit hyperactivity disorder (ADHD), epilepsy, and autism spectrum are three such examples. The hyperactivity sometimes accompanied by inattentiveness, impulsiveness, and forgetfulness are cardinal symptoms associated with ADHD. As a result, ADHD is known to bring about usually short-lived (though sometimes dramatic)<unk> s. The communication difficulties associated with autism, and the associated changes in neurochemistry, are also known to cause autistic fits (autistic<unk> s). The seizures associated with epilepsy involve changes in the brain's electrical firing, and thus may also bring about striking and dramatic<unk> s. If the<unk>  is not associated with a<unk>  disorder, treatments are harder to assign. Most commonly, however,<unk> s are the result of dealing with stressful and/or unexpected situations in daily life. Degenerative diseases of the human central nervous system such as Parkinson's disease, Alzheimer's disease, multiple sclerosis, and Huntington's disease may also produce<unk> s. Celiac disease can also affect the nervous system and<unk> s can appear. Not eating on time can contribute, or eating too much sugar, can cause fluctuations in blood sugar, which can cause<unk> s. Brain chemistry If a person has an abnormal level of one or several of certain neurotransmitters (NTs) in their brain, it may result in having<unk> s or a<unk>  disorder. Serotonin is one such neurotransmitter that is involved with sleep,<unk> s, and emotional states. A slight imbalance of this NT could result in depression. Norepinephrine is a neurotransmitter that is involved with learning, memory, and physical arousal. Like serotonin, an imbalance of norepinephrine may also result in depression. List of conditions known to cause<unk> s * Anabolic steroid abuse * Attention deficit hyperactivity disorder * Autism or other pervasive developmental disorder * Bipolar disorder or cyclothymia * Borderline personality disorder * Dementia, including Alzheimer's disease, Parkinson's disease and Huntington's disease *Dopamine dysregulation syndrome * Epilepsy * Hypothyroidism or hyperthyroidism * Intermittent explosive disorder * Major depression * Post traumatic stress disorder * Pregnancy * Premenstrual syndrome * Schizoaffective disorder * Schizophrenia * Seasonal affective disorder * XXYY syndrome
Mood swing
Sleep-talking
Moonrise 
Microsleep
Jet lag
Deviated gaze
Free-running sleep
Wandering 